US1728439A - Single-phase-motor system - Google Patents

Description

Sept. 17, 1929. J N Es SINGLE PHASE MOTOR SYSTEM Filed May 25, 1927 77 655 I I I Patented Sept. 17, 1929 UNITED STATES PATENT OFFHCE JOHN D. NIES, OF ST. CHARLES, ILLINOIS, ASSIGNOR TO KIMBLE ELECTRIC COMPANY,

. OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS SINGLE-PHASE-MOTOR SYSTEM Application filed May 23,

The present invention relates to single phasemotor systems, and has for one of its objects the provision of means whereby the advantages of direct current systems may be '5 had in single phase alternating current systems. When the rotor of a single phase motor is in motion, a reversal of the connections, as ordinarily provided, has no effect in reversing the direction of motor rotation.

A further object of the present invention is to provide means whereby with a sim ple reversal of switch connections when the rotor is in motion said rotor is automatically slowed down to a stop and brought up to speed '15 again in the reverse direction.

'A further object is to provide a single phase alternating current system, applicable to elevator systems, which is simple and well adapted to meet the needs of commercial operation.

Further objects will appear as the description proceeds.

The one figure of the drawing indicates diagrammatically one embodiment of the present invention.

The two sides of an alternating current system are indicated by the characters L and L The numeral 10 indicates the rotor of a singlephase motor, which rotor is provided with a commuted winding. The numeral 11 indicates the field winding and the numeral 12 indicates the main winding or counter- E. M. F. winding, both windings 11 and 12 being located upon the stator and cooperating with the rotor 10. The numeral 13 indicates a forward switch and the numeral 14 indicates a reverse switch. The numeral 15 indicates a main line switch and the numeral 16 indicates a delayed action contact, which operates in response to operation of the main line switch 15. The numeral 17 indicates a conversion switch, which conversion, switch controls the characteristics of the motor. The rotor 10 of the motor is provided with the short-circuited commutator brushes 1818 and with the auxiliary brushes 1919, which auxiliary brushes are adapted to be shortcircuited by the conversion switch 17. The switch 17 is controlled by the magnetic coil 20, which is responsive to the E. M. F. across 1927. Serial No. 193,489.

the main or counter-E. M. F. winding 12 when certain switch connections, to be referred to hereinafter, are established. The numeral 21 indicates an accelerating switch responsive to the magnet coil 22. The magnet coil 22 is energized from the main line when the delayed action contact 16 is closed. The numeral 23 indicates a starting resistor, which, it will be noted, is adapted to be connected through the right-hand blade of main line switch 15 in circuit with the motor.

The numerals 24 and 25 indicate forward and reverse push buttons, respectively, which push buttons may take any of the embodiments encountered in practice. Said push button switch 24, at one limit of its range of movement, is adapted to make a connection between the stationary contacts 2626 and at the other end of its range of movement is adapted to engage the relatively stationary contacts 27-27. In the operation of the present invention the contacts 2626 are normally closed and the contacts 2727 are normally open. The push button switch 25 at one limit of its range of movement is adapted to engage the relatively stationary contacts 2828 and at the other limit of its movement is adapted to engage the relatively stationary contacts 2929, the contacts 2828 being normally closed by the push button switch 25 and the contacts 2929 being normally open. The main line switch 15 is controlled in response to the magnet coil 30; the forward switch 13 is controlled in response to the magnet coil 31; and the reverse switch 14is controlled in response to the magnet coil 32. For reasons which will be referred to hereinafter, the magnet coil 30 is connected in series with the auxiliary brushes 1919 on the motor rotor 10.

From an inspection of the figure of the drawing it will be noted that one of the relatively stationary contacts 27 and one of the relatively stationary contacts 29 are connected to the side L of the mainline. The other of the relatively stationary contacts 27 is electrically connected to one of the relatively stationary contacts 28.- The other of the relatively stationary contacts 29 is connected'to one of the relatively stationary contacts 26. The other of the relatively stationary contacts 26 is connected through the magnet coil 32 to the side L of the main line. The other relatively stationary contact 28 is connected through the magnet coil 31 to the side L of the main line. Disposed upon the extreme left-hand leg of the forward switch 13 is the auxiliary contact 34 adapted to make and break contact with the relatively fixed contact 33', which contact 33 has electrical connection with contacts 27 and 28, which cooperate with the push buttons 24 and 25 and which are electrically connected together. The extreme left-hand leg of the reverse switch 14 is provided with the auxiliary contact 35 adapted to make and break contact with the relatively stationary contact 36, which is electrically connected to the stationary contacts 26 and 29 which cooperate with the push button switches 24 and 25, which contacts 26 and 29 are connected together. I

