USRE23314E - Genekatoe-motor driving- system - Google Patents

Description

Dec. 26, 1950 P. "r. NIMS Re. 23,314

GENERATOR MOTOR DRIVING SYSTEM Original Filed Aug. 12, 1947 3 sheets sheet 1 Dec. 26, 1950 P. T. NIMS GENERATOR mo'roa DRIVING s sm 3 Sheets-Sheet 2 Original Filed Aug. 12, 1947 array/1153's Dec. 26, 1950 P. T. NlMs R 23,314

v GENERATOR MOTOR DRIVING SYSTEM origina l Filed Aug. 12, 1947 I5 Sheets-Sheet 3 INVENTOR. Fax/ 2' 7/1 1777:

wiiwm 2W FTTOF/VIKS' Reissueci Dec. 26, 1950 Paul T. Nims, Detroit, Mich, assignor to'Ghrysler Gorperation, Highland Park, Mich, acor-poration of Delaware (IriginaiNOL 2,506309; dated May 9; 1950,- Serial No. 7635118; August 12, 1947.

A plication. for.

reissue; June 9 1950;; Serial N 167 ,1 68

18 Claims.

Matterenclosed inheavy brackets [I Iappears in the original patent but forms no partof this reissue specification; matter printed in italics indicates the? additions made by reissue This invention relates to electrical controlling systems and more particularly to a system for driving; a motor'vehicle which is an improvement. on the system shown in my co-pen'ding application Serial No. 681,630; filed July- 6; 1.946, for Electric Drive.

The principal objects ofthe present invention are to provide a system of the aforesaid type which: is. simple in arrangement, requiring; a: minimum? number of structure elements; is relatively light in weight,.andis reliable and efilcient' inoperation; to. provide: a motor vehicle driving" system which is operable: to provide: rapid ac-' celeration from a. condition of rest of. the. vehicle; to provide-such a-system" in which: the:size. and weight ofv the electrical elements are a minimum; to-providev such a systemin which: the most efficient use of the. electrical equipment is maintained at all conditions of operation; to provide such a system in which an. alter-- nator driven by thesource. of prime power com prises a plurality of windings which may beconnected inparallelrelationship for. high current low voltage starting. of the vehicle and" of: series. operation at high voltage low current higher speed: operation of the: vehicle; to pro-' vide such' asystem: in which alternating; electrical power is rectified,. by means. of mechanically operated switches, to direct-cin'rent power for operation of the driving motors; to provide. a controlling. system for providing. a wave shape of: the alternating voltage and: current whereby a sufiicient time interval may be provided for actuation of the switches at substantially: zero current. flow therethrough; to provide such a controlling system which will automatically control in accordance with the power bein trans:- ferred. through the rectifying switches.-

With the above as well as other more de-- tailed objects in View which. appear in the following description and ini the appended claims,- preferred but illustrative: embodiments of the; invention? are shown in the: accompanying drawings' throughout the several views of which. corresponding reference characters are used. to: designate corresponding partsandin which:

Figure 1'. is a diagrammatic view: of avehicle chassis embodying the invention;

Fig. 2 is a schematic diagram of thegelectris cal controlling circuit for the drive. shown in. Fig. 1;

Fig. 3 is a schematic diagram showing a modified form of electrical circuit utilizing. mechanisally-actuated switches for rectifying: the alter:- nating power;

Fig. 4 is a schematic view of the wave shape: of the current flow through the mechanicallyactuated switches'showing the substantially zero current port-ion during. the period inwhich. the switches" are actuated; and

Fig. 5 is a schematic. view showing a further modified form; of electrical circuit utilizing mechanically-actuated rectifying switches.

Referring; to the drawings, the numeral I designates generally a motor vehicle chassis-'- having. the: usual internal combustion engine 2 connected for driving the rear. wheels 4 of the vehicles The engine 2: has an output shaft 6 driving a double planetary-type gear train generally; designated: 8- which drives the: propeller shaft H3.- connected. with the" rear wheels 4 through adifierential mechanism M. An input sun gear L5: is driven by shaft 6 which drives planet gear I6 of the planetary gear train- 8 which: mesh with thesun gear [5 and antoutput sungear I1 secured to the shaft It: and. or lesser diameter than. the sun gear 15.. The planet gears l6 are journaled in a rotatable spider i=8" which has a shaft portion t9 extending; concen t-rically' with the propeller: shaft illfor driving; the rotors. 2%}. and 2| of an: alternator 22 and an exciter 23 respectively having? stators Z4 and- 25 suitably held against rotation by any desired:

means (not shown). The electricalv output of the: alternator 22' is controlled by the exciter 23 and is transmitted by a: control circuit such as is showninFigs. 2, 3. or 5 for driving aneleetric motor 25 having an output pinion 28 meshing; with agear 3.9 suitably connected to the pro:

peller shaft I!) by means to: be later described. If desired, a pair of motors 26 maybe utilized:

instead of the single motor 2-5= as shown in" thisv case,,.- which pair. ofv motors may be arranged to. operatein series and parallel relationship such as is shown in the said application Serial No. 681,630.

An electrically-operated clutching: mechanism- 3'2 selectively couples the spider ls directly to the output shaft ftheengine' 2 toprovide' a direct.

drive from the engine 2' to the propeller shaft 3 section lDb from section lfla and to couple the shaft section We to a concentrically extending portion 3'! held against rotation for locking the shaft section [a against rotation. The gear 30 is preferably coupled to the propeller shaft section [0b by means of an overrunning clutch 38 which operates in the usual overrunning mannor for forward direction of the motor vehicle [except when dynamic braking, later to be noted in detail, is applied] but which, when the motor vehicle is to be operated in a backward or reverse direction, is locked securely to shaft section b by operation of the lever 39 whereby reverse rotation of the gear by the pinion 28 will cause the shaft section lllb to rotate in a reverse direction,

The exciter 23 has a usual rotor 2| and a pair of field windings iii and 42. The winding 40 cooperates with the exciter 23 in the usual manner of a self-excited direct-current generator in which the excitation of the winding 40 is controlled by means of a variable resistor 43. The winding 42 is arranged to oppose the excitation provided by the field winding 40 so that when high current is being generated by the alternator 22, the excitation thereof, as controlled by its field winding 44, is reduced in a manner to be more specifically set forth hereinafter. One terminal '46 of the exciter 23 is directly connected to one terminal of the field winding 44 of the alternator 22, while the other terminal 48 of the exciter 23 is connected through contacts a of relay SWI to the opposite terminal of the field winding 44.

