CA1293789C

CA1293789C - Control system for an electronically commutated motor, electronically commutated motor system, laudry apparatus and methods for controlling same

Info

Publication number: CA1293789C
Application number: CA000615744A
Authority: CA
Inventors: John Henry Boyd, Jr.; Alexander Muller
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1990-05-24
Filing date: 1990-05-24
Publication date: 1991-12-31
Anticipated expiration: 2005-04-18

Abstract

CONTROL SYSTEM FOR AN ELECTRONICALLY COMMUTATED
MOTOR, ELECTRONICALLY COMMUTATED MOTOR SYSTEM, LAUNDRY APPARATUS AND METHODS FOR CONTROLLING SAME
Abstract of the Invention Control system for an electronically commutated motor (ECM). The ECM includes a stationary assembly having a plurality of winding stages adapted to be selectively commu-tated, and rotatable means associated with the stationary as-sembly in selective magnetic coupling relation with the wind-ing stages. A circuit commutates the winding stages by selec-tively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered. The control system includes a circuit coupled to the winding stages for simultaneously converting the voltages across the winding stages to digital form thereby to digitize the voltages, and a circuit for producing successive patterns of digital signals in at least one preselected sequence, for selecting the digitized voltage across the at least one unpowered winding stage depending on the digital signal pat-tern produced, and for producing a following pattern in se-quence after at least one predetermined logic level of the selected digitized voltage has occurred. Another circuit responds to the successive patterns of the digital signals for generating the successive patterns of the control signals for the commutating circuit. Other control systems, electronical-ly commutated motor systems, laundry apparatus, and methods for controlling them are also described.

Description

1293'7~9 CONTROL SYSTEM FOR AN ELECTRONICALLY COMMUTATED
MOTOR, ELECTRONICALLY COMMUTATED MOTOR SYSTEM, LAUNDRY APPARATUS AND METHODS FOR CONTROLLING SAME
This application is a division of Canadian application Serial No. 479,501, filed April 18, 1985.
Field of the Invention This invention relates in general to dynamoelectric machines and domestic appliances and more particularly to control systems with special applicability to electronically commutated motors, electronically commutated motor systems, laundry apparatus and other appliances, and methods for operating them.
Background of the Invention While conventional brush-commutated DC motors may have numerous advantageous characteristics such as convenience of changing operational speeds and direction of rotation, it is believed that there may be disadvantages, such as brush wear, electrical noise, and radio frequency interference caused by sparking between the brushes and the segmented commutator, that may limit the applicability of such brush-commutated DC
motors in some fields such as the domestic appliance field including the laundry apparatus field.
Electronically commutated motors, such as brushless DC
motors and permanent magnet motors with electronic commutation, have now been developed and generally are believed to have the above-discussed advantageous characteristics of the brush-commutated DC motors without many of the disadvantages thereof while also having other important advantages. Such electronically commutated motors are disclosed in the David M. Erdman U.S. patents 4,005,347 and 4,169,990 and Floyd H.
Wright U.S. Patent 4,162,435, all of which are commonly assigned with the present application. These e~ectronically commutated motors may be advantageous 1293'789 employed in many different fields or motor applications among which are domestic appliances, e.g., automatic washing or laundry machines such as disclosed in commonly assigned Canadian Patents No. 1,193,651 - Boyd, Jr., issued September 17, 1985; No. 1,140,658 - Erdman et al, issued February 1, 1983; No. 1,150,962 - Hershberger, issued August 2, 1983;
and No. 1,199,997 - Erdman, issued January 28, 1986.
Laundry machines as disclosed in the above patents are believed to have many significant advantages over the prior art laundry machines which employ various types of transmissions and mechanisms to convert rotary motion into oscillatory motion to selectively actuate the machine in its agitation washing mode and in its spin extraction mode.
Such prior art laundry machines are believed to be more costly and more complicated to manufacture, consume more energy, and require more servicing. Laundry machines with electronically commutated motors require no mechanical means, other than mere speed reducing means, to effect oscillatory action of the agitator or tumbler, and in some applications, it is believed that the spin basket might be directly driven by such a motor. While the past control systems, such as those disclosed in the aforementioned coassigned patents for instance, undoubtedly illustrated many features, it is believed that the control systems for electronically commutated motors in general, and for such motors utilized in laundry machines, could be improved, as well as the methods of control utilized therein.
In some of the known control systems, the position of the rotatable assembly (i.e., the rotor) of the electronically commutated motor was located by sensing the back emf of one of the winding stages on the stationary assembly (i.e., the stator) thereof. More particularly the back emf of an unenergized winding stage was sensed and integrated to determine rotor position during any one commutation period in a lZ93'7~9 sequence of commutation. With the advent of inexpensive microprocessor chips, controlling an electronically commutated motor with a microprocessor and discrete element control system has been described. Coassigned U.S. Patent 4,250,544, "Combination Microprocessor and discrete Element Control System for a Clock Rate Controlled Electronically Commutated Motor" issued February 10, 1981 to R.P. Alley discloses such an arrangement. It is believed that further improvements and other departures can be made in methods and systems for controlling electronically commutated motors and for domestic appliance applications including laundering apparatus applications.
Summary of the I~vention Among the objects of the present invention are to provide improved control systems for an electronically commutated motor, improved electronically commutated motor systems, improved laundry apparatus, and improved methods for controlling them which do not require position sensing by integration during a commutation period: to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus and other appliances, and methods for controlling them which can screen out unexpected or accidentally produced signals and transients from a microprocessor or digital computer to maintain proper operation of the system, the motor, or the appliance; to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus, and methods for controlling them which can reliably start an electronically commutated motor and insure its operation in a selected direction of rotation; to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus, and methods in which the motor is protected from excessive current; to provide such improved control systems for an electronically commutated motor, ~3789 03AM 5939 electronically commutated motor systems, laundry apparatus, and methods in which the speed of the motor is adjustably controlled; to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus, and methods for controlling them in which the rotor position is sensed from the back emfs of the winding stages when the rotor is coasting and there are no commutation periods; to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus, and me.thods for controlling them which are resistant to error in determining the rotor position from the back emfs of the winding stages when the rotor is coasting and there are no commutation periods; to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus, and methods for controlling them which can commutate an electronically commutated motor in a preselected sequence, discontinue the commutating, and then resume commutating at a proper point in the sequence to keep the motor running smoothly determined from the back emfs of the winding stages when the commutating was discontinued; to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus, and methods for controlling them which accelerate the motor in a low speed connection arrangement of the winding stages, change from the low speed connection arrangement to a higher speed connection arrangement of the winding stages and sense the rotor position to smoothly resume accelerating the motor in the high speed connection arrangement; to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus, and methods for controlling them which brake the motor; to provide such improved control systems for an electronically ~37~ 03AM 5939 commutated motor, electronically commutated motor systems, laundry apparatus, and methods for controlling them which smoothly and rapidly reverse the motor; to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus, and methods for controlling them which periodically reverse the motor; and to provide such improved control systems for an electronically commutated motor, electronically commutated motor systems, laundry apparatus, and methods for controlling them which power at least some of the winding stages and rotate the rotor, and then leave all the winding stages temporarily unpowered and provide a current path for the previously powered winding stages to facilitate rotor position monitoring and accomplish other purposes.
Other objects and features will be in part apparent and in part pointed out hereinafter.
In general and in one form of the invention, a control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, comprises circuitry coupled to the winding stages for simultaneously converting the voltages across the winding stages to digital form thereby to digitize the voltages. The circuitry for digitizing the voltages is combined with circuitry for producing successive patterns of digital signals in at least one preselected sequence, for selecting the digitized voltage across the at least one unpowered winding stage depending on the digital signal pattern produced, and for producing a following pattern in sequence after at least one predetermined logic level of lZ~37~
Lhe seler~eà àigiti~ea ~Ltaqe has occur,ea: and also combined ~lith circuitry responsive to the successive patterns of the digital signals for generating the successive patterns of the controi ~ignals for t~,e commutating means.
In general and in another form o~ the invention, a control system for an eiectronically commueated motor includ-ing a stationary assemDly having a plurality of winding stages adaptea to be selectively commutated, and rotatable means associa.ed with the statlonary assembly in selecti-e ~agnetic coupling relation with the winding stages, and means for com-mutating the ~inding stages ~y selectively supplying power thereto in response to a pattern of control signals leaving at least one of Lhe winding stages unpowerea a~ any one time while the other winding stages are powered, comprises cir-lS cuitry coupled to the winding stages for digitizing the volt-ages across the winding stages and circuitry responsive to successive patterns of digital signals for generating succes-sive patterns of the control signals for the commutating means. r digital computer operating under stored program con-trol has inputs for the digitized voltages. The computer hasmemory elements for storing data representing at least one preselected sequence of the patterns of the digital signals and for storins data, corresponding to each pattern of the digital signals, identifying the respective input for the digitizeà voltage for the at least one unpowered windinq stage. The computer successively produces one of the patterns of the digital signals, senses only the digitized voltage at the identified input corresponding to the one pattern and pro-duces the following pattern in sequence after at least one predetermined logic level of the digitized voltage at the identified input has occurred.
In general, and in a ~urther form of the inYention, an electronically commutated motor system comprises an elec-tronically commutated motor including a stationary assembly having a plurality of winding stages aàapted to be selectively cammutatea, and rotatable m~ans associated ~l~h the stationary assembly in selective magnetic coupling relation with the ~ln~lng stages, first and second conductors for supplying power, and a circuit ~or commutating the winding stages by selectively switching the winding stages to the supply conduc-tors in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered. A circuit is cou-pled to the winding stages for digitizing the voltages across the winding stages, and another circuit responds to successive patterns of digital signals for generating successive patterns of the control signals for the commutating circuit. The sys-tem has a digital computer operating under stored program con-trol and having inputs for the digitized voltages. The com-lS ?uter has memory elements for storing data representing atleast one preselected sequence of the patterns of the digital signals and for storing data, corresponding to each pattern of the digital signals, identifying the respective in-~ut for the digitized voltage for the at least one unpowered winding stage. The comuter successively produces one of the patterns of the digital signals, senses only the digitized voltage at the identified input corresponding to the one pattern and pro-duces the following pattern in sequence after at least one predetermined logic level of the digitized voltage at the 2S identified input has occurred.
In general, and in still another form of the inven-tion, laundry apparatus comprises means operable generally in a washing mode for agitating water and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of water from the fabrics, an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assemblv in selective macnetic coupling relation with the windina stages for driving 12~37~9 ~he a~itating and s~inninq means in the wasning moàe operation and in the spin mode operation thereof upon the commutation of said winding stages. ~i~st and second conauctors are provided or 5l~DDlying power. The laundry apparatus also includes a circuit for commutating the winding stages Dy selectively Switching the winàing stages to the supply conductors in response to a pattern of contrcl signals leaving at least one o~ the winding stages unpowered at any one time while the other winding stages are powered. A circuit is coupled to the winding stages for digitizing the voltages across the winding stages. A circuit responds to successive patterns of digital signals for generating successive patterns of the controL sig^
nals for the commutating means. The laundry apparatus has a digital comput_r operating unaer stored program control and having inputs for the aigitized voltages. The computer has memor~ elements for storing data representing at least one - preselected sequence of the patterns of the digital signals and for storing data, corresponding to each pattern of the digital signals, identifying the respective input for the digitized volta~e for the at least one unpowered winding stage. The com?uter successively produces one of the patterns of the digital signals, senses only the digitized volt2ge at the identified input corresponding to the one pattern and pro-duces the following pattern in sequence after at least one 2S predetermined logic level of the digitizea voltage at the identified input has occurrea.
In general, and in a method form of the invention, a method for controlling a system having an electronically com-mutated motor including a stationary assembly having a plural-ity of winding stages adapted to be selectively commutated,and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages un~owered 03AM 5g3g ~2937~9 t any ^ne time wnile t~e other winding s~a~es are powered, compris2S the seeps of digitizing the voltages across t~.e windir.g stages and generating successive patterns of the con-trol sl~nals 'or the commutating means in response to succes-sive patterns of diqital signals. Data is prestored represent-ing at least one preselected sequence of the ~atterns of the digital signa}s. Data is also prestored correspondinq to each pattern of the digital signais, identifying the respective digitized voltage for t~e at least one unpowered winding stage. One of the patterns of the digital signals is succes-sively produced and only the identified digitized voltage cor-responàing to the one pattern is sensed. The following pat-tern in sequence is produced after at least one predetermined logic 'evel o~ the identified digitized voltage has occurred.
Generally, and in another method form o the inven-tion, c method for controlling a system having an electrcnic-ally commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commu-tated, 2nd rotatable means associated with the stationary assembly in sel~ctive magnetic coupling relation with the winding stages, first and second conductors for supplying power, and means for commutating the winding stages and pro-ducing a current in the winding stages by selectively switch-ing the winding stages to the supply conductors in response to a pattern of control signals, comprises the steps of producing successive patterns of digital signals in at least one prese-lected sequence and generating patterns of the~ control signals for the commutating means in response to the successive pat-terns of the digital signals. The current in the winding stages of the electronically commutated motor is compared with a predetermined level, and a preestablished pattern of the digital signals is produced for a predetermined period of time to reduce the current in the winding stages, whenever the pre-determined level is exceeded. The current reducing pattern of lZ5~3~7~9 the afgital signais is periodically producea at an adjustable rate wnen the predetermined level is not e~ceeàed.
Generally, and in a still further form of the inven-tion, a control system for an electronically commutated motor includin9 a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assemDly in selective magnetic coupling relation with the winding stages, first and second conductors for supplying power, and a circuit for com-mutating the winding stages and producing a current in thewinding stages by selectively switching the winding stages to the supply conductors in response to a pattern of control sig-nals, comprises a circuit for generating patterns of the con-trol signals for the commutating circuit in response to the lS successive patterns of the digital signals and a circuit for comparing the current in the winding stages of the electronic-ally commutated motor with a predetermined level. A further circuit is provided for producing the successive patterns of digital signals in at least one preselected sequence for the generating circuit, for producing in response to the comparing circuit a preestablished pattern of the digital signals to reduce the current in the winding stages upon the predeter-mined level being exceeded, for monitoring the voltage across the winding stages to monitor the position of the rotatable means when the current is being reduced, and for resuming pro-ducing the successive patterns of digital signals in sequence after a predetermined time interval.
Generally, and in yet a further form of the inven-tion, a control system for an electronically commutated motor including a stationary assembiy having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals lZ93789 leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, comprises a circuit coupled to the winding stages for converting the voltages across the winding stages to digital form thereby to digitize the voltages. The circuit for digitizing the voltages is combined with a circuit for producing successive patterns of the control signals in at least one preselected sequence to rotate the rotatable means, for subsequently producing a pattern of the control signals which causes the commutating means to leave all of the winding stages temporarily unpowered, for sensing the digitized voltage while the winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.
Generally, and in an even further form of the invention, laundry apparatus comprises means operable generally in a washing mode for agitating water and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of water from the fabrics and an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the station-ary assembly in selective magnetic coupling relation with the winding stages for driving the agitating and spinning means in the washing mode operation and in the spin mode operation thereof upon the commutation of the winding stages. First and second conductors are provided for supplying power. The laundry apparatus has a circuit for commutating the winding stages by selectively switching the winding stages to the supply conductors in response to a pattern of control signals and a circuit coupled to the winding stages for converting the voltages across the winding stages to digital form thereby to digitize the voltages. In the 12937~9 laundry apparatus is a circuit operable generally for switch-ing the winding stages from a first connection arrangement to a second connection arrangement, and a circuit for producing successive patterns of the control signals in at least one preselected sequence to rotate the rotatable means, for sub-sequently producing a pattern of the control signals which causes the commutating means to leave all of the winding stages temporarily unpowered during switching of the winding stages from the first connection arrangement to the second connection arrangement, for sensing the digitized voltages while the winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.
In general, and in an additional form of the inven-tion, a control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, comprises a circuit for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered.
Another circuit responds to successive patterns of digital signals for generating the successive patterns of the control signals for the commutating circuit. Still another circuit is provided for producing the successive patterns of the digital signals in at least one preselected sequence, and for subsequently producing a different pattern of the digital signals which causes the commutating means to connect all of the winding stages together, thereby braking the motor.
In general, and in a further method form of the invention, a method for controlling an electronically commu-tated motor including a stationary assembly having a plurality . "

l~g*~of ~incin~ staaes adaDted to be selectiveiy commutated, and r~tatable means associated with the stationarY assemDly in select;ve magnetic coupling relation with the windinq stages, and means for commutating the winding s~ages by selecti;ely suppl~ing power thereto in response to a pattern of control signals leaving at least one o~ the winding stages unpowered at any one time while the other winding stages are powered, comprises the steps of producing successive patterns of the control signals in at least one preselected sequence for com-mutating the winding stages in a first connection Irrangementand producing a pattern of the control signals which causes the commutating means to leave all of the winding stages tem-porarily unpowered. The winding stages are switched to a second connection arrangement, and the position of the rotat-ing means is sensed while the winding stages are temporarilyunpowered. Production or the successive patterns of the con-trol signals in sequence is resumed beginning with a pattern of the control signals determined from the position of the rotating means sensed while the winding stages are temporarily unpowered.
Generllly, and in still another method form of the invention, a method for controlling an electronically commu-tated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and a circuit for commutating the winding stages by selective-ly supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, comprises the steps o~ converting the voltages across the winding stages to digi~al form thereby to digitize the vol-tages and producing successive patterns of the control signals in at least one preselected sequence to commutate the winding 1~937~9 03AM 5939 staces and rotate the r~eatable means. ,~ pattern or the con-trol si~nals is subsequently produced whicn causes the commu-tating circuit to leave all of the winding stages temporarily unpowered. The digitized voltages are sensed while the wind-ing staqes are temporarily unpowered. ~ patter~ of the con-trol signals is determined from the sensed digitized voltages.
Production of the successive patterns of the control signals in sequence is resumed beginning with the pattern so determined.
Generally, and in yet a further method form o~ the invention, a method of controlling laundry apparatus compris-ing means operable generally in a washing mode for agitating water and fabrics to be laundered therein and operable gener-ally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of water from the fabri~s, an electronically commutated motor including a stationarv assem-bly having a plurality of winding stages adapted to be selec-tively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the windina stages for driving the agitating and spinning means in the washing mode operation and in the spin mode oper-ation thereof upon the commutation of the winding stages, and first and second conductors for supplying power. The method comprises steps of converting the voltages across the winding stages to digital form thereby to digitize the voltages and commutating the winding stages by selectively switching the winding stages to the supply conductors in at least one prese-lected sequence. The commutating is temporarily interrupted to leave the winding stages temporarily unpowered, and the winding stages are switched from a first connection arrange-ment to a second connection arrangement. The digitized vol-tages are sensed while the winding stages are temporarily unpowered, and the commutating is resumed beginning at a point in the sequence determined from the sensed digitized voltages.

