US1580629A - Motor-starting apparatus - Google Patents

Description

April 13,1926.v

I l v v C. D. AINSWORTH rMOTOR `STARTING APPARATUS v Filed Nov. 6. 1923 ,Th1/6777er,

Patented Apr. 13, 192' Unirse .eter

CHESTER T). AINSWGR' IPE, CIF W'LLASTON, MASSACHSETTS, ASSGNGR, BY I/IESNE ASSIGNMENTS, TO CONDIT 'LLCTRECA'L MANUFACTURNG CORPORATION, 0F BOS- TON, MASSACHUSETTS, A CORFORA'IN OF MASSACHUSETTS.

MOTGR-STARTING APPARATUS.

Application led November 6, 1923.

T all whom, it may concern:

Be it known that I, CHESTER D. Ainswonrrr, a citizen oit the United States, rosiding;` at Vo-llaston, in the county of Nortolk and State of Massachusetts, have invented an Improvement in Motor-Starting Apparatus, of which the following is a specification.

This invention relates to apparatus and systems tor starting electric motors.

A relatively large electric motor may take many times its normal full load runningjr current when it is first brought up to normal runuing'speed and it connected directly to the line tor starting, may cause considcrable disturbance to the line` For this reason appropriate motor starting apparatus is o-r may be provided which is adapted to reduce line disturbance during the starting of the motor.

The motor starting apparatus usually includes a starting switch and an independent running switch. The starting switch is adapted to be closed first and to connect the motor to the line through a transformer or the equivalent whereby to reduce the voltage on the motor at the instant ot' starting. After the motor has been brought up to speed the starting switch is adapted to be opened and the running switch closed where by to connect the motor directly to the line and exclude the transformer.

An object ct this invention is the proviw sion ot means to govern the closing' et the running switch automatically so that the running switch can net bc closed until the motor has been brought up to about its normal running speed and the starting` current has dropped to some predetermined low value. In carryingout this cbject ot the invention, I may provide means governed by the starting current to lock the runningv switch against closing and said means may be so arranged that when the starting current has dropped to a predetermined value, as normal full load, it will operatepto ref lease the lock on the running switch, and thereby permit the running switch to close andthe motor te he cennected directly to i die Serial No. 673,199.

A further object oi the invention is generally to improve the construction and operation ot motor starting apparatus and sys-' tems.

Fig. 1 is a diagran'imatic representation 55, ot the motor starting apparatus and system embodying the invention.

Fig. 2 is a detailed elevation partly insection ot a portion ot the operating mechanism ot a switch with which the invention 00 is associated.

F ig. 3 is a sectional view taken along line 3*.3 of Fig. 2.

The motor starting apparatus and system embodied in this invention may include a 05 switch 10 which is adapted to connect the line 1l with an autotranstormer 12 or equivalent device whereby to energize the trans-v former.` A starting,- switch 13 may serve to connect intermediate taps ot the ante-transformer with circuit leads 14, which leads may extend to the motor, not shown.

The switch 10 and the starting switch 13 maybe mechanically interconnected as by the rod 13a whereby both switches may be 75 opened or closed simultaneously and both switches may be herein termed the starting switch.

A running switch 15 is provided to connect the motor directly to the line ll and exclude the auto-transformer 12 when the running switch 15 is closed. In starting they motor, the switches 10- and 13 are rst closed and the motor is connected to the line through the auto-transformer and supplied with a reduced potential. VJ hen the motor has been brought up to speed the switches 10 and 13 are adapted to be opened and the switch 15 is adapted to be closed and the motor may thereby be connected directly to 00 the line.

This invention may be associated with many types ot motor starting` apparatus, as automatically operated apparatus but, for purposes of simplicity, itis herewith described in connection with inanually-opeian ated apparatus.J y l A switc 'iicll adapted tor this inve t1 maybe tenderly ser fornita in" mechanism.