The alternator 22 comprises in essence two three-phase windings having the phases A, B, and C and A, B and C, respectively, having their phase relationship such as are diagrammatically shown in Fig. 2. This relationship of alternator may be provided by winding a sixphase alternator and interconnecting the alternate phases in Y connection whereby two sets of three-phase windings arranged with corresponding phases spaced 180 apart may be provided. In some instances, it maybe desirable to wind the alternator 22 with the corresponding phases AA', B-B', and CC in the same sets of slots and arranged whereby they may be connected in parallel or in series relationship.

Each of the individual terminals of the phases A, B, and C are connected by means of conductors to the anodes of discontinuous-type control valves VI, V2, and V3 respectively. The common junction of the phases A, B, and C are connected by means of a conductor 50 to one of the sets of contacts b and c of the relay switch SW2. The other of the set of contacts b is connected by a conductor 52 to the common terminal of the phases A, B, and C. The other of the set of contacts 0 is connected to the anodes of the valves V4, V5, and V6 respectively, the valves V4, V5, and V3 being of the same general type as the valves VI, V2, and V3. Each of the cathodes of the valves Vi, V2, and V3 is connected together to a conductor 54 and through the contacts a of the switch SW2 to the conductor 52 connected to the common terminal of the phases A, B, and C. A, B, and C are each connected by individual conductors to the cathodes of the valves V4, V5, and V?) respectively One terminal of the energizing winding of the switch SW2 is connected to the con-ductor 54 and its other terminal is connected by means of a conductor 53 to one terminal of th opposing energizing winding 42 of The individual end terminals of the phasesof the contacts 0 of the switch SW I.

the exciter 23. The other terminal of this winding 42 is connected by means of a conductor 58 to the common conductor which connects to the anodes of the valves V4, V5, and V6. A variable current-controlling resistor GE is arranged in shunt circuit with the coil 42 between the conductors 56 and 58 whereby the relative amounts of current flowing through the variable resistor 60 and through coil 42 may be controlled.

The motor 25 which is of the series-wound direct-current type has one terminal 6| thereof directly connected to the conductor 55 and its other terminal 63 directly connected to the conductor 54 whereby it is arranged in parallel circuit with the energizing winding of the relay switch SW2. A usual reversing switch RS is provided for the motor 26 whereby the polarity of the field may be selectively controlled relative to the armature whereby the direct current motor 26 may be made to run in either direction. Preferably the lever '39 is mechanically coupled to the switch RS for concurrent operation therewith. [Also connected across the terminals of the motor 26 are two series-connected dynamic braking resistors 62 and 64, the circuit through which is controlled by the contacts a of the switch SW3 operated by the engine throttle 66 and the switch SW4. The switch SW3 is arranged so that the contacts a thereof are closed when the engine 2 is in idle operation. The resistor 62 is selectively shunted by the switch SW4 operated by a suitable pressure element .68 in connection with the usual hydraulic brake system 10 of the motor vehicle. When a predetermined pressure has been reached within the hydraulic brake system 10, the switch SW4 will be closed, shunting out the resistor 82 for dynamic braking of the motor 26.]

A governor generally indicated 12 is driven in accordance with the speed of the motor 26 and/or the vehicle I andoperates, at a predetermined vehicle speed, through a lever system generally designated 74 to close the contacts a and b of a switch SW5 for a purpose to be described in detail hereinafter. The reversing switch RS is coupled as diagrammatically shown .by the dotted line '16 to lock the lever system 14 when the reversing switch is in a position to cause reverse rotation of the motor 26 whereby the governor 12 is rendered ineffective to actuate the lever system 74 for closing the contact a and b of the switch SW5, the purpose for all of which will be described in detail hereinafter.

One terminal [9 of a battery 18 is directly connected to one terminal of the energizing winding of the switch SWI and also to ground as indicated at 80. The other terminal 820i the battery 18 is connected-through a switch SW6 which is preferably actuated in accordance with the ignition switch for the engine 2,

through the contacts a of an accelerator-actuated switch SW1 directly to the other terminal of the energizing winding for the switch SWI. The terminal 82 of the battery 78 i also connected through a conductor 84 and through normally closed contacts b of the switch SW7 to one each of the contacts a and b of the switch SW5. The other contact a of the switch SW5 is connected by means of a conductor 85 to one The other one of the contacts c of the switch SWI is connected to one terminal of the clutch-actuating coil 88, the other terminal of which is connected to ground as at 90. The other contact b of the switch SW5 is connected by means of a conducthe energizing winding for the switch SWI as isthe switch SW6.

