US1658918A - Motor-control system - Google Patents

Description

Feb. 14, 1928. 1,658,918

R. BROOKS ET AL MOTOR CONTROL SYSTEM Filed Jan. 8, 1923 WITNESSES: P g 5 INVENTORS Robert Brooks and 7 Edward Hush Croft ATTORNEY Bonner BRGOKS, or ASETGlW nnonann, assist? HOUSE ELECTRIC 35 n'oivan-n (more, on Lnnns,

rarer, a conronarron' or r nnnsrnvnnia.

MGTOR-COI'ITRGL SYS'iEI-I.

Application filed January 2, 1923 Serial No. 611,264,

Our invention relates to control systems and it has special relation to control systems in which the acceleration of a motor by short-cir'cuiting a series resistor is automatically efiected by means of electrically actuated switches or contactors. In these systems, the operation of the switches is usually controlled in accordance wit-h the armature current of the motor by a current limiting relay, whereby the switches are prevented from operating until the main armature current falls to a predetermined sate value.

An object of our invention is to provide, in an automatic control system employing a current-limiting rel-Cy, means whereby, under abnormal conditions, the necessary accelerating steps may be effected independently of the normal relay action.

Another object of our invention isto provide, in a system of the class described above, means whereby certain circuits normally controlled by a current-limiting relay may be controlled independently of the current relay.

In systems of the class referred to, ditficulty is sometimes experienced under severe conditions of track or gradient in starting the train. For enainple, it one motor on a locomotive is out of condition, the accelerating current for which the relay set may be insutlicient to effect the'starting of the train, and the relay will, therefore, hold the equipment on the first accelerating notch or step, so that the other contactors control ling 1 other notches or steps cannot close.

According to our invention, a push-button switch, under the control of the driver, is arranged in such manner that the contactor circuits, or the energizing circuits of the electrically operated switches that effect the accelerating steps, may be directly energized independently of the operation of the current-limiting relay even it the relay does not operate by reason 01 a relatively high armature current.

In order that the invention may be clearly understood, it will now be described with reference tothe accompanying drawings, in which a diagrammatic representation and in Great Britain January 11, 1922.

01 a main or motor circuit including a variable resistor and a current-limitin relay,

Fig. 2 is a di' glttllllllltlC representation of our control circuits and control devices for automatically or manual effecting accelera tion of the motor shown in 1, and

Fig. dis a dia rammatic representation of a modification of part of the circuits and devices shown in Fig. 2.

The main inotor circuit illustrated in Fig. 1 comprises an armature 1 and field winding 2 of a series motor which may be connected to a supply conductor 3 and ground G through a variable resistor 5, aline switch 6, and a current-limiting rela 29. Sections 7, 8 and 9 t tl e variable resistor 5 are adapted to be sl'iort-circuited respectively by switches 10, 11 and 12, which are controlled respectively by coils 14:, 15 and 16.

ltei erringto Fig. 2, the control system here shown comprises the supply conductor 3, a plurality ot coils 13, l t, and 1G for operating lOSPBCtlVGly the main switches 6. 10, 11 and 12, shown in 1, and certain interlocking switches, in a manner to be hereinafter set forth, together with a master controller 19, having three positions a, Z) and 0, which acts in conjunction with a currentlimiting relay 29 to successively energize the coils 18, 1e, 15 and 16. ii push-button switch 19 is connected to one of the stationary contact members of the relay 29, for a purpose to befisubsequently set forth. 7

The current-limiting relay hereinafter described in the specification and illustrated in the drawinq'is preferably of the type shown in Patent rlo. 1,077,972, granted to E. R. Carichotl, Nov. 11, 1913, to which reference may be made for a detailed description.

The relay 29 comprises essentially a plurality of coils 2'7 and which, during certain operative positions of the iii-aster controller 19 respectively control the operation of plungers or cores 53 and 51. A plurality of movable contact members 30 and 31 cooperate with the plungers 53 and 5% to bridge stationary contact members 32 and 33, and and respectively. coil 36 of the relay 29 is connected in series relation with the main motor circuit, as shown in Fig. 1. and is adapted, when the motor current on ceeds a predetermined value, to retain either I of the movable contact members 30 and 31 in l are closed and the interlock switch 45 of.

its open position after actuation thereto by its own coil 27 or 28, irrespective of the continuance or discontinuance of the Ile1g1Z2l tion of that coil.