In general, ~nd in an even f~rt~er method form of the i~ention~ a method for controlling an electzonicalli com-mutatea ,notor including a stationary assemDly having a plural-ity of ~inding stages aaapted to be selecti~ely commutated, S and r~tatable means associated with the stationary assemDly in selecti~e magnetic coupling relation with the winding stages, and means for commutatlng the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least;of the winding stages unpowered at any one time while the other winding stages are powered, com-prises the steps of generating successive patterns of the con-trol signals for the commutating means in response to succes-sive patterns of digital signals and producing the successive patterns of the digital signals in at least one preselected sequence. A different pattern of the digital signals is pro-duced ~hich causes the commutating means t~ connect all of the winding stages together, thereby braking the motor.
In general, and in a yet additional form of the invention, a control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages Idapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and first and second conductors for supplying power, comprises a circuit for commutating the winding stages in response to successive patterns of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered. The commutating circuit includes sets of electronic devices connected across the supply conduc-tors, each set having a junction point connected to a respec-tive one of the winding stages. Each of the electronic devices is respectively able to be switched by a correspondinq one of the control signals in each pattern of control signals.

1~ ~ 3'~89 03AM 5939 The ~ntrol s~stem incl~_es a circuit for ?.oducing the cuc-cessi~e patterns of the c~ntrol signals in ae least one prese-lected sequence to switc.~ on only one elect.onic device in each o~ at least two of tne sets of the electronic devices at once and cause a current to flow in the winding stages to rotate the rotatable means, and for subsequently producinq a pattern of the control signals to switch orf one Ot the lec-tronic switching devices which was previously switched on so that the commutating means leaves all of the winding stages temporarily unpowered and also provides a current path for the previously-powered winding stages.
Generally, and in a yet further additional form of the i~vention, a control system for an electronically commu-tated motor including a stationary assemblv having a plurality of winding stages adapteà to be selectively commutated, and rotatable means associated with the stationary assemDly in selectiye magnetic coupling relation with the winding stages, and a circuit for commutating the winding stages by selective-ly supplying power thereto in response to a pattern of control signals leaving ~t least one of the winding stages unpowered at any one time while the other winding stages are powered, comprises a circuit coupled to the winding stages for simul-taneously converting the voltages across the winding stages to digital form thereby to digitize the voltages and a circuit responsive to successive patterns of digital signals for gen-erating successive patterns of the control signals for the commutating circuit. The control system includes a circuit for producing successive patterns of the digital signals in a first preselected sequence, producing a different pattern of the digital signals for causing the commutating circuit to remove power from all of the winding stages, sensing the digi-tized voltages while the power is so removed, and producing successive patterns of the digital signals in a second prese-lected sequence to rotate the rotatable means in the reverSe lZ~3789 direction after a predetermined time period has elapsed subsequent to the last occurrence of a predetermined logic level in any of the digitized voltages.
Brief Description of the Drawings FIG. 1 is a block diagram showing a control system having a high-low speed switching circuit, a commutating circuit, a power supply, a control signal generator, a micro-computer, a voltage digitizing circuit, and a current interrupt and speed controlling circuit with an electronically commutated motor in a laundry machine according to the invention;
FIG. 2 is an exploded, perspective view of the main elements of an electronically commutated DC motor which is controllable by the control system of FIG. l;
FIG. 3 is a schematic diagram of the high-low speed switching circuit, the commutating circuit, the power supply and the motor of FIG. 1;
FIG. 4 is a schematic diagram of the control signal generator with the microcomputer of FIG. l;
FIG. 4A is a diagram of current flowing in the motor as a result of commutation in a preselected sequence;
FIG. 4B is four schematic diagrams of circuits effectively resulting in the commutating circuit of FIG. 1 from different digital signal patterns and corresponding control signal patterns produced in accordance with the invention;
FIG. 5 is a voltage versus time diagram of a waveform of voltage across an unpowered winding stage of the motor during a commutation period;
FIG. 6 is a schematic diagram of the voltage digitizing oircuit and of switches for providing commands to the microcomputer of FIG. 1 according to the invention;
FIG. 6A is a voltage versus time diagram of a digitized voltage to which the voltage of FIG. 5 is converted in accordance with the invention;

lZ~3789 FIG. 7 is a schematic diagram of current interrupt and speed controlling circuit of FIG. 1 in accordance with the invention;
FIG. 7A is a voltage versus time diagram of outputs Q
and Q-bar of a latch or flipflop in the circuit of FIG. 7 for interrupting the microcomputer and causing the control signal generator of FIG. 1 to generate a pattern of control signals to reduce the current flowing in the winding stages of the motor;
FIG. 8 is part of a flow diagram of operations of the microcomputer of FIG. 1 in accordance with the invention;
FIG. 9 is an additional part of the flow diagram of operations performed by the microcomputer of FIG. 1 in accordance with the invention in accomplishing a washing mode selected in the operations of FIG. 8;
FIG. 10 is a flow diagram of operations performed by the microcomputer of FIG. 1 in accordance with the invention in a low speed back emf routine of FIG. 9;
FIG. 11 is a flow diagram of operations performed by the microcomputer of FIG. 1 in accordance with the invention in a reversing routine of FIG. 9;
FIG. llA is a flow diagram of operations performed by the microcomputer of FIG. l in accordance with the invention for braking the motor as during a reversing routine;
FIG. 12 (appearing on the same sheet of drawings as FIG. 8) is a flow diagram of operations performed by the microcomputer of FIG. l in accordance with the invention upon interruption by output Q-bar of FIG. 7A;
FIG. 13 (appearing on the same sheet of drawings as FIG. 8) is a flow diagram of operations performed by the microcomputer of FIG. l in accordance with the invention for varying a duty cycle for the circuit of FIG. 7;
FIG. 14 is a flow diagram of operations performed by the microcomputer of FIG. l in accordance with the invention in accomplishing a spin mode selected in the operations of FIG. 8;

1~3789 FIG. 15 (appearing on the same sheet of drawings as FIG. 10) is a flow diagram of operations performed by the microcomputer of FIG. 1 in accordance with the invention in a high speed back emf routine of FIG. 14;
FIG. 16 is a flow diagram of operations performed by the microcomputer of FIG. 1 in accordance with the invention in advancing in a sequence of commutation and turning off the motor on command;
FIG. 17 (appearing on the same sheet of drawings as FIG. 11) is a flow diagram of operations performed by the microcomputer of FIG. 1 in accordance with the invention in a relaying routine of FIG. 14;
FIG. 18 (appearing on the same sheet of drawings as FIG. 8) shows voltage versus time diagrams of waveforms of the digitized voltages of all of the winding stages when the rotor of the motor is coasting clockwise or counterclockwise as during the relaying routine of FIG. 17;
FIG. 19 is a flow diagram of operations performed by the microcomputer of FIG. 1 in accordance with the invention for determining a proper point in sequence to begin or resume commutation when the rotor of the motor is turning, as in the relaying routine of FIG. 17.
Corresponding reference characters refer to corre-sponding parts throughout the several views of the drawings.
The exemplifications set out herein illustrate preferred embodiments of the invention in one form thereof, such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Detailed Description of Preferred Embodiments Referring now to the drawings, and more particularly to FIG. 1, a laundry apparatus 11 includes an electronically commutated motor (ECM) M adapted to be energized from a DC
power supply 12 and having (see FIG. 2) a stationary assembly including a stator 13 and a rotatable assembly including a permanent magnet rotor 15 and a shaft 17. Stator 13 includes a plurality (e.g., three) of winding stages Sl, S2 and S3 (FIG. 3). Winding stages Sl, S2 and S3 have coil sets of sections SlA and SlB, S2A and S2B and S3B respectively.
Winding stages S1, S2 and S3 are adapted to be electronically commutated in at least one preselected sequence. Each winding stage has an end terminal Tl, T2, and T3, respectively, and an intermediate tap I1, I2, and I3, respectively. The winding stages Sl, S2, and S3 are adapted to be electronically commutated at end terminals T1, T2, and T3, so that both coil sets or sections in each winding stage are commutated, for turning the rotor 15 at a low speed. It is noted that sections SlA, S2A, and S3A define tapped sections of the winding stages which are adapted to be electronically commutated at intermediate taps Il, I2, and I3 respectively for turning rotor 15 at a higher speed. When the winding stages S1, S2, and S3 are energized or powered in a temporal sequence, three sets of eight magnetic poles are established that provide a radial magnetic field that moves clockwise or counterclockwise around the bore of stator 13 depending on the preselected sequence or order in which the stages are powered.
This moving field intersects with the flux field of the permanent magnet rotor to cause the rotor 15 to rotate relative to the stator 13 in the desired direction to develop a torque which is a direct function of the intensities or strengths of the magnetic fields. If a more detailed description of the construction of electronically commutated motor M is desired, reference may be had to the aforementioned Canadian Patent No. 1,193,651 to John H. Boyd, Jr.
ECM M thus constitutes an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages.

12~137~39 ~urther, ~hile electronically commutated motor M is illus-trated herein for purposes of disclosure, it is contemplated that o~her such motors of different constructions, having 2, 4, 6, etc. poles and having 2, 3, 4 or more winding staqes and/or different winding arrangements may be utilized in one or another form of the invention so as to meet at least some of the objects thereof.
The winding stages of motor M as explained for instance in the aforementioned Alley U.S. patent 4,250,544 are commutated without brushes by sensing the rotational position of the rotatable assembly or rotor 15 as it rotates within the bore of stator 13 and utilizing electrical signals generated as a func~ion of the rotational position of the rotor to sequentially apply a DC voltage to each of the winding stages in different preselected orders or sequences that determine the àirection of the rotation of the rotor. Position sensing may be accomplished by a position detecting circuit responsive to the back emf of the EC~ to provide 2 simulated signal indicative of the rotational position of the ECM rotor to con-trol the timed sequential application of voltage to the wind-ing stages of tne motor Referring back to FIG. 1, laundry apparatus 11 also has a basket 23 which is rotatable within a tub (not shown) which holds the water for washing the fabrics to be laundered, and a coaxially mounted agitator 25, both of which are rotat-able independently or jointly about their common axis. Agi-tator 25 and basket 23 together comprise means operable gener-ally in a washing mode for agitating water and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal dis-placement of water from the fabrics. However, it is contem-plated that such means may also include only a basket which is mounted on a horizontal or inc~ined axis and there is no sepa-rate finned agitator ~ut the basket is operated in an oscilla-tory mode to agitate t~e wash water and fabrics to launder 03A~1 5939 12~3'7~`~
t~em- ;?on the commuta.lon of the winding stages, ~he rotat-able assembly of motor ~I drives the agitatin~ and spinning means and is coupled selectively to the agi.ator alone during the washing mode operation and to both the basket and the agi-tator in the spin mode oDeration through a connection mecha-nism 27 which suitably comprises a fixed ratio speed reducer, such as a gear box or a pulley arrangement, for instance, or in some applications, the shaft 17 of motor M can be directly coupled to the agitator and the basket. The rotatable assem-bly of motor M and any such fixed ratio speed reducer consti-tute means for driving the agitating and spinning means in the washing mode operation and in the spin mode operation thereof upon the commutation of the winding stages.
Commutating circuit 31 is provided with power from ?ower suDply 12 and constitutes means for commutating the winding stages by selectively supplying or switching power thereto in response to a pattern of control signals 32 leaving at least one of the winding stages unpowered at any one time while t.~e other winding stages are powered. Commutating cir-cuit 31 also corstitutes means for controlling the applicationof DC ~oltage t~ the winding stages to provide a resultant effective voltage thereto.
A high-low speed switching circuit 41 couples commu-tating circuit 31 to motor M, and constitutes means operable generally for switching the winding stages from a first con-nection arrangement (connecting each of winding stages Sl, 52, S3 as a whole through terminals Tl, T2, and T3 to commutating circuit 31) to a second connection arrangement (connecting the coil sections SlA, S2A, and S3A of the winding stages Sl, S2, and S3 through terminals Il, I2, and I3 to commutating circuit 31). In the present em~odiment the first connect~on arrange-ment is a low speed connection arrangement and the second con-nection arrangement is a higher speed connection arrangement.
It is to be understood that other connect on arrangements lZ93789 involving two or more speeds, or not involving speed considerations at all are contemplated in the practice of the invention for accomplishing the objects thereof. High-low speed switching circuit 41 is responsive to a High on line H
for relaying the winding stages from the low speed connection arrangement to the high speed connection arrangement and responsive to a Low on line H for relaying the winding stages from the high speed connection arrangement to the low speed connection arrangement.
Commutating circuit 31 responds to a set of six control signals, collectively designated 32 and individually designated A+, A-, B+, B-, C+, and C-, from a control signal generator 51. Since each of the control signals A+, A-, B+, B-, C+, and C- can be high or low, there are 26 or 64 lS permutations or patterns of the control signals. Control signal generator 51 constitutes means responsive to successive patterns of digital signals 52 for generating successive patterns of the control signals 32 for the commutating circuit 31.
A microcomputer 61 in FIG. 1 produces successive patterns of the digital signals 52 in at least one preselected sequence, which causes the control signal generator 51 to produce successive patterns of the control signals 32 in the at least one preselected sequence and in turn cause the motor M to be commutated in the at least one preselected sequence by the commutating circuit 31 to make the rotor 15 turn. The direction of rotation which results is clockwise when a first preselected sequence is used, and counterclockwise when a second preselected sequence is used.
In the preferred embodiment disclosed herein, micro-computer 61 is an Intel 8748 microcomputer having lK bytes of user programmable and erasable read only memory (EPROM), an 8 bit central processing unit (CPU), 27 input/output (I/O) lines, an 8-bit timer counter, reset and interrupt capability, and an on-board oscillator and clock. The instruction set for 1293~
the 8748 is set forth in ~1CS-~8 (~! F2milv ~ Sinqle ~hi~
~icroc~m~uters ~ser~s M2nual, Intel Corporation, Santa Clara, California~ September, '981, ~ages 4-5, in addition to other technical information. Since the im?lement~on and use o~
microcomputers as a general matter is well known to the person skilled in the art, the details of the 8748 are omitted for brevity. The microcomputer 61 is shown as a rectangle in several of the ~igures with only those pin designations for the 8748 shown for connections involved in the operations and circuits of any given Figure, all other pins in a given Figure being suppressed for clarity. It is to be understood that the 8748 is but one example of a digital computer which can be utilized in the practice of the invention. In addition, it is contemplated that the f~nctions of the microcomputer illus-trated in the drawings can be alternatively implemented in thepractice of the invention by any appropriate means, including but not limited to digital or analog circuits of a variety of types whether operating from a stored program, utilizing firm-ware, or being implemented in hardware, in custom or semi-custom integra~d circuit form or having discrete components.
A vo'tage digitizing circuit 71 is coupled to thewinding stages and receives their terminal voltages Va, Vb, and Vc through high-low speed switching circuit 41 and constitutes means for simultaneously converting the voltages across the winding staces to digital form thereby to digitize the voltages. Digitizing circuit 71 also constitutes means for generating a first logic level when the voltage across a respective winding stage exceeds a predetermined value and a second logic level when the voltage across it falls below the predetermined value, the digital form of the voltage across each respective winding stage comprising the logic levels so generated. Digitizing circuit 71 has outputs A, B, and C
which are connected to corresponding inputs of microcomputer 61.

1Z93'7~9 ;~icrocom~uter 51 or FIG. 1 constituteS means for ?rd~cinq successive patterns of digital signals in at least ~ne preselecteà sequence, for selecting the digitized voltage across the at least one unpowered windina staae dependirg on ~he digital signal pattern produced, and for producing a fol-lowing pattern in se~uence after at least one predetermined logic level of the selected digitized voltage has occurred.
In the preferred embodiment the following pattern in sequence is produced after complementary logic levels of the selected digitized voltage have occurred in a predetermined order depending on the pattern which is being produced. ,~icrocom-puter 61 is a digital computer operating under stored program control and having inputs for the digitized voltages on lines ~, B, and C. ~icrocomputer 61 has memory elements for storing data representing at least one preselected se~uence of the patterns of the digital signals and for storir.g data, corre-sponding to each pattern of the digital signals, identifying the respective input for the digitized voltage for the at least one unpowered winding stage. ~icrocomputer 61 succes-sively producec one of the patterns of the digital signals,senses only the digitized voltage at the indentified input corresponding to the one pattern and produces the following pattern in sequence after at least one predetermined logic level of the digitized voltage at the identified input has occurred. ~hen the motor ~l is first being started, there is no back emf to digitize until the rotor 15 begins to rotate.
For this reason, microcomputer 61 operates to produce the fol-lowing pattern in~sequence after a predetermined time period if the at least one predetermined logic level of the selected digitized voltage has not occurred during the predetermined time period. Then as soon as the rotor 15 begins to turn, the following pattern is produced in se~uence in response to the digitized voltage and the successive patterns are effectively synchronized with the rotor and accelerate the rotor to an operating speed.