It is believed that the remaining details of'the'" system as shown in Figs. 1 and 2 may be best described by a description of operation thereof, which is as follows:

Very briefly stated, the engine 2 is started inan well-known manner and drives the sun gear 85 through its outputsha-ft 6. Rotation of this gear I5 will rotate the planet gears l6 either" bodily or about-their own axes as will presently be described. The switch SW5 is interconnected for operation simultaneously with o prior to the starting of the engine 2 and acts to energize the relay switch SWI whereby the contacts a thereof are opened to maintain the inding tie-energized and substantially eliminate any torque on the spider l8. Upon opening of the throttle 6%, the contacts a of the switch SW1 will open and de-energize the relay'switch SWI, thereby closing its contacts a and energizing the a;ternator field 44. Energization of the field 44 introduces torque reaction to the spider it which controls the torque applied to the shaft l0. Since the shaft It is connected to the wheels 4, and assuming that the vehicle is parked, the torque required to rotate the. shaft I13 will be high made substantial torque v reaction must be applied by the alternator 22 before any rotation of' the shaft It will occur. The output of the alternator 22' is fed, as will be escribed in greaterdetail' below, to the motor 25; and since motor 26 is geared to the shaft section Illa, will be applied to aid in rotation of shaft it and the rear wheels 4. After the Vehicle has attained a predetermined speed, the governor l2 wiil close the contacts a and'b of the switch SW so that when the operator releases the throttle 38 of the clutch whereby the spider it is locked for unison rotation with the shafts 6 and [0.

More specifically, the system is placed in idling condition by starting the engine 2 in a manner usual for the type of engine used and such start ing will be accompanied by the closure of the usual starting switches, not shown. Switch SW6 is arranged as by a mechanical interlock, not shown, to be closed by such starting operation. Closure of the switch SW5 completes a, circuit from the terminal 82 of the battery 18 through the contacts a, of the switch SW! and through the energizing winding of the switch SW1 back to the battery terminal F9, whereby the switch SWI is energized, opening the contacts a thereof and closing the contactsb and 0 thereof. Closure oi the contacts b and 0 thereof is without immediate effect, since the contacts a and b of the switch SW5 are held in open-circuit position by the governor 12. Opening of the contacts a of the switch SWI deenergizes the exciting winding 44 of the alternator 22 so that subsequent rotation of the alternator 22 will not cause a voltage to be generated thereby. Operation of the engine 2 will rotate its shaft 6 which acts through the gear train 8 to rotate the shaft IQ of the alternator 22 a generate an output voltage.

6 and the excite 23. Since the contacts a of the: switch SWI are now open due to closed condition of the contacts a of the switch SW1, the alternator 22 will have nosignificant' output voltage and motor 26 will not rotate.

To initiate movement of the vehicle from itsparked condition and from the just-described idling condition of the system, the accelerator or throttle E6 is moved toward open position. This will increase the energy output of the engine 2" [and open the contacts a of the switch SW3 to disconnect the dynamic braking system] and open the contacts a of the switch SW1. Opening ofthe' latter contacts ole-energizes the switch SWI causing the contacts a thereof to close and the con tacts b and c thereof to open. Closure of these contacts a connects the output voltage of' theexciter' 23' to the exciting winding 44 of the alternator whereby the alternator will be caused to Openin of" these contacts b and c is without effect, since the contacts a and b of the switch SW5 are in open-circuit position. As the speed of the engine 2 is increased by the accelerator 66, the speed of rotation of the shaft it will increase, thereby increasing the output of the alternator 22. Since initially the shaft it isstationary, due to the parked condition of the vehicle I and the high torque required for rotation thereof and initial movement of the Vehicle, the engine 2 will rotate the shaft IS and the shaft I ll initially will absorb the reaction torque without rotation. As the torque transmitted to the shaft 10 increases above that required to rotate the same, the shafts I0 and I9- will rotate in accordance with the torque required for their respective rotation, and the relative speeds thereof consequently will be variable.

The output voltage of the alternator 22 is fed to the valves VI through V6 inclusive. Since this voltage is initially relatively small, insufii'cient current will flow through the energizing winding of the switch SW2 to actuate the same, the contacts a and c thereof 'will remain in closed-circuit condition, and the contacts b thereof willremain open. Through an easily traced circuit itwill be obvious that with the contacts a and c' of the switch SW2 closed, the phases A, B and C and phases A", B and C of the alternator 22 will be respectively in parallel-circuit condition. This arrangement provides high current at low Voltage for the motor 26 which at this time is just beginning to rotate and consequently will have a very low back E. M. F. Since the output current of the alternator 22 flows through the auxiliary or bucking winding 42 of the exciter 23, initially the high current will maintain a lowoutput voltage of the alternator 22 so that the current output thereof is kept within safe limits and the power output thereof is kept within the rated power outputof the engine 2. Preferably, the current voltage output relationship of the alternator is controlled so that the product of the two-is substantially constant and equal to the rating of the engine 2 at the speed at which it happens to be running. As the speed of rotation of the motor 26 increases, the back E. M. F. will increase and at some given desired value of the back E. M. P, will be sufficient to cause actuation of the switch SW2 and open the contacts a and 0 thereof and close the contact b thereof, whereby the phases A, B and C and A313 and C are changed from their present parallel connec-- tion to a Series, connection. By such an arrangement, the alternator 22 will at no time require more power than the engine 2 will produce and the maximum current output may be obtained with minimum size of alternator.

In parallel operation, curent from the phase A flOWs outwardly through the free terminal thereof, through the valve VI, through the conductor 54, through the motor 28, through conductor 5t, through the winding 42, and through conductor 58 back through the now-closed contact of the switch SW2 to the other terminal of the phase A. Current will also fiOW from the common terminal of phase A which, it will be noted, is displaced electrically 180 from phase A, through the conductor 52, through the now-closed contacts a of the switch SW2 to the conductor 54 where it will follow the same path through the motor 26 and the energizing winding c2 of the cxciter the valve VI to the conductor 54 whence it flowsthrough the motor 2a, through conductor 58, through the winding 42 and conductor 53, and through the valve V4, through the phase A, it

being remembered that phase A is located electrically 186 out of relationship with the phase A, and through conductor 52 and now-closed contacts b of the switch SW2 back to the other common terminal of the phase A. The circuits for the phases B and C and B and C, when their voltage relationships are suitable, are substantially the same as that described for phases A g and A.

