US2056020A - Circuit breaker - Google Patents

Description

Sept. 29, 1936. 5 T SCHOF1ELD 2,056,020

CIRCUIT BREAKER Filed April 13, 1935 4 SheetS-Sheec 2 Sept. 29, 1936. s. r. SCHOFIELD CIRCUIT BREAKER 4 Sheets-Sheet 3 Filed April 1a, 1935 INVENTOR 7." 5 Of//d Sept. 29, 1936. s. T. SCHOFIELD C IRCUIT BREAKER F-iled April 13 1935 4 Sheets-Sheet 4 INVENTOR y 5c of7'e/a B @VLILN2SSES; W"

Patented Sept. 29, 1936 PATENT OFFICE Stanley T. Sohofield, Williinsblllg, Pa., assignor to .Westinghonse Electric & Mannl'acturing Company, Bast Pittsbnrgh, Pa. a. corporatlon of Pennsylvania Application April .13, 1935, Serial N0. 16,186

12 Claims.

The invention relates generally 120 clrcuit breakers ancl more particularly to mecha-nlsms for actuating the cooperative swltch members 01" clrcuit breakers.

An object cf the invention ls eo provlc'le a quick acting multiple pole circult intermpter Chat will respond to abnormal circuit condltions in the switch members of any pole to trip the swlcch members of all the poles.

I1: is also an objecit of the invention o provicle for the ind'ependent operatlon cf the switch members o1 any pole of a multiple pole circuit breaker upon the development of abnormal circult sonditions to interrupt the circuit through the switch members of that pole, anti to effect the operation of the swltch members of the other poles, in quicl; succession to the actuation of the swltch membexs operated in response to the abnormal circult cou dltions, a0 interrupt the circuits through the switch members of all the poles.

Other objects of the invention will in i:warl; be obvious and will in part appear herelnafter.

The inventlon accordingly is disclosed in the embodlment thereof shown in the accompanying drawing anti comprises the features qf construction, conibination of elements anal arrangement of parts which will be eXemplified in the constructiori hereinafter sei: forth and the scope of the application of which will be indlcated in the claims. For a fuller understandingof the natura, anal objects ofthe lnventlon, reterenca should be had to the followlng detall descrlptlon taken in connection wlth the 9.ccompahying dra wlngs in which 5 Figure 1 ls a perspedlsive view of the actuatlhg mechanism of a clrcuit breaker -c:onstructecl in accordance wfth thls inventlon; Fig. 2 is a. view in side elevation of theclrcult; breaker illustrated in Flg. 1 shqwing how the 0 mer nbers of the mechanlsm are disposed relatlve to one another,

Flg. 3 ls a view, in front elevatlon, of the actu.ting mechanlsm f the clrcuit breaker showing the relation Qf. the members, 45 Flg. 415 a view, in top plan, o1 a balanclng lever,

Flg. 5 ls a. vlew,'in freut elevatlon 01' the balancing lever, shown In Flg. 4,

Fig. 6 is a. vlew in end ele vation of the balanclng lever shown In Fig.. 5,

Flg. 7 ls a. vle':w part)ly in section and partly in end elevatlon.taken along the llne VII-VII Flg. 5, Flg. 8 ls a vlew in front elevatlon of a supportin g lever showlng detalls of its constructlon.

-'Flg. 9 is a.. v1ew partly In sgctlon a.nd partly in with standarcl practice.

- I1. As illustrated, a. projection top elevation takten 'Flg. 8,

Fig. 10 ls a view'in end elevatlon 0f the lever lllustrated in F'lg'. 3, anal F1g. 11 is a, vlew partly in sectlon and partly in elevatlon taken along the Eine ZI-Xl 8.

Referring'now t0 the clr-awings am: Figs. l anal 23 in partlcular, the circut brealzer er intemupter comprlses a cast irren Emma, lnclicaizecl generally by the numeral l5, pr0videcl with cr0ss members 19 l3 may be utilized for attachiz1g to a switchbeard 311 am]. a plurallly 026 supportlng members, the functiams 0f which will be set forth hereinafter as ihr: siructure of the breaker Es desaribecl Wnlle a caso frma H5 illusizratefi, lt tube 5 unde1stood thai; a fabrlcatedirame may also l2e employed.