3~9 Current inter.upt and speea controlling circuit 81 compareS the current ~lowing in the other poweced winding stages o~ the eiectronically commutated motor M with a prede-termineà level ~ sensing a voltage ~JI proportional to the current on line 83, and upon the level being exceeàed, inter-rupting microcomputer 61 on line 85 and sending a signal Q on line 37 for causing the control ~ignal generator 51 to gener-ate a pattern of control signals 32 to reduce the current.
In FIG. 3 power supply 12 has diodes 101, 103, 105 and 107 connected as a full wave bridge rectifier for 117 volt single phase AC power received at plug 109. Full wave recti-fied DC is filtered by capacitor 111 and applied as voltage across ~irst and second conductors 1}3 and 115 for supplying DC power to com~utating circuit 31 and motor M. A voltage drop V; is developed across shunt resistor R5 proportional to the current from power supply 12 which is flowing in the motor ~t.
Commutating circuit 31 is composed of three identi-cal switching circuits 121, 123, and 125 which selectively switch the winding stages to supply conductors 113 and 115 leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered. For con-ciseness only switchinc circuit 121 is described in further detail.
Switching circuit 121 has a set or pair o~ series-connected upper and lower electronic devices 127 and 129 con-nected across the supply conductors 113 and llS. The pair of devices 127 and 129 has a junction point 131 connected through high-low speed switching circuit 41 to winding stage Sl in the connection arrangement selected by high-low speed switching circuit 41. ~witching circuits 123 and 125 are respectively connected to winding stages S2 and S3 similarly.
The switching circuits 121, 123, and 125 each con-stitute sets o~ electrcnic devices connected across supply 37 conductors 113 and 115, each set having a. least one junction lZ93789 03AM 5939 point c~nected to a respective one of the winding stages Each o. .he electronic devices, e.g., 127 and 129, is able to be Switched by a corresponaing one of the control signals in each pattern of control signals 32 For instance, when con-trol signal A+ is high, transistors 133 and 135 turn on tran-Sistor 137 in electronic device 127. ~1hen control signal Ais high, .ransistors 139, lÇl, and 143 turn on transistor 145 in electronic device 129. When transistor 137 is on in elec-tronic device 127, and a relay 147 in high-~ow speed switching 10 circuit 41 is set as shown in FIG. 3, then winding stage 51 terminal Tl is effectively switched to supply conductor 113.
When transistor 137 is off in electronic device 127 and tran-sistor 145 is on in electronic device 12g, winding stage Sl terminal Tl is switched to supply cond~ctor 115.
It is evident that when a control signal A+, ~+, or C+ is High, a corresponding winding stage Sl, S2, or S3 is switched to supply conductor 113, and when a control sign~l A-, B-, or C- is High, a corresponding winding stage Sl, S2, or S3 is switched to supply conductor 115.
Relay 147 in High-low speed switching circuit 41 has three-pole-dou~,le-throw (3PDT) contacts for electrically sub-stitutinq sections SlA, S2A, and S3A of the winding stages Sl, S2, and S3 in place of the winding stages as a whole The winding stages are connected together at neutral N. Relay 197 is driven by transistor 149. Transistor 149 is protected by base resistor 151 and freewheeling diode 153. When a Hign appears on line H, transistor 149 conducts, closing re}ay 147 and moving relay armature 155 upward from the Low Speed posi-tion shown to a High Speed position, which accomplishes the substitution o~ the high speed winding sections SlA, 52A, S3A
in place of the winding stages 51, S2, S3 and thereby selec-tively electrically energizes at least one of the winding sec-tions SlA, S2A, S3A of each winding stage Sl, S2, 53 to effect lZ~37~9 03AM 5939 ^ommuta-lon~ `hen relavina ~om low tO hign s~eea is to o_cur, icrocomputer 61 outputs a Low on line DB6, ~hich is invertea bv ~TAND-gate 157 and fed as the ~iah on line H.
Lines marked for voltages Va, V~, and Vc are connecte~ to relay armature 155 to allow sensing of voltages on terminals Tl, T2, T3 or Il, I2, I3 for each winding stage as selected by relay 147. The Va, Vb~ Vc lines are con-nected to the voltage digitizing circuit 71 as shown in FIG. 1.
In FIG. 4, control signal generator 51 generates successive patterns of highs and lows for control sianals 52 on the lines respectively marked for each control signal A+lA-~B+rB-~c+~ and C- which are fed to the correspondingly marked inpNts of commutating circuit 31 of FIG. 3. The suc-cessive Datterns of the control signals are Droducea in response to successive patterns of digital signals produced by ~icrocomputer 61 on lines 62.
Control signal generator 51 acts in the preferred embodiment as a protective device and switching means for pulse width modulation. If a pair of the control signals hav-ing the same l~ter designation, such as A+ and A-, were both high simultaneo~sly, electronic devices 127 and 129 o FIG. 3 could short the supply conductors 113 and 115. Microcomputer 61 is capable of producing patterns of digital signals at extremely high rates, and an undesired pattern of control sig-nals such as A+,A- high s~ould not be permitted to occur over an extended period of operation. Control signal generator 51 is hardwired logic circuitry which constitutes means for pre-venting control signa1 patterns such as A+,A- high from being generated regardless of the patterns of digital signals pro-duced by microcomputer 61.
Control signal generator 51 has three identicalprotective circuits 161, 163, and 165. For conciseness, only protective circuit 161 is described in detai}. Protective circuit 161 has first and second AND-gates 157 and 169 feeding control signals A+ and A- to the sets of electronic devices ~Z937~9 127 and 129. AND-gates 167 and 169 have inputs 171 and 173 driven by a respective pair of digital signals through inverting buffers 175 and 176 from port P2 lines 0 and 3 from microcomputer 61. Corresponding AND-gates in protective circuits 163 and 165 respectively feed control signals B+, Band C+, C- to switching circuits 123 and 125 in FIG. 3.
These corresponding AND-gates in protective circuits 163 and 165 have their own inputs driven by digital signal pairs through inverting buffers 177,178 (port P2 lines 2 and 5) and inverting buffers 179,180 (port P2, lines 4 and 1) respectively.
Exclusive-OR gate 183 has inputs connected to the inputs of AND-gates 167 and 169 driven by a pair of the digital signals. Exclusive-OR gate 183 has its output feeding both AND-gates 167 and 169 for disabling them when the pair of digital signals on lines 0 and 3 of port P2 identical logic levels in the pair. Exclusive-OR gates corresponding to gate 183 in protective circuits 163 and 165 are identically wired so that no pair of the control signals 52 having the same letter designation can become high simultaneously. In this way the contingency of control signals occurring which could short the power supply is prevented, and reliability is enhanced.
Control signal generator 51 thus constitutes means for preventing at least one pattern of control signals 52 from being generated regardless of the patterns of digital signals on lines 62 produced by microcomputer 61.
Microcomputer 61 produces an additional pair of digital signals, which are different an logic level from each other, on lines 7 and 6 of port P2 which respectively feed NAND gates 185 and 187. A disabling input Q on line 87 is provided to both NAND gates 185 and 187 when power is to be removed from the winding stages. In this way NAND-gates 185 and 187 constitute means for disabling in response to disabl-ing signal Q a single one of the NAND-gates 167 and 169 in lZ937~9 each of the protective circuits 161, 163, and 165. The NAND-gate 167 or 169 to be disabled in each protective circuit is effectively identified by the additional pair of digital signals on lines 7 and 6.
The control signal patterns during commutation are normally the logical complements of the digital signal patterns on lines 0-5 from port P2. FIG. 4A illustrates currents 190 being caused to flow in motor M in the low speed connection arrangement in a preselected sequence 190.0, 190.1, 190.2, 190.3, 190.4, 190.5 in response to successive patterns of the control signals 52. Terminals Tl, T2, and T3 of motor M are selectively switched to "+" supply conductor 113 of FIG.
3 and to "-" supply conductor 115 depending on the direction of desired current flow indicated by the current arrows in FIG. 4A. For instance, the first current 190.0 in the seguence is to flow inside motor M from terminal Tl to terminal T3. Terminal Tl is switched to "+" conductor 113 by A+ high, and terminal T3 is switched to "-" conductor 115 by C- high. Next, current 190.1 is produced by keeping C- high, returning A+ low to disconnect terminal Tl, and bringing B+
high to connect terminal T2 to "+" conductor 113. Next, current 190.2 is produced by keeping B+ high, returning C-low, to disconnect terminal T3, and bringing A- high to connect terminal Tl to "-" conductor 115. The sequence is continued to produced currents 190.3, 190.4, and l90.S and then repeated beginning with current 190.0 again. It is seen that during commutation at least one of the winding stages is unpowered at any one time while the other winding stages are powered by application of the current in sequence through selective switching.
Table I has columns corresponding to each point or current step in the preselected sequence just described above.
Currents 190.0-190.5 in FIG. 4A correspond to the columns of control signals shown in Table I in order from left to right and indexed from O through 5 therein. The control signals 12~3~39 esult ~ ~loc~ise rotati~n o~ t~e rotatable assemDly o~
~otor ; when a?plied in t~.e preselected sequence of Table I.
Counter-l~ckwise rotation is obtained by applying the control Signais in a second preselected sequence snown in Table lI
:~hich is the reverse of ~e sequence o~ Ta~le I. The column entries for the control signals of Table II are seen to be the same when read fr~m right to left as the column entries of Table I read from left to right.
In FIG. 4 the control signals 52 are normally the complement of the digital signals on lines 0-5 of port P2 of the microcomputer 61. Tables I and II summarize the relation-ship o~ the digital signals to the control signais in each column. The first eight rows of each ~able show the outputs for each digital signal pattern in sequence from each P2 port line from 7 down to zero. It is seen that in lines 5 through zero there are exactly two lines in any one column which are logic zero, or low. For example, in the left-most column in the sequence in Table I, these two lines are lines 1 and 0.
By inspection of FIG. 4, lows on lines 1 and 0 are inverted by invert~ng buffers 175 and 180 and bring control signals A+ and C- high throug~ protective circuits 161 and 165. Table I, left-most column, also shows control signals A+ and C-tabulated at this point in the sequence. Comparison of the rest or the columns of Tables I and II with FIG. ~ demon-strates the preselected sequences of digital signal patternscorrelated with control signal patterns for clockwise and counterclockwise rotation.
The digital signal pat~erns and control signal pat-terns are here recognized as signifying directives produced by microcomputer 61 and control signal generator 51 for motor M.
The directives are not only used for commutation in clockwise and counterclockwise directions but for other operations of motor M.

lZ937~9 03AM 5939 F~G. .a iilustrates interpretations of some o~ the digital and control sianai ?atterns by showlng corresponding eauivalent circu1ts in t~.e electronic àevices 127 and 129 o~
switching circuits 121, i23, and 125 of FI5. 3.
When microcom~uter 61 produces all ones on lines 0 througn 7, (11111111 binary which is FF hexadecima_), a con-trol signal pattern consisting of all Lows i5 generated by Control signal generator 51. Commutating circuit 31 has tran-sistors 137 and 145 off in each switching c rcuit 121, 121, and 125 and motor ~ is turned off. Only freewheeling diodes, such as diode 197 in electronic device 127 and its counterpart in electronic device 129 of FIG. 3, appear 25 shown in FI~. 4B
in the equivalent circuit.
The motor .'l is effect-Yely braked when the rotor is spinning, by connecting all of the winding s.ages together.
In FIG. 4B this is acccmplished by bringina A+, B~, and C+
high, corresponding to control signals 101010 and digital sig-nals 10010101. ~he electronic device 127 in FIG. 3 in each of switching circuits 121, 123, and 125 becomes conductive and the winding stages of motor M are all tied to the positive supply conducto.- or rail 113. Mechanical energy in motor ~1 is rapidly dissipated, braking the rotatable assembly lS of FIG.

2. It is to be noted that a complementary braking pattern (not s;~own) brings A-, 3-, and C- high when A+, 3+, and C+ are low.
As already discussed in connection with Tables I and II, two of the windings in a wye-connecteà motor are powered at any one time, leaving the third unpowered, by bringing two control signals high in two of the switchinq circuits 121, 123, and 12S of FIG. 3. In F~G. 4B, for illustration, control signals a+ and A- are brought high, causing current I to flow from voltage V through an upper transistor turned on by control signal B+ through two winding stages of motor ~ and to ground through a lower t.ansistor turned on by control signal A-. Different "Commutate" patterns are applied in at least lZ~3789 one preselected sequence to rotate the rotatable assembly in a predetermined direction.
When the Commutate patterns are applied, at least one of the winding stages is unpowered in sequence (see FIG. 4B) while the other winding stages are powered in sequence. FIG.
5 illustrates the voltage behavior across an unpowered winding stage from a terminal thereof to neutral N during a commutation period when the other winding stages are powered.
Initially a voltage 191 having a high magnitude occurs because of the collapsing field of the unpowered winding resulting from its having been previously powered in the sequence. Field collapse voltage portion 191 dissipates, revealing a ramp-shaped back emf 195 induced in the winding by virtue of the rotation of rotatable assembly 15. Back emf 195 is useful for position sensing of the rotatable assembly 15, while field collapse voltage 191 is not believed to be so useful for position sensing~
The position of the rotor 15 is able to be monitored as it is coasting, by allowing "half" of an electronic switching device to be connected to "half" a winding stage, by turning off one of the two electronic switching devices which would otherwise be both on. Then the proper pair of electronic switching devices is turned on, as dictated by the present rotor position (and not by the position when the power was turned off), and the ECM M continues normal operation.
In FIG. 4B a pattern herein called a "Monitor"
pattern is temporarily applied to eliminate the field collapse voltage 191 and reveal the back emf 195 sooner. A single one of the control signals, e.g., B+, is kept high while a previously high control signal, e.g., A- from the Commutate pattern, is brought low. The current I freewheels through the B+ transistor and diode 197 and the voltage at neutral N rises from about half the supply voltage V to essentially the full supply voltage V. The unpowered winding stage in FIG. 4B has lZ937~9 a current flowing therein when the field collapse voltage 191 of FIG. 5 is occurring. When the other winding stages are being powered by the commutating circuit 31 in response to a Commutate pattern of control signals B+ and A- as shown, the unpowered winding stage temporarily has current 198 circulating through the system as shown and transferring energy from its magnetic field to the rest of the system at a moderate rate because the voltage at neutral N is about half of the supply voltage V. When a monitor pattern for a fast rate of energy extraction is applied as shown, for example by turning off control signal A- and thereby removing its transistor from the circuit, the current in the unpowered winding stage, now designated 199, must release its energy into the full voltage of the power supply 12 through diode 197, thereby transferring energy away from the unpowered winding stage at a much faster rate. In this way, temporary application of a monitor pattern as shown in FIG. 4B
eliminates the field collapse voltage 191 of FIG. 5 and reveals the back emf 195 sooner.
It is also recognized that a monitor pattern for slow rate of energy extraction exists when control signal A is kept on and control signal B+ is turned off, thereby removing the B+ transistor and keeping the A- transistor. Then current I
freewheels through ground (conductor 115) and the voltage of neutral N i~ brought near ground potential (not shown in FIG.
4B), resulting in a relatively slow rate of energy extraction for current 198. Since in some of the contemplated applica-tions of the invention, the control signals such as A- or B+, are pulse width modulated as a result of the disabling signal Q of FIG. 4 or by means of microcomputer 61 directly, the rate of energy extraction is of interest and can be chosen, for instance, between fast and slow by the proper selection of the monitor patterns for achieving at least some of the objects of the invention.