As the speed of the motor 25 and consecguently of the vehicle I increases, the governor 72 will actuate its lever linkage It to close the contacts a and b of the switch SW5. Subsequent temporary closure of the throttle it closes the con tacts a of the switch SW'E whereby the relay switch SW I is energized through the closed switch SW5 whereby the contacts b and c of the switch SW I are closed. and its contacts a opened. Closure of the contacts is of the switch SW 1 establishes a circuit from the battery terminal 82,

through the switch SW5, through the closed con- .1

tacts b of the switch SW7, through the contacts b of the switch SW5 and the closed contacts b of the switch SWI, whereby the energizing winding of the switch SWI is energized through the holding circuit just described, so that subsequent opening of the contacts a of switch SW1 is without effect. Ciosure of the contacts 0 of the switch SW1 establishes a circuit, as above described, from termnal 82 to the, contacts b of switch SW! and therefrom through the closed contacts b of the switch SW5 and contacts 0 of the switch SW! for energizing the clutch coil 88 which locks the spider i8 for synchronous rotation with the engine output shaft 6. Continued operation of the vehicle under control of the accelerator 56 will be accomplished throu h a direct mechanical drive transmitted to the shaft portion Ifia by the planet gears I5 which are bodily rotated and held against rotation about their own axis by the spider I8 held by the clutch 32 to the shaft 5.

If now it is desired to place the motor vehicle I again in electric drive, the accelerator 65 is opened wide whereby a pin I 09 carried by the actuating rod of the switch SW7 engages the closing member for the contacts b whereby the same are opened and the holding circuit through the energizing winding of the relay SWI is deenergized as well as the clutch coil 88. The deenergization of the switch SWI closes the contacts a thereof and opens the contacts 10 and 0 thereof. Closure of the contacts a of the switch SWI connects the exoiter 23 to the exciting winding 44 0f the alternator 22 whereby it is again in a condition to generate electrical energy, and the vehicle will be driven as before described. As long as the speed'of the vehicle is above the speed of which the governor I2 closes the contacts a and b of the switch SW5, movement of theaccelerator 66 to idle position again will place the vehicle in direct mechanical drive as before described.

When the speed of the vehicle, during its normal operation, decreases so that the governor I2 acts to open the contacts a and b of the switch SW5 so that, irrespective of the condition of contacts b or the switch SW1, the holding circuit for the switch SWI will be opened to ale-energize the switch SW I for closing its contacts a and opening its contacts b and 0. Opening of these switches acts to de-energize the clutch coil 88. Closure of the contacts a of the switch SWI causes the exciter 23 to energize the exciting winding 44 and the alternator 22 to operate as above described under control of the back E. M. F. of the motor 25 for determining the parallel and series relationship of the phases A, B, C and A, B, C respectively.

When it is desired to drive the vehicle rearwardiy, the reversing switch RS is thrown to reversed position. A lever 92 will be actuated to actuate the clutch 35 to lock the shaft section IIia against rotation. Lever 39 will also be ac-' "I6, a holding connection for the lever system I4 is provided whereby the switch SW5 will be maintained open irrespective of the operation of the governor I2. Because the shaft section Ifla is now locked against rotation, rotation of the output shaft 6 of the engine 2 will rotate the sun gear I 5, causing axial rotation of the planet gears I6 which rotate about the stat'onary sun gear ll whereby the spider I8 will drive the rotors of the alternator 22 and exciter 23. The alternator 22 acts to generate an output vo.tage which is applied to the motor 2% as above set forth, except that because of the new poiarities of the field and rotor of the motor 26 it will be rotating in the opposite direction. Since the lever 39 has locked the overrunning clutch 38 so that the gear as is efiectively locked to the shaft section IOb, reverse rotation of the motor 26 will operate the vehicle I in a reverse direction. Such reverse drive is purely electrical under control of the alternator 22. The interlock I5 between the reversing switch RS and the switch SW5, whereby the contacts a and b thereof are maintained open, prevents any operation of the governor I2 or of the accelerator 66 from energizing the clutch coil 88 whereby the spider I 8 might be locked for unitary rotation with the output shaft 6 of the motor 2.

When it is desired to stop the vehicle, lever 39 is moved to lock up overrunning clutch 38 such that gear 39 is effectively locked to the shaft sea section Hlb similarly as noted above 'for reverse drive or back-up of the vehicle and the throttle 66 is closed, closing the contacts a of the switch SW1, thereby energizing 'the switch SW1 .whereby the contacts a thereof will open and deenergize the alternator 22. {Such movement of the throttle 56 will also close the contacts a of the switch SW3, thereby connecting the resistors 52 and '64 across the output of the motor 26 to provide a load, for the motor 25 will now regenerate and dynamically brake the vehicle 1. If it is desired to slow down still further, the foot brake EB is pushed further, causing the pressure in the actuator 58 to close the contacts of the switch SW4 to thereby short out the resistor 64 and increase the dynamic braking eiiect of the motor 26. Further inward movement of! Inward movement of the foot brake [PB] will apply the usual mechanical friction brakes.

The system shown in Fig. 3 is quite similar to that shown in Fig. 2, except that switches are used to rectify the current, and the series-parallel connections for the phase windings A, B and .C and A, B and -C are made on the alternating :current side of the electrical circuit. In this form, the common terminal of the phases A, B and C are connected by means of a conductor Hill to one each .of the contacts e, f, and g of the switch SW2. The opposite end of each of the phase windings A, B and C are respectively connected through saturablereactors SR, the phase A being connected to one each of the contacts c and d of the switch SW2, the phase B being connected to one each :of the contacts a and b of the switch SW2, and'the-phase C being connected to one each-of the contacts h and i of the switch SW2. The outward end :of the corresponding phase windings A, B and C are respectively connected through saturable reactors SR to the other of .each of the contacts 0, a and h respectively. The inner ends of the phase windinrs A, B and C are respectivey connected to the switch SW2, the phase A being connected to the other of each of the contacts 01 and e, the phase B being connected to the other of each of the contacts b and f, and the phase C being connected to the other of each of the contacts .g and i. With the switch SW2 in itsde-energized position as shown, the contacts a, c, e, f, g, and h will be closed and the contacts b, d, and i will be open, whereby the phases A, 'B and C will be respectively parallel with the phases A, B and C'.. With the switch SW2 in its energized position, the contacts a, c, e, f, g, and h are .open and the contacts b, d, and i are closed, and the phases A, B and C will be respectively in series with the phases A, B and C.

