US1761773A - Motor-starting switch - Google Patents

Description

'June 3,` `1930. c. F. CARPENTER 1,761,773

MOTOR STARTING SWITCH Filed OOIT., 21, 41926 2 SheebS-Sheet l Ffg. 2.

27 lrwvelcor (Shades F Carpenter,

by His 5953sofwel);n

June-3, 1930. c. F. CARPENTER MOTOR STARTING SWITCH Filed oct. 21, Y 192e 2 ggeets-fsheet 2 lli the connection of the motor to the source and causing the autotransformer to serve as a reactor to maintain the applied voltage to the motor. The next operation effected by the forward movement of the operating handle will effect the closing of the running set of contacts 15, thereby connecting the motor to the source through the starting and running sets of contacts, leaving the antotransformer connected in such a Way that it does not take any charging current from the line.

By referring to Figs. 1 and 2 it will be seen that the switch mechanism for controlling the starting of the motor is mounted Within a supportingframework 16 and that the operating` handle 17 is disposed on the outside of a panel supported by this frameivork. An oil Well (not shown) which surrouncs the switch eontacU mechanism where by this contact mechanism may be immersed in oil so as to reduce the effect ot arcingi at the switch contacts7 arranged to be sup ported on the insulators 18 ilforining a part of a shelf supported by the framework This shelf arranged to support the, oiJV .rell in position when the oil Well is low-ered to permit inspection of the switch contacts and when the switch is in operating condition the oil `well is adapted to be secured :in an elevated position so that the switch contacts are immersed in the oil. The lover part of he framework provides a space 1S) within which the autotranstormer (shown in Figi'. 23) may be securely mounted in a convenient position with respectto the switch contact mechai'iism. The Whole assembly thus forms a complete unit which may be manufactured and, Wired ready for installation with the cu... nie1"s source of supply and the motor to be controlled. The interconnections bctivecn the autotransitormer and the oil switch arc not shown in Figs. l. and 2, since it is believed that those skilled in thc art will readily understand the same from a consideration of Fig. 3.

lt will be seen from reference to Fig. 2 and more particularly in connection with Figs. elto 6, inclusive, that the startii'ig set ol contacts is mounted so as to be operated by a shaft 52() and the running; contacts are mounted so as to be. operated by a parallel disposed shalt 21, these shafts beine' secured in the ilranie\.r k 1 6, Link nie-chai sin, ineludina the link 22. connects the npcratinif;

handle li with the safts '12() and 21 and thi) si itch cont ts so that a forward moiv nient of the oper-:ning haut le Yill eil-ect the operationsl above stated. An automatic rcicasc mechanism 223 provided. for effectingA the release of the switch Contact ineclian'-fm so that the of contacts retinn 'o their respective positions indicatei'l in spense to abnormal circuit conditi-o details of this releasing mechanism :irc not shown, since this forms vno part ol" my invention and furthermorm arrangements of this sort are old and well known to those skilled in the art.

Reference is now had more particularly to Figs. l to 6, inclusive, for an explanation of the details of construction and arrangiement whereby the sequential operation of the sets of contacts is secured. It will be seen that the startine' set of contacts 12 comprises three movable contact members, cach ol which is arranged to make engagement with a pair of stationary contacts. The ruiming! of contact-s 15 is of similar construction and each contact member of the set is arranged to make engagement with. a pair ot stationary contacts, as shoivn. Each Contact member of the two sets 12 and 15 is similarly mounted for reciprocatory movement Yith respect to its operative shaft. Thus, the Contact member 15 is pivotally suspended from an operating rod, of which the parl' 24 is of insulating material so as to insulate the contact member from its operatingl shaft and the other parts of the switch mechanism. The insulating part 24 is secured to an operating rod 25 which is pivotall'rY c With a. lever 2G secured to the opt 1 2l. The other contacts of this se., are siini larly connected With the shaft 21 and it will also be seen that the contact members of the. starting set 12 are individually connected to the operating` shaft 20 by similar mechanism.

The neutral closing set of contacts comprises the switch member 27 Which is pivotally connected with a post 28 of insulating n'iateriai7 which is in turn pivotally c.' nnected with one arm of a. bell crank lever 29. The other end of this bell crank lever is connected by means of a link 3() with the lever 31 secured to the operating shaft 21. 'ihe bell crank le vver 29 is mounted upon the shari- 20 and is arranged so as to rotate with rcspcct thereto. The. contact member 2T is also pivotally ci'innccted withv a bridging; inem-- ber 32, which is pivotallj.Y counccti-ail to the insulatingsupport or post 233. The other end of this .lever 3Q is connected to ore end of the terminals of the autotranshirn1er t3 as .indicated in Fig. 3 and the contact. meniber 27 together with its correspondini;l set f Vtatioiuiry contacts forniv the .set ol'feoin tarts .iS-i uhich establish the neutral of the autotransformer.

