US1560216A - Motor controller - Google Patents

Description

A. J. CLINE ET AL MOTOR CONTROLLER Filed June '7, 1923 mwmmSmz Patented Nov. 3, 1925.

UNITED "STATES PATENT OFFICE.

ALLAN J. GLINE AND THELMA I. DEKLE, OF CHICAGO, ILLINOIS, ASSIGNORS TO ULINE ELECTRIC MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION or ILLINOIS.

MOTOR CONTROLLER.

Application "tiled June 7, 1923. Serial No. 643,840.

To all whom it may concern Be it known that we, ALLAN J. Gum: and THELMA I. DEKLE, citizens of the United States, and residents of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Motor Controllers, of which the following is a specification.

The invention relates to controllers for starting and stopping and govcrnin the speed of electric motors that are emp oyed for operating printing presses, machine tools and the like, and in which manually operable controlling switches are provided for stopping the motor and for starting it for operation at different speeds, and the invention seeks'to provide improved means for roviding a high torque for starting.

,1! ore particularly the improvement re lates to a controller in which means automatically controlled by the counter electromotive force developed in the motorcircuit protects the motor and controls its rate of acceleration, such for example as set forth in the prior patent to A. J. Cline, No. 1,405,-

493, dated February 7, 1922. With counter M. F. acceleration the motor circuit is efiectively protected but it is sometimes difficult, in case of excessive loads, to start the motor when its rate of acceleration is so controlled and the present invention pare ticularl seeks to provide improved means adapts for operation in connection with counterE. M. F acceleration for providing a high starting torque. The invention also seeks to otherwise improve the controller shown in the Cline patent above noted and consists in the fdatures of improvement hereinafter set forth, illustrated in the preferred arrangement in the accompanying drawing and more particularly pointed out in the appended claims.

The drawing is a diagrammatic illustration of the preferred arrangement of the improved controller.

The conductors 10 and 11 of the motor supply circuitare connected to the mains 12 by spline switch 13. The switches and other parts which carry the armature current are located at a main station A and the manually operable controlling switches are usually located at another station or stations B and B. The main controller station comprises a resistance 14- for the armature a, separate electro-magnetic starting and reversing switches 15 and 16 and a series of electro-magnetic resistance or accelerating switches 17, '18 and 19. The main station is also provided with two relays 20 and 21 for controlling the operation of the starting, reversing, and resistance switches and preferably also with afiutterlng switch relay 22 which is arranged. to short circuit the resistance for the shunt field in case excessive current flows through the armature circuit.-

The positive supply conductor 10 is connected to the normally engaged contact of the reversing switch 16 and through a brake resistance 23 to the normally engaged contact of the starting switch 15. The negative supply conductor 11 is connected to one terminal ot the armature resistance 14, the other terminal ofwhich is connected by a conductor 24L to' the normally disengaged contact of the starting switch. Preferably, as shown, the normally disengaged contact of the reversing switch is connected by a conductor 25 to an intermediate point of the armature resistance. The coil of the relay 22 is interposed as shown in the conductor The armature terminals are connected respectively to the movable contacts of the starting and reversing switches by conductors 26 and 27 The starting and reversing switches are provided with ener izing coils 28 and 29 and are also preferahly' provided with coils 30 and 31 which are connected across the terminals of the armature and conveniently to the movable contacts of the starting and reversing switches. Coils 30 and 31 are thus controlled by the counter E. M. F. in the motor circuit and they serve respectively to seal, the normally engaged contacts of the starting and reversing switches. The movable members of these switches are provided with pivoted, spring pressed contacts, ofwell known type, having a rolling engagement with the stationary switch contacts, and the coils 30 and 31 serve to shift the movable switch members slightly and seal or firmly press to ether the normally engaged con-' tacts. hen the coil 28 of the starting switch 'is energized, the motor circuit is closed from conductor 10 to the reversing switch, by conductor 27 to the armature, by conductor 26 to thestarting switch and its normally disengaged contacts, thence by the conductor 24 through coil 22 and the armature resistance to the supply conductor 11. When the coil 29 of the reversing switch is energized, current flows from the positive main through conductor 10, brake resistance 23, the starting switch and conductor 26, through the armature in the opposite direction and thence by conductor 27, reversing switch 16, conductor 25 and a portion of the armature resistance to thenegative conductor 11. When both switches 15 and 16 are deenergized, the armature is connected in series with the brake resistance 23 which serves to quickly bring the motor to rest. The brake resistance is also interposed in the armature circuit when the reversing switch 16 is energized. The contacts of the accelerating or resistance switches 17, 18 and 19, operate in' the usual manner to cut out difierent sections of the armature resistance 14, but, in the arrangement shown, these switches are only brought into operation when the motor is operated in normal direction and it is desired to accelerate its. speed.