The center terminals of the phases A, B and C are connected together by c osure of the switch contacts e, f, and gof the switch 'SW 2,and closure of its contacts c, a, and h connects the outer ends of the phases A, B and C to the outer ends of the phases A, B and C respectively. Referring specifically to the phases A and A with the switch SW2 in its energized position, the circuit may be traced from the common terminal of the phase A through the phase A and outwardly through the saturabjle reactor SR associated therewith to one of the contacts d of the switch SW2, from .theother of the closed contacts .d of

the switch SW2, through a conductor to the inner end of the phase A andoutwardlyitherethrough, through the saturable reactor SR, to the contacts e of arectifying switch .156 mechanically coupled .for drive by the alternator When this switch is in the proper position, the circuit will continue on across through these closed contacts e, through the motor 26, and through the winding '42 to the inner or common terminal of the phaseA. A similar series circuit isprovided for the phases 3 and B and C and C respectively through the switches SW2 and I59. The switch l5il .is of rotary-actuated type comprising cams a, b, and c for closing the contacts d, e, and 1" respectively and is so arranged thatat least one of the sets of contacts d, e or f is closed at all times. Thecams b and c of the switch 45%.! are directly and mechanically driven in accordance with the rotation of the alternator 22 and arearranged so that they will close the circuit therethrough in a predetermined timed relationship with respect to the voltage wave of the various phases of the alternator 22 as is diagrammatically shown in Fig. 4.

Referring to Fig. 4, the reference character Va indicates the voltage wave produced by the phases A and A, while the reference characters Vband Vc indicate respectively the voltage waves of the BB and C-C phases of the alternator and their respective phase relationship. It will be noted that only the positive half cycles of the voltage waves are made use of and therefore in effect the system operates as a half-wave rectifier. As the magnitude of the voltage wave Va passes its crest, it will then diminish; and at a point just before it crosses the rising voltage wave Vb, the line current flowing to the motor as represented by the reference character Io will become zero and remain zero until the wave Va crosses the increasing voltage wave Vb. It is during this zero value of current that the switch contacts e of the switch use are o ened. Prefdecreasing voltage wave Va crosses the increasing voltage wave Vb,,since due to the effect of the reactors, to .be more fully described below, the

current Io iszero for a substantial time before and after the interval that the voltage waves Va and Vb cross. Itiis .a desiderative but not an essential that the contacts e and f of the switch lfili are actuated at this exact instant. However, by designing these contacts to open and close respectively at this instant any slight variation in timing of the voltage wave with respect to the operation .of the switches or tolerance in the manufacture of various switches which may render their. operation slightly variable will not 'place their operation outside the flat portion of the current wave 10. l

. Subsequently, the contacts f of the switch L555 will remain closed throughout the increasing va ue of the volta e wave Vb and along its decreasing value until substantially the time that the decreasing voltage wave Vb .crosses the increasing voltage wave Vc. As occurred upon the decreasing voltage wave Va, the current '10 will fall to zero value slightly ahead of the intersection of the two voltage waves Vb and Vc and will remain zero until a time which is slightly after the voltage wave Vc has increased above the value of the voltage wave Vb. The contacts i will open and the contacts :d of the switch 150 will close during this zero value of the current 10 and preferably are designed to :open .and close 11 respectively at the instant the voltage Vb is equal to the voltage Vc. Subsequently, the voltage Vc will pass through its crest and again decrease while the voltage Va will again rise so that the current Io will again fall to zero. The contacts d and the contacts e of the switch I55 will open and close respectively during this zero value of the current I0, and the phases A and A will again be connectedto supply current to the condenser-motor load circuit.

The cams a, b and c of the switch I50 are arranged substantially 120 apart, whereby the contacts d, e, and f associated therewith will be closed and opened in the manner before described to connect the various phases of the alternator 22 in sequence to the load circuit and connected at such time that the current output of the alternator 22 to the load circuit is of zero value so that there will be no arcing at the switch I50. Such arcing would, of course, have a deleterious effect upon the contacts and would quickly render the switch I50 inoperative.

Saturable reactors SR associated with each of the phases A, B and C and A, B and C are provided so that upon initial current-flow in any direction through the various phases, the reactors will absorb the entire phase output voltage. At greater current flows, the reactor will become saturated so that its effect on current flow therethro-ugh will be substantially that of pure resistance equal in magnitude to the resistance of the reactor. This resistance is purposely maintained very low to increase the output cfiiciency of the electrical system.

The voltage of the output circuit as measured across the terminals of the motor 26 will be determined primarily by the speed of the motor, whose back E. M. F. is determined primarily by its speed of rotation. Because of this, the decreasing value of the voltage wave Va will approach the back E. M. F. of the motor 25, and as it soapproaches this back E. M. F. which is maintained across the motor 26 and the terminals of the condenser I52, the current output of the phase producing the voltage wave Va will decrease, and if the contacts of the switch I50 connecting the phases A and A were not opened the current would reverse in its flow direction. At the instant of attempted reversal, the reactors SR associated with these phases will be completely void of flux and as these reactors again tend to become saturated in the reverse direction the current flow thercthrough will be substan tially zero, it being remembered that the magnetizing current of the reactors is a very small portion of the load current. The current flow through the contacts e of the switch I 50 as represented by the line Io will fall to substantially zero and will be held at this value for an appreciable time interval. Likewise, when the contacts f of the switch I50 are closed to connect the voltage wave Vb to the motor-condenser cirsubstantial current flow across the contacts 1 of I the switch I50 for a predetermined time interval until the current value has saturated the reactor SR, thereby permitting the current Io to flow.