12937~9 It is conte~plated that the various digLtal signal patterns and control slgnal patterns be applied as directives to an electronically commutatea motor M in any sequence or order, so as to accomplish at leas~ some of the objects of the invention.
The voltage behavior (see FIG. ~ across the unpowered winding stage during a commutation period is inverted in polarity compareà to the voltaae across the wind-ing stage which was unpowered in the next ?revioùs commutation period. Accordingly, FIG. S shows but one example of volta~e behavior across an unpowered winding staqe, and it is to be noted that the bac~ emf l9S a?proaches the zero level from opposite directions in successive commutation periods. !~
other word5, in one commutation period the back emf 1~5 ramps lS up as shown, and in the next commutation period the back e~f 195 ramDs down with inverted polarity com~arec to FIG.
In FIG. 3, terminal voltages Va, Vb, and V
for the winding stage terminals selected by relay 147 are all available. Microcomputer 61 automatically and correctly selects the vo tage for the unpowered winding stage by looking up an identifi_ation corresponding to the unpowered winding stage in a table relating the point in the sequence of commu-tation to the identification of the unpowered winding stage.
The relationship, or function, is different for clockwise and counterclockwise rotation.
In a further feature the voltages across the winding stages are simultaneously converted by circuit 71 to digital form thereby to digitize the voltages. As shown in FIG. 6, the digitizing is accomplished with the use of voltage compar-ators 201, 203, and 205. Comparators 201, 203, and 205 eachhave noninverting (+) and inverting (-) input terrinals for accepting signals to be compared. and when one signal falls below the other at a given comparator, ,he output of the respective comparator ~hanges state. The noninverting input 1Z~33~89 03AM 5939 erminais of t;e comparators 201, 203~ and 205 are res~ective-Iy coupled by three voltage dividers having resistors 207,209, 211,213; and 215,217 to the the respective winding stages via the li~es 206 bearing terminal voltages Vc, ~, and Va, ~he voltage dividers are equal in their voltage division ratio. The inverting in?ut terminals of the comparators are coupled by direct connection to a network of resistors 219, 221, 223, 225 for synthesizing a neutral ~!' from the voLtages available from the voltage dividers having resistors 207,209;
211,213; and 215,217. The resistor network constitutes means for providing a voltage corresponding to the neutral N of the winding stages in FIG. 3. The output terminals C, B, and A of comparatorS 201, 203, and 205 are respectively coupied to port Pl input lines 2, 0, and 1 of microcomputer 61 and provided l; with pullup resistors collectively designateà 227. It is noted ~hat the neutral `.~ can be directly brought to the cir-cuit o FIG. ; without use of the resistor network for synthe-SiZing a neutral and that a variety of circuits for digitizing the voltages can be utilized for achieving at least some of the objects of the invention.
Because of the voltage dividers 207,209; 211,213;
and 21S,217 each comparator 201, 203, and 205 respectively sees at its noninverting input terminal a voltage proportional to a terminal voltage ~ia~ Vb~ and Vc of a respective 2S winding stage Sl, S2, cnd S3. Each comparator at its invert-ing input terminal sees the voltage VNI which is proportion-al with the same constant of proportionality to the voltage VN of the neutral N. ~he constant of proportionality is then effectively disregarded in the comparing process. Each of the comparators generates a first logic level (one) when the voltage Va - VN~ Vb - VN~ or Vc N
respective winding stage exceeds a predetermined value of zero (i.e. when the voltage across a respective winding stage is positive) and generates a second logic leYel when the voltage ~ 3~ ~9 03AM 5939 ~cro5a ;z ~alls below r;~ ~re~e~ermrnea vai~e or ~ero (i.e.
~hen t:~e voitage across a respective winaing stage is negativel.
Where it is cesired to provide a voltage offset such as by aijustment of the value of resistor ~,9 or by other means, it is to be understood that the predetermined voltage ~alue departs from zero.
The voltage digitizing circuit of FIGS. 1 and 5 thus consti~uteS means for providing a voltage corresponding to a neutral for the winding stages and further includes a plural-ity of comparators each having an output and first and second input terminals, the first input terminals being respect~vely coupled to the respecti~e winding stages, ~he second input terminals being coupled to the neutral voltage means, the out-put terminals being resoectiveiy coupled to the inputs of thedigitai computer (microcomputer 61).
The digital form of the voltage across each respec-tive winding stage comprises the logic levels so generated at outputs C, B, and A. rIG. 6A illustrates a digitized voltage at output B corresponding the analog voltage Vb - VN of FIG. S. The d gitized voltage in FIG. 6A begins high during the field collapse voltage 191, goes low when the field col-. lapse voltage 191 ends, and then goes back high as soon aszero crossing 229 occurs. It is to be understood that in the ~ollowing commutation Deriod, the voltage oehavior shown in FIG. 5 is inverted in polarity, so that the digitized voltage corresponding to FIG. 6A for the unpowered winding in the fol-lowing commutation period is the logical complement of the pulses shown in FIG. 6A. In either event a transition 230 occurs in the digitized voltage of FIG. 6A substantially simultaneous ~ith zero crossing 229 and corresponding to a speci'ic physical position of the rotatable assembly 15 in relation to the poles of motor M. In the Dreferred e~bodi-ment, the zero crossing 229 is used to trigger the beginning 1~937~9 of the next commutation period by causing microcomputer 61 to advance in the sequence of commutation and produce a following pattern of control signals.
Referring again to FIG. 5, microprocessor 61 is provided with a set of switches 231.1-231.9 for providing the Commands indicated in FIG. 1. Switches 231.1-231.9 are provided with pullup resistors collectively desi~nated 233 and are respectively connected to lines 3,~,5,6,7 (in Port Pl) and lines DB0, DBl, DB2, and DB3. One or more of switches 231.1-231.9 are incorporated in user-operable mechanisms of any familiar type on laundry apparatus 11 which accomplish laundering of different types of fabrics by washing, rinsing, and spinning the fabrics with different temperatures of water and by executing the various operations of the laundry apparatus for different lengths of time. Switches for operations which are relevant to controlling an electronically commutated motor M in laundry apparatus 11 are discussed below.
ON/OFF switch 231.5 is used to signal microprocessor 61 to tell it whether the laundry apparatus is to be on or off. This switch 231.5 is suitably polled every six commutations, or each revolution of the motor. Reception of a logic 0 at line 7 of port Pl indicates the Off condition.
Line 7 is polled continuously when line 7 is low. When line 7 goes high, the microcomputer 61 commences operations to run the motor M.
WASH/SPIN switch 231.4 provides a logic level on line 6 of port Pl by which microcomputer 61 determines whether a washing or spinning mode is called for.
CW/CCW rotational direction switch 231.3 provides a logic level on line 5 of port P1 for setting the direction of rotation of motor M in the SPIN mode. Microprocessor 61 utilizes this direction information in determining whether a preselected sequence of digital signal patterns should be produced for clockwise rotation or another preselected sequence 1~93'~9 03AM 5939 _ho~ e prod~cea for ~unterclockwise rotation. ~n some e~bodi ents the settin9 o~ the C~/CC~ switca 231.3 is i~nored by micr~computer 61 when the ~ASH/SPIN switch 231.~ is set to WASH.
5/250 REV switch 231.2 provides a logic level on line ~ of port Pl. This switch 231.2 is used when microcom-puter 61 counts revolutions of the rotatable means 15 b~
counting successive patterns of digital signals produced. A
revolutlon counter in microcomputer 61 is s_t to 5 when the switch 231.2 is set to the "5" position, as for setting the number of revolutions of motor M in a washing mode of a center-pOst-a9itator-type laundry apparatus. When an 8:1 speed reducer is used with motor M, a stroke of agitation of less than one revolution results in the laundry apparatus.
The revolution counter .s illustratively s~t to 250 by switch 231.2 Cor setting the number of revolutions to be simila!ly reduce~i in a washing mode of tumbler-type laundry appa~atus.
HI/LOW SPEED switch 231.1 is connected to line 3 of port Pl, and is usable, for instance, to indicate when micro-computer 61 is to issue a signal on line D36 for controllingHigh-low speed switching circuit 41 of FIG. 1.
Switches 231.6, 231.7, 231.8 and 231.9 are able to be utilized for other control functions as desired by the skilled worker. ~or instance, if the SPI~ mode is selec~ed on switch 231.4, these switches are suitably used to provide logic levels on lines DB0-DB3 which determine the maximum speed to which the ECM M accelerates. The motor is caused to accelerate or decelerate to the speed selected at a maximum rate preestablished in memory. A value is suitably selected from a table stored in the microcomputer 51 to determine the desired elapsed time between commutations and therefore the maximum speed. Power to the motor is pulse width modulated with adjustable duty cyc}e to accelerate as fast as possible without exceeding a maximum motor current level to the ~937~9 03AM 5939 ~elec~ea s~ee~ l~vel. ~icroco~puter 61 can aiso be programmed to execu~e dynamic brakina to zero motor s?eed when the lines D30-DB3 are all low.
In further control functions obtainable with the awitches 231.6-231.9, ,icrocomputer 61 interprets any one of 16 possible settings or the four switches as instructions for amplitudes and waveshaoes of agitation soeed profiles (effec-tive volta~e to motor ~1) or torque profiles (current in motor ~I) when s~itch 231.4 is in the WAS~ position.
In FIG. 6, hexadecimal numbers are set off in quotes and marked inside the rectangle symbolizing microcomputer 61 to identify the lines 0-7 of port l when microcomputer 61 selects or "masKs~ the port to read the logic level on a given one of t.~e lines. It is noted that each of the hexadeci,,al 1~ numbers 01,02,04,08,10,20,40,80 in binary notation is all zeros except for a "1" in a bit position corresponaing to the number of its respective line. When the hexadecimal number is ANDed with the logic leve}s of the lines in an accumulator register (not shown) of microcomputer 61, only the logic level, if a one (1), of the line signified by the hexadecimal number remains in the accumulator. When it is desired to mask the port for a multiple number of lines such as lines 0,1, and 2 to determine whether any of the lines is active, the masking number ALLHI = 07 (00000111) is ANDed with the logic levels of the lines in the accumulator.
~ eferring again to Tables I and II, each of the digital signal patterns and control signal patterns in the sequence is identified by values of an index in the row marked INDEX, Another index row is designated I~SDEXR to correlate with the flow diagrams discussed below in connection with FIGS. 9,11,14,16, and 19. The INDEXR row has entries which are distinct to each pattern in the sequence and different for Table I and Table II, so that a given pattern is uni~ue}y identified for clockwise and counterclockwise rotation.

lZ93789 03AM 5939 In T~bles I ana II, ;;~e hexadeci al value for "ask-ing ~.t Pl a~d thereDv selecting the digitized voitage across the 2t least one unpowe~ed winding stage is tabulated in the row "~igitized Voltage ~lask. n The mask number depends on, and is a function of, INDEX and therefore also depends on and is a funct~on of the digital signal pattern produced by microcom-puter 61. The comparator 201, 203, 205 output desiqnation A, ~, or C which is selected is also entered for mnemonic pur-poses in Tables I and II ~eneath the hexadecimal mask number.
Microcomputer 61 outputs a pattern of digital sig-nals from a column in Tab~e I when clockwise rotation is selected on switch 231.3 of FIG. 6. The next pattern of digi-tal signals is produced by incrementing INDEX after comple-mentary logic levels are sensed on the masked line from the unpowered winding stage. The complementary logic levels which microcomputer 61 seeks depend on the point its operations have reached in the sequence, so the logic levels are tabulated in the row "Test Bit Order~' in Table I as a function of INDEX.
For example, assume that INDEX is zero, and microcomputer 61 has just produced the àigital signal pattern 01111100 causing control signal; A+ and C- to go high. Then microcomputer 61 masks port Pl with "01" to obtain only the B output from the comparators corresponding to winding stage S2. As shown in FIG. 6A, microcomputer 61 senses the digitized voltage for that ~inding stage in repeated operations indicated by arrows 235.1-235.8. (It is to be understood that the arrows do not necessarily correspond in number and spacing to the actua}
rate of instances of sensing by microcomputer 61 in any par-ticular embodiment.) During the duration of field collapse voltage 191 in ~IG. 5, only logic ones are sensed correspond-ing to arrows 235.1 and 2~5.2. Since the test bit order in Table I calls ~or 0,1 the operations continue looking first for the initial zero. ~t arrow 235.3, the initial zero i5 found. Now microcomputer 61 looks for the logic level one in 1 2 9 3 71~g 03AM 5939 the 0,1 test bit order. It continues looking but ~nses 0 at times indicated by arrows 235.4, 235.5, 235.6 and 235.7. Then at the time indicated b- arrow 235.8, just when the back emf 195 has had i~s zero crossing 229 and transition 230 has occurred in the digitized voltage, microcommputer 61 senses a logic level 1 matching the second entry in the test bit order.
The complementary logic levels 0,1 of the selected digitized voltage B have now occurred in the predetermined order.
Microcomputer 61 now advances in the se~uence of commutation by incrementing INDEX by 1, produces the digital signal pat-tern 10111001, masks with mask 02 (comparator output A), and advances in sequence after complementary logic levels in the order 1,0 for the digitized voltage A have occurred, indicat-ing another zero crossing.
In FIG. 7, a source of 5 volts DC is connected to positive voltage supply pin Vcc of microco puter 61, and supply return pin VDD is connected to ground. A crystal 241 with associated capacitors 243 and 245 is connected to pins XRLl and XRL2. The operations of microcomputer 61 are reset by a circuit connecting input RESET-bar to reset switch 247 and capacitor 249 to ground, and RESET-bar is also connected to Vcc through reverse-biased diode 251. Pin EA of the 8748 chip is connected to ground. The connections described in this paragraph are conventional and are not descri~ed furt.~er.
The current interrupt and speed circuit B1 of ~IG. 1 is now described in more detail using FIG. 7. Comparator 261 has its inverting input connected through resistor 263 to voltage VI from shunt resistor R5 of FIG. 3. The nonin-verting input of comparator 261 is connected to a voltage divider 265 consisting of resistors 267 and 269 ano variable resistor 271 for setting a ~urrent interrupt level. Adjusting variable resistor 271 sets a predetermined level. Comparator 261 with its pullup resistor 262 compares the current flowing in the powered winding stages of motor .~ with the predeter-mineà level fed to the noninverting input of comparator 261.

lZ93'7t~9 03AM 5939 ~pon t-e Dredeterminea '_vel heing eYceeaed by voltage V , the output of comparator 261 goes low at t~,e PRESET input of a 74Ls74 flipflop, or latcn, 273, so that output Q of flipflop 273 goes high and output Q-bar (complement or Q) goes low.
5 Output Q-bar going low interrupts microcomputer 61 at low-active interrupt pin IMT-bar. Output Q going high causes the control signal generator 51 of FIG. 4 to generate 2 pattern of control signals to reduce the current in the winding stages by changing the Commutate pattern to a Monitor pattern (see FIG.
4B3.
Current interrupt and speed circuit 81, microcom-puter 61, and control signal generator 51 together constitute means 'or producing the successive patterns of the control signals in at least one preselected sequence to s~itch on only one electronic device in each of at least two of the sets of the electronic devices,at once and cause a current to flow in the winding stages to rotate the rotatable means, and for sub-sequently producing a pattern of the control signals to switch off one of the electronic switching devices which was pre-viously switc~ed on so that the commutating circuit 31 leavesall of the win~ing stages temporarily unpowered and also pro-vides a current path for the previously-powered winding stages. Current interrupt and speed circuit 81 together with microcomputer 61 consti ute means for proàucing the successive patterns of the diqital signals in at least one preselected sequence to switch on only one electronic device in each of at least 'wo of the sets of the electronic devices at once and cause a current to flow in the winding stages to rctate the rotatable means, and for subsequently producing a pattern of the digital signals to switch off one of the e}ectronic switching devices which was previously switched on, the identit~I of the one device switched off depending on the last pattern produced in the sequence (e.g. as a result of the Rail Disable information in the first two rows of Tables I and II), 12~37~9 so that ~he commutatir,~ ~eans leaves all Ot the winding s~ages temporarilv unpowered and also provides a current ~ath for the previou5ly-powered winding stages.
Control signal generator 51 constitutes means responsive to successive patterns of digital signals for gen-erating the successive Datterns of the control signals for the commutating means, the generating means including first and second logic gate means (e.g. 167 and 169~ feeding the sets of eLectronic devices in the commutating means and having inputs driven by respective pairs of digital signals (e.g. inverting buffers 175,176; 177,178; and 179,180) in the digital signal patternS, means for disabling the first and second logic gate means when any of the pairs of digital signals has identical logic levels in the pair (e.g. exclusive-OR gate 183), and means for disabling (e.g. NAND gates 185 and 187) in response to a disablin- -ignal (~.g. Q) a single one of the first and second logic gate means identified by an additional pair of digital signals in the digital signal patterns (e.g. on port P2 lines 7 and 6). Microcomputer 61 constitutes means for producing the successive patterns of the digital signals in at least one preselected sequence to switch on only one elec-tronic device in each of at least two of the sets of the elec-tronic devices at once and cause a current to flow in the winding stages to rotate the rotatable means, and for p~oduc-ing the additional pair of digital signals to have logiclevels depending on each pattern in the sequence ~e.g. top and bottom disable signals in first two rows of Tables I and II).
Current interrupt and speed circuit ~1 constitutes means for providing the disabling signal (e.g. Q) in response to an occurrence of a predetermined condition (e.g. excessive current) thereby to switch off one of the electronic devices which was previously switched on.
FIG. 7 illustrates an embodiment adapted for supply-ing t~e disabling signal Q by a hardwired circuit comprised in 1~33~7~39 current ~terrupt and ~?eea circuit 81 ~nich is outboard of microcon~uter 61. It is to be understood t~at Monitor pat-terns as in FIG. 4B are in alternative embodiments produced by performing operations inside microcomputer 61. In order to accomplish such operations in microcomputer 61, monitor pat-terns wnich vary as a function of INDEX are stored in the memory. These monitor patterns are output on lines 62 when-ever desired, and they are tabulated for clockwise and Countercloc~wise rotation respectively in Tables V and VI.
In Fig. 7A, logically complementary waveforms for the Q and Q-bar outputs of flipflop 273 show Q low ~ntil the PRESET input of flipflop or latch 273 receives the aforemen-tioned output from comparator 261 or becomes otherwise preset.
After a predetermined period of time Tl of nominally 100 microseconds, microcomputer 61 completes an interrupt routine and senas a pulse on line DB7 to input CLR to clear flipflop 273, causing the Q output to go low again, and Q-bar to go high. If and when the motor current rises above the predeter-mined level again, comparator 261 again presets flipflop 273, protec~ing motor M from overcurrents. Flipflop 273 has its data (D) input and cloc~ ~CL~) inputs grounded. The output of comparator 261 is also connected to the T0 testable input of microcomputer 61 for advantageous f lexibility of operations.
In addition to pcotecting motor .~., circuit 81 also provides a means for producing pulses at an adjustable rate, as if the predetermined level were exceeded, when the current is actually less than the predetermined level, so that the speed of the motor in the laundry apparatus 11 is adjustable.
With output Q of flipflop 273 low, inverter 27S produces an output High, charging capacitor 277 through resistor 279. The time constant of capacitor 277 with resistor 279 is on the order of one millisecond, for e~ample. The voltage acroSS
capacitor 277 is appLied through a voltage divider consisting of resistors 281 and 283 to the inverting (-) input of 2 com-parator 285. Comparator 285 has a positive feedbacK resistor 1233~39 87 f~r ~ysteresis. ~he noninverting (+~ input of comparator285 i~ fed with the adjustable speed-related output o~ a volta~e divider consisting of resistor 289 and potentiometer 291 t.~rough resistor 293. As capacitor 277 char~es, it reaches a voltage greater than that set by potentiometer 291, causin~ the output of comparator 285 to go low. The low out-put of comparator 285 is fed to the preset input of flipflop 273, causing output Q to go high and Q-bar to go low, inter-rupting microcomputer 61. During time Tl, the High from out-put Q is inverted by inverter 27S so that the output ofinverter 27S goes low and at least partially discharges capac-itor 277. Microcomputer 61 clears flipflop 273 after time Tl, causing output Q to go low. Inverter 275 in turn goes high, progressively char~ing capacitor 277. Then comparator 285 in circuit portion 295 of current interrupt and speed circuit 81 causes flipflop 273 to produce a disablin~ si~nal Q high and interrupt microcomputer 61 again when a second time interval T2 has elapsed. Setting potentiometer 291 to a higher voltage position increases the time interval T2. Increasing time intervai T2 increases the speed of the motor because the speed of the motor increases with increasing duty cycle, and the duty cycle is the ratio T2/(T2 ~ Tl). It is noted that in the embodiment of FIG. 7, Tl is set inside the microcomputer 61, and T2 is set outside bv circuit 295. In other embodiments Tl is set outside microcomputer 61 and T2 is set inside the microcomputer 61. In still other embodiments both Tl and T2 are set inside microcomputer 61. In yet other embodiments both Tl and T2 are set outside microcomputer 61.