Assuming the'various switches and other apparatus to occupy the illustrated inoperative' positions, the operation of the automatic I accelerating system illustrated in Fi 2 is as follows: W hen the master controller '19 is moved from the off position a to the initial operative position b, a circuit will be established from supply conductor 3 through contact segment of the controller 19, control finger 21, coil 13, of switch 6' and interlock switches 22, 23 and 24 of switches 10, 11 and 12, respectively, to ground G. In

this manner, the line switch 6 is closed byreason of the energization of its operating coil 13 and the motor is connected to the supply conductor 3' and ground G, through the accelerating resistor 5. r r

If the master controller 19 is actuated to its second operative position 0, a circuit switch 11 is open, the coil 27 only of the relay 29 will be energized and the contact member thereof will be raised. The circuit being described thus continues from the common relay terminal 26 through 0011 27, contact members 34, 31 and 35, interlock switches 37 and 38, actuating coil 14 of contactor switch 10, conductor 39, and interlock switches 23 and 24 to ground G. The resistance'step 7 being thus short circuited, the motor will'accelerate to a given speed, in accordance with familiar principles. 2

By reason of the closure of contactor switch 10, interlock switches 22 and 38 will open and interlock switches and 41 will close, sothat the energization of coil 14 of the contactor switch 10. is transferred through interlock switch 40 to the circuit by means of which the line-switch actuating coil 13 is energized, this circuit extending as follows: From" supply, conductor 3 through contactsegment- 20, of controller 19, contact finger 21 thereof, coil 13, interlock switch 40, actuating coil 14, conductor 39, and interlock switches23 and 24 to ground G. Since interlock switch 38 opens with contactor switch 10, coil 27 of relay 29 will be de-energized, butthe contact member 30 thereof is in the meantime held in its upper position by reason of the flux produced by series coil 36 of the relay 29, which coil is carrying the same current as the main motor. As soon'as this current falls to the proper safe value, the movable contact mem-,

ber 30 of the relay 29 ill drop, so that current will flow through the coil 28 of the relay 29, and the movable contact member 31 thereof will assume its upper position.

A circuit will thereupon be established from the contact member 32 of relay 29,

. throughinterlock switches 41 and 42, actu V atiiig coil 15 of cont actor switch 11, conducf tor 44, and. interlock switch 24 to ground G. The circuit previously traced through the actuating coil 13,-interlock switch40, ac:

tuating coil 14, conductor-39 and interlock switches23 and 24 is still energized. Upon the closure of contactor switch 11, the in terlock switches 23 and 42 immediately open and the interlock switches 43 and 45 immeciately close, so that in the manner already described, in connection with the energization of the actuating coil 14, the coil 15 is transferred to a circuit which traverses coil 13, interlock switch 40, coil 14, interlock switch 43, coil 15, conductor 44 and interlock switch 24 to ground 18. Since the closure of the switch '11 short circuits the resister 8, the current'in the motor circuit is increased.

' -The relatively high cu rent traversing the motor 1 again effects the lifting of the relay contact member 30 by reason of the series coil 36, but, in the meantim'e, a circuit from stationarycontact member 35 through interlock switches 45 and 46 and actuating coil- 16 of the contactor switch 12 to ground G, is prepared.

member 31 of relay 29, interlock switches 45 and 46, actuating coil 16 of switch 12 and conductor 47 to ground G. V r 7 Upon the closure of contactor switch 12,

V This circuit is obviously completed, when the armature current'falls' iill) interlock switches 24v and 46- immediately open and interlock switcli '48 closes, so that coil 16 is transferred to the previously traced circuit from the actuating "coil 15, which is already energized through conductor 44, in-

terlock switch 48, actuating coil 16 and conductor 47 to ground G. The resistor 9 is cut; 7

out of the motor circuit and the current in the motor circuit temporarily increased.

I Although only three resistance steps and only a single motor have been shown and described, it will be readily understood that the circuits illustrated in Fig.2 may be en tendedindefinitely,and that our invention may he applied to other types of control.

in Fig.2, the reference character 52 r presents substitutional' resistors, the introduction of which into the control circuits is usually necessary for the etl'icient working of such a control system, as is well known.