Since the back E. M. F. of the motor Will remain substantially constant and in general roportion to the speed of its rotation, the condenser I52 tends to be charged by the flow of current I0 and to discharge into the motor 26 when the current flow I0 is insufhcient to satisfy the needs of the motor 26. Broadly, therefore, the motor 26 may be considered to be supplied with electrical energy from the condenser I52 which is intermittently charged by the alternator 22 under control of the switch E59. In other respects, the system shown in Fig. 3 is similar to that shown in Fig. 2 in that th voltage of the alternator 22 is controlled in accordance with the current flow of the motor 25 and the phase windings thereof will be arranged in series and parallel connection in accordance with the back E. M. F. of the motor 26. It differs in that the sw tching of the phases to series and parallel arrangement occurs in the alternating current circuits intermediate the phases and the rectifying means rather than as shown in Figs. 2 and 5 in the unidirectional current circuit intermediate the rect'fying means and the load. The operation of the electrical system in connection with the operation of the vehicle is substantially as set forth in the more detailed explanation of the form shown in Fig. 2.

The form as shown in Fig. 5 includes a camactuated switch I directly driven by the alternator 22 having the cams a, b, c, d, e and f and contacts g, h, i, j, k and 1 associated for actuation by the respective cams. It will be noted that the alternator is arranged similarly to that disclosed in Fig. 2; and the switch SW2, for arranging the phase windings A, B and C and A, B and C respectively in series and parallel relationship, is located in the unidirectional current circuit and is operated not according to the back E. M. F. of the motor but by the current flow therethrough. With the switch SW2 in the unidirectional current circut, a rectifying switch must be used for each of the phases in series with saturable reactors VSR. The reactors VSR are of the type in which the core may be magnetized in one direction or the other by means of a direct current winding I52 havng output terminals xx which are respectively connected across the potential which supplies the energizing current for the field 44 of the alternator 22. In this manner the degree of saturation of the reactors VSR may be varied in direct accordance with the current flow through the various phases of the alternator 22. When the motor-condenser load circuit draws only a small current and if the saturat on of the reactors VSR is not altered, a relatively long flat portion on the curve Io as shown in Fig. 4 is provided. If the current supplied by the various phases of the alternator 22 was of much greater magnitude, this flat portion of the curve Io would be decidedly of shorter length.

It is the purpose of this form of the invention to vary as necessary the length of the flat port'on of the curve Io to meet the various current output demands of the alternator 22. This is accomplished by suitably rare-magnetizing the reactors VSR so that when high current output of the alternator 22 is being-delivered, the degree of pre-magnetizaticn of the reactors VSR is substantially lowered so that the current flow from the alternator 22 at the time that the current wave Io breaks away from its fiat portion is substantially greater than when the output current of the alternator 22 is at a much lower value.

Preferably, since the switch I68 is mechanically 113 actuated and the variation .and time intervals in which the various contacts thereof will be closed or opened by the came a, vb, c, d, :e and "f are :sub- :stantially constant, it becomes desirable to .so arrange the saturation of the saturable reactors VSR to produce-.flatportions on the current wave 10 of substantially 'equal :time length irrespective of the current :output of the alternator 22 as determined :by the condenser motor load circuit.

The switch IsGB of Fig.5 corresponds generally to :the :switch SW2 .of .the other figures :and has a pair of energizing coils no and I12. Thecoil I410 is connected in series with conductor 54. The contacts a and c of theswitch IE8 are normally open while the contacts bare normally closed. Therefore, when the back E. M. F. of the motor :25 .is low and high current is flowing, the contacts a and c will be closed placing the phases .A-.A B--B' and 0-0 respectively in parallel. When the motor current is below ;a predetermined value, the switch I68 will be in its deenergized position with its contacts a and 0 open and its contacts b closed whereby the phases .A-A., BB' and C-C' will be respectively in series. Since when the vehicle I is parked .and the engine 2 is idling no current .is flowing through the coil i 1 n, the switch I68 would .be in the de-energized position when it should be in the energized position. Consequently, the second coil IE2 is provided to maintain the switch 1 I58 in :an energized position whenever the en- ,gine v5! is idling. Current for the coil [12 is fur- ;nished by the battery I8. A conductor IM .con- ,nects the conductor 84 :to one end of the coil while the other end is connected to the terminal :3"

119 through the ground connections IIii and 8B. The contacts of a time delay relay I18 con- .trol :the'circuit through the conductor I'M. One terminal of the energizing coil of the relay H8 .is connected to the terminal of .the energizing winding of the switch SW1 which is directly-connected to the contacts a of the switch SW1 so that it will be energized in accordance with the ,energization of the switch SWI. The other terminal of the coil of the relay I18 is grounded .as at I80. The relay I18 will close it contacts :sub- .stantially immediately upon .energization :of its coil but will retain .its contacts closed for a short time interval after deenergization of its coil,

whereby it maintains the coil I12 energizeduntil the current flow through the coil IIll isind'icative of the runningconditionof 'the motor-'25 and vehicle I. Since current flow through'the coil Ill] subsequent to initial operation of the motor 2 5 at any given time is generally proportional to the back E. M. F. of the motor 25, the functioning of the s ries-parallel switch I68 will be'substantially the same as that of the switch SW2 and a further more detailed explanation of its operation is deemed unnecessary to a complete :understanding of the invention. It is believed that since. the operation of the remainder of the con- .trolcircuitby which the alternator 22 drives the motor 25 for movement of the vehicle is similar to that d scribed above inconnectionwith Fig.2 th t .a further .detailed description is not warranted.