The operating handle 17 is pivotz'iilv mounted with respect to the shaft 2li-l. sind rou iected through a unirersal joint 35 with the operating` rod 3G. rfhis operating; rod pivolaily mounted in one arm of Ywha; "ul'es ii cli'lecl' a bell crank lever Si', i the heretofore referred to link 21.2 also pivotfilly connected. The other arm of this bell cra.7

.ik lever connected with t i. shaft '151 by means of a link 38 which has one end thereof l rif'etally connected with the lever 39 secured to the operating shalt .1. The bell crank lever 37 is mounted tor rotation on the shaft 40 and the spring 4l. mounted on this shaft provides a means for biasing the bell crank lever and the sets oi' switch contacts to their respective positions indicated in 1, 2, 3 and 4.

As before stated, Fig. 4 shows the relative position of the various parts ot the switch mechanism in their respective positions preparatory to the operation ot' the handle 17 to etl'ect the final connection et' the controlled motor iO directly to its source ot' supply 11. lt will be seen. that the set ot starting contacts 12 is in its iiormal open position and tho ruiming set of contacts 15 is also in its normal open position. The neutral closing switch mechanism is in its normal closed position. llllhen the Vhandle 17 is rctated clockwise to the position indicated in F 5, the various parts ci the switch mechanism will assume their respectivepositions indicated in Fig. 5. 1t will be seen that through the link 22 the shait 20 has been rotated so as to etlect the closingl oi the starting set ot contacts 12, and it will also be seen that through the link 38 the running set of contacts 15 moved slightly farther away from its corresponding stationary contacts. t vill also be seen that although the shaft 2l is rotated slightly through the action of the link 38, nevertheless the neutral closing set of contacts 13 will remain in the closed posiz tion, a slightly greater pressure being applied to these contacts. This is by reason et the 'interconnection of the shaft 21 with the neutral closing contacts 18, by means oi the link 30 and the bell crank 29. It will be observed that the right-hand end 4, 5 and (S) of the link 22 is of hook shape so that a continuation ot a clockwise torward movement of the operating handle 17 will cii'cct no further rotation of the shaft il), although the bell crank lever 37 will be rotated `from its position indicated in Fig. 5 lo its position indicated in 6 when the handle 17 has been operated to its Yfull ci;- tent ot movement. During this linal movement. the link 538 comes into play to c'llect counter clockwise rotation of shaft 21. This arrai'igement, therefore, provides for an initial movement of the starting contacts to their closed positions and limits the pressure applied to these contacts during a continuation ot the movement ot the operating handle during which the neutral closing switch first opened and then the running set of rontacts closed, as is indicated in Fig. 6.

The neutral closing switch is first opened alter the operation has proceeded to the point indicated in F ig. 5 by reason oi' the rotation oit the shaft 21 in a counter-clockwise direction through the action of link 38. This counter-clockwise rotation of the shalt 21 ilirst eillects through the link 3() a counter-clockwise movement ot the bell crank lever 29 and this movement eiiects the opening of thc neutral closing contacts 13. A continuation. ot the counter-clockwise movement ot the shaft 21 as the operating handle is advanced. to the position indicated in Fig. 6, causes the running set of contacts 15 to be operated into engagement with its respective stationary contacts. Then this operation has been completed, the spring 41 has been wound up so as to place the mechanism under a strain tending to open the starting and the running set of contacts and the closing of the neutral controlling set of contacts. rlhe strain ot the spring 41 is resisted by the pivoted catch 42 which is Linder the control of the relay 23 indicated in Figs. 1 and 2. rlhis catch is also under the control of a manually operable tripping button 43 which provides a means whereby the motor may be disconnected from the source of supply at the will ot the operator without forcibly moving the handle 17 in the opening direction.

It will be seen from the above that I have provided a simple and edective mechanism whereby the starting, the running and the neutral contacts may reciprocate in pa 1allel planes and whereby the oil switch type` ot contacts and contact construction may be employed. It will also be observed that the interconnections between. the sets of contacts, the parallel operating shafts 2O and 21 and the operating handle 17 are such that a single handle is eiiective to cause the desired sequence of operation of the various sets ot contacts. It will also be observed that the mechanism is such that the handle 17 mayk be rotated in substantially a contimious forward movement, thereby rendering the operation very simple so that unskilled operators will bc unable to make mistakes in effecting the starting of the motor.

Vilhile my invention is particularly applicable to the starting ot alternating current motors of relatively large capacity, nevertheless the invention is also applicable to the starting and control of electric motors generally, as will be umlerstood by those skilled in the art from a consideration ot the foregoing.

ln order to insure that the handle 17 will be moved to the deiinite starting position and that this exact position will be understood by the operator, I have provided the arrangement shown in Figs. 7 and 8 which show respectively the side and plan views of the guide for the handle 17. This guido comprises the side plates 44 and 45 of the shape shown so as to form a slot between them similar to a portion oit` the familiar H slot of automobile gear shift mechanisms. The resiliently mounted detent 46 serves to

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