As a safety precaution, it should be impossible to start the motor in case the auxiliary brushes 19-19 are not operative for any reason, as for example if said brushes should become worn or dirty, whereby they would not function properly. For this reason the present invention provides that the current for energizing the magnet coil 30 which controls the main line switch 15 shall pass through said brushes 1919. If said brushes are worn or dirty or out of proper position, it will be impossible to complete the circuit of the magnet coil 30, and the motor will not start. I I

In operation, when the operator desires to start the elevator motor for forward rotation he will put in force certain instrumentalities to operate the push button switch 24 to' cause same to'break engagement between the contacts 26'26 and to make engagement with the contacts 27'27. The breaking of electrical connection between the contacts 26 26 insures the; deenergization of the magnet coil 32, rendering it certain that the reverse switch 14 will not be closed at this time. The making of the electrical connection between contacts 27-27 will close the circuitfroni the side L of the line through the push button switch 24, through the push button switch 25 and magnet coil 31, to the side L of the line. Energization of the magnet coil 31 will close'the forward switch 13. The three blades of saidforward switch 13 will be mechanically connected together, and the closure of this switch will cause the closing of a circuit from the side L of the main line, through brushes 19 19, through the extreme right-hand blade of the switch 13 and through the magnet coil 30 to the side L of the. line.' ,Energization of the magnet coil will result in' the closure of the main line switch 15. The closure of the main line switch 15 completes a circuit from the side L through the extreme left-hand blade of the forward switch 13 to the terminal F of the field winding 11, from the terminal F of said field winding 11, through the middle blade of the forward switch 13, to the terminal T of the counter-E. M. F. winding 12 of the motor, from the terminal T of said counter-E. M. F. winding, through the starting resistor 23, through the right-hand blade of the main line switch 15, to the side L of the main line. The motor will thus be started in a forward direction. Closure of the main line switch 15 has resulted in the initiation of the closure of the delayed action contact 16. Said contact 16 may be adjusted as desired. After the lapse of a predetermined time interval, said contact 16 will close. The closure of the contact 16 completes a circuit from the side L of the main line, through the main line switch 15', contact 16, magnet coil 22, and through the right-hand blade of the main line switch 15 to the side L of the main line. Energization of the magnet coil 22 results in the closure of the accelerating switch 21. Closure of the accelerating switch 21 doestwo things; first, it shortcircuits the resistor 23 through the right-hand blade of the switch 21; second, it completes a circuit for the magnet coil 20 across the terminals of the counter-E. M. F. winding 12 of the motor. When the E. M. F. across the terminals of the winding 12 of the motor has reached a predetermined value, the switch 17 will be closed, short-circi'iiting the brushes 19-49 of the motor, converting the motor from series characteristics to shunt characteristics. This completes the circuit for bringing the rotor motor up to speed. In case an overloaded elevator cage is being lowered oran underweighted elevator cage is being lifted, the shunt characteristics of the motor enable the motor to hold back with a braking action. The auxiliary contact 34 upon the left-hand switch blade of the switch 13 controls a maintaining circuit whereby the forward switch 13, and therefore also the main line switch 30, will be held closed after a momentary operation of the push button switch 24. When the main line switch 15 is in closed position and the auxiliary contact 34 is in engagement with the relatively stationary conta'ct33, circuit will be completed from the side L of the main line, through the left-hand blade of main line switch 15, through the left-hand blade of forward switch 13, through contacts and 34, through contacts 28-.-25 -28 of the push button station, through magnet coil 31, to the other side L of the main line. Current is therefore maintained on coil 31, so that this switch remains closed. This switch being closed, current, will be maintained through its right-hand blade for coil 30, so that both switches 13' and 15 remain closed, thus mainswitch 14, through "the brushes 19 taining current oil the motor for forward operation. a

In order to stop the operation of the motor when said motor is rotating in a forward direction it will only be necessary to move the reverse push button switch 25 momentarily to a mid position, breaking circuit between the relatively stationary contacts 2828. This action will result in the deenergization of the magnet coil 31, allowing the switch 13 to open. The opening of the extreme righthand blade of the switch 13 will result in the deenergization of the magnet coil 30, resulting in the opening of the main line switch 15. Opening of main line switch 15 results in the opening of the delayed action switch 16, which results in the deenergization of the magnet coil 22. Deenergization of the magnet coil 22 results in the opening of the accelerating switch 21, causing the deenergization of the magnet coil 20, which opens the shortcircuit across the brushes 1919 of the motor. Moreover, the opening of the accelerating switch 21 removes the short-circuit around the starting resistor 23.