The main controlling station B is provided with a master controlling or speed regulating switch comprising a brush or switch arm 32 movable over a series of con tact bars 33, 34, 35 and 36, and a series of contacts designated 0, 1, 2, 3, and 4, and a number of contacts designated 5. Current is supplied to the master controlling switch from the os'itive conductor 10 by a conductor 37 which is connected 'to the contact bar 33. In the normal or 05 position, the brush of the main controlling switch member 32 rests upon the contact ,0 and the contact bars 33 and 35 so that current is supplied from contact bar 35 through a conductor 38 to the shunt field 7 of the motor, and thence by return conductor 39 to the negative main. The contact bar 35 at the main controlling station is alsoconnected to a iield resistance 40, the sections of which are connected to the contacts 5. The conductor bar 34 is connectedto contact 1, so that in all of the positions of the controlling switch 32, except. its off position, positive current is supplied to a conductor 41 which leads to one or more sets of auxiliary controlling switches which are preferably in the form of push button switches. A set of push button switches is preferably provided at the main controlling station Byand one or more sets of similar switches are arranged at one or more auxiliary stations B, as shown. The supply con' duct-or 41 extends in series through the nor 'mally closed contacts of the stop buttons,

thence in series through the normally closed contacts of the reverse buttons to a branched conductor 42 which leads to one of the normally open contacts of all of the other push button switches. The supply conductor 41 is also connected to one of the normally open contacts of each of the reverse push button switches and to two sets of normally open contacts 43 and 44 controlled by the relay 21. The remaining contacts of the push button switches are connected by a series of conductors 45, 46, 47 and 48 to the energizing coils of the starting and reversing switches and of the relays 20 and 21, the conductors 45 and 47 from the run and slow push buttons being connected respectively to the energizing coils of the relays 20 and 21 and the conductors 46 and 48 from the inch and reverse push buttons being connected respectively to the energizing coils 28 and 29 of the starting and reversing switches.

Relay 20 controls a set of normally open contacts 49 interposed in the circuit of the relay 21, and contacts 43 of the latter are arranged to close the energizing coil 28 of the starting switch 15. The contacts 44 of the relay 21 serve to close a locking circuit ture and extending in series through the coils of the accelerating or resistance switches 17,18 and 19, and thence by a conductor 52 to the contact 4 and contact bar 36 of the master controlling switch at station E. The

coils of the resistance switches 17 and 18 are also connected respectively by conductors 53 and 54 directly to the contacts 2 and 3 of the master controlling switch.

The relay 20 thus serves to connect the coils of the accelerating switches by means of the conductor 51 to the negative pole of the armature, and the master controlling switch serves to connect one or more of the resistance switches to the conductors 37 and 10 which, when the motor is run in normal direction, are connected by the normally engaged contacts of the reversing switch 16 and the conductor 27 to the positive pole of the armature. The coils of the resistance 'or accelerating switches are thus connected across the terminals of the motor; and are responsive to the counter E. M. F. developed in the motor circuit, and these coils of acceleration of the motor is automatically controlled in accordance with the load on the motor. To insure successive operation of the resistance switches when two or more are in circuit, each switch, except the last to operate, i. e., the switches 17 and 18, are provided with normally closed contacts and 56 which are interposed in shunts around the coils of the succeeding switches 18 and 19 respectively. The resistance switch 19 is also provided with a set of full field contacts 57 which normally close a shunt around the field resistance 40. The normally open contacts 58 of the fluttering switch relay 22 are also interposed in .a shunt around the field resistance.