Asbest shown m Fig. 2, the cr-oss members of the clrcull; breaker frame E5 are atached to the switchboard' l'l by means of belts 38511 accorfiance 20 'Ifhe switchboard H 1's preferably made from marlole, slate or some otl1er material commonly employed m switchboards. In the present breaker strucv'sure many standard parts are employed, such as an arc lnterrupter l8, switch-arm structure 20 end tripplng mechanism 2I.

In the present structure, the arc lnterrupter (9 ls of the type in which the am isrotated between spaced plates, as shown for example in Brainard 30 Patent N0. 1,896764, issued. February 'l', 1933, and therefore e, detailed descriptlon o! lt will not be lncluded'. As illustrated, the am extingulsher is mounted on the swltchboard l! by means of screw bolts '2. 35

The switch-arm 20 which has been employed heretofore in such structures, comprises a. cast iron member 22 pivota.lly connected at 23 i;o a bracket orsupport 24 carried by the swit0hboard 25 I[S provided on the lower end of the member 22 and shaped to receive the end of a. c011 spring 26. 'Ihe other end of the spring ls connected. 1:0 a projectlon 21 provlded an the spport 24.

'I'he spring 26 belng in tension biases the memher 20 to the positlon illustrated in Flg. 2. -This spring coqperaces in the operation of the sw:ltcharm as will be explalned hereinafter. A plurallty of copper blocks 28 and 29 are supported an the switch member 22 by means cf bolts 30 und II, respectively. 'Coll sprlngs 32 and 33 are mounted on the bolts 30 and 3I respectlvely, and biss the copper blocks 28 and 29 away 1'rom the swltcharm 22. Contacl: members I I are provlded 011 tlie blocks 28 a.nd 29 a.nd disposed to align wlth con- 5 along the line 1X-IX cf in supporting the contact members II in alignment with the eontaet members 34.

In the breaker illustrated, a stationary conductor 39 extends between the bus 38 and a. member which is electrically connected to a. plate f the am interrupter I9. 'Ihis conductor and member 46 are employed, in accordance with well known practice, to carry current during the am interrupting process.

A shunt 43 extends between the shunt 36 and the arc tip 42 shown in dotted lines. These members are also empldyed in accordance with standard practice and function 130 maintain a circuit to the am interrupter during a switc'hing operatio'n. The shunt 4I and arb tip. 42 constitute a comparatively high resistance circuit.

The mechanisxn of the breaker br interrupter illustrated is for actuating the switch members of a. multiple pole unit. In this instance it is shown applied 170 operate a three-pole switch such as may be employed for interrupting a. threephase circuit, but it is to be understood that other applications of this mechanism may readily be made by following the teachings of this invention.

Referring to Fig. 1 in particular, the switch actuating mechanism is illustrated as applied 1 1' operating the cooperative switch members of a. three-pole switch. In order to simplify the drawings, onlythe switch arms 43, 44 and 45 of the switch units are shown. Each switch unit represented by the switch arms 43, 44 and 45 will be similar to the one disclosed in Fig. 2 and described hereinbefore. Therefore, as the description of tl1e mechanism proceeds, it will be understood that when reference is made 1:0 the switch- arms 43, 44 and45, it is intended to mean switching units sil nilar to that cf Fig. 2.

In moi1nting the switching units of the difierent poles, they are separated by barriers 46 ma.de Irom suitable insulating material. These barriers will prevent arcing between the switch units under abnormal voltage conditions.

' Ihree toggle linkages 41, 48 and. 49 are provided for the switch members 43 to 45, inclusive, respectively. These toggle linkages are pivotally counected to the swifch-arms 43 to 45, inclusive, as shown at 50. The togglezlinkages employed in this particular embodiment cf the invention each include two links of substantially equal length pivota.lly connected.

In order to support the toggle linkages so that they may be utilized for operating the switch arms 43, 44 and 45, three arms I, 52 and 53 are provided. The arm 52 performs an additional func-' tion to the arms 5I and 53 and-for that reason will bereferred to as a. supporting arm. As illustrated, the three arms are pivotahy connected tq Vshapedbrackets 54 and 55 provided on the frame I5.