It will be understood, of course, that when the operator desires to start from rest in a reverse direction, he will operate the push button switch 25 to its position bridging the relatively stationary contacts 2929. At tais time the push button switch 24 is in its position bridging the relatively stationary contacts 26 26. Under these conditions circuit is completed from the side L of the main line through right-hand contact 29, push button switch 25, left-hand contact 29, through push button switch 24, through the magnet coil 32 of the reverse switch lt, to the side L of the main line. Energization of the magnet coil 32 will result in the closure of the reverse switch 14. Circuit is now completed from the side L of the main line circuit, through the extreme right-hand blade of the reverse 19, through the magnet coil 30, to the side L of the line. Energization of the magnet coil 30 results in the closure of the main line switch 15. Circuit is now completed through 'the side L of the line, through the left-hand blade of the main line switch 15, through the extreme left-hand blade of the reverse switch 1 1, through the field winding 11 of the motor, from the terminal F to F through the center blade of the reverse switch 14, through the counterE. M. F. winding 12 of the motor, through the starting resistor 23, to the side L of the main line. Closure of the reverse switch 1 1 will also close the auxiliary contact 35 upon the contact 36, resulting in the closure of a maintaining circuit similar to that described in connection with the forward switch 13. It will be noted that the direction of curscribed above for forward rotation, whereby 'line switch 15. tion, the closure of the accelerating switch 21 the relative polarities of coils 12 and 11 is reversed from the relative polarities for forward rotation. The circuits will operate in the manner described above in connection with forward rotation to close the accelerating switch 21 and the short-circuiting switch 17 to change the motor from series characteristics to shunt characteristics. stoppage of the motor may be accomplished by momentary operation of the push button switch 24 to a mid position.

When it is desired to bring about a reversal of motor rotation when said motor is rotating either forward or reversely, it is necessary in the practice of the present invention only to operate either push button switch 24 or push button switch 25 to its extreme position, depending upon whether it is desired to change to forward rotation or to reverse rotation.

Assuming for the purpose of example that the motor is operating with forward rotation and the operator closes push button switch 25 upon the contacts 2929, the first effect will be to open-circuit the magnet coil 31, causing the opening of the forward switch 13. As will be clear from the above description, opening of the switch 13 results in the opening of the main line switch 15 and the delayed action contact 16, resulting in the deenergization of the magnet coil 22, reinserting the starting resistor 23 in circuit. Deenergization of the magnet coil 22 will also open-circuit the magnet coil 20, resulting in the opening of the switch 17, restoring series characteristics to the motor.

These series characteristics are maintained during the negative acceleration of the motor to a position of rest. It is necessary in order to produce the reversal referred to for the operator to close circuit between the contacts 2929 only momentarily. As will be clear from the description given above for starting the motor in a reverse direction from rest, the closing of the push button switch 25 across the contacts 2929 will result in the closure of the reverse switch 14, causing the auxiliary contact 35 to engage the relatively fixed contact 36, which closes a maintaining circuit for the magnet coil 32, which will hold the reverse switch 14 in contact-making position. In order that insurance may be had that the motor will reverse, it is essential that the conversion switch 17 be prevented from closing until the E. M. F. across the winding 12 has died down to zero and built up due to rotation of the motor rotor in the reverse direction. This delay is accomplished by means of the delayed action contact 16, which prevents the energization of the magnet coil 32 until after the lapse of a predetermined time interval after the closure of the main By'reason of this delayed acis delayed, thereby delaying the cutting out of the starting resistor 23. The inclusion of the starting resistor 23 in circuit, together with the slowing down of the rotor of the motor and the action of the brake as ordinarily supplied on elevator installations, all combine to insure the falling to zero of the E. M. F. across the Winding 12 before said E. M. F. can build up due to operation o't' the motor rotor in a reverse direction.

Though a preferred embodiment of the present invention has been described in detail, many modifications will occur to those skilled the art. It is intended to cover all such modifications that fall within the scope of the appended claims.