Means are also provided for reducing or cutting out a portion of the armature resistance 14 to provide a'high starting torque. For this purpose a coil 59 is arranged to close a shunt around a section of the armature resistance. This coil may be provided with contacts separate from those of the 'resistance switches but preferably it forms a second coil on the core of one of the switches and preferably on that of the switch 17, as shown. One terminal of the starting torque coil 59. is connected to a conductor 60 which leads through a resistance 61 to the return conductor 39 which extends to the negative supply conductor 11. The other terminal of the starting torque coil 59 is connected to a supply conductor 62 which extends in series through a set of normally closed contacts 63. The conductor 62 may, if desired, be connected directly to the positive supply conductor 16 so that the coil 59 will be energized to cut out a considerable portion of the armature resistance 14 whenever the line switch 13 and the contacts 63 are closed. Preferably, as shown, the conductor 62 is connected to the conductor 46 so that the startingtorque coil is energized whenever the operating coi 28 of the starting switch is energized. The contacts 63 are arranged to be opened by a counterE. M. F. coil to disable the starting torque coil when the motor reaches a predetermined speed, say for example, half the normal speed. The contacts 63 are conveniently arranged to he opened by the reversing switch 16 when its counter E. M. F. sealing coil 31 is energized and slightly shifts the movable member of this switch... But, obviously, if desired. a separate counter E. M. F. coil may be provided for this purpose.

When the line switch 13 is closed a-cir cuit is completed from the positive conductor 10 through the conductor 64 and the initial full field contacts 57 to the conductor 38 and shunt field f, and thence by the return conductor to the positive supply conductor 11. If the starting torque coil 59 is also connected to the conductor 10, its circuit will be closed from this conductor through the contacts 63, conductor 62, coil '59, conductor 60, through the normally closed contacts 65 to the return conductor 39, and, when the coil 59 is energized it will open the contacts 65 and the return from the coil will then be through the resistance 61. If, as preferred, the coil of the starting torque conductor is connected to the energizing circuit of the starting switch coil 28, it will not be energized unless the master switch 32is shifted from its zero or off position and either a run, ,inch, or slow button is operated.

In the off position of the master controlling switch arm 32 on contact 0, the supply conductor 41 of the controlling circuit is open but, in any other position of the switch arm 32 this conductor is connected to the main supply conductor 10 by the conductor 37 and the contacts of the master controlling switch. Thus, in its first opera tive position on contact 1, the master controlling switch 32 mer'ely serves to connect the supply conductor 41 of the controlling circuit to the positivemain. As ,it is moved. into engagement with the contacts 2, 3 and 4, it also successively closes the circuits at these points of the main energizing coils of the resistance switches 17, 18 and 19, and, b its further movement into engagement with contacts 5, it cuts in different portions of the field resistance. The position of the master controlling switch arm 32 thus predetermines the motor speed.

In any of the operating positions of the master controlling switch, the operation of the run button-will close a circuit from conductor 41, by conductor 45 ,through the coil of therelay 20 and throng a resistance 66 to the return conductor 39. The operation of the relay 20 will close the contacts 49 and complete a circuit by conductor 67 through the energizing coil of the relay 21 and thence throughresistance 68 and a con ductor 69 to the return conductor 39. Proferably, as shown, the conductor 67 is connected to the coil of relay 21 by the -up or normally engaged contacts provided on the slow push buttons so that the locking circuit of relay 20 can be opened by depressing one,v of the slow buttons without opening the circuit of the relay 21. The operation of the latter relay will engage the contacts 44 and thus close a locking circuit from the conductor 41 through its own coil and by means of conductors 47 and 67 andcontacts 49, through the coil of the relay 20,

so that the coils of both these relays will remain energized when the run button is released. The operation of the relay 21 will engage the contacts 43 and thus close a circuit from conductor 41 by the conductor 69 and the conductor 46, through the energizing coil 28 of the starting switch 15 and by a conductor 7 0 to the return conductor 39. The starting switch will thus be operated to close the motor circuit and startthe motor in operation in' forward or normal direction, and, since-the circuit of the coil 28 is held closed by the relays and 21, the motor will continue in operation until the holding circuits of the relays are opened by operating one of the stop but tons. Also, of course, the circuits of these relays can be opened by returning the master switch 32 to its oil position or by opening the line switch 13, or in case of failure of voltage or excessive voltage drop in the line circuit. relay 2O alone can be opened by depressing one of the slow buttons.

