US1110039A - Series-parallel control system. - Google Patents

Description

E. R. OARICHOFF. SERIES PARALLEL CONTROL SYSTEM.

APPLICATION FILED APR-15, 1913.

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Witnesses Inventor-z Eugene F?.Car*ichoffl P b I H Hisa ttc' rne g.

E. R. CARIGHOPP. SERIES PARALLEL CONTROL SYSTEM.

APPLICATION IILBD APR.15, 1913.

1,1 10,039. Patented Sept. 8, 1914. 2 SHEETSSHEET z.

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Witnesses Inventor":

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EUGENE GARICEUFF, F SCIl'ENEC-TADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORIORATION OF NEW YORK.

SERIES-PARALLEL CONTROL SYTEM.

To all whom it may concern Be it lrnown that I, EUGENE R. CART- onorr, a citizen of thc United States, residing at rlchenectady, in the county of ischencctady, State of New York, have invented certain new and useful improvements in. Serieslarallei Control Systems, of which the following is a specification.

This invention relates to the control of electric motors and more particularly to the control of a plurality of motors operating ir proved series parallel control electric motors in which the eleclc switches for short circuiting the re thetype in which the op gs are in the motor circuit. the series parallel control sysen ctistoinary to employ a single which-ls first connected in the of the rnolxarsin series position'and "1 connected in series with the motors allel position. it is essential that the switches shall d 21 open upon. being; denergized before it llel connections are made, otherwise tors may be connected incircuit with tie protecting resistance. This diiliculty is sometimesoveroonie by the use of interlocking contacts for insuring the proper sequence or operation.

I in carrying out my invention I employ a resistance for the motors in the series posi tion which is separate and distinctfrom the it istsnce employed in the parallel position of the motors. The resistanoeis short circuited b the electromagnetic switches and then is t short circuited while the other resistances are connected in circuit with the motors in the arallei position. With my va.rrangemem". toe motors go through the complete cycle from the series to the par allel" position employing electromagnetic switches having operating windings in the motor circuit for short circuiting all ofthe resistances, without opening the motor ciroiiit in making the transition, and the use of interlocking contacts on the resistance switches may be entirely dispensed with.

@ther objects and purposes of in" ,lnvention will appear in the course iii-g specificationin which 1 have shown my Specification of Letters Patent. Application filed April 15, 1913.

on what is known as the series parallel sysof the objects of my invention is to Viith this arran e of the' follow- Patented Sept. 8, 1914. Serial No. 761,241.

invention embodied in concrete form for purposes of illustration. 4

in the accompanying drawings, Figure 1 illustrates one form of my invention, and Fig. 2 illustrates a modification thereof.

Referring to Fig. l of the drawings, A and A represent the armatures of two motors to be controlled and F. F the series fields of the motors. ii, R, R represent the sections of resistance which are to be con nccted in circuit with the motor in the series position and are known as the series resistance. R R and R are sections of resistance to be connected in series with the a-rmatures A and A respectively, in the parallel position. S and S are the two electromagnetic switches for short cirouiting the resistance while similar switches S S 5* and S short ei'rcut the resistances R and PM respectively. The particular construction and arrangement of these electromaga netic switches forms no part or my present. invention, teristic features of these switches are of importance in the operation of my system.

,These switches have their operating windings in the motor circuit and have the characteristic that they are held in the open QOSl'tlOY-l when the current relatively high and (h. not close until the current falls to a predetermined value.

The particular form of switch which is diagriumnafically illustrated in the drawing is covered by a prior application of Edwin J. liiurphy. Serial No. (108,652, filed Febi ary 15, I911. 1

8 and (T are two contactors of the. ordi nary type for controlling the motor circuit. These contactors are controlled by the Inaster controller M, contactor B being energized in the first position and contactor O in the second troll'er.

D represents an electromagnetic switch for changing the connections the motors,

from series to parallel. The particular construction of this switch forms no part of my present invention but is coveredby a separate implication filed by me, Serial No. 755,399, filed March 2 1913. This switch consists of a magnetizing winding 1O adapted to be connected in the motor circuit and a core or plunger 11 having pivoted thereto a switch arm 12. The core 11 is connected although the charac position of the master con-f to the central point ofthe switch arrh 12 and the latter cooperates at either end with the contacts 13, 14:; A spring 15 presses the left hand end of the lever into engagement with the contact I l. ,lVhen the winding is energized the core is raised and with it the lever 12. During the first portion of the movement, the contz ct it acts as a fulcrum forthe lever until the right hand end of 10 the contact is brought into engagement with the contact 1.3. When the engagement is made'with the contact 13 the latter becomes the fulcrum so that further movement of the core. compresses the spring 15, and moves the 15 lever -l2 out; o;fi engagement with the con- 9 "3; h he circuit of the winding 10 is controlled by contacts]: .T which operates in the same mannergaslthe icontactors, S, S, S 800.,

f 29, with the exception that the moving contact is .notconnected withthe operating winding but is insulated from the switch structuren zihe switch, therefore, is held 0 en when ecurrent is high and closed w en I the ,ou rrent falls to apredetermined value.