\Vhat is claimed isp v 1. In an electrical system, a single phase alternating current motor having a field winding, a counter-E. M. F. winding, a rotor having a commuted winding, a set of shortcircuited brushes and a second set of brushes which may be short-circuited to change the characteristics of said motor, means responsive to the speed of said motor for causing the short-circuiting of said second set of brushes, switching means for connecting said motor to a source of alternating E. M. F., and means for reversing the relative polarities of said field and counter-E. M. F. windings to cause a reversal in the direction of rotation of said motor. I

2. In an electrical system, a single phase alternating current motor having a field winding, a counter-E. M. F. winding, a rotor having a commuted winding, a set of shortcircuited brushes and a second set of brushes which may be sho'rt-circuited to change the characteristics of said motor, switching means for connecting said motor to a source of alternating E. M. F., means for reversing the relative polarities of said field and counter- E. M. F. windings to cause a reversal in the direction ofrota'tion of said m'otor, and delayed action switching means responsive to said first-mentioned switching means for con trolling the short-circuiting of said secondmentioned pair of brushes.

3. In a system, a single phase alternating current motor having a commuted winding upon its rotor. a set of short-circuited brushes cooperating with said commuted winding, a set of auxiliary brushes adapted to be shortcircuited to change the characteristics of said motor from series to shunt, a field winding, a counter-E. F. winding cooperating with said field winding and commuted winding, switching means for connecting said motor to a source of alternating E. M. F. and shortcircuiting means conjointly responsive to said switching means and to the speed of said motor for short-circuiting said auxiliary brushes.

4. In a system, a single phase alternating current motor having a commuted winding upon its rotor, a set of short-circuited brushes cooperating with said commuted winding, a set of auxiliary brushes adapted to be short-circuited to change the characteristics of said motor from series to shunt, a field winding, a counter-E. M. F. winding cooperating with said field winding and commuted winding, switching means for connecting said. motor to a source of alternating E. M. F., shortcircu'iting means responsive to said switching means for shortcircuiting said auxiliary brushes, and delayed action means responsive to said switching means, said short-circuiting means being under the control of said delayed action means.

5. In a system, a single phase alternating current motor having a commuted winding upon its rotor, a set of short-circuited brushes cooperating with said commuted winding, a set of auxiliary brushes adapted to be shortcircuited to change the characteristics of said motor from series to shunt, a field winding, a counter-E. M. F. winding cooperating with said field winding and commuted winding, switching means for connecting said motor to a source of alternating E. M. F.,'short-circuiting means responsive to said switching means for short-circuiting said auxiliary brushes, and eclayed action means responsive to said switching means, said short-circuiting means being under the control of said delayed action means, said short-circuiting means being also responsive to the E. M. F. across said counter- E. M. F. winding.

6. In an electrical system, a single phase alternating current motor having a commuted winding upon its rotor,,sl1ort-ci1:cuited brushes cooperating therewith, a set of auxiliary brushes cooperating therewith, a field winding and a counter-E. winding cooperating with said rotor, switch means for connecting said motor to a source of alternating E. M. E, a starting resistor between said switching means and said motor, a conversion switch for short-circuiting said auxiliary brushes to control the characteristics of said motor, operating means for said conversion switch, and delayed action contact-making means for short-circuiting said resistor and for controlling said operating means.

7. In an electrical system, in combination, a single phase alternating current motor having a commuted winding on its rotor, shortcircuited brushes cooperating with said commuted winding, auxiliary brushes and conducting means cooperating with said auxiliary brushes adapted to change the characteristics of said motor, a field winding and a counter-E. M. F. winding adapted to cooperate with said commuted winding, a main switch for connecting said motor to a source of alternating E. M. F., and magnet means for controlling said main switch, said magnet means being connected in circuit through said auxiliary brushes.

8. In an electrical system, in combination,

a single phase alternating current motor having a commuted winding on its rotor, shortcircuited brushes cooperating with said commuted winding, auxiliary brushes cooperating with said winding and adapted to change the characteristics of said motor, a field winding and a counter-E. M. F. winding adapted to cooperate with said commuted winding, a main switch for connecting said motor to a source of alternating E. M. F., magnet means for controlling said main switch, said magnet means being connected in circuit through said auxiliary brushes, and means for shortcircuiting said auxiliary brushes which means is responsive to the E. M. F. across said counter-E. M. F. windin 9. In an electrical system, in combination, a single phase alternating current motor having a commuted winding on its rotor, shortcircuited brushes cooperating with said commuted winding, auxiliary brushes cooperating with said winding and adapted to change the characteristics of said motor, a field winding and a counter-E. M. F. winding adapted to cooperate with said commuted winding, a main switch for connecting said motor to a source of alternating E. M. F., magnet means for controlling said main switch, said magnet means being connected in circuit through said auxiliary brushes, means for short-circuiting said auxiliary brushes which means is responsive to the E. M. F. across said counter-E. M. F. winding, and delayed action means responsive to the closure of said main switch for controlling said short-circuiting means.