In the operation thus described of starting the motor, a circuit is also closed from the controlling supply conductor 41 through the contacts 43 of the relay-21, thence by conductors 69, 46 and 62, through the normally closed contact 63 to the starting torque coil 59 and thence by conductor 60 and contiicts. to the return conductor 39, thus closing the contacts of the resistance switch 17 to reduce or cut out a section of the armature resistance 14 and provide a high starting torque to enable the motor to overcome the inertia and resistance of the load. The operation of the switch 17 also opens the contacts 65 and introduces the protective resistance 61 into the circuit of the starting torque coil 59. Then, when the motor reaches a certain predetermined speed the counter M. E. coil 31 is energized to seal the normally engaged contacts of the switch 16-and open the contacts 63 to deenergize the starting torque coil 59. Then unless the main coil of the switch 17 is energized at this time, the main contacts of this switch will be opened and the motor will continue operation at slow speed with the entire resistance 14 interposed in the armature circuit.

Similar operations take place when either one of the inch or of the slow push buttons is operated. Thus, if the motor is ata stand-still and the contacts of one of the inch buttons areengaged, a circuit is completed from supply conductor 41 to conductor 46 and thence as before through the energizing coil 28 of the starting switch and through the starting torque coil 59, and the motor will start with reduced resistance in its circuit and, 1 when sufficient counter E. M. F. is developed in its circuit, the coil 31 will open the contacts 63 and tie-energize the coil 59 to thus include the entire armature resistance in the motor circuit.

The motor will thus run at slow speed as long as the inch button is held down but, since the latter does not energize the locking relay 21, the coil 28 will be deenergized and the motor stop when the inch,

push button is released. When a dow Also, as noted. the circuit otaseaam i the coil of the relay 21 and the latter will operate as :before to lock in its own coil and complete the circuits of the coils 28 and 59, the latter being de-energized as described, when the motor has accelerated to a predetermined speed. Inasmuch as the slow push button energizes-the relay 21, the motor will continue operation at its low or first speed till the coil of this relay is de-energized, say by pushing one of the stop buttons. 'However, the relay 20 is not energized by the slow button and the contacts 50 which control the counter E. M. F. coils of the resistance switches 17, 18, and 19, will remain open and the resistance switches will not be operated to accelerate the motor, no matter what may be the position of the master or speed controlling switch 32. There will also be no operation ofthese switches to accelerate the motor when the inc-h button is operated.

When, however, the relay 20 is energized by the operation of one of the run buttons, the contacts 50 are engaged and the speed of the motor will be accelerated-if the master or speed controlling switch 32 has he no acceleration if the master switch arm 32 is in its first operating position on contact 1, but. if it is in engagement with contact 2, a circuit is completed when the relay 20 is energized from the positive terminal of the'motor through conductor 27, normally engaged contacts of switch 16, conductors 10 and 37, to contact bar 33, thence by switch arm 32, contact 2 and conductor 53, through the main coil of the switch 17 and thence by conductors 51 and 26 to the negative terminal of the armature and, when sufiicient counter E. M. F. is developed in the motor circuit, the main coil of the switch 17 will be energized. Preferably, this main coil is so arranged that when its circuit is closed as described, the switch 17 will not open when the contacts 63 are disengaged by the counter E. M. F. coil 31 to tie-energize the starting torque coil 59. If the master controlling switch 32 engages its contact 3 and the relay 20 is operated by, one of the run buttons, a circuit will be completed, if the resistance ,switch 17 has operated, from the positive terminal of the motor, as before, to the switch arm 32, thence by conductor 54 through the coils of switches 18 and 17 in series and back as before to-the negative motor terminal, and, when the motor reaches a predetermined speed, the switch 18 will be operated to cut out another section of the armature resistance. If the speed controlling switch 32 is in engagement with the contact 4 or with the contactbar 36 when resistance 40.