The arms 5I and 53 are of shpe and are pivotally connected at 56 and 51 to the upper arms of the V-shaped brackets 54 substantially tri'angular in shape being provided the same size and with spacedmembers ab the base which are pivotally connected a1: 58 to the lower arms of. the V-shaped brackets 54 and 55.

The upper ends of the arms 5I 130 53, inclusive, are pivotally connected a1: 59, 60 and 6I to the outer ends of the toggle linkages 41 to 49, inclusive, respectively. As shown, the upper ends of the arms 5I to 53, lnclusive, are b'ifurcated to receive the outer members of the toggle linkages and facilitate the making of the pivotal connections.

In order to balance the reaictive pressur es receive'd from the switch members through the toggle linkages 41 to 49, inclusive, against one another, a. balancing lever 62 is pivotally mounted on the supporting arm 52 at 63. As illustrated, the pivot point 63 is approximately midway between the pivotal connections 58 and. 60.

The balancing lever 62 is hast illustrated in Fig. 5 and is provided with two arms 64 and 65.

The arms are spaced angularly arou nd its pivotal ax1s.

As shown, the lengtli of the balancing lever along its pivotal axis is substantially that of the spacing of the arms 5I and 53. The purpose of making this lang lever is 130 align the arms 64 and 65 with the arms 5I and 53, respectively.

members of the linkages 41 tn 49, inclusivm These toggle linkages 41 I:o 49, inclusive, may be actuated in any suitable manner as by a lever er an electromagnet. In the present instance, the extensions 68 are connected through links 69 to a lever 10 pivoted at I3 for manually operating the linkages to their in-line o1 switch closing positions and an electromagnei: 1I connected 1:0 the l'ever for effecting a power operation.

A spring I4 is provided for biasing the lever 10 and the armatu1e of I;he electromagnet 1I to predetermined positions where they stand inactive and permit the tripping of the breaker.

The electromagnet 1I may be operated in any well known manner a.t the will of an'operator and means for energizing it a1'e not illustrated.

A tripping device is provided in conjunction with each toggle linkage. The tripping mechanism is best illustrated in Fig. 2 and comprises a depending rod 12 connected to the outer members 12 to trip the linkages-together or independently,

hell cranks 13 are provided. As illustrated, each hell crank is. pivotally mounted a1: 14 on projections 15 provided on the frame I5. One arm of each hell crank is pivotally connected to a. rod 12. Wl1en circuit interrupters or breakers of this Rind are utilized in electric power systems, it may be desirable to efiect their operation when abnormal circuit conditions develop. For exa.mple, it may-be desira.ble to operate the breaker upon predetermined overload conditions either of curreritbr voltage 01' when the circuit breaker is used in a, network it may be desirable to trip lt upon, the occurrence of a reverse power flow.

In the present embodiment, electtomagnets 16 carried by the hell cranks I3. In this manner any one r all of the toggle linkages 41 to 49, inclusive, may be actuated.

In additlon to the electromagnetic means provided for tripping the linkages, a. manually oper able lever 18 may be provided for tripping one of the linkages. As lllustrated, this manually oparable lever 18 is biased to a predermined position by a coil spring 19. A (log 80 is provided on the inner end of the manually operable lever 18 in alignment with a latch 8I carried by the rod I2. W'hen the linkages stand in their in-line position with the switches closed, the latch 8I engages the (log 88. Consequently, if lt is desired to trip the breaker manually the lever 78 is raisecl and a downward pull may be exerted on ;he rocl "12 which will trip the linkage. As will be explained hereinafter, when any one linkage is tripped, the breaker as a Whole is tripped.

Referring; again to Fig. l, a bar 82 having a pluraliy 016 downwardly extending members 83, ana is carried by webs 86 formed integral 1 the 1rame I5. These members 88 to 85, inclusve, are disposed in alignment with the linkages 41 to 49, inclusive. Each member 83 120 85, inclusive, is provided with a cam face B's which cooperates with a. corresponding cam fac(a 88 provided an t;he linkages 41 to 49, lnclusive, 80 trip the latter when they move outwardly in a manner that; will be described hereinafter.