=~

1Z93'7~9 03AM 5939 TABLE I

DATA FOR CL~CKWIS- ROTATION

P2 Rail Line Disable Seouence of Patterns D 7 Top 0 1 0 1 0 I

G 5 Btm 1 0 1 0 1 0 I

T _____________________-______________ L

S

G

A

S

____________________________________ INDEX: 0 1 2 3 4 5 INDEXR: 0 1 2 3 4 5 CONTROL A+ B+ B+ C~ C+ A+
SIGNALS: C- C- A- A- B- B-MASK: (B~ ~A) (C) (B) (A) (C~

TEST BIT
ORDER: 0,1 1,0 0,1 1,0 0,1 1,0 1~93~7~9 03AM 5939 TABLE II

DATA EOR COUNTERCLOCKWISE ROTATION

P2 Rail Line Disable Seauence o~ Patterns D 7 Top 0 1 0 1 0 I

G 6 Btm 1 0 1 0 1 0 ____________________________________ A

I

N

L

____________________________________ INDEX: 0 1 2 3 4 5 INDEXR: 12 13 14 15 16 17 CONTROL A+ C+ C+ B+ B+ A+
SIGNALS: B- B- A- A- C- C-DIGITIZED

MASK: (C) (A) (B) (C) (A) (B) TEST BIT
ORDER: 0,1 1,0~ 0,1 1,0 0,1 1,0 ~Q

1~37~39 TAB LE I I I

CLOCK~ISE ROTOR POSITION S_NSING

Pl Diaitized Back EMFs ____________________________________ HEX: 6 2 3 1 5 4 R3: -4 1 -2 4 -1 2 OFFSETR3: -8 5 -6 8 -5 6 INDEX: ` 1 0 5 4 3 2 INDEXR: 1 0 5 4 3 2 DIGITI ZED
VOLTAGE ALLHI=07. `lask for A, B, C at same time.
MASR:
_ 125'37~9 TABLE IV

COUNTERCLOCXhISE ROTOR POSITION SENSING

P1 Diaitized ~ack EI~Fs

3 1 0 0 0 ____________________________________ HEX: 3 2 6 4 5 R3: -~ 4 -2 1 -4 2 INDEX: 1 0 5 4 3 2 INDEXR: 13 12 17 16 15 14 DIGITI,ZED
VOLTAGE ALLHI=07. .~lask for A, B, C at same time.
~IASK:
.

lZ~33~7~9 TABLE ~

MONITOR PATTERNS FOR CLOCKWISE ROTATION

P2 Rail Line Disable Seauence o~ Patterns D 7 Top 0 1 0 1 0 G 6 Btm 1 0 1 0 1 0 I

T ____________________________________ A 5 ` 1 1 1 1 1 0 L

4 1 1 1 1 0 S

G

A

s O
____________________________________ INDEX: 0 1 2 3 4 5 INDEXR: 0 1 2 3 4 5 CONTROL
SIGNALS: A~ C- B~ A- C~ 8-1~37~9 03AM 5939 TAaLE VI

;~IONITOR PATTERNS FOR COUNTERCLOC~hISE ROTATION

P2 Rail Line Disable Seauence o. Patterns D 7 Top 0 1 0 1 0 I

G 6 Btm 1 0 1 0 1 0 ______________________--_-__________ A

I

N

L

INDEX: 0 1 2 3 4 5 INDEXR: 12 13 14 15 16 17 CONTROL
SIGNALS: A+ B- C+ A- B+ C-.

12~37~9 The flow diagrams of FIGS. 8-17 and 19 describe processes, methods, and operations contemplated in some of the embodiments of the invention, regardless of any particular manner of implementation using hardware or software. A listing of an illustrative assembly language program for the Intel 8748 microcomputer as microcomputer 61 is included in the present application as Appendix I. A table correlating the listing of Appendix I with the flow diagrams is included as Appendix II.
It is to be understood that the assembly language program is used in microcomputer 61 to make it perform many of the same processes, methods and operations shown in the flow diagrams while differing in order of listing and in some details from the flow diagrams of FIGS. 8-17 and 19. Thus Appendix I
further illustrates and discloses some of the variety of implementations possible in the practice of the invention according to the principles thereof.
In FIG. 8, operations commence at START 301 and at step 305 equates are made to set up in memory some or all of the information contained in Tables I through VI of the present specification. More specifically, the information includes the patterns of digital signals for clockwise and counterclockwise rotation, which are designated "Control Driver Pattern For Clockwise Direction" and "Control Pattern For Running Counter Clockwise Direction" in Appendix I. In addition, the information includes identified inputs to the microcomputer 61 in the rows designated "Digitized Voltage Mask" in Tables I and II and the lines designated "Test Pattern For CW/CCW" in Appendix I. Control equates are also made in Appendix I for maskinq the input lines to port Pl from the switches for On/Off, Wash/Spin, CW/CCW, 5/250 REV, and Hi/Low Speed, for clearing flipflop 273 of FIG. 7, setting certain time values, and for other purposes.
At step 307 and step 309 outputs are turned off and other housekeeping functions are accomplished. These include producing a digital signal pattern "OFF" consisting of all 1~3~7~9 03AM 5939 ~nes f.om output port ~ on lines 62 of FIG. ~ so that ail zeros are ~enerated by c~ntrol signai generatOr 51 for turning off the motor M. Flipflop 273 is cleared, ~igh/Low Speed circuit ~1 of FIG. 1 is set to Low, and initializing of the microcomputer 61 is performed.
A point 311 in the operations is designated ST~TST.
STRTST is located at the beginning of operations which deter-mine whether the laundrv apparatus is still on and whether the wash or spin mode is to be changed. At step 313 the state of On/Off switch 231.5 is read at port Pl, line 7, and at step 315 operations branch back to STRTS~ until switch 231.5 is turned from the Off position to the On position. When switch 231.5 is on, point 316 designated RUN is reached. Then at step 317 the C~J/C~J switch 231.3 is read at port Pl, line 5, and the setting as clockwise or counterclockwise is storeà.
At step 319 the Wash/Spin switch 231.4 is read at port P1, line 6, and the mode commanded by it is stored. At step 321, the mode stored is tested, and if it is "Wash", operations proceed to point 323 and FIG. 9, otherwise to "Spin" point 325 and FIG. 14.
In FIG. 9, the wash mode is executed beginnin~ at point 323. A predetermined point in the preselected sequence for clockwise rotation (left-most column of Table I) is selected by setting I~EX and INDEXR to zero at step 351.
Flipfloo 273 is cleared and current and timer interrupts are enabled at step 353. Steps 355, 357, and 359 check INDEXR to assure that it does not have a value clearly indicating some error in the system. If INDEXR is negative or greater than 23, an 0FF digital signal pattern ~all ones~ is produceà at step 3~9, and operations loop back to step 351.
Next at step 363 a digital signal pattern is obtained from memory and stored in the accumulator. For example, the first digital signal pattern so obtained is 01111100 from the leftmost column of Table I. Next at seep 365, the digital signai pattern is produced from the 12~37~9 03AM 5939 ~ccu~lluia~or as an o~tpu~ ~n l~nes 62 ror c~n~roi signal ener-ator ~. (termeà '`~river 109ic" on the flow ciagram). In step 367 a test pattern, whiah is 0,1 or 1,0 is obtained ~rom mem-ory for use in testing t~.e digitized voltage as explainea in connection with FIG. 6A. ~he test pattern to be used is tabu-lated i~ Tables I and IT i~ the same column as the digital signal ~attern whicA has just ~een producea. Equivalentl~, and as discussed in connection with FIGS. 10 and 15, the test bit order is directly implemented in the coding as a function of whether INDEX is even or odd, and step 367 is omitted. At step 369 a register for a flag ~LGl is set to zero, indicating that the low speed connection zrrangement for the winding stages is intended. At step 371 and as more fully discussed in connection with FIG. ~, the digitized voltage of F;G. 6A
is tested, and as soon as complementary bits, or logic levels, in the ~ODer test bit order have been sensed, operations pro-ceed to advance in sequence to commutate the winding stages.
If complementary bits are not sensed in the predetermined proper lest bit order in a predetermined time period, opera-tions proceed to advance in the sequence anyway andforce-commutate the motor.
At step 372 the rail disable signals on lines 7 and 6 of port P2 of microcomputer 61 are reversed. "~ail" as used herein means either one of SuDply conductors 113 and 115. In 2S this way control signal generator 51 is prepared by microcom-puter 51 for any pulse width modulation (PWM~ which may occur by output Q going high as soon as the back emf routine 371 is complete. As such, microcomputer 61 constitutes means f or also selecting the digitized voltage across the at least one unpowered winding stage when digital signal patterns are pro-duced in sequence and changing the logic levels of the zddi-tional pair of digital signals (e.g. on lines 7 and 6 of port P2~ as soon as at least one predetermined logic level (e.g. of the test bits) of the selected digitized voltage has occurred.

12~37~9 03AM 5939 At s-eps 373 anà 375, I~lDEXR and I~DEX are resDac-tively incremented, ~oving one coLumn to the right, in effect, in Table I or II. If I,~DEX has not reachea the number 6 at step 377, operations loop back to a point 3,9 designated :IAINl ~nd continue with the sequence of steps 355-377, commutating the motor until INDEX reaches 6. ~hen INDEX reaches 6, a brancn is made from step 377 to step 381. The value Il~DEX is eSsentially treated modulo 6, so that opera~ions cycle through Tables I and II, to commutate the motor as long as desired.
INDEX is reset to zero at step 381. At step 333, INDEX~ is decreased by 6. The latter operation reco~nizes that when counterclockwise rotation i5 being executed in Table II, INDEX~ reaches the number 18 when INDEX is 6, so that I`'DEXR
m~st be cycled back to a permitted number 12 in Table I; by subtraction by 6.
At step 3~5 the On/Off switch 2'1.5 of FIG. 6 is tested. If the switch has been turned off, a branch is made from step 387 to step 3ag whence the pattern OFF (all ones on lines 62) is output to shut the motor off, and operations return to STRTST point 311 in FIG. 8 to poll the switch until it is turned on. Assuming On/Off switch is on when step 387 was first reached, operations proceed to step 391 to decrement a eevolution counter which has been originally loaded in step 309 o. FIG. 8 with a number 5 (center-post agitator laundry apparatus) or a number 250 (tumbler-type laundry apparatus~.
In this way microcomputer 61 counts revolutions of rotatable means 15 in step 391 by counting at steps 37S, 377, and 381 the successive patterns of digital signals produced. When the revolution counter has been decremented at step 391, a test of its contents at st~p 393 for the number zero is made to deter-mine whether all of the revolutions in a stroke of aqitation have been completed by motor M. If not, operations loo~ to MAINl and continue with step 355 and the subsequent steps to continue commutating motor M in the same direction of rota-tion. If the revolution counter has reached zero, a branch is lZ~3~789 made from step 393 to step 395 where the counter is reloadedwith the number 5 or 250, depending on the setting of switch 231.2 of FIG. 6. In step 397, operations are performed to prepare for commutation in the opposite direction, as discussed more fully in connection with FIG. 11.
In FIG. 10, low speed back emf routine 371 commences with BEGIN 401. A two-millisecond interrupt timer is started running at step 403. At step 405, the value of INDEX
representing the point in the sequence in the Table I or II is checked for being even or odd. If it is even (INDEX = 0,2,4) the test bit order is 0,1. The digitized voltage of FIG. 6A is tested at step 407 and the testing is prepared by branching back from step 409 until the first test bit of 0 is found, whence the two-millisecond interrupt timer is cleared at step 411 and step 417 is reached. It is noted that the repeated execution of steps 407 and 409 until the zero (0) is found corresponds to arrows 235.1-235.3 in FIG. 6A. If INDEX is odd (1,3,5), the test bit order utilized is 1,0. The digitized voltage (which is inverted in polarity from that of FIG. 6A) is tested at step 413 and the testing is repeated by branching back from step 415 until the first test bit of 1, this time, is found, whence the two-millisecond interrupt timer is cleared at step 411 and step 417 is reached. If the repeated testing at either step 407 or 413, as the case may be, continues for 2 milliseconds without avail, a timer interrupt occurs and operations proceed to step 417.
An 18-millisecond interrupt timer is started running at step 417. At step 419, the value of INDEX representing the point in the sequence in the Table I or II is checked for being even or odd. If it is even (INDEX = 0,2,4) the test bit order is 0,1 as already stated. The digitized voltage of FIG. 6A is tested at step 421 and the testing is repeated by branching back from step 423 until the second test bit of 1 (in 0,1) is found, whence the 18-millisecond interrupt timer 12S~37~39 is cleared at step 425 and RETURN 427 is reached. It is noted that the repeated execution of steps 421 and 423 until the one (1) is found corresponds to arrows 235.4-235.8 in FIG. 6A. If INDEX is odd (1,3,5), the test bit order utilized is 1,0 as already stated. The digitized voltage (which is inverted in polarity from that of FIG. 6A) is tested at step 429 and the testing is repeated by branching back from step 431 until the second test bit of 0 (zero), this time, is found, whence the 18-millisecond interrupt timer is cleared at step 425 and RETURN 427 is reached. If the repeated testing at either step 421 or 429, as the case may be, continues for a full 18 milli-seconds without avail, a timer interrupt occurs and operations proceed to RETURN 427.
FIG. 11 shows the reversing routine 397 of FIG. 9 in greater detail~ Operations commence therein at BEGIN 451.
INDEX is initialized to zero at step 453. The direction variable DIRECT is tested at step 455. If DIRECT is 0, for clockwise (CW) rotation, step 457 changes it to 1, for counter-clockwise (CCW) rotation, and INDEXR is increased by 12 at step 459 in order to enter the range of INDEXR in Table II. If DIRECT is 1 for CCW rotation in step 455, step 461 changes it to 0, for CW rotation, and INDEXR is decreased by 12 at step 463 in order to enter the range of INDEXR in Table I. Steps 455-463 in effect are operations by which microcomputer 61 changes INDEXR and the direction variable DIRECT which are subsequently used in producing successive patterns of digital signals for achieving the desired direction of rotation of motor M.
Before the motor M is commutated in the opposite direction from that in which it was turning previously, it is caused to stop rotating by operations which commence at MTROFF
point 465, and proceed to produce an OFF pattern (all ones on lines 62) at step 467. The motor M, having its power removed, coasts to a stop. However, microcomputer 61 needs to know when the motor has actually stopped. This information is 3~9 obtained by first loading a counter at step 469 with a predetermined number indicative of a predetermined time period during which there should be no back emf observed when and if the motor has actually stopped. Next at step 471 one or more of the port P1 inputs 0, 1, and 2 is sensed for its digitized voltage. As long as the rotor is coasting, the digitized voltage from each of the winding stages is a succession of highs and lows. If a zero, or low, is sensed, the rotor may still be coasting or it may have stopped, but if a one, or high, is sensed, the rotor must still be coasting.
Accordingly, a branch is made from step 473 if a high bit, or logic level of one, is sensed and the counter is reloaded with the predetermined number at step 469 since the rotor must still be coasting. On the other hand, operations proceed from step 473 to step 474 if a low bit, or logic level of zero, is sensed, and the counter is decremented. Since the rotor may still be coasting, however, a branch is made from step 477 back to testing step 471 unless the counter has been decremented to zero. In this way if the rotor is still coasting, a one (1) bit indicating existence of back emf is sensed sooner or later at step 471 and the counter can be reloaded at step 469 as a re~ult of the branch from step 473.
Eventually the rotor stops and a sufficient time period elapses without back emf to assure microcomputer 61 that the rotor has stopped. The counter is decremented to zero and operations proceed from step 477 to RETURN 479.
In having the capability to perform the reversing routine of FIG. 11, microcomputer 61 and control signal gener-ator 51 together constitute means for causing the rotatable means to reverse in its direction of rotation by producing a pattern of the control signals for causing the commutating means to remove power from all of the winding stages, for sensing the digitized voltages while the power is so removed, and for producing successive patterns of the control signals in a second preselected sequence to rotate the rotatable means 12937~9 in the reverse direction only after a predetermined time period has elapsed subsequent to the last occurrence of a predetermined logic level in any of the digitized voltages.
FIG. llA shows a series of operations of microcomputer 61 for braking motor M to stop the rotation more quickly than occurs when motor M is permitted to coast to a stop as in FIG.
11. The operations of FIG. llA are performed in substitution for the steps 467, 469, 471, 473, 475, 477 and 479 of FIG. 11 in a reversing routine and performed at any point in the operations of microcomputer 61 where braking is deemed desirable by the skilled worker. Braking operations commence with BEGIN 481 and proceed to produce an OFF pattern 483 (all ones on lines 62) for leaving all of the winding stages of motor M unpowered. Microcomputer 61 waits for a delay period of illustratively 3 milliseconds at step 485 before proceeding to step 487. At step 487 a braking pattern of the digital signals is produced as shown at FIG. 4B in connection with the entry "BRAKE." The braking pattern causes commutating circuit 31 to connect together all of the terminals of the winding stages selected by High-low speed circuit 41. The mechanical energy stored in the rotor is rapidly dissipated electrically because the winding stages are in effect shorted together. At step 489 another delay period, this time for 12.5 milliseconds, is executed by microcomputer 61. Another OFF pattern is produced at step 491, followed by another 3 millisecond delay by the microcomputer 61 at step 493, and braking operations are completed at RETURN 495.
In having the capability to perform the steps described in connection with FIG. llA, microcomputer 61 and control signal generator 51, as pattern producing and digitized voltage sensing means, constitute means for also producing a pattern of the control signals which causes the commutating circuit 31 to switch all of the winding stages to one of the supply conductors 113 or 115, thereby braking the motor M.