the relay 20 is operated, a circuit will be completed, after the operation of the switches 17 and 18, from the switch arm 32 to the conductor 52, and thence through the coils of the switches 19 and 18 and the main coil of the switch 17 and, when the motor reaches a predetermined speed, switch 19 will cut out the remaining portion of the armature resistance. The shunt contacts and 56 insure the successive operation of the resistance switches, even though the speed controlling switch is in engagement with contact 4 or contact bar 36 when the motor is started, by operating relay 20. In this case the circuit is completed through the conductor 52, thence through the shunt contacts 56 and 55 in series to the main or counter E. M. F. coil of the switch 17 and when this switch operates it opens the shunt contacts 55 and includes the coil of switch 18 in the circuit. The operation of the latter will open the shunt contacts 56 and include the coil of switch 19. While theopening and closing of the circuits of the counter E. M. F. coils of the resistance switches is thus controlled by the position of the switch arm 32, the shunt contacts 55 and 56 and the contacts 50 of the relay 20, these coils are responsive only to different predetermined conditions established in the armature circuit as the speed. of the motor is increased, so that the rate of acceleration is automatically controlled in accordance with the load on the motor.

When the last resistance switch 19 is operated, it opens the initial full field contacts 57 and thus opens the shunt normally closed by these contacts around the field The amount of this resistance which is thus connected in circuit with the field will, of course, depend upon the position of the switch arm 32. But, irrespective of the position of the switch 32, no portion of the field resistance can be cut in until all of the armature resistance has been cut, out of the motor circuit. If the introduction of the field resistance so reduces the field current that excessive flow of current is caused in the armature circuit, the field relay 22, the coil of which is included in the armature circuit, is energized to engage its contacts and close another shunt around the field resistance and this relay will flutter or close and open until proper conditions are established in the motor circuit.

From the foregoing it will be apparent that the switch 32 may be set in any desired position to prcdetermine the motor speed and that by operating one of the run but tons the motor may be started and its speed automatically accelerated in accordance with the conditions established in the motor circuit to an extent determined by the position of the master controlling switch Or if the relay 20 has been operated by means or" the run button, the speed of the motor can be accelerated or deceleratedl by adjusting the position of the master switch 32. The inch and slow buttons can be operated as described to start the motor for limited or continuous operation at slow speed in any of the operating positions of the main controlling switch. However the motor is started, the coil 59 will be energized to reduce the armature resistance and provide a high starting torque and this coil will be de-energized when the motor accelerates to a predetermined speed and, unless the speed of the motor is to be accelerated, the contacts of the switch 17 will then be opened to include the entire armature resistance Within the motor circuit.

It is noted that, while the coil 59 may if desired operate contacts separate from those of the resistance switch 17, it does not, in the preferred arrangement shown, interfere with the operation of the main coil of. this switch, so that the latter serves both as a starting torque switch and also as a resistance switch. Thus if a slow button is operated to start the motor the E. M. F. coil 59 and the counter E. M. F. coil 31 will operate as described, first to reduce or out out a portion of the armature resistance and provide a high starting torque, and then again include the entire resistance in the armature circuit to effect the continued operation of the motor at slow speed. Then it a run button is operated and the master switch 32 is in position to include the main coil of the switch 17, the latter, when sufficient counter E. M. F. is developed in the motor circuit, operates to cut out a section of the armature resistance and accelerate the motor.