011 'the back of the bar 82 a plurality er" bumpers 89 are disposed in alignment with the switch arnls 43 to 45, inclusive. These bumpers receive the switch armswhen the circuit breaker is opaned.

Assuming now that the circuit breaker is counected in a. three-phase netwgrk system, and that the magnet 16 1's adapted to respond' to what is generally termed reverse power flow in any pole of the breaker, and that the breaker stancls in lts open Position, then to establish clrcuit counections, the breaker is actuated either manually through lever III or by means '0f the magnet H, to move the switch mernbers into circuit closing posilzions, if the lever ls pullecl downwardly, the toggle linkages are moved upwardly to their overcenter positioris and the movable switch contact members 33 are moved into engagement wu'th the stationary switch contact members 34. The springs 32 and 33 which are employed to give the desired contact pres sures between the switch coutact members 33 and 34 make it possible to move the toggle linkages to their over-center positions.

The reactive pressures resulting from the blasing cf the switch contact members into pressure engagement are transmitted through the toggle linkages to the arms 51 1:0 53, inclusive. The reactive pressures received by the arms I to 53, inclusive, are balanced against one another.

Referring now to F'ig. l, the reactive pressure transmitted to arm 53 biases it counter-clockwise about its pivot point 51. 'I'his biasing force is transmitted through link 67 to the arm 65, bias ing the balanclng lever 62 counter-clockwise about its pivotal mounting 63. The reactive pressure transmitted 150 the arm 51 applies a. blasing force counter-clockwise abol lt lts pivot point which is transmitted through links 66, arm 64, biasing the balancing lever clockwise about its pivot point 63.

. pivot points 58.

From the foregoing, it will be clear that the reactive pressures delivered through the arms 5l and 53 to the balancing lever 82 will set the balancing 1ever in a predetermined position on its pivotal axis 63 where the reactive pressures are in equilibrium. The balanced. reactive pressures will bias the supporting arm 52 clockwise about its pivot points 58 which are in line. The biasing force: applied to the supporting arm 52 through the balancing lever 62 is opposed by the reactive pressures received through the toggle linkage 48.

The reactlve pressure transmitted directly from the swltch mernbers. 44 is in opposition 120 the biasing force applied to the pivot point 53.

The reactive pressure recelved. from one switch unit is opposed 120 the reactive pressures recelved Irom the other two switch units. In order to obtain a balanced conditlon and state of etlullibrium between the reactive pressures recelved from the switch units, the satisfactory pivotal connections of the arms on the frame are sd positioned relative 120 the line 01' action of the reactive forces that the reactive force delivered to the supporting arm 52 will balance the reactive forces clelivered through thearms 5I and 53 120 the supporting arm 52 through the balancing lever 62.

In t;his manner; when the switch is closed, the conta'ct members of the switch units are held in pressure engagement. The means for retaining the contact members in pressure engagement is in the nature of a system 01' floating levers.

Assuming now that; abnormal circuit condltions develop and that an electromagnet 16 is energized, efi'ecting the operation of the armature H, then a rod 12 is drawn downward ly tripping a toggle linkage. As soon as one toggle linkage' is broken, the whole breaker is immedlately tripped.

In order to explain the Operation in response to the tri pplng E)f one linkage, we will assume that the toggle linkage 49 is the one that has been tripped in response to abnormal circuii; conditions. As soon as the toggle linkage 48 is broken, the arm 53 will no longer balance the reactive pressure delivered to the balancing lever 62 through the arm 5l. The reactlve pressure clelivered from the switch unit 43 to the arm 51 will rotate this arm counter-clockwlse about its pivol;

'87 and the member 83. These cam faces are so designed that as the linkage moves outwardly, lt

will be broken and the switch-arm 43 will be pr jected outwarclly by springs 32, 33 and 26.