1~937~9 03AM 5939 .`.n in~errupt ~w at the INT-bar -in of miczoco~Duter 61 can occur at any ti~e auring the washin mode or spin mode operationS of laundry apparatus 11. FIG. 12 illustrates a sequence of operations which occurs upon interrupt. Interrupt operations commence at BEGIN 501. Optional step 507 is descri~ed later in connection with FIG. 13. The high-low speed flag FLGl is checKed at step 513. ,f the flag is a zero (low s?eed winding selection~, an internal timer (not shown~
in microcomputer 61 is loaded with a number correspondina to the predetermined time period Tl ~FIG. 7~) of 100 microseconds in step 515, and if the flag is a one (high speed winding selection~, the timer is loaded for a predetermined time period Tl of 50 microseconds at step 517 to take account of the higher motor s~eeds. ~ex~ at steps 5'9 and 521 the timer is decremented until i' reaches zero thereby to execute a delay for the time period Tl and indicati.? that ti~e period Tl has elapsed. An optional step 523 is discussed below in connection with FIG. 13. At step 525 microcomputer 61 trans-mits a pulse on the line DB7 of FIG. 7 to clear the latch or flipflop 273 whence interrupt operations are completed at RETURN 527.
In FIG. 7A the duty cycle of pulse width modulation (PWM) for motor M is controlled by causing the ~ and Q-bar outputs of latch 273 to change state between time periods Tl and T2 as shown. FIG. , reflects a hardware approach for set-ting T2 by means of circuit portion 295, and the microcomputer 61 sets Tl in the interrupt routine of FIG. 12.
In FIG. 13 a software approach is suggested for con-trolling the time period T2 when the motor M is powered. The circuit portion 295 of FIG. 7 is deleted in a now-described alternative embodiment. An otherwise unused output line such as DB5 (not shown) is connected to the PPESET input of latch 273. '~ariable duty cycle instructions corresponding to the operations called for in FIG. 13 are inserted between steps 315 and 317 of FIG. 8 at the point designated RUN. At step 1293'î~89 531 input information corresponding to the desired duty cycle is read in to microcomputer 16 as from switches 231.6, 231.7, 231.8, and 231.9 at pins DB0-DB3 of FIG. 6. This duty cycle information is a 4 bit binary code when pins DB0-DB3 are used for input, so that 16 values of duty cycle Dl are selectable.
Given a predetermined time period Tl value, there corresponds a particular value of T2 which solves the duty cycle equation Dl = T2/(T2 + Tl) (1) The duty cycle equation (1) is solved for time period T2 for time-on with result:

T2 = Tl(Dl/(l-Dl)) (2) Values of T2 are stored in a table in memory corresponding to the values of desired duty cycle D1 which can be read in in step 531. When one of the values Dl is read in, the corre-sponding value of T2, or time-on, is fetched from the table in step 533. At step 535 the interrupt process is enabled so that microcomputer 61 can be interrupted by excessive current sensed by comparator 261 of FIG. 7. Then at step 537 a timer is loaded with a number corresponding to the time-on T2 and set running. The timer (not shown) is an internal timer in microcomputer 61 which is for present purposes called a duty interrupt timer. Microcomputer 61 executes the operations of FIG. 8 and of the washing and spin modes selected, but is interrupted when the duty interrupt timer times out at the end of time period T2, beginning the interrupt routine of FIG. 12.
The FIG. 12 interrupt routine now is described with the optional steps 507 and 523 included. At step 507 inter-rupt pin INT-bar is masked to avoid interaction with latch 273, and latch 273 of FIG. 7 is set by transmitting a zero or Low from microcomputer 61 to its PRESET input. The Q output 1~93789 of latc.~ 273 goes high, leavin~ motor ~l unpowered througn con-trol signal generator 51 and commutating circuit 31. The interru?t operations proceed in steps 513-521 so that prede-termined time period Tl elapses. At step 523, the duty inter-~upt timer in microcomputer 61 is reloaded with a value corre-sponding to time period T2 and set runnina again. Latch 273 is cleared at step 525, bringing its Q output low and powering the motor M again. Also at step 525 interrupt pin INT-bar is enabled so that any overcurrent interrupt caused by comparator 261 can be sensed.
The spin mode of laundr~ ap ara~us 11 has operations shown in FIG. 14 which commence at point 325. ~icrocomputer 61 clears latch 273 and enables interrupts in step 551. ~he value of INDEX is set to zero (O) for purposes of Tables I and iI in s.ep 553. The directi~n in which the motor M is to turn during the spin mode is determined from the setting of switch 231.3 (CW/CCW in FIG. 6) in step 555. If switch 231.3 is set to CW, operations proceed from step 557 to step 559 and the preselected sequence defined in Table I is selected by setting INDEXR to zero in step 559. If switch 231.3 is set to CCW, operations proceed from step 557 to step 561 and the preselec-ted sequence defined in Table II is selected by setting INDEXR
to 12 in step 561. Ope~ations of microcomputer 61 reach point 563 designated MAIN2 when either step 561 or step 559 has been completed.
Steps 565, 567, and 569 check INDEX~ to assure that it does not have a value clearly indicatinq some error in the system. If INDEX~ is negative or greater than 23, an OFF
digital signal pattern (all ones) is produced at step 569, and operations loop back to step 553.
When operations reach step 571, the high-low speed winding flag FLGl is tested to determine which selection is being made by high-low speed circuit 41. Assume that the 7~39 selection is initially io~ and the spin mode is just begin-ning. FLGl is zero, indicating low speed winding, and oDera-tions pass through point ~ to step 573 where HI~LOW Speed switch 231.1 is tested. In the present embodiment, switch ; 231.1 can be initially set in the LOW speed position and the motor ~ is brought up to a steaày speed. Then switch 231.1 is changed to the HI speed position for commandina microcomouter 61 to cause relaying bv High-low speed switching circuit 41 and causing motor M is accelerate to a higher speed. The operations of microcomputer 61 in responding to switch 231.1 are described in greater detail next.
When switch 231.1 is set to LOW, indicating that the motor M is to be in the low speed connection arrangement for the time being, a branch is made at step 575 to step 577. At step 577 a digital signal pattern is obtained from memory and stored in the accumulator. For example, the f.rst digital signal pattern so obtained is 01111100 from the leftrost col-umn of Table I when C~/CC~ switch 231.3 is in the C~ position.
Next at step 579, the digital signal pattern is produced from the accumulator as an output on lines 62 (termed "output run patrn" on the flow diagram) for control signal generator 51.
In step 581 a test pattern, which is 0,1 or 1,0 is obtained from memory for use in testing the digitized voltage as explained in connection with FIG. 6A. The test pattern to be used is tabulated in Tables I and II in the same column as the digital signal pattern which has just been produced. Equiva-lently, and as discussed in connection with FIGS. 10 and 15, the test bit order is directly implemented in the coding as a function of whether INDEX is even or odd, and step 531 is omitted. At step 583, depending on whether FLGl is set for Low (0) or High (1) speed, a branch is made through point F to low speed back emf routine 371 or through point E to high speed bac~ emf routine 585. In each of back emf routines 371 and 535 and as more fully discussed in connection with FIGS.

fi4 3~9 10 and lS, the digiti-e~ voltage of ~TG. ~A is tested '-~r com-21ementary bits, or logic levels, in the ~roper test bit order whence point G is reacheà.
When motor ~l is running at low speed, f~ag FLGl has been set to zero. Assume that it is desired to accelerate motor `~ to a higher s?eeà so that switch 231.1 is physically changed to HI. (It is also contemplated that the change from low to high can be alternatively accomplished in software.) FLGl is still set to zero and in FIG. 14 operations pass through point D to step 573. Now when switch 231.1 is tested at step 573, a branch is made from step 575 to step 587 where flag FLGl is set to one for High Winding Tap. Then a relaying routine at step 588 is executed for actuaily relaying from the low speed to the high speed winding connections to motor M and for determining the proper point in the sequence for resuming commut2tion when the relaying is completed. Relaying routine 588 is described in qreater detail in connection with FIG.
17. When operations at steps 573, 575, 587, and 588 have been completed, motor M is commutated and accelerated, and steps 573, 575, 587, and 588 are bypassed by a NO branch from step S71 to step 577 subsequently during high speed rotation.
Steps 577, 579, and 5Bl are performed. At step 583 flag FLGl is now set for High speed and operations pass through point E
to high speed back emf routine 585.
2S In FIG. 15 high speed back emf routine 585 is simi-lar to low speed back emf routine 371 of FIG. 10 except in being adapted for the shorter time intervals encountered at higher rotor speeds. Operations commence at BE~IN 589 and a one-millisecond interrupt timer is started at step 590. Step 591 unifies the operations performed in steps 405 and 419 of FIG. 10. At step 591, the value of INDEX representing the point in the sequence in the Table I or II is checked for being even or odd. If it is even (INDEX = 0,2,4) the test bit order is 0,1. The digitized voltage of ~IG. 6A is tested at step 593 and the testing is repeated b~ brancning back from G~

1'~93~789 s~ep 595 until the first test bit of 0 is found. The digi-tized voltage of FIG. 6A is again tested at step 597 and the testing is repeated by branching back from step 599 until the secona test bit of 1 is founa. Then the one-milliseconG
S interrupt timer is cleared at step 601 and RETU~N 603 is reacheà. It is noted that the repeated execution of steps 593 and 595 until the zero (0) is found corresponds to arrows 235.1-235.3 in FIG. 6A, and repeated execution of steps 597 and 599 until the one (1) is found corresponds to arrows 23s.4-235.8~ If INDEX is odd (1,3,5), the test bit order uti-lized is 1,0. The digitized voltage (whicn is inverted in polarity from that of FIG. 6A) is tested at step 605 and the testing is repeated by branching back from step 607 until the first test bit of 1, this time, is founa. Then the digitized voltage is tested at step 609 and the testing i5 repeated by brancning back from step 611 until the second test bit of 0, this time, is found, whence the one-millisecond interrupt timer is cleared at step 601 and ~ETURN 603 is reached. If the repeated testing at steps 593-599 or 605-611, as the case may be, continues for a full one millisecond without avail, a timer interrupt occurs and operations proceed to RETURN 603.
FIG. 16 shows more operations of microcomputer 61 in the spin mode continuing from point G from FIG. }4. The oper-ations advance in sequence ol commutation beginning at step 621. At steps 621 and 623, INDEXR and I~IDEX are respectively incremented, moving one column to the right, in effect, in Table I or II. If INDEX has not reached the number 6, opera-tions branch from step 625 to the point 563 designated MAIN2 in FIG~ 14 and continue with the sequence of steps from MAIN2 to point G, commutating the motor until INDEX reaches 6. When INDEX reaches 6, a branch is made from step 625 to step 627.
The value INDEX is essentially treated modulo 6, so that oper-ations cycle through Table I or II, depenàing on rotation direction, to commutate motor M as long as desired in the spin lZ93'789 mode. INDEX is reset to zero at step 627. At step 629, INDEXR is decreased by 6. The latter operation recognizes that when rotation is being executed in either Table I or II, INDEXR reaches the number 6 or 18 when INDEX is 6, so that INDEXR must be cycled back to a permitted number 0 or 12 in Table I or II by subtraction by 6.
At step 631 the On/Off switch 231.5 of FIG. 6 is tested. If the switch is still set to "On," operations pass from step 633 back to FIG. 14 point MAIN2 so that commutation continues. If the switch has been turned off, a branch is made from step 633 to step 635 whence the pattern OFF (all ones on lines 62) is output to shut the motor off. At step 637 a loop or counting operation is provided so that microcomputer 61 waits 100 milliseconds or for any other desired time interval. In step 639 microcomputer 61 issues a High on line DB6 (FIG. 3) producing a Low on line H from NAND
gate 157, and causing relay 147 in high-low speed circuit 41 to switch back to a low speed connection arrangement. The high-low speed flag FLGl is reset to zero (low speed) at step 641, and operations pass to STRTST point 311 of FIG. 8, there to poll On/Off switch 231.5 until it is turned on.
In FIG. 17 the relaying routine of step 588 of FIG.
14 is shown in greater detail. Operations commence with BEGIN
651 and proceed to produce the OFF pattern (all ones on lines 62) at step 653 to turn off the motor M. At step 655 micro-computer 61 issues a Low on line DB6 (FIG. 3) producing a High on line H from NAND gate 157, and causing relay 147 in high-low speed circuit 41 to switch from the low speed connection arrangement to a high speed connection arrangement.
Microcomputer 61 waits for ten milliseconds as by any suitable routine, such as counting from a preset number down to zero, in step 657 in order to permit the relay 147 armature 155 to come to reset in the high speed position. However, during this waiting period, the rotor 15 of motor M has, or may have, ,, , l Z~3'~9 rotateà a throuaA a significant angle ror oommutation pur-poses. Accordingly, at step 6~9 a routine is executed for determining the value of I~DEX from the sensed digitized ~olt-ages on comparator outputs A, B, and C of FIG. 6 when the ~inding stages are temporarily unpowered, and resuming produc-lng patterns o~ digital signals on lines 62 beginning with the pattern of digital signals (and thus a corresponding set of control signals from control signal generator 51) identified by the value of INDEX so determined. After step 659 RETURN
661 is reached.
Step 659 of FIG. 17 recognizes that when motor M is unpowered and the rotor is coasting, all of the winding stages are producing bac~ emfs. As shown in FIG. 6, the back emfs are digitized by comparators 201, 203, and 205. The digitized back emfs for three wye-connected winding stages Sl, S2, and S3 are illustrated in FIG. 18 and tabulated in Tables III and IV for clockwise and counterclockwise rotation respectively.
In FIG. 18 and in the first three rows of ~ables III
and IV, the logic levels of the digitized voltages on input lines 0, 1, and 2 of microcomputer 61 are shown when rotor 15 is coasting. Each of the six columns shows the logic levels of the digitized back emfs present at any given time. As the rotor turns, the logic levels of a given column are replaced by the logic leveLs in the column next to the right. When the right-most column is reached, the logic levels begin again in the left-most column, cycling through the columns as before.
FIG. 18 shows superimposed on the logic zeros and ones a wave-shape of the digitized back emfs on the input lines 0, 1, and 2. The digitized bac~ emfs at any one time and their changes to other values at other times bear sufficient information to permit sensinq the position of the turning rotor 15 and to identify the proper point in sequence for be~inning commuta-tion of such turning rotor and for resuming commutation when-ever commutation is interrupted or discontinued. Accordingly, 1~937~9 03AM 5939 the i~àex-determinin9 operati~ns of s.ep 659 as described in further detail in ~IG. is are ~sed in relaying rout~ne 588 in the preferred embodiment, and are used in other e~bodiments of the invention whenever it is desired to begin commutation in sequence.
In FIG. 19 operations commence with BEGIN 671, and microcomputer 61 inputs all the lines 0,1, and 2 of port Pl at once by masking with ALL~I=07 (binary 00000111). As a result there resides in microcomputer 61 a three bit binary number having binary digits correspondin~ to each of the digitized voltages on the ~hree lines. This binary n~mber is designated DATAl and stored in step 673. Then at step 675, microcomputer 61 inputs all the lines 0,1, and 2 of port Pl again in search of digitized voltages corresponding to an adjacent column of digitized voLtaqes in FIG. 18. In order to avoid error, if the latest set of digitized voltages is all zeros (decimal zero (0~) or all ones (decimal seven (7)), then the index determining routine is aborted by passing to RETURN 679. The reason for this is that as shown in FIG. 18, the digitized voltages are never all high at the same time when the rotor is coasting. Also, the digitized voltages are all zero only when the rotor has stopped.
If the digitized voltages are not 0 or 7 as just discussed, then operations proceed from step 677 to step 6Bl where the digitized voltages just obtained in step 675 are stored and designated DATA2. In step 683, DATAl is compared with DATA2. If they are the same number, (i.e. DATAl-DATA2=0) the rotor has not turned sufficiently to move to the adjacent rightward column in FIG. 18 and in the Table III or IV corre-sponding to the direction of rotation. ~hen DATAl=DATA2 abranch is made back to step 615 to input another set, or instance, of digitized voltages until an instance of digitized voltages is found at step 67~ which is different f om DATAl.
At step 685, the difference DATA2-DATAl is computed. Step 687 12937~9 03AM 5939 chec~s the value of the difference, which from inspect~on of àifferences between the hexadecimal eauiYalents o~ the digi-tized voltages (tabulated in row HEX of Tables III and IV) should not be equal to 3 or -3 if the data is unaffected by noise. If the difference is eqùal to the unpermitted numbers 3 or -~<, a branch is made from step 687 to step 675, until a value of DATA2 is foun~ which passes the test of step 687.
When step 689 is reached, microcomputer 61 has stored values of DATAl and DATA2 which are in adjacent columns of one of the Tables III or IV. Each Table III or IV lists values of R3, which is the difference DATA2-~ATAl, in the column corresponding to the digitized back emfs in DAT~l.
Beneath a va~ue of difference R3 in each of column of Table III or IV are values of INDEX and INDEXR. The values of INDEX
lS and I~DEXR are precisely the values for identifying the Droper Table I or II and the proper column therein containing the diqital signal pattern which microcomputer 61 can and does then produce to resume commutation of the winding stages at the proper point in sequence. (Beneath the tabulated value of R3 in Table III is an entry designated "Offset R3" which is a number calculated in the program listing of Appendix I for microcomputer table lookup purposes.) At step 689 microcomputer 61 determines which direction the rotor 15 has been made to turn in. When switch 231.4 is in the spin mode, the direction is given by the setting of switch 231.3 as CW or CCW. When switch 231.4 is in the wash mode, the direction is given by the value of the variable DIRECT of FIG. 11. In either mode the direction can also be obtained from INDEXR. If INDEXR is in the ranqe 0-5, the direction is clockwise, and if INDEX~ is in the range 12-17 the direction is counterclockwise.
If the direction determined is counterclockwise, a brancn is made from step 689 to step 691 for table lookup in a table in microcomputer 61 having the information found in lZ937fi9 03AM 5939 Table I~. in rows R3 and I~DE~ hen I~DE~ is founa, I.~E~ is reset ~ adding 12 to I,IDEX. If the direction determined is clockwise, a branch is made from step 689 to step 693 for table lookup in a table in microcomputer 61 having the infor-; mation found in Table III in rows R3 and INDEX. INDEXR isreset as equal to INDEX when the direction is clockwise.
After step 691 or step 693 is executed, .-~TU~N 679 is reached.
The operations of ~IG. 19 can be described more gen-erally as follows. ~,~icrocomputer 61 identifies successive patternS of the control signals and of the digital signals of Tables I and II by values of an index designated INDEX. A
value of the index is determined from the sensed digitized voltages when the winding stages are temporarily unpowered.
~licrocomputer 61 resumes producing successive patterns of the lS digital signals which causes control signal generator 51 to generate successive patterns of the control signals in se-quence beginning with a pattern of the digital signals and control signals determined from the sensed digitized voltages.
The lookup table information stored in microcomputer 61 is a function, i.e. a predetermined correspondence bet~een members of two sets of numbers. The sets of numbers involved here are values of INDEX on the one hand and values of the differences R3. Equivalently, Tables III and IV can be regarded as tabu-lating INDEX as a function of digitized back emf itself. It is also to be understooà that there are a multitude of equiva-lent ways made known by the disclosure made herein, of setting up a function relating the digitized back emf information to some variable such as INDEX which can be used to determine the proper point for beginning in sequence when commutation begins again. When the successive patterns of digital signals and control signals are identified by values of an index, the index is advantageously determined as a function of a number represented by the sensed digitized voltages when the winding stages are temporarily unpowered, and microcomputer 61 resumes ~ 3789 03AM 5939 proà~c a patterns Deg1nning ~ith the pattern o~ the conerol Sisnal5 identified bv the value of the index 50 determinea.
The index is determined as a first function of a number repre-sented by the sensed digitized voltages when the winding stages are temporarily unpowered and the preselected sequence is ~or cloc~wise rotation of the rotatable means 15 and deter-mined as a second function of the number so represented ~hen the preselected sequence is for counterclockwise rotation, and microcomputer 61 resumes producing patternS beginning with the pattern of the control signals identified by the value of the index so determined. The value of the index is also deter^
mined as a function of the difference of first and second num-bers represented by different instances of the sensed digi-tized voltages, and microcomputer 61 begins with the pattern of the control signals identified by the value of the index so determined. The value of the index is determined as a func-tion of the difference of first and second numbers represented by different instances of the sensed digitized voltages unless one of the numbers is in a set of predetermined numbers, such as 0 and 7, and microcomputer 61 begins with the pattern of the control signals identified by the value of the index so determ-ned. A difference of first and second numbers repre-sented by different instances of the sensed digitized voltaqes is calculated and a value of the index is determined as a function of the difference unless the difference is in a set of predetermined numbers, such as 0, +3, and -3, and microcom-puter 61 begins with the pattern of the control signals iden-tified by the value of the index so determined. Microcomputer 61 in this way prevents sensed digitized voltages representing a number in a predetermined set, such as 0 and 7, from being used to determine the beginning pattern of control signals.
Microcomputer 61 in FIG. 19 repetitively senses the digitized voltages while the winding stages are temporarily unpowered and determines the beginning pattern of the control signals as 1'~3789 03AM 5939 soon as a change occucs in any one of the sensed digitized volt2ges.
In some applications of the inYention involving cur-rent interrupt as in FIG. 7, the time period Tl when the motor ~l is unpowered can be long enough to make index-determination as in FIG. 19 advisable. In such circumstances, the index-determining operations of FIG. l9 are inserted in the inter-rupt routine of FIG. 12 immediately following step 521 so as to update INDEX and INDEXR. Then the control system of FIG. l constitutes means for comparing the current flowing the other powered winding stages of the electronicallY commutated motor with a predetermined level, and upon the level being ex-ceeded, interrupting the digital computer and also causing the control signal generator 51 to generate a pattern of control 1~ signals to discontinue the supply of power to the winding stages, the digital computer comprising means for also moni-toring the position of the rotatable means lS when the winding stages are thus unpowered and resuming producing patterns of the digital signals after a predetermined time interval begin-ning with a pattern then corresponding to the posi_ion of the rotatable means.
In view of the above, it.will be seen that the . several objects of the invention are achieved and other advantageous results attained.
As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the control system comprising:
means coupled to the winding stages for simultaneously converting the voltages across the winding stages to digital form thereby to digitize the voltages;
means for producing successive patterns of digital signals in at least one preselected sequence, for selecting the digitized voltage across the at least one unpowered winding stage depending on the digital signal pattern produced, and for producing a following pattern in sequence after at least one predetermined logic level of the selected digitized voltage has occurred; and means responsive to the successive patterns of the digital signals for generating the successive patterns of the control signals for the commutating means.