In the above-described control system, if the master controller 19 is moved first to the notch b, and then to the notch c, the section 7 of the resistor will be sl'iort-circuited by the closure of the contactor switch 10 in the manner hereinbefore described. Further automatic progression may be prevent ed by reason of the train being on a gradient or by reasons of other serious conditions of track, in which case the relay contact men'iber 30 will be held up indefinitely by reason of the current in the series coil 36 ot the rela 29.

Under such conditions, further operation may be manuallycontrolled as follows: If he push-button switch 4-9 is depressed, the circuit of the actuating coil 15 of contactor switch 11 will be energized by a circuit traversing interlock switches ll and 4-2 and contact members 35 and 31, as the latter has remained in its lower position.

Upon releasing the push button switch 49, the circuit through interlock switches el-l and 42 will be broken and a circuit will be established through interlock switches and and coil 16 to ground G, so that coil 16 of contactor switch 12 will be energized, thereby further accelerating the train.

With the above described arrangement, it will be seen that alternate depressing and re leasing of the push button switch 49 enables the other vise automatic starting operation to be efiected under manual control up to the full speed condition.

In certain instances, however, the operation of one extra step manually will be suliicient to start the train and according to the modification illustrated in Fig. 3, a push button switch 51 is so arranged as to normally close the first oi the contactor coil-energizing circuits connected with the relay contact member and when depressed, to shunt the contact members 32 and 83, pertaining to the contact member 80 and coil 28, by means 01": which the second energizing circuit is controlled, he first energizing circuit being atthe same time broken.

ll ith this arrangement, it will be seen that when the push-button 51 is depressed, the coil 28, controlling the movable contact member 31, which governs the circuit that is broken by-the depression of the button, is energized so that the said first circuit, extending from the contact member 35, is dc-energized, the relay contact member 31 being held up until the current in the series coil falls to the value to which the relay is set. The release oi the push button switch 51 will not, therefore, erlect the closure of any further contactor switches until the contact member 31 falls. Alternate automatic and non-automatic operation of the contactor switches is thus obtained.

e do not wish to be re icieil to ti" ciiic circuit connections or ai parts herein set forth tions therco; and scope oil tore, that only posed as are claims.

We claim as our invention:

1. A control system comprising a motor, an accelerating relay therefor, proviced with a plurality of movable members respectively correspoi'iding to successive increments of acceleration and manually operative means for elliecting the continuance of said acceleration upon failure of said relay to operate at any stage or said acceleration.

A control system comprising a motor, a relay for automatically accelerating said motor COIDPIlSlIlQ a pair of switches, a pair of coils for opei ting said s itches, current coil adapted, under predetermined conditions or" motor current, to prevent the closing of either ol said switches, and manually controlled means for eliecting the continuance of said acceleration upon failure of one of said switches to close.

A control system con'iprising a plurality 'ol coils, a plurality of circuits for successively energizing said coils, a relay having a pair or actuating coils, a pair oi movable cores co-operating respectively with said coils, a pair of switches respectively actuated by said cores and adapted to control said circuits, a third coil located between said pair of coils and adapted under predetermined conditions to prevent the closing of either of said switches, and manually controlled means for successively energizing said circuits on failure of one of said switches to close.

l. A control system comprising a plurality of circuits adapted to r spectively energize a plurality of actuating coils a relay for automatically eli'ecting the energization oi said circuits successively, comprising a pair of actuating coils, a pair of switches operated by said last-mentioned coils and adapted to successively close said circuits, a third coil located between said pair of coils and adapted, under predeteri'nined conditions to prevent either of said switches from closing and manually controlled means for succe energizing said circuits independently of the normal operation of s .d relay.

5. A control system comprising a pair of switches having respectively a plurality of stationary conta t members and a movable contact member co-operating therewith, an operating coil for each of d switches, having one terminal connected to on of said stationary contact members of the other switch,

indicated in the a 'ipemleil switches to open said other switch, a plurality of circuits connected respectively to the other stationary Contact members of said" switches, means for opening and closing said circuits successively, a current COll adapted,

upon energization by predetermined values 10 of current, to hold either of said switches in the open position; and manually operated means whereby said circuits may be successively energized upon failure of one of said switches to close. i

in testimony whereof we have hereunto subscribed our names this 20th day of De ceinber, i922.

ROBERT :esooirs; EDWARD HUGH snow.

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