Decemberl 13, i922, and Figs. 2 and 3 illustrate certain details ot the switch operating Vllhe starting switch and the running switch inay be substantially alike although this is not essential. Each switch inay coinprise the tace plate 20, the lower end ot which is torined to provide a co-il coinpartnient 2l. Tripping coils Q2 inay be received in said.coinpartinent and a third coil E23 inay also be received in said coin-- partinent andthe function ot said third coil 23 will hereinafter be niore lully set forth. Each coil inay be provided with a core or plunger 2l which, when the coil is suli'iciently energized, is adapted to be inoved upwardly and strike against a trip pin 25. Saidtrip pin is extended upwardly troni within the coil and through a pedestal 2o and is torined with an enlarged and grooved head Q7 at its upper end. il triangularly shaped tripping` plate is disposed'above the coil compartment andinay be torined with' notches Q9 therein into which the grooved heads 27 ol said tripping pins are adapted to be loosely received. The ar4 rangement is or inay be such that when any one oit said tripping pins is elevated it serves corresjiiondingly to elevate the trip` ping plate, said tripping plate being rotated about the other two pins as ulcruins, or, it all oi said pins are elevated, they all serve to inove the tripping plates bodily upward for the purpose of tripping the switch'I The switch operating mechanism'includes an operating handle 30 which inay be pivoted at 31 to the rontvwall of the coil coinpartinent. A latch 32 inay be arranged to engage said handle when it is inoved into a vertical position or in a position corresponding with the closed condition of the switch and thereby hold the switch closed. Said latch inay be elevated manually to perinit the handle to be nioved outwardly away 'liroin the 'tace plate or into a position corresponding to the. open position. ol the switch. iin arin 353 is or'inay'be pivoted'at 3l concentrically with said operatingv handle 30 and an operating link or rod 3G inay` be pivoted to said arin and extend to the movable contact ineuibers ot the switch. Means are or niay be providedto connect said handle St) reloasingly with said a-rin "75, whereby the switch inay be opened and said ari'n inay be nioved to a switch-open position independently ol a corresponding nioveinent with the switch operating. handle SO Said ineans inay include a latch 258, which latch inay be pivoted to a bracket 39 ot the operating. handle 80. S' id latch is' adaptedto engage a projection as the latch roller all ot' said arni 35 and the arrangement or inay be such that when said latch is in engageinent with said roller7 as indicated in Fig. 2, said arin may be nioved with said handle E() between switch-open and switch-closed positions and when said latch 38 is inoved into a disengaged position with said latch roller 40, said arin 35 inay be tree to inove into switch-open position independently ot the handle. Said latch 38 is adapted to be tripped by the tripping plate S and, lor this purpose, inay have a depending ear which is adapted to be disposed above and in a. position to be engaged and elevated by said tripping plate. .lt is apparent that an upward inovenicnt ot the tripping plate, due to the energiza-tion ot one o't the coils 22, or the coil Q3, will cause the disengagement oit the latch Ylfroin the roller et() and thereby per init the switch to open independently ot the corresponding niovenient et the operating handle.

hleans are preferably provided to interconnect the mechanisms et' the starting and running switches so that but one switch can be closed at atiine and when the running` switch is closed, the starting switch inust be opened. Any suitable torni oli'interlocking inechan'isin inay be provided. As here shown, the inechanisin inay coinprise the interlocliing rod Said rodinay extend be tween the arins 35 olf the starting and running switches and may be provided with elongated slots 5l and 52 in the ends thereof. The starting switch arni inay be provided with a projection as the pin 53 which .is adaptedt-o be received within the slot 'llhe running switch arin inay be provided with a siinilar projection as the pin 54 which is adapted to be received within the slot The arrangement is or may be such that il the starting switch is closed and the running switch is inoved toward closed position, the inoveinent thereof will cause the starting switch to be opened. For this purpose, the latch on the starting handle corresponding to' the latch on the ruiming han lle inay be on'iitted so that the starting` switch inust be held rnanually inclosed position while the niotor is brought up to speed.

In accordance with this invention, lf provide ineans to prevent the closing ot the running switch until the inotor has been brought up to speed or at least until the starting current has been reduced to a value corresponding about with the nornial lull load running value. Said nieans inay include a current transformer GO which trans- 'lorincr inay be associated with the circuit including the starting switch lil and are ranged to be energized by the starting current. Said current transformerr inay be arranged to energize the tripping coil 28 associated with the runningA switch l5 insuch a inanner as to hold the tripping plate ot said running` switch in elevated Yposition and thereby prevent the closing o't'the switch untilithe current has fallen to a predetermined low value. For this purpose, an excess current relay 62 may be arranged in lll.l

the circuit leads 63 and in series with the secondary of the current transformer and said coil 23. Said excess current relay is or may be arranged to have relatively low resist-ance and also be so arranged that, when the current in the current transformer 60 is at some predeterminedV low value, its movable member 64 is in a position to bridge the stationary contact members 65 and thereby shunt the trip coil 23 and prevent current passing through said coil. lVhen, however, t-he starting switch is operated and a heavy current passes through the motor said excess current relay is adapted to be energized by the current transformer to elevate its movable bridgingmember 64 and break the connection between its stationary Contact members whereby to cause the current to flow from said current transformer through the tripping coil 23 and thereby raise the tripping plate of the running switch and prevent the running switch from being closed.