When the reaotlve pressure appliecl to the balancing lever 82 through the arm 53 is released, the fioating levers are no longer in a state of equilibrium and the supporting arm 52 responding 130 the reactlve pressure from the swItch-arm 44 is causecl to rotate counter-clockwise about its' The result cf this ls tl1at the linkage 48 moves outwardly and 1'ts cam face 83 'engages the cam face of the member 34 wlth the result that i;his linkage is also broken.

From the foregoing, it wlll be evident that wher'1 the toggle linkage supporting bhe switch contact members of any pole in pressure engagement ls broken that the other to ggle linkages will immecliately be moved outward and broken by the correspon'ding members 83 to 85,inc1usive;

From the foregoing, lt will be obvlous that when abnormal circuit conditlons develop and the switch members o1. any one pole of the breaker a1'e actuated to interrupt the circuit through that pole, then all of the switch members of the other poles will be operated immediately to operate the breaker to its open circuit position.

I claim as my mvention:

1. In a multiple pole circuit breaker, in combination, a plurality of cooperaive switch members, means for actuating thec00perative switch members 015 each pole intq pressure engagement, the actuating miaans having fixed pivot points, a balancing lever pivotally connected to the actuating means of the cooperative swltch members of the dlfferent poles, for balancing the reactive pressures from the swltch members for the difierent poles about the pivot points of said actuating means to retain the cooperative switch members of the diiferent poles in pressure engagement.

2. In a multiple pole circuit breaker, a plurality of cooperative switch members for euch pole, means for actuating the switch members 120 perform switching operations, membexs' l1airing fixed pivot points operable to support the switch actuating meanato maintain the cooperatlve -switch members in pressure engagement and means counected to the plvoted members for balancing the reactive pressures received from the switch members for the different poles about the pivot points of said plvoted members thereby to retain the cooperative switch members 01 the cllfferent poles in pressure engagement.

3. In a multiple pole circuit breaker, in complnation, a plurality of cooperative switch members, pivotally mounted arms connected to one 01 the co0peratlve switch members o1 each pole, a balancing lever pivot.lly Connected to the arms and operative to retain the cooperative swltch members in pressure engagement, the points 015 the connectlons between the arms and the balancing leverbeing so dlsposed relative to the pivot points of the arms that the reactive press'ure from the contact members received by one arm is balanced against the reactive pressure received from the contact members by the other arms whereby if the pressure transmitted through one arm is released, movexnent of all the arms is effected to operate the breaker.

4. In a, multiple pole circult breaker, in eo bination, a plurallty of cooperatlve switch members, pivotally mounted arms connected to one of the c6operatlve switch members of each pole. a balancing lever pivotally counected to the arms and cooperative to retaln the swltch. members in pressure engagement, the points of the connections between the arms and the balanc- Ing. lever being so disposed relative to the pivot points of the arms that the reactlve pressure from the contact members recelved by one actuating arm is balanced against the reactlve pressure received from the other actuatlng arm thereby if the pressure transmitted through one arm is released, the ino'vement of all the arms is efiected and means cooperatlve to eflect the opening of the breaker. when the arms move in response to the releasing 01 one of the arms from the reactive pressure transmitted from the corresponding contact members. 5. In a multiple pole eircult breaker, in combinatlon; a plurality of cooperative switch men bers, toggle linkages connectetl to the coopera= tive switch members ot the different poles for operating them, pivotally mounted arms cannected to the 'toggle linkages a balanclng lever ivotally connected to the arms am! cooperatlve m retain the swltch members of the dlflerent poles in pressure engagemnt the points of .connections between arms and balancing lever being so dlsposed relative to the pivot polnts of the arms that the reactive pressure Irom the contsict members received byone arm is balanced against the reactive pressure received by the other arms, whereby lf the pressure transmittecl through one arm is released, movement of all the arms is etfected and means oooperative wlth the toggle linkages to break them as they move thereby to operate the breaker.

6. In a multiple pole circuit breaker, in combination, a. plurality of cooperative switch members, a pivotally mounted arm for the cooperatlve switch members 'of each pole of the breaker, the pivotally mounted arms being'disposed for retaining the cooperative switch members in pressure engagement, a balancing lever pivotally connectecl to the pivoted arms, the points of the connections between the arms und the balanclng lever being so dlsposed relative to the pivot points of the arms that the reactive pressures from the contact members are balanced against -one another when the breaker stands closed.