10. In an electrical system, in combination, a single phase alternating current motor having a commuted winding upon its rotor, shortcircuited brushes cooperating with said commuted winding, auxiliary brushes cooperating with said commuted winding a field winding, a counter-E. M. F. winding, forward and reverse switching means for controlling the relative polarities of said field and counter-E. M. F. windings, and means for short-circuiting said auxiliary brushes conj ointly responsive to the closure of either of said forward and reverse switches and to the potential difference across said counter- E. M. F. winding.

11. In an electrical system, in combination, a single phase alternating current motor having a commuted winding upon its rotor, short-circuited brushes cooperating with said commuted winding, auxiliary brushes cooperating with said commuted winding, a field winding, a counter-E. M. F. winding, forward and reverse switching means for controlling the relative polarities of said field and counter-E. M. F. windings, means for short-circuiting said auxiliary brushes conjointly responsive to the closure of one or the other of said forward and reverse switches and to the potential difference across said counter-E. M. F.

winding, and delayed action means responsive to the operation of said forward and reverse switching means for controlling the action of said short-circuiting means.

12. In an electrical system, in combination, a single phase alternating current inotor having a commuted winding upon its rotor, short-circuited brushes cooperating with said commuted winding, auxiliary brushes cooperating with said commuted winding and adapted to change the characteristics ofsaid motor, a field winding and a counter-E. M. F. Winding cooperating with said commuted winding, forward and reverse switches for controlling the relative polarities of said field and counter-E. M. F. windings, a starting resistor in series with said counter-E. M. F winding, and switch means responsive to said forward and reverse switches for controlling said resistor and con jointly with said counter-E. M. F. winding for controlling the short-circuiting of said auxiliary brushes.

13. In an electrical system, in combination, a single phase alternating current motor having a comn'iuted winding upon its rotor, short-circuited brushes cooperating with said con'imuted winding, auxiliary brushes cooperating with said commuted winding and adapted to change the characteristics of said motor, a field winding and a counter-E. M. F. winding cooperating with said commuted winding, forward and reverse switches for controlling the relative polarities of said field and counter-Ii). M. F. windings, a starting resistor in series with said counter-E. M. F. winding, switch means responsive to said forward and reverse switches for controlling said resistor and conjointly with said coun- 105 ter-E. M. F. winding for controlling the short-circuiting of said auxiliary brushes, and delayed action means for controlling said switch means.

1 2. In an electrical system, in combination, 110 a single phase alternating current motor having a field winding, a counter-E. M. F. winding and a rotor, said motor normally having series characteristics, means to change the characteristics of said motor, forward and re 1 15 verse switching means for controlling the relative polarities of said field and counter- E. M. F. windings, said characteristic changing means being responsive to said forward and reverse switching means.

15. In an electrical system, in combination, a single phase alternating current motor having a field winding, a counter-E. M. F. winding and a rotor, said motor normally having series characteristics, means to change the 125 characteristics of said motor, forward and reverse switching means for controlling the relative polarities of said field and counter- E. M. F. windings, said characteristic changing means being responsive to said forward and reverse switching means, and delayed action means responsive to the operation of said forward and reverse switching means for controlling the action of said characteristic changing means.

16. 'In an electrical system, a single phase alternating current motor having a field winding, a counter-E. M. F. winding, a rotor having a commuted winding, aset of shortcircuited brushes and a second set of brushes which may be short-circuited to change the characteristics of said motor, means responsive to the rise in E. M. F. in said counter- E. M. F. winding for causing the short-circ uiting of said second set of brushes, switch means for connecting said motor to a source of alternatin E. M. F., and means for reversing the relative polarities of said field and counter-E. M. F. windings to cause a reversal inthe direction of rotation of said mot-or.

17. In a system, a single phase alternating current motor having a commuted winding upon its rotor, a set of short-circuited brushes cooperating with said commuted winding, a set of auxiliary brushes adapted to be shortcircuited to change the characteristics oi said motor from series to shunt, a field Winding, a counter--15. M. F. winding cooperating with said field winding and commuted winding, switching means for connecting said motor to a source of alternating E. M. F. and shortcircuiting means conjointly responsive to said switching means and to the E. M. F. developed within said counter-E. M. F. winding for sh'ort-circuiting said auxiliary brushes.

Signed at Chicago, Illinois, this 17th day of May, 1927.

JOHN D. N IES.

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