It will be noted that the connections ot the excess current relay are such that when sutiicient current tlows through the coil 23, the bridging member 64 of said relay is maintained in elevated position and free from bridging contact with the stationary contact members 65. lhen the motor has been brought up to speed and the starting current has dropped to the normal running current or some other predetermined reduced value, said excess current relay is arranged to be insufficiently energized whereby to permit the bridging member 64; thereof to drop and shunt the trip coil 23 thereby to lower the trip plate of the running switch. The running switch may then be closed and connect the motor directly to the line and exclude the auto-transformer. For certain purposes, the excess current relay may be omitted and the tripping coil 23 connected directly to the current transtormer.V

lVhen the apparatus is associated with manually controlled starting and runmng switches visual means are preferably pro-` vided to indicate to the operator the proper time to close the ruiming switch. Said means may include a target of some distinctive color visibly displayed. As here shown, said target 70 is applied to the lower end ot' the plunger of the coil 23, see Fig. i2. lVhen said target is in an elevated posit-ion, it serves as an indication that the motor has not yet attained its normal ruiming speed and the running switch should not be closed. lVhen, however, said target drops, it indicates to the operator that the running switch may be closed.

The invention may be otherwise modilied without departing from the spirit thereof.

I claim:

1. Motor starting apparatus including manually operable starting and running switches and means rendered eiliectivc'liiy an excessive motor current to prevent the closing o the running switch. I

2. Motor starting apparatus including a starting switch free for movement in a closing direction and a running switch and means governed by the motor startingcurrent to prevent the closing of the running switch.

3. Motor startingapparatus including a starting switch and a running switch and means associated with the starting switch arranged to hold the running switch against closing until the motor starting current is at a predetermined value. f

4. Motor starting apparatus including independently operable starting and running switches, interlocking means arranged to hold either switch open when the other switch is closed, and means governed by the speed of the motor to prevent the'closing of the ruiming switch.

5. Motor starting apparatus including independently operable starting and running switches, interlocking means arranged to hold either 'switch open when the other switch is closed, and means governed by the motor starting current to disable the running switch an'd prevent the closing thereof.

6. Motor starting apparatus including a starting switch, a running switch, interlocking mechanism arranged to hold either switch open when the other switch is closed, and means governed by the motor starting curr-ent to disable the running switch and prevent the closing thereof until the starting current has dropped to a predetermined value. l

7. Motor starting apparatus including independently operable starting and running switches, interlocking means arranged to. hold either switch open whenl the other switch is closed, and means energized by the motor current arranged to disable the running switch to prevent the closing thereof until the starting current has dropped to a predetermined' value.

S. Motor starting apparatus including a manually-operated starting switch, aI manually-operated running switch and visual means governed by the motor starting current to indicate the proper time for opening the starting switch and closing the rainning switch. i l

9. Motor starting apparatus including a starting switch, a running switch, a coil arranged to be energized by current traversing the starting switch to disable the running switch, and a relay energized by the current traversing the starting switch arranged to govern the operation of said coil.

l0. Motor starting apparatus includino1 a starting switch, a running switch havin@a locking means arranged to hold the switci in closed position, and means governed by the motor starting current arranged to disable said locking means and prevent the closing oit' the running switch until the motor starting current has dropped to a predetermined low value.

ll. Motor starting apparatus including a starting switch, a runningswitch having operating mechanism, an operating member and means releasingly connecting said operating member' and mechanism, whereby to permit said operating member to close the switch, and means governed by the current traversing the starting switch to disable said connecting means and prevent the closing of the running switch.

1Q. Motor startingapparatus including a starting switch, a ruiming switch having operating mechanism, an operating member, a latch connecting said member and vmechanism releasingly, a tripping device arranged to be moved to actnate said latch and release the connection between said operating member and mechanism, and means governed by. the current traversing the starting switch arranged to operate said tripping device and said latch and prevent the closing of the running switch.

In testimony whereof, l have signed my namepto this specication.

CHESTER D. AINSWORTH.

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