When the motor is placed in operation by depressing one of the run buttons, the circuits of relays 20 and 21 are closed and locked in closed condition as described, and the motor will accelerate in accordance with the setting of the master controlling switch. The motor can then be arrested by depressing one of the stop buttons which will open the locking circuits of the relays 20 and 21. But, if when the motor is thus in operation a slow button is depressed, then only the locking circuit of relay 20 will be opened which will in turn deenergize any of the accelerating switches 17, 18 and 19 that may have been operated and thus throw the entire armature resistance into the motor circuit; but inasmuch as relay 21 remains energized, starting switch 15 will remain closed and the motor will continue its operation but at slow speed. It is thus possible to reduce the speed of the motor by operating one of the slow buttons without first operating one of the stop buttons. Also, of course, when the motor is operating at slow speed it can be arrested by deall) , the reversing pressing a stop button and thus open the locking circuit of relay 21. q

The operation of one of the reverse buttons will disconnectthe main supply conductor of the controlling circuit from the run, .inch and slow pushbuttons and will complete a circuit from conductor 11 to conductor 48, through the energizing coil 29 of the reversing switch 16, and thence by conductor 70 to the return conductor 39.

The sWitch'17 will then be shifted to close the motor circuit and start it in operation in reverse direction. When the reversing switch 16 is thusoperated, the motor circuit will be closed through a section of the armature resistance 14 and through the brake resistance 23 and the motor will continue operation in reverse direction at a speed predetermined by this resistance as long as one of the reversing push buttons isheld denot serve to shift the reversing switch.

Hence, the motor must be stopped before its direction of movement can be reversed. The reversing push buttons are,-h'owever, preferably, arranged to disconnect the con ductor 41. from the conductor 42, so that the o eration of the frun, inch and slow buttons at the diiferentstations will have no effect if one of the-reverse buttons is depressed.

Obviously, changes ma be made in the .details set forth without eparture-from the essentials of the invention as defined in the claims.

We claim as our invention:-

1 In combination in a motor controller, separate, electromagnetic starting, accelerating and torque switches, a speed regulating l member adapted to be pre-set to determine the running speed of the motor, said torque switch being operable in any of the running positions of said. regulating member to provide a predetermined high torque for starting, and means automatically controlled by the acceleration of the motor to a predetermined speed for disabling said torque switch.

2. In combination in a motor controller, separate, electromagnetic starting and accelerating switches, a regulating member manually operable to predetermine the running speed of the motor, manually operable contacts foropening and closing the circuit of said switches to stop and start the motor, an electromagnetic torque switch controlled by said contacts and operable in any of the running positions of said regulating member for providing a predetermined high torque for starting,-and means automatically controlled by a condition developed in the motor circuit for disabling said torque switch.

3. In combination in a motor controller, accelerating means responsive to conditions established in the motor circuit, controlling switch means manually operable to start and stop the motor and variably control the operation of said accelerating means to predetermine the running speed of the motor, a device operative on starting the motor for. providing a high torque, 'and means controlled by the acceleration of the motor to a predetermined speed for disabling said starting torque device.

4. In a motor controller, the combination with electro-responsive starting and accelerating means and controlling switch means cooperating therewith to stop the motor and start the motor and including a member for predetermining the operation of saidaccelerating means, a device operative on starting to reduce the motor resistence and provide a high starting torque, said acceleratingv means being responsive to counter electro-motivc force developed in the motor circuit and means also responsive to counter electro-moti-ve force for disabling said high starting torque device.

5. In combination in a motor controller, electro-magnetic starting means, electromagnetic accelerating means responsive to electrical conditions established in the motor circuit, a speed controlling switch for directing the operation of said accelerating means, auxiliary control push-button switches cooperating with said starting and accelerating means to stop the motor and start the same for operation at slow speed or at a speed determined by said speed controlling switch, and means, adapted to be disabled by a condition established in the motor circuit for providing a high torque for ,starting.

6. In combination in a motor controller, an electromagnetic starting switch, a series of electro-magnetic resistance switches responsive successively, when in circuit, to

different conditions established in the mo- 'tor circuit, manually operable switches for and contacts controlled by a predeterminedcondition established in the motor circuit for deenergizing said coil.

7. In combination in a motor controller, an electro-magnetic starting switch, a series of electromagnetic resistance switches responsire successively, when in circuit, to different conditions established in the motor circuit, a speed controlling switch for directing the operation of one or more of said resistance switches, auxiliary controlling push-button switches for opening and closing the circuits of said electromagnetic switches to start andstop the motor,-a device for reducing the motor resistance for starting, and means responsive to counter electro-motive force for disabling said device.