The,, -r'vindingof this contactor 1s ener zed t open by the nch s so that even thoughthe'. resistgnceisall cut out and the current has fallen ton predetermined value, the contactor T will ..not close to estghli-sh the llel.

position untilfthe master 'oh trol er has. 40 movedztothe third positlon and electromafi;

net '17 is e'nergiz which attracts the late 16 and moves it against the tension of sprin f 16 to release the.;contact of the contactor As thus constructed and arranged the operationof my system is as follows, assuming the Part r master controllefihgs moved into the first position a, contactor 'B will be energlzgdy thereby closing the motor circuit frifi the 1 botrolleyto the contacts of contactor B, re-

sistances R, armature A, field F, throu h the contact 14 and lever 12 of switch I), armature A and field F to ground. In this first position of the master controller, therefore, the motors are in series with all the series resistance in circuit. When the master controller is moved to the position b the contactor C. is energized which upon closing short circuits the first section of resistance so B through the operating winding of the switchS. The cutting out of a section of re sistance It causes rush of current through the motor circuit a d winding of the switch S. All the switches S are constructed, in a '55 manner now well understood, so that they the position shown. When thewill not close at the first rush of current but only after the current has dro pod to a predetermined lower value. W en, however, the motors speed up so as to reduce the'current to a predetermined value the. switch S will close, thereby short circuiting the sec- 1 0nd section of resistance It and connecting the oper'atin winding of the switch S in circuit. In like manner, when the switch S. closes the last section of resistance R is short circuited through the winding of the contactor T. The two motors are now connect,-

cd in series through the contacts of the contactors B and G, S and S, and through the winding of the contactor T. If new the master controller is moved into the-position c the. wire leading to the electromagnetg,'17 will be connectedto trolley so that the latch 16 will be moved torelease the contact of the contactor T, which will therefore close ea '86 soon as the .current in the motor circuit drops. to '9, predetermined value and therebyclose. the clrcuit' of the winding 10 of parallel switch D. The winding 10 being energized, the parallel connection of-the motors will first be made at the contact 13, and the series connection then'brok'en at the contact/i4.

The motor circuit now divides into two par.- allel paths, one leading from trolley through the contacts of the contactors B, C, S, .S' and? or? the winding of contaetorf T, armature A,

field F, contacts of contactor; T, winding 1D} of switch D, thence thr'ou h the winding ofii" switch S. and resistances 2 to ground,-,and .theother leading'throu h the contacts. o'flrloo contactor B, resistances it B to thewind in; of the switch S contact 18, armature A "and field F to ground. It will be noted [that the current to motor A is still supplied through the contacts of the series switches 195 S S so that the latter must be maintained in closed position. In other words, successful operation does not depend u on the open' 0 the switches S and S-. he first rush hfi current upon connecting the motors in paral- 101 causes the switches S and S to hold open until the motors speed up and reduce the current, whereupon the switches S, and

'sfi close and short circuit the first section of\-resistance B and R? respectively In H5 like manner switchesS and S close and short circuit the last section of resistance; 'thejreh connecting the two motors in parsllel wit all resistances short circuited.

In Eig.- 2, I have shown a modified form of my invention in which one of the parallel resistances is also used in series. In order to bring about this result the arrangement of the switchesf'B f11151 0, corresponding to the arrangement ot-sviitchea B and .G of 120 which are closed, whenthe switch 010508. 30