2. The control system as set forth in claim 1 wherein said converting means comprises means for generating a first logic level when the voltage across a respective winding stage exceeds a predetermined value and a second logic level when the voltage across it falls below the predetermined value, the digital form of the voltage across each respective winding stage comprising the logic levels so generated.

3. The control system as set forth in claim 1 wherein said control signal generating means comprises means for also preventing at least one pattern of control signals from being generated regardless of the patterns of digital signals produced by said producing and selecting means.

4. The control system as set forth in claim 1 wherein said producing and selecting means comprises means for producing each pattern in the sequence after complementary logic levels of the selected digitized voltage have occurred in a predetermined order.

5. The control system as set forth in claim 1 wherein said producing and selecting means comprises means for also producing the following pattern in sequence after a predetermined time period if the at least one predetermined logic level of the selected digitized voltage has not occurred during the predetermined time period.

6. The control system as set forth in claim 1 further comprising means for comparing the current flowing in the other powered winding stages of the electronically commutated motor with a predetermined level and upon the level being exceeded, causing said control signal generating means to generate a pattern of control signals to reduce the current.

7. A method for controlling a system having an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the method comprising the steps of:
digitizing the voltages across the winding stages;
generating successive patterns of the control signals for the commutating means in response to successive patterns of digital signals;
prestoring data representing at least one preselected sequence of the patterns of the digital signals and prestoring data, corresponding to each pattern of the digital signals, identifying the respective digitized voltage for the at least one unpowered winding stage;
successively producing one of the patterns of the digital signals and sensing only the identified digitized voltage corresponding to the one pattern; and producing the following pattern in sequence after at least one predetermined logic level of the identified digitized voltage has occurred.

8. The method as set forth in claim 7 further comprising the step of preventing at least one pattern of control signals from being generated in the generating step regardless of the patterns of digital signals produced in the producing steps.

9. The method as set forth in claim 7 wherein the step of producing the following pattern is performed after complementary logic levels of the identified digitized voltage have occurred in a predetermined order.

10. The method as set forth in claim 7 wherein the step of producing the following pattern in sequence is performed after a predetermined time period if the at least one predetermined logic level of the selected digitized voltage has not occurred during the predetermined time period.

11. The method as set forth in claim 7 further comprising the steps of comprising the current flowing in the other powered winding stages of the electronically commutated motor with a predetermined level and, upon the predetermined level being exceeded, generating a pattern of control signals to reduce the current.

12. The method as set forth in claim 11 further comprising the step of enabling motor operation to resume after a predetermined time interval upon the generation of the current-reducing pattern of control signals.

13. The method as set forth in claim 11 further comprising the step of periodically producing the current reducing pattern of control signals at an adjustable rate when the predetermined level is not exceeded.

14. A method for controlling a system having an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, first and second conductors for supply power, and means for commutating the winding stages and producing a current in the winding stages by selectively switching the winding stages to the supply conductors in response to a pattern of control signals, the method comprising the steps of:
producing successive patterns of digital signals in at least one preselected sequence;
generating patterns of the control signals for the commutating means in response to the successive patterns of the digital signals;
comparing the current in the winding stages of the electronically commutated motor with a predetermined level; and producing a preestablished pattern of the digital signals for a predetermined period of time to reduce the current in the winding stages, whenever the predetermined level is exceeded and periodically producing the current reducing pattern of the digital signals at an adjustable rate when the predetermined level is not exceeded.

15. The method as set forth in claim 14, wherein the commutating means comprises sets of electronic devices connected across the first and second supply conductors, each set having at least one junction point connected to a respective one of the winding stages, each of the electronic devices respectively being able to be switched by a corresponding one of the control signals in each pattern of control signals, the method further comprising the steps of prestoring data identifying one of the first and second conductors corresponding to each pattern of the digital signals in the sequence and disabling switching by the electronic devices to the identified conductor corresponding to the pattern of the digital signals which is being produced just prior to producing the preestablished current reducing pattern.

16. The method as set forth in claim 14 further comprising the step of preventing at least one pattern of control signals from being generated in the generating step regardless of the patterns of the digital signals produced.

17. A control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, first and second conductors for supplying power, and means for commutating the winding stages and producing a current in the winding stages by selectively switching the winding stages to the supply conductors in response to a pattern of control signals, the control circuit comprising:
means for generating patterns of the control signals for the commutating means in response to successive patterns of digital signals;
means for comparing the current in the winding stages of the electronically commutated motor with a predetermined level; and means for producing the successive patterns of digital signals in at least one preselected sequence for said generating means, for producing in response to said comparing means preestablished pattern of the digital signals to reduce the current in the winding stages upon the predetermined level being exceeded, for monitoring the voltage across the winding stages to monitor the position of the rotatable means when the current is being reduced, and for resuming producing the successive patterns of digital signals in sequence after a predetermined time interval.

18. The control circuit as set forth in claim 17 wherein the commutating means comprises sets of electronic devices connected across the first and second supply conductors, each set having at least one junction point connected to a respective one of the winding stages, each of the electronic devices respectively being able to be switched by a corresponding one of the control signals in each pattern of control signals, and the producing means comprises means for also prestoring data identifying one of the first and second conductors corresponding to each pattern of the digital signals in the sequence and disabling switching by said electronic devices to the identified conductor corresponding to the pattern of the digital signals which is being produced just prior to producing the preestablished current reducing pattern.

19. The control circuit as set forth in claim 17 wherein said generating means comprises means for also preventing at least one pattern of control signals from being generated regardless of the patterns of the digital signals.

20. The control circuit as set forth in claim 17 wherein said comparing means comprises means for also causing said control signal generating means to generate a pattern of control signals to reduce the current in the winding stages upon the predetermined level being exceeded.

21. The control circuit as set forth in claim 17 wherein said comparing means comprises means for also producing pulses at an adjustable rate when the current is less than the predetermined level, so that the speed of the motor is adjustable.

22. A control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the control system comprising:
means coupled to the winding stages for converting the voltages across the winding stages to digital form thereby to digitize the voltages; and means for producing successive patterns of the control signals in at least one preselected sequence to rotate the rotatable means, for subsequently producing a pattern of the control signals which causes the commutating means to leave all of the winding stages temporarily unpowered, for sensing the digitized voltages while the winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.

23. The control system as set forth in claim 22 wherein said producing and sensing means comprises:
means responsive to successive patterns of digital signals for generating successive patterns of the control signals for the commutating means; and digital circuit means for producing successive patterns of the digital signals in at least one preselected sequence, for sensing the digitized voltages while the winding stages are temporarily unpowered and then resuming producing the successive patterns of the digital signals in sequence beginning with a digital signal pattern determined from the sensed digitized voltages.

24. The control system as set forth in claim 23 wherein said control signal generating means comprises means for also preventing at least one pattern of control signals from being generated regardless of the patterns of digital signals produced by said digital circuit means.

25. The control system as set forth in claim 23 wherein said digital circuit means comprises means for also selecting the digitized voltage across the at least one unpowered winding stage depending on each of the successive patterns produced, and for producing a following pattern in sequence after complementary logic levels of the selected digitized voltage have occurred in a predetermined order.

26. The control system as set forth in claim 23 wherein said digital circuit means comprises means for also selecting the digitized voltage across the at least one unpowered winding stage depending on each of the successive patterns produced, and for producing a following pattern in sequence after at least one predetermined logic level of the selected digitized voltage has occurred and for producing the following pattern in sequence after a predetermined time period if the at least one predetermined logic level of the selected digitized voltage has not occurred during the predetermined time period.

27. The control system as set forth in claim 23 further comprising means for comparing the current flowing in the other powered winding stages of the electronically commutated motor with a predetermined level and, upon the level being exceeded, causing said control signal generating means to generate any pattern of control signals which causes the commutating means to reduce the current in the winding stages.

28. The control system as set forth in claim 27 wherein said current comparing means comprises means for electrical comparison of the current with a voltage corresponding to the predetermined level and latch means fed by said electrical comparison means, said latch means having at least one output coupled to said control signal generating means and to said digital circuit means.

29. The control system as set forth in claim 28 further comprising means for supplying a series of pulses at an adjustable rate to said latch means.

30. The control system as set forth in claim 28 wherein said digital circuit means has a line coupled to said latch means to clear said latch means.

31. The control system as set forth in claim 22 wherein said converting means comprises means for generating a first logic level when the voltage across a respective winding stage exceeds a predetermined value and a second logic level when the voltage across it falls below the predetermined value, the digital form of the voltage across each winding stage comprising the logic levels so generated.

32. The control system as set forth in claim 22 further comprising means operable generally for switching the winding stages from one connection arrangement to at least another connection arrangement thereof.

33. The control system as set forth in claim 32 wherein said producing and sensing means comprises means for also producing a signal to effect the operation of said switching means when all of the winding stages are caused to be temporarily unpowered.

34. The control system as set forth in claim 32 wherein one of the connection arrangements is a low speed connection arrangement and at least another connection arrangement is a higher speed connection arrangement.

35. The control system as set forth in claim 22 wherein said producing means comprises means for also identifying the successive patterns of the control signals by values of an index, determining a value of the index from the sensed digitized voltage when the winding stages are temporarily unpowered, and beginning with the pattern of the control signals identified by the value of the index so determined.

36. The control system as set forth in claim 22 wherein said producing means comprises means for also identifying the successive patterns of the control signals by values of an index, determining a value of the index as a function of a number represented by the sensed digitized voltages when the winding stages are temporarily unpowered, and beginning with the pattern of the control signals identified by the value of the index so determined.

37. The control system as set forth in claim 22 wherein said producing means comprises means for also identifying the successive patterns of the control signals by values of an index, determining a value of the index as a first function of a number represented by the sensed digitized voltages when the winding stages are temporarily unpowered and the preselected sequence is for clockwise rotation of the rotatable means and determining the value of the index as a second function of the number so represented when the preselected sequence is for counterclockwise rotation, and beginning with the pattern of the control signals identified by the value of the index so determined.

38. The control system as set forth in claim 22 wherein said producing means comprises means for also identifying the successive patterns of the control signals by values of an index, determining a value of the index as a function of the difference of first and second numbers represented by different instances of the sensed digitized voltages, and beginning with the pattern of the control signals identified by the value of the index so determined.

39. The control system as set forth in claim 22 wherein said producing means comprises means for also identifying the successive patterns of the control signals by values of an index, determining a value of the index as a function of the difference of first and second numbers represented by different instances of the sensed digitized voltages unless one of the numbers is in a set of predetermined numbers, and beginning with the pattern of the control signals identified by the value of the index so determined.

40. The control system as set forth in claim 39 wherein the set of predetermined numbers includes 0 and 7.

41. The control system as set forth in claim 22 wherein said producing means comprises means for also identifying the successive patterns of the control signals by values of an index, for calculating a difference of first and second numbers represented by different instances of the sensed digitized voltages, for determining a value of the index as a function of the difference unless the difference is in a set of predetermined numbers, and beginning with the pattern of the control signals identified by the value of the index so determined.

42. The control system as set forth in claim 41 wherein the set of predetermined numbers includes 0, +3 and -3.

43. The control system as set forth in claim 22 wherein said producing means comprises means for also preventing sensed digitized voltages representing a number in a predetermined set from being used to determine the beginning pattern of the control signals.

44. The control system as set forth in claim 22 wherein said producing means comprises means for also repetitively sensing the digitized voltages while the winding stages are temporarily unpowered and determining the beginning pattern of the control signals as soon as a change occurs in any one of the sensed digitized voltages.

45. A control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, the control system comprising:
means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered;
means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means; and means for producing the successive patterns of the digital signals in at least one preselected sequence, and for subsequently producing a different pattern of the digital signals which causes said commutating means to connect all of the winding stages together, thereby braking the motor.

46. The control system as set forth in claim 45 further comprising means coupled to the winding stages for converting the voltages across the winding stages to digital form thereby to digitize the voltages; said producing means comprising means for also selecting the digitized voltage across the at least one unpowered winding stage depending on the digital signal pattern produced, and for producing a following pattern in sequence after at least one predetermined logic level of the selected digitized voltage has occurred.

47. The control system as set forth in claim 46 wherein said converting means comprises means for generating a first logic level when the voltage across a respective winding stage exceeds a predetermined value and a second logic level when the voltage across it falls below the predetermined value, the digital form of the voltage across each respective winding stage comprising the logic levels so generated.

48. The control system as set forth in claim 46 wherein said selecting and producing means comprises means for producing the following pattern after complementary logic levels of the selected digitized voltage have occurred in a predetermined order.

49. The control system as set forth in claim 46 wherein said selecting and producing means comprises means for also producing the following pattern in sequence after a predetermined time period if the at least one predetermined logic level of the selected digitized voltage has not occurred during the predetermined time period.

50. The control system as set forth in claim 45 wherein said control signal generating means comprises means for also preventing at least one pattern of control signals from being generated regardless of the patterns of digital signals produced by said producing means.

51. The control system as set forth in claim 45 further comprising means for comparing the current flowing in the other powered winding stages of the electronically commutated motor with a predetermined level and upon the level being exceeded, causing said control signal generating means to generate a pattern of control signals to reduce the current.

52. The control system as set forth in claim 45 wherein each of the winding stages includes winding sections adapted to be commutated, and said control system further comprises means operable generally for connecting said control signal generating means to a selected section of each winding stage.

53. The control system as set forth in claim 52 wherein said producing means comprises means for also producing a signal for the connecting means to effect the selection of the section of each winding stage to be commutated.

54. The control system as set forth in claim 45 further comprising means coupled to the winding stages for converting the voltages across the winding stages to digital form thereby to digitize the voltages, said producing means comprising means for also producing a pattern of the digital signals which causes said commutating means to leave all of the winding stages temporarily unpowered, for sensing the digitized voltages while the winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.

55. A method for controlling an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the method comprising the steps of:
producing successive patterns of the control signals in at least one preselected sequence of commutating the winding stages in a first connection arrangement;
producing a pattern of the control signals which causes the commutating means to leave all of the winding stages temporarily unpowered;
switching the winding stages to a second connection arrangement;
sensing the position of the rotating means from the winding stages while they are temporarily unpowered;
and resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the position of the rotating means sensed while the winding stages are temporarily unpowered.

56. The method as set forth in claim 55 wherein one of the first and second connection arrangements is a low speed connection arrangement and the other of the first and second connection arrangements is a higher speed connection arrangement.

57. The method as set forth in claim 55 wherein the position sensing step comprises converting the voltages across the winding stages to digital form and storing the digital form of the voltages as soon as a change occurs in the digital form of the voltages.

58. The method as set forth in claim 57 wherein the determining step comprises the steps of identifying the successive patterns of the control signals by values of an index, determining a value of the index as a first function of a number represented by the sensed digitized voltages when the winding stages are temporarily unpowered and the preselected sequence is for clockwise rotation of the rotatable means and determining the value of the index as a second function of the number so represented when the preselected sequence is for counterclockwise rotation.

59. The method as set forth in claim 57 wherein the determining step comprises the steps of identifying the successive patterns of the control signals by values of an index and determining a value of the index as a function of the difference of first and second numbers represented by different instances of the sensed digitized voltages.

60. The method as set forth in claim 57 wherein the determining step comprises the steps of repeating the position sensing step while the winding stages are temporarily unpowered and determining the beginning pattern of the control signals as soon as a change occurs in any one of the sensed digitized voltages.

61. A method for controlling an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the method comprising the steps of:

converting the voltage across the winding stages to digital form thereby to digitize the voltages;
producing successive patterns of the control signals in at least one preselected sequence to commutate the winding stages and rotate the rotatable means;
subsequently producing a pattern of the control signals which causes the commutating means to leave all of the winding stages temporarily unpowered;
sensing the digitized voltages while the winding stages are temporarily unpowered;
determining a pattern of the control signals from the sensed digitized voltages; and resuming producing the successive patterns of the control signals in sequence beginning with the pattern so determined.