8. In combination in a motor. controller, an electromagnetic starting switch, a series of electro-magnetic resistance switches responsive successively when in circuit, to different conditions established in the motor circuit, a speed controlling switch for directing the operation of one or more of said resistance switches, and manuallyjshiftable to accelerate ordecelerate the motor, pushbutton switches for opening and closing the circuits of electro-magne'tic switches to stop the motor and start the same for limited or continuous operation at'slow speed or for continuous operation at a speed determined by said speed controlling switch, on E. M. F. starting torque coil torreducing the motor resistanceon starting and a counter E. M. F. coil for ,de-energiz'ing said starting torque coil.

9. In a motor controller, the combination with electro-magnetic starting and resistance switches and controlling contacts there- .for operable to start and stop the motor, of an E. M. F. coil for reducing the motor resistance to provide a high torque for starting, normally closed relay contacts in the circuit of said coil, and 'a counter E. Ml F. coil for opening said contacts.

I 10. In combination in a motor controller, an electro-responsive starting switch, a series of electro-responsive resistance switches having counter E. M. F. coils operable in succession when in circuit, starting, stopping and speed determining contacts for controlling the energizing circuits of said switches, an E. M. F. coil for providing a high starting torque, and a counter E. M. F. coil for deenergizing said starting torque coil. c

11. In combination in a motor controller, an electro-responsive starting switch. a series of electro-responsive resistance switches having counter E. M. F. coils operable in succession :when in circuit, starting, stopping and speed determining contacts for controlling the energizing circuits of said switches, an E. M. F. coil for operating the contacts of one of said resistance switches to provide a high torque for starting. and a counter E. M. F. coil for deenergizing said starting torque coil.

12. In combination in a motor controller, an electro-responsi-ve starting switch, a series a high torque for starting, a counter E. M.

F. coil t'or deenergizing said starting torque coil, master controlling contacts for directing the operation of one or more of said resistance switches, and a number of sets of push botton contacts, one set operable to open the energizing circuits of said switches to stop the motor, and other sets operable to close the same and the energizing circuit of said starting torque coil to start the motor for operation at slow speed or at a speed determined by said master controlling contacts.

13. In combination in a motor controller, separate electro-responsive starting and resistance switches, energizing and holding circuits for said switches, and a series of push button controlling switches, one operable to close the energizing and holding circuits of said starting and resistance switches and another operable to close the energizing and holding circuits of said starting switch alone.

i 14:. In combination in a motor controller, separate electro-responsive starting and resistance switches, energizing and holding circuits for said switches, and a series of push button controlling switches, one operable to close the energizing and holding circuits of said starting and resistance switches, another operable to close the energizing and holding circuits of said starting switch alone, and a third operable to open said circuits.

15. In combination in a motor controller, separate electro-responsive starting and resistance switches, energizing and h lding circuits for said switches, and a series of push button controlling switches operable respectively, one to close all of said circuits, another to open the same. another to close only the energizing and holding circuit of said starting switch, and another to c ose only the energizing circuit of said starting switch.

18. In combination in a motor controller, separate electro-responsive starting and resistance switches, two re ays. one operable to close and maintain the energizing circuits of said switches and the other operable to close and maintain the circuit of sai-l startin switch only, and separate n'mnuully operable switches for selectively controlling the circuits of said relays.

'17. In combination in a motor controller,

separate electro-responsh-c starting and resistance switches, two relays, one operable to close and maintain the energizing circuits of said switches and the other operable to close and maintain the circuit of said starting switch only, manually operable. speed controlling contacts for predetcrmining the operation of the resistant switch or switches, I

and a number of sets of push-button contacts for variably controlling the circuitsof said relays and of said starting switch to stop able to close and maintain the circuit ofsaid starting switch only, manually operable speed controlling contacts for predetermining the operation of the resistance switch or switches, and three sets of push button contacts for variably controlling the energizing circuits of said relays and said starting switch and operable respectively to start the motor for limited or continuous operation at slow speed or for continuous operation at a speed determined by said speed control contacts, and another set of push button contacts for opening said circuits-to stop the motor.