a, a mess With this arrangement one of the switches for controlling the resistances R is dispensed with, since the function is accomplished by a second operation of the switch B The operation of this form oi my invention is as follows: When the master controllcr M is moved to the first position. the contactor B is energized through the interlocking contacts 19 of the contactor G. This closes the motor circuit from the rolley through the contacts of the coutactor B, through the resistance R, thence through the resistances it, armature A, field i con tact- 1430f the parallel switch D, armature A, field F to ground. lVhen the controller is moved to the second position shown at I), contactor C is energized which closes the interlocking contacts 18 and opens the interlocking contacts 19 to decnergize the contactor B. The closing of the switch C short circuits the resistance R and completes a circuit from trolleythrough the contacts of contactor C, through the winding of switchS, resistance R, armature A, field l contact 14, armature A, field F to ground. The remaining sections of resistance R are cut out of circuit as described above. When the controller is moved to the third position 0 the parallel switch D closes as betore, the connection of the motors being as follows: From the trolley through the contacts of the contactor C, through the winding of contactor S, thence through two paths, one through the. contacts and windings of the switches S and S contactor T, armature A, field F, thence to the contacts of contactor T, winding of parallel switch D to the switch S, resistances R to ground,

while the other path is fromthe winding of the switch S, through the resistances R, winding of the switch S contact 1.3 of switch D, armature A, field F, to ground. The first rush of current upon connecting the motors, in parallel causes the switches S and S to hold open until the motors speed up to reduce the current, whereupon these switches close and short circuit the first section of resistance R and R respec; tively. When the switch S closes it short circuits the section of resistance B through the winding of'switch S and when the current drops to a proper value the switch S will close and short circuit the second section of resistance R The closing of the switch S closes the interlocking contacts 20 which completes a circuit through the wires 21 and 22 to the contactor B independently of the contactor C, The closing of the contactor B short circuits the second section of resistance R and places the two motors in parallel across the line. Contactor B, therefore, serves the double purpose of closing the motor circuit in the first position of the master controller and of acting as a resistance switch to cut out section of resistsigned to break current.

R in the last position of the master auce' controller. The interlock 18 on contactor C insures that the two controller's B, and C will both drop out at the same time when .the controller is returned, thereby preventing the current from being broken on some of the other contactors which are not do Aside from the use of? the resistance R in the series position this system operates practically the same as the system shown in Fig", l. The advantage of the use of this resistance in the series position that a very slow speed may he obtained in the first position of the master cos'itrollcr without unduly increasing the amount of resistance.

' While it have described my invention as emho-died'in concrete form and asoperating in a specific manner for purposes of illustration, it should he-understooelt'hat i do not limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of which is. set forth in the annexed claims. lVhat I claim as new and desire to secure by Letters Patent of the United States, is' 1. In a series parallel control system, a. pair of electric motors, electromagnetic means for connecting said motor in series or in parallel, a resistance for the motors in the series position, additional resistances one for each motor in the parallel position, and

electromagnetic switches having their operating windings in the motor circuit for controlling said resistances.

2. In a series parallel control system, a pair of electric motors, resistances for the motors, electromagnetic witches having their operating windings in the motor circuit for short circuiting said resistances, and means whereby said motors are connected first in series and then 'in parallel with a resistance in circuit in each position without opening the motor circuit.

3. In a series parallel control system, a pair of electric motors, a series resistance, a master controller, means controlled thereby for connecting said motors and resistance in series with each other, electromagnetic switches having their operating windings in the motor circuit for cutting ,said resistance out of circuit, means for connecting the motors in parallel through the closed contacts of said resistance switches, a resistance in series with each motor in the parallel position, and electromagnetic switches having their operating windings in'the motor circuit for cutting out said resistances.

4. In a series parallel control system, a pair of electric motors, a resista'ncefor the motors in the series position, a resistance for" each motor in the parallel position, electromagnetic switches having their operating windings in the motor circuit for short cir- 'euiting said resistances, and means whereby parallel with a resistance in series with each motor without openin the motor circuit.

5. In a series para lel control system, a pair of electric motors, a resistance for the motors in the series positiom a resistance for each motor in the parallel position, electromagnetic switches having their operating windings in the motor circuit for short cirouiting said resistances, and an electromagnetic switch for connecting the motors in parallel with a resistance in series with each motor through the closed contacts of the series resistance switches.

6. In a series parallel control system, a pair of electric motors, a series resistance, a

master controller means controlled thereby for connecting sald motors and resistance in series with each other, electromagnetic switches having their operating windings in' the motor circuit for short circuiting said resistance, a resistance for each motor in the parallel position an electromagnetic switch for connecting the motors in parallel each with a resistance in circuit therewith through the closed contacts of the series re sistance witches. v

In witness whereof, I have hereunto set my hand this 14th day of April, 1913.

Y EUGENE R. GARICHOFF.

Witnesses;

Y BENJAMIN B. HUL

IIELEN ORFORD.

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