It is believed that it :will be obvious from the Ioregoing that numerous modifications and changes in circuit arrangement and in the various ,timingand arranging of the operation of the circuit elements may bemade within thespirit and scopeof the present invention. It .is-desired that the scope of this invention be limited .solely by the scope of the hereinafter app nded claims.

:What le -claimed and is desired to be :secured :by United-States Letters Patent is as follows:

I claim:

.1. "In an electrical network, an alternator having a plurality :of :pairs :of :phase windings, a unidirectional current electric motor, circuit vmeansincluding rectifying means and an electric swi ch connecting saidzmo cr to said al rnator,

said switch means being positioned intermediate said rectifying :means and said alternator and operable to connect each of said pairs of phase windings in :series circuit at back electromctive forces of said motor above a predeterrn-ined value and to connect eech of said pairs-of phase windings in parallel circuit at back electromotive forces of :said :motor below said value.

2. {The combination of :claim .1 in which said switch means ;is positioned intermediate said .rectiiyingmeans andsaidmotor.

3. In an electrical system Whereinan alternator having at least two phase windingsis adapted to be driven'by a source of cnergyandisadapted to drive an electric motor arranged :to :drive load, :an electrical network interconnecting the alternator with the motor comprising circuit means including va switch for connectin the al- =ternator phases in -.parallel relation when said switch is in a first positionand Tinseries relation when said switch is in a second position, magnetic means for operating @said switch to said positions, and circuit means connectin (Sa magnetic ,inea-ns across the rector whereby ,it is responsive to theback:electroinotive forces :of the motor, said magnetic means being operable zb Lowe predetermined value .ofzt-he back electronictive ierces to actuate ,isaid switch to said firs :Position and operable above said predetermined value of the'back. :electromotive forces to actuate said switch ltosaid second position.

4. in :an electrical system'whereintan alternator having :at least two phase windings is adapted to 'be-dr-iven byz-arscurceof energy and is adapted :to drive an electric :motor arranged-to drive a load, an electrical network interconnecting the alternator with the motor comprising circuit means including .a switch for connecting the :alternatcrphases to the motor in parallel relation when aid switch .isainaa'iirst position and inseriies relation when said switch :is :in :a second position, magnetic means for operatingsaid :switch to said second position, and circuit means connecting said magnetic means to :said network whereby it is responsive to the back electromotive forces oi the motor, said magnetic means being operable above a predetermined value :of'the back electromotive :forces :to actuate said switch to said second position. I

1.5. In an electrical system :adapted to drive a vehicle, an alternator having .at least :two phase windings-and adapted to :be driven iby'a source of prime energy, an electric motorarranged to apply torque to :thevehicle-wheels, an electrical network interconnecting the alternator with the motor comprising circuit means including a switch for connecting the alternator phases to the :motor in parallel relation .when said switch :is in a first position and in series relation when said switch is in a second position, magnetic means for pperating said switch to said ccciticn. nd circuit means connecting said-magnetic an ans in circuit operating characteristic of said motor, said magneticnieans being operable abovewa predetermined value of motor current to actuate said switch to said first position and operable below said predetermined value of motor current to actuate said switch to said second position.

6. In an electrical system adapted to drive a vehicle, an alternator having at least two phase windings and adapted to be driven by a source of prime energy, an electric motor arranged to apply torque to the vehicle wheels, an electrical network interconnecting the alternator with the motor comprising circuit means including a switch for connecting the alternator phases to the motor in parallel relation when said switch is in a first position and in series relation when said switch is in a second position, magnetic means for operating said switch to said position, circuit means connecting said magnetic means in circuit with said motor whereby said switch is moved to said positions in accordance with the speed operating characteristic of said motor, said magnetic means being operable above a predetermined value of motor current to actuate said switch to said first position and operable below said predetermined value of motor current to actuate said switch to said second position, and voltage regulating means for said alternator actuated in response to the energy absorbed by said motor whereby the output of said alternator is maintained below a predetermined desired value.

7. In an electrical system adapted to drive a vehicle, an alternator having at least two phase windings and adapted to be driven by a source of prime energy, an electric motor arranged to apply torque to the vehicle wheels, an electrical network interconnecting the alternator with the motor comprising a rectifying circuit means, including a rotary rectifying switch having contacts for connecting each said alternator phase to said motor in a predetermined pattern, said switch being mechanically driven by said alternator, saturable reactors in series with said phases, said switch being driven by said alternator and operable to open the contacts thereof solely during periods in which said reactors are unsaturated.

8. In an electrical system adapted to drive a vehicle, an alternator having at least two phase windings and adapted to be driven by a source of prime energy, an electric motor arranged to apply torque to the vehicle wheels, an electrical net work interconnecting the alternator with the motor comprising a rectifying circuit means, including a rotary rectifying switch having contacts for connecting each said alternator phase to said 'motor in a predetermined pattern, said switch being mechanically driven by said alternator, saturable reactors in series with said phases, said switch being driven by said alternator and operable to open the contacts thereof solely during periods in which said reactors are unsaturated, and means controlling the magnitude of phase current required to saturate said reactors.

9. In an electrical control system, an alternator having output terminals and an exciter circuit, a unidirectional current load circuit for said alternator, circuit means including a switch operatively connecting said load circuit to said output terminals, saturable core reactor means in series circuit with one of said output terminals, means associated with said exciter circuit and operable to control the amount of alternator current required to saturate said reactor means, means including a bucking coil associated with said exciter circuit and being with it responsive to the magnitude of current supplied by said alternator to said load circuit for regulating said exciter circuit and control means, and pure mechanical means primarily and directly 'operable by motion of said alternator thereby being indirectly albeit positively locked in with the frequency of oscillation of the voltage generated by said alternator for closing said switch during periods in which the polarity of said terminals matches that of said load circuit, said switch closing means being operable to open said switch during the period in which said reactor means is being saturated and in which current flow therethrough is of substantially zero magnitude with respect to peak current flow.