19. In combination in ainotor controller, an electro-magnetic starting switch, a series of electro-magnetic resistance switches responsive to predetermined conditions established in the motor circuits,,a master controlling switch for'directing the operation of one or more of said resistance switches, separate relays, one operable to close and maintain the energizing circuits of said starting switch and of one or more of said resistance switches-in accordance with the setting of said speed control switch and the a other operable to close and maintain the circuit of the starting switch only, and a series of push button switches for variably controlling the circuits of said starting switch and of said relays to stop'the motor and I start the same for limited or continuous operation at one speed or for continuous operation at any one of a number of different speeds.

20. In a motor controller, separate electro-responsive starting, reversin and resistance switches, a master contro ling switch .for 'p'redetermining the o eratiolrof said resistance switch or switc es and a series of push-button switches operable, one to 'close the circuits of said starting and resistance switch, another to close the circuit of said reversing switch, and a third to open the circuits of all of said electro-responsive switches.

21. In a motor controller, separate electroresponsive starting, reversing and resistance switches, a master controlling switch for predetermining the o eration of said resistance switch or switc es, and an auxiliary control station comprising a number of starting push-buttonswitches for variably controlling the circuits of said starting and resistance switches to operate the motor at slow speed or at a speed determined by said master switch, a reversing push-button switch arranged to open the circuits through said starting push-button switches-and close the circuit of said reversing switch, and a stopping push-button switch for opening the circuits closed by .the other push-button switches. 1

22. In a motor controller, separate electroresponsive, starting and reversing switches, each having normally engaged and disengaged contacts and arranged, when either is operated, to supply current to the motor through the normally disengaged contacts of the operated switch and the normally en'- gaged contacts of the other switch, separate operating coils for said switches, counter E. M. F. coils for sealing the normally engaged contacts of said switches, and separate pushbutton switches for energizing the circuits of said operating coils'respectively.

tro-magnetic accelerating switches operative,

when in circuit in succession and in response to different electrical conditions established in the motor circuit to cut out diflferent sections of the armature resistance, and starting, stopping and speed determining contacts controlhngthe circuits of said switches and said field resistance, the resistance switch last to operate being arranged to open a normally closed shunt around the field resistance.

24. In combination in a motor controller, armature and fieldresistances, an electromagnetic starting switch, a series of electromagnetic accelerating switches operative, when in circuit,-in succession and in response to different electrical conditions established in the, motor circuit to cut out different sections of the armature resistance, and starting, stopping and speed determining contacts controlling the circuits of said switches and said field resistance, the resistance switch last to operate being arranged to open a normally closed shunt around the field resistance and each of the other resistance switches being arranged to open a normally closed shunt around the coil of the succeeding resistance switch.

25. In combination in a motor controller, separate electro-responsive starting and resistance switches, energizing and holding switches and close those of said starting switches, a second relay operable to close auxiliary adapted to stop the motor, start the same for.

continuous operation at slow speed or at a and maintain the circuit of said starting switch alone, and a number of push-button contacts for variably controlling the circuits of said relays, two of said sets being operable toenergize and'de-energize both of said relays and another of said sets being oper able to deenergize said first relay and deenergize said second relay.

27. In combination in a motor controller, an electro-responsive starting switch, a series of electro-responsive resistance switches, a master speedcontrollingswitch for directing the operation of one or more ofcsaid resistance switches, and a series of control pu'sh button swit hes speed determined by the setting of said master switch and to decelerate the motor to slow speed without first stopping the same.

28. In combination in a motor controller, en electro-responsive starting switch, a series of electro-responsive resistance switches, a master speed controlling switch for directing the operation of one or more of said resistance' switches, separate relays, one operable to close and'maintain the energizing circuits of saidstarting switch and of one or more of said resistance switches in accordancewith the setting of said master switch,

and the other relay operable to close and maintain the circuit of the starting switch only, and a series of push-button switches for variably controlling the circuits of said relays to stop the motor, start the same for continuous o ration at slow speed or at a speed determined by the master switch and vto reduce the speed without stopping the motor.

ALLAN J; CLINE. THELMA 1. DEKLE.

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