62. The method as set forth in claim 61 further comprising the steps of:
selecting the digitizing voltage across the at least one unpowered winding stage depending on each control signal pattern produced in sequence; and producing a following pattern in sequence after complementary logic levels of the selected digitized voltage have occurred in a predetermined order.

63. The method as set forth in claim 62 wherein the step of producing the following pattern in sequence is performed after a predetermined time period if the complementary logic levels of the selected digitized voltage have not occurred in the predetermined order during the predetermined time period.

64. The method as set forth in claim 61 wherein the converting step comprises generating with respect to each of the winding stages a first logic level when the voltage across a respective winding stage exceeds a predetermined value and a second logic level when the voltage across it falls below the predetermined value, the digital form of the voltage across each respective winding stage comprising the logic levels so generated.

65. The method as set forth in claim 62 wherein the determining step comprises the steps of identifying the successive patterns of the control signals by values of an index and determining a value of the index from the sensed digitized voltages when the winding stages are temporarily unpowered.

66. The method as set forth in claim 61 wherein the determining step comprises the steps of identifying the successive patterns of the control signals by values of an index and determining a value of the index as a function of a number represented by the sensed digitized voltages when the winding stages are temporarily unpowered.

67. The method as set forth in claim 61 wherein the determining step comprises the steps of identifying the successive patterns of the control signals by values of an index, determining a value of the index as a first function of a number represented by the sensed digitized voltages when the winding stages are temporarily unpowered and the preselected sequence is for clockwise rotation of the rotatable means and determining the value of the index as a second function of the number so represented when the preselected sequence is for counterclockwise rotation.

68. The method as set forth in claim 61 wherein the determining step comprises the steps of identifying the successive patterns of the control signals by values of an index and determining a value of the index as a function of the difference of first and second numbers represented by different instances of the sensed digitized voltages.

69. The method as set forth in claim 68 wherein the set of predetermined numbers includes 0 and 7.

70. The method as set forth in claim 61 wherein the determining step comprises the steps of identifying the successive patterns of the control signals by values of an index and determining a value of the index as a function of the difference of first and second numbers represented by different instances of the sensed digitized voltages unless one of the numbers is in a set of predetermined numbers.

71. The method as set forth in claim 61 wherein the determining step comprises the steps of identifying the successive patterns of the control signals by values of an index, calculating a difference of first and second numbers represented by different instances of the sensed digitized voltages, and determining a value of the index as a function of the difference unless the difference is in a set of predetermined numbers.

72. The method as set forth in claim 71 wherein the set of predetermined numbers includes 0, +3 and -3.

73. The method as set forth in claim 61 wherein the determining step comprises the step of preventing sensed digitized voltages representing a number in a predetermined set from being used to determine the beginning pattern of the control signals.

74. The method as set forth in claim 61 wherein the determining step comprises the steps of repeating the sensing of the digitized voltages while the winding stages are temporarily unpowered and determining the beginning pattern of the control signals as soon as a change occurs in any one of the sensed digitized voltages.

75. A method for controlling an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the method comprising the steps of:
generating successive patterns of the control signals for the commutating means in response to successive patterns of digital signals;
producing the successive patterns of the digital signals in at least one preselected sequence; and producing a different pattern of the digital signals which causes the commutating means to connect all of the winding stages together, thereby braking the motor.

76. The method as set forth in claim 75 further comprising the steps of:
converting the voltages across the winding stages to digital form thereby to digitize the voltages;
selecting the digitized voltage across the at least one unpowered winding stage depending on the digital signal pattern produced; and producing a following pattern in sequence after at least one predetermined logic level of the selected digitized voltage has occurred.

77. The method as set forth in claim 76 wherein the converting step comprises generating a first logic level when the voltage across a respective winding stage exceeds a predetermined value and a second logic level when the voltage across it falls below the predetermined value, the digital form of the voltage across each respective winding stage comprising the logic levels so generated.

78. The method as set forth in claim 76 wherein the last named producing steps comprises producing the following pattern in sequence after complementary logic levels of the selected digitized voltage have occurred in a predetermined order.

79. The method as set forth in claim 76 wherein the step of producing the following pattern in sequence is performed after a predetermined time period if the at least one predetermined logic level of the selected digitized voltage has not occurred during the predetermined time period.

80. The method as set forth in claim 75 wherein the method further comprises the step of preventing at least one pattern of the control signals from being generated regardless of the patterns of the digital signals produced.

81. The method as set forth in claim 75 further comprising the steps of comparing the current flowing in the current flowing in the other powered winding stages of the electronically commutated motor with a predetermined level and upon the level being exceeded, causing a pattern of the control signals to be generated to reduce the current.

82. The method as set forth in claim 75 wherein each of the winding stages includes winding sections adapted to be commutated, and the method further comprises electrically energizing a selected one of the winding sections of each winding stage to effect commutation.

83. The control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and first and second conductors for supplying power, the control system comprising:
means for commutating the winding stages in response to successive patterns of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, said commutating means including sets of electronic devices connected across the supply conductors, each set having a junction point connected to a respective one of the winding stages, each of said electronic devices respectively being able to be switched by a corresponding one of the control signals in each pattern of control signals; and means for producing the successive patterns of the control signals in at least one preselected sequence to switch on only one electronic device in each of at least two of the sets of said electronic devices at once and cause a current to flow in the winding stages to rotate the rotatable means, and for subsequently producing a pattern of the control signals to switch off one of said electronic switching devices which was previously switched on so that said commutating means leaves all of the winding stages temporarily unpowered and also provides a current path for the previously-powered winding stages, said control signal producing means comprising means responsive to successive patterns of digital signals for generating the successive patterns of the control signals for said commutating means, said generating means including first and second logic gate means feeding said sets of electronic devices in said commutating means and having inputs driven by respective pairs of digital signals in the digital signal patterns, means for disabling said first and second logic gate means when any of the pairs of digital signals has identical logic levels in the pair, and means for disabling in response to a disabling signal a single one of said first and second logic gate means identified by an additional pair of digital signals in the digital signal patterns.

84. The control system as set forth in claim 83 wherein the control signal producing means further comprises:

means for producing the successive patterns of the digital signals in at least one preselected sequence to switch on only one electronic device in each of at least two of the sets of said electronic devices at once and cause a current to flow in the winding stages to rotate the rotatable means, and for subsequently producing a pattern of the digital signals to switch off one of said electronic switching devices which was previously switched on, the identity of said one device switched off depending on the last pattern produced in the sequence, so that said commutating means leaves all of the winding stages temporarily unpowered and also provides a current path for the previously-powered winding stages.

85. The control system as set forth in claim 83 wherein said control signal producing means further comprises:
means for producing the successive patterns of the digital signals in at least one preselected sequence to switch on only one electronic device in each of at least two of said sets of said electronic devices at once and cause a current to flow in the winding stages to rotate the rotatable means, and for producing the additional pair of digital signals to have logic levels depending on each pattern in the sequence; and means for providing the disabling signal in response to an occurrence of a predetermined condition thereby to switch off one of said electronic devices which was previously switched on.

86. The control system as set forth in claim 85 further comprising means coupled to the winding stages for converting the voltages across the winding stages to digital form thereby to digitize the voltages, said digital signal producing means comprising means for also selecting the digitized voltage across the at least one unpowered winding stage when digital signal patterns are produced in sequence and changing the logic levels of the additional pair of digital signals as soon as at least one predetermined logic level of the selected digitized voltage has occurred.

87. The control system as set forth in claim 83 further comprising means coupled to the winding stages for converting the voltages across the winding stages to digital form thereby to digitize the voltages, said control signal producing means further comprising means for also sensing the digitized voltages while the winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals beginning with a pattern of the control signals determined form the sensed digitized voltages.

88. A control system for an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with the stationary assembly in selective magnetic coupling relation with the winding stages, and means for commutating the winding stages by selectively supplying power thereto in response to a pattern of control signals leaving at least one of the winding stages unpowered at any one time while the other winding stages are powered, the control system comprising:
means coupled to the winding stages for simultaneously converting the voltages across the winding stages to digital form thereby to digitize the voltages;
means responsive to successive patterns of digital signals for generating successive patterns of the control signals for the commutating means; and means for producing successive patterns of the digital signals in a first preselected sequence, producing a different pattern of the digital signals for causing the commutating means to remove power from all of the winding stages, sensing the digitized voltages while the power is so removed, and producing successive patterns of the digital signals in a second preselected sequence to rotate the rotatable means in the reverse direction after a predetermined time period has elapsed subsequent to the last occurrence of a predetermined logic level in any of the digitized voltages.

89. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
means coupled to said winding stages for simultaneously converting voltages across said winding stages to digital form thereby to digitize the voltages;
means for producing successive patterns of digital signals in at least one preselected sequence, for selecting the digitized voltage across said at least one unpowered winding stage depending on the digital signal pattern produced, and for producing a following pattern in sequence after at least one predetermined logic level of the selected digitized voltage has occurred; and means responsive to the successive patterns of the digital signals for generating the successive patterns of the control signals for said commutating means.

90. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages and producing a current in said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
means for producing successive patterns of digital signals in at least one preselected sequence;
means for generating patterns of the control signals for said commutating means in response to the successive patterns of the digital signals; and means for comparing the current in said winding stages of said electronically commutated motor with an electrical level representative of a predetermined current, said pattern producing means including means for also producing a preestablished pattern of the digital signals for a predetermined period of time to reduce the current in said winding stages whenever the predetermined level is exceeded, and periodically producing the current reducing pattern of the digital signals at an adjustable rate when the predetermined level is not exceeded.

91. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages and producing a current in said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
means for generating patterns of the control signals for said commutation means in response to successive patterns of digital signals;
means for comparing the current in said winding stages of said electronically commutated motor with a predetermined level; and means for producing the successive patterns of digital signals in at least one preselected sequence for said generating means, for producing in response to said comparing means a preestablished pattern of the digital signals to reduce the current in said winding stages upon the predetermined level being exceeded, for monitoring voltages across said winding stages to monitor the position of said rotatable means when the current is being reduced, and for resuming producing the successive patterns of digital signals in sequence after a predetermined time interval.

92. Laundry apparatus comprising:
agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages; and means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, for subsequently producing a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered, for sensing the digitized voltages while said winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.

93. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means; and means for producing the successive patterns of the digital signals in at least one preselected sequence, and for subsequently producing a different pattern of the digital signals which causes said commutating means to connect all of said winding stages together, thereby braking said motor.

94. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics:
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to successive patterns of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered, said commutating means including sets of electronic devices connected across said supply conductors, each set having a junction point connected to a respective one of said winding stages, each of said electronic devices respectively being able to be switched by a corresponding one of the control signals in each pattern of control signals; and means for producing the successive patterns of the control signals in at least one preselected sequence to switch on only one electronic device in each of at least two of said sets of said electronic devices at once and cause a current to flow in said winding stages to rotate said rotatable means, and for subsequently producing a pattern of the control signals to switch off one of said electronic switching devices which was previously switched on so that said commutating means leaves all of said winding stages temporarily unpowered and also provides a current path for the previously-powered winding stages.

95. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
means coupled to said winding stages for simultaneously converting voltages across said winding stages to digital form thereby to digitize the voltages;
means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means; and means for producing successive patterns of the digital signals in a first preselected sequence, producing a different pattern of the digital signals for causing said commutating means to remove power from all of said winding stages, sensing the digitized voltages while the power is so removed, and producing successive patterns of the digital signals in a second preselected sequence to rotate said rotatable means in the reverse direction after a predetermined time period has elapsed subsequent to the last occurrence of a predetermined logic level in any of the digitized voltages.

96. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
means coupled to said winding stages for digitizing the voltages across said winding stages;
means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means; and a digital computer operating under stored program control, said computer having inputs for the digitized voltages, said computer having memory elements for storing data representing at least one preselected sequence of the patterns of the digital signals and for storing data, corresponding to each pattern of the digital signals, identifying the respective input for the digitized voltage for said at least one unpowered winding stage, said computer successively producing one of the patterns of the digital signals, sensing only the digitized voltage at the identified input corresponding to the one pattern and producing the following pattern in sequence as soon as complementary logic levels of the digitized voltage at the identified input have occurred in a predetermined order if they so occur within a predetermined time period and otherwise producing the following pattern in sequence after the predetermined time period.
97. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means

Claim 97 continued:
associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered, said commutating means including sets of electronic devices connected across said supply conductors, each set having a junction point connected to a respective one of said winding stages, each of said electronic devices respectively being able to be switched by a corresponding one of the control signals in each pattern of control signals;
means coupled to said winding stages for digitizing voltages across said winding stages;
means responsive to successive patterns of digital signals for generating successive patterns of the control signals for said commutating means, including first and second logic gate means feeding said commutating means and having inputs driven by respective pairs of digital signals in the digital signal patterns, means for disabling said first and second logic gate means when any of the pairs of digital signals has identical logic levels in the pair, and means for disabling one of said first and second logic gate means in response to a signal to cause the current in said other powered winding stages to be reduced;
a digital computer operating under stored program control, said computer having inputs for the digitized voltages, said computer having memory elements for storing data representing at least one preselected sequence of the patterns of the digital signals and for storing data, corresponding to each pattern of the digital signals, identifying the respective input for the digitized voltage for said at least one unpowered winding stage, said computer successively producing one of the patterns of the digital signals, sensing only the digitized voltage at the identified input corresponding to the one pattern and producing the following pattern in sequence after at least one predetermined logic level of the digitized voltage at the identified input has occurred; and means for comparing currents flowing in said winding stages of said electronically commutated motor with an electrical level representative of a predetermined current, and upon the level being exceeded, interrupting said digital computer and supplying the signal to said disabling means, said digital computer also having memory locations for storing data identifying one of said first and second conductors corresponding to each pattern of the digital signals, said digital computer including means for causing said disabling means to disable switching by said electronic devices to said one identified conductor corresponding to the pattern of the digital signals which is being produced when the interrupting occurs.
98. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means

Claim 98 continued:
associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages;
means for selecting the laundering mode and the spin mode;
means operable generally for switching said winding stages from a first connection arrangement to a second connection arrangement, wherein one of the first and second connection arrangements is a low speed connection arrangement and the other of the first and second connection arrangements is a higher speed connection arrangement; and means coupled to said selecting means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, for also counting revolutions of said rotatable means in the laundering mode by counting the successive patterns of control signals produced and, when the counting reaches a predetermined value, causing said rotatable means to reverse by also producing a pattern of the control signals which causes said commutating means to switch all of said winding stages to one of said supply conductors and then producing the patterns of control signals in a second preselected sequence, and for subsequently producing in the spin mode a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered during switching of said winding stages from the first connection arrangement to the second connection arrangement, for sensing the digitized voltages while said winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the second digitized voltages.
99. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages;
means for selecting the laundering mode and the spin mode;
means operable generally for switching said

Claim 99 continued:
winding stages from a first connection arrangement to a second connection arrangement, wherein one of the first and second connection arrangements is a low speed connection arrangement and the other of the first and second connection arrangements is a higher speed connection arrangement; and means coupled to said selecting means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, for also counting revolutions of said rotatable means in the laundering mode by counting the successive patterns of control signals produced and, when the counting reaches a predetermined value, producing a pattern of the control signals for causing said commutating means to remove power from all of said winding stages, sensing the digitized voltages while the power is so removed, and producing successive patterns of the control signals in a second preselected sequence to rotate said rotatable means in the reverse direction only after a predetermined time period has elapsed subsequent to the last occurrence of a predetermined logic level in any of the digitized voltages, and for subsequently producing in the spin mode a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered during switching of said winding stages from the first connection arrangement to the second connection arrangement, for sensing the digitized voltages while said winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.
100. Laundry apparatus comprising:
means operable generally in a laundering mode for

Claim 100 continued:
agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals;
means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages;
means operable generally for switching said winding stages from a first connection arrangement to a second connection arrangement; and means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, the successive patterns of the control signals being identified by values of an index, for subsequently producing a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered during switching of said winding stages from the first connection arrangement to the second connection arrangement, for repetitively sensing the digitized voltages while said winding stages are temporarily unpowered, determining a value of the index as a function of the difference of first and second numbers represented by different instances of the sensed digitized voltages as soon as a change occurs in any one of the sensed digitized voltages, and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals identified by the value of the index so determined.
101. Laundry apparatus comprising:
means operable generally in a laundering mode for agitating fluid and fabrics to be laundered therein and operable generally in a spin mode for thereafter spinning the fabrics to effect centrifugal displacement of fluid from the fabrics;
an electronically commutated motor including a stationary assembly having a plurality of winding stages adapted to be selectively commutated, and rotatable means associated with said stationary assembly in selective magnetic coupling relation with said winding stages for driving said agitating and spinning means in the laundering mode operation and in the spin mode operation thereof upon the commutation of said winding stages;
first and second conductors for supplying power;
means for commutating said winding stages by selectively switching said winding stages to said supply conductors in response to a pattern of control signals, leaving at least one of said winding stages unpowered at any one time while the other said winding stages are powered;
means coupled to said winding stages for converting voltages across said winding stages to digital form thereby to digitize the voltages, said converting means including means for generating a first logic level when the voltage across a respective winding stage exceeds a predetermined value and a second logic level when the

Claim 101 continued:
voltage across it falls below the predetermined value, the digital form of the voltage across each winding stage comprising the logic levels so generated;
means operable generally for switching said winding stages from a first connection arrangement to a second connection arrangement; and means for producing successive patterns of the control signals in at least one preselected sequence to rotate said rotatable means, selecting the digitized voltage across the at least one unpowered winding stage depending on each of the successive patterns produced, producing a following pattern in sequence after complementary logic levels of the selected digitized voltage have occurred in a predetermined order if they so occur within a predetermined time period and otherwise producing the following pattern in sequence after the predetermined time period, and subsequently producing a pattern of the control signals which causes said commutating means to leave all of said winding stages temporarily unpowered during switching of said winding stages from the first connection arrangement to the second connection arrangement, sensing the digitized voltages while said winding stages are temporarily unpowered and then resuming producing the successive patterns of the control signals in sequence beginning with a pattern of the control signals determined from the sensed digitized voltages.