10. In an electrical control system, an alternator having an exciter circuit and output terminals, a unidirectional current load circuit for said alternator, circuit means including a switch operatively connecting said load circuit to said output terminals, saturable core reactor means in series circuit with one of said output terminals, means controlled by said exc er circuit operable to control the amount of alternator current required to saturate said reactor means, means responsive to the magnitude of currentsupplied by said alternator to said load circuit for regulating said exciter circuit and control means, and other means for closing said switch during periods in which the polarity of said terminals matches that of said load circuit, said other means being driven directly by said alternator by a mechanical connection whereby exact synchronism therewith may be maintained at all times regardless of line disturbances and drastic speed fluctuations, and being operable to open said switch only during the period in which said reactor means is being saturated and in which current flow therethrough is of substantially zero magnitude with respect to peak current flow;

11. In an electrical control system, an alternator having a plurality of phases, a unidirectional current load circuit for said alternator, circuit means including a switch having a separate contact for operatively connecting each of said phases to said load circuit, saturable core reactor means in series circuit with each of said phases,

- means operable to control the amount of phase current required to saturate its respective said reactor means, means responsive to the magnitude of current supplied by said alternator to said load circuit for regulating said control means, means mechanically driven by said alternator for closing said switch during periods in which the polarity of said terminals matches that of said load circuit, said means being operable to open said switch during the period in which said reactor is being saturated and in which current flow therethrough is of substantially zero magnitude with respect to peak current flow, and means responsive to current flow through said load circuit to control the voltage or said phases.

12. In an electrical control system, an alternator having a plurality of phases, a unidirectional current load circuit for said alternator, circuit means including a switch having a separate contact for operatively connecting each of said phases to said load circuit, saturable core reactor means in series circuit with each of said phases, means operable to control the amount of phase current required to saturate its respective said reactor means, means responsive to the magnitude of current supplied by said alternator to said load circuit for regulating said control means, means mechanically driven by said alternator for closing said switch dur ng periods in which the polarity of said terminals matches that of said load circuit, said means being operable to open said switch during the period in which said reactor is being saturated and in which current flow therethrough is of substantially zero magnitude with respect to peak current fiow, and means responsive to current flow through said load circuit for grouping said phases in series and parallel connections.

13. In an electric drive for a vehicle having an engine, an alternator arranged to be driven by the engine and having a phase winding for supplying load current, a unidirectional current motor arranged to supply power to drive the vehicle, an electrical network interconnecting said alternator winding with said motor, voltage control means for said winding, means responsive to the current flow through said motor for regulating said voltage control means whereby the power output of said winding is maintained below a predetermined maximum, rotary switch means mechanically driven b y said alternator and connected intermediate said winding and said motor for periodically connecting said winding to said motor in accordance with the magnitude and polarity of the voltage of said winding,

and saturable reactor means in series circuit with said winding, said switch means being arranged in phase relation to said alternator voltage for disconnecting said motor from said winding solely during periods in which said recator means is unsaturated.

14. The combination of claim 13 in which said reactor means has a control winding for determining the magnitude of load current required to saturate said reactor means, said voltage control regulating means being electrically connected to regulate the energizations of said control winding whereby said reactor means is variably premagnetized to provide for complete saturation thereof by said load current in substantially equal time intervals irrespective of variation in the magnitude of said load current.

15. In an electrical network, the combination with an alternator having a plurality of pairs of phase windings, an electric motor, and circuit means connecting said windings to said motor and including switch means having two positions of operation, said switch means when in one of its said positions being operable to connect each of said pairs of said windings in series circuit and when in another of its said positions being operable to connect each of said pairs of said windings in parallel circuit, of automatic means for actuating the switch means to said one position, said automatic means being responsive to an operating characteristic of said motor indicative of attainment of a predetermined minimum speed.

16. In an electrical system wherein a pair of multiphase rectifier banks each delivers its output into the load circuit through an individual common, the combination with an alternator for supplying the rectifier banks and having a plurality of pairs of windings, one winding of each pair being segregated into a group constituting one multiphase set of windings arranged in a permanent star-connection having a common to the center point, and the other winding of each pair being segregated as the cooperating multiphase, set having another common to its center point, and means for forming contact terminals for said commons, or" switch means for corn necting said contact terminals to pair selectively each star common with a rectifier common and with one another whereby a parallel-series transition may be afforded said pairs of windings in supplying input to the rectifier banks.

17. In an electrical system wherein a pair of multiphase rectifier banks each deli ers its output into the load circuit through an indivdual common, the combination with an alternator for supplying the rectifier banks and having a plurality of pairs of windings, one winding of each pair being segregated into a group constituting one multiphase set of windings arranged in a permanent star-connection having a common to the center point, and the other winding of each pair being segregated as the cooperating multiphase set having another common to its center point, and means for forming contact terminals for said commons, of switch means for connecting said contact terminals to pair selectively each star common with a rectifier common and with one another whereby a parallel-series transition may be afiorded said pairs of windings in supplying input to the rectifier banks and an electromagnetic relay associated with said load circuit for responsively operating said switch means at predetermined load conditions.

18. In an electrical network an alternator having a plurality of pairs of phase windings, an electric motor circuit means connecting said windings to said motor and including switch means having two positions of operation, said switch means when in one of its said positions being operable to connect each of said pairs of said windings in series circuit and when in another of its said positions being operable to connect each of said pairs of said windings in parallel circuit, and automatic means for actuating said switch means to said one position in accordance with the predetermined desired operating characteristic of said motor of the attainment of a predetermined minimum self-induced E. M. F.

PAUL T. NIMS.

REFERENCES CITED The following references are of record in the file of this patent or the original patent:

V UNITED STATES PATENTS Number

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