7. In a multiple pole circuit breaker. in combinatlon, a plurality of Cooperative switch members, a pivotally mounted arm for the cooperative switt:h members of each pole of the breaker,

the pivotally mounted arms being 'disposed for plied to the actuatlng lever to which the balancing lever is pivoted when the breaker stands closetl.

8. In a multiple pole ccuitbreaker, in combination, a plurallty of cooperative switch members, a pivotally mounted arm for the cooperative switch members of each pole of the breaker, a toggle linkage disposed between ea.ch arm and the correspondlng coritact members, a balancing lever plvotally mounted an one of the arms, means connecting the balancing lever to the other arms, the o ther arms b eiug disposed to balance about the pivotal axis of thebalancing lever, the plvotal axis of the arm carrying the balancing lever und the pivotal axes of the other arms being so disposed relative to one another and to the pivotal axis of the balancing lever that when the brea.ker stands closed, the pressure is distributed in a predetermined relatlon between the cooperative contact members.

9. In a multiple pole circuit breaker, in combinatlon, a plurallty of cooperative contact members, a -toggle. llnkage connected to the cooperative cont'act members o1 each pole; means Ior actuating the toggle linkages 01 the difierent poles to the lr over-center pofsitlons, a plura.llty' of levers pivotally connected to the toggle linkconnected to the other supportinglevers, the

p'ivotally connected levers belng balanced about the pivotal axis of the balancing lever and disposed to apply a reactive force received from the corresponding contact members through the axis of the balancing lever which is opposed to the reactive pressure from the contact members transmitted through the supporting lever ca!- rying the balancing lever whereby the pressures between the contaci; members are distributed from one pole to the other.

10. In a multiple pole circuit breaker, in combination, a plurality of cooperative contaci; members, a toggle linkage connected to the cooperative contact members of each pole, means for actuat- Ing the toggle linkages o:f the poles to iheir overcenter positions to move the cooperative contact members into pressure engagement, a plurallty of levers pivotally connected t0 the toggle linkages to support them to cooperate in the closing of the contact members of the difierent poles of the breaker when the toggle linkages are actuated to their over-center positions, a. balancing lever pivotally mounted on one of the Supporting lever s and pivotally connected to the other supporting levers, the pivotally connected levers being balanced about the pivotal axis of the balancing lever and disposed apply a reactlve force received from the corresponding contact members through the axis cf the balancing lever which is opposed to the reactlve pressure of the contact; members transmitted through the supporting lever carrying the balancing lever whereby the pressures between the contact, members are distributed from one pole to the other, and mea.ns associated with each toggle linkage to break it'when the toggle linkages move with the supporting levers when any one toggle linkage is broken in response t0 predetermined operating conditions, and a tripping member associated With each toggle linkage.

11. In a multiple pole circuit breaker, in combinatlon, a plurality of cooperative swltch members, a toggle linkage connected to the cooperative switch members of ea.ch pole for biasing the switch members into pressure engagement, means for actuating the toggle linkages of the poles t0 their over-center positions to close the breaker,

a tripping member associated with each toggle llnkage, a pivotally mounted balanclng lever, means for balanelng the rea.ctive pressures from the switch members 015 the differeni; poles about the pivotal axis of the balancing lever, the balanbing lever being disposed to move as a unit to efiect a. movement of the toggle linkages relative to the tripping members, thereby to provide for actuating the switch members of the breaker.

12. In a multiple pole circuit breaker, in combination, a plurality of cooperative switch members for each pole of the breaker, a toggle linkage' connected to the cooperative switch members cf each pole to a.ctuate them, means for actuating the toggle linkages of the poles to their overcenter positions to close the breaker, a tripping member associated with each toggle linkage, a. pivotally mounted balaneing lever, means for balancing the reactive pressures frcm the switch members 0f the difierent poles about the pivotal axis of the balancing lever, the balancing lever being disposed move as a unit to effect a movement of the toggle linkages relative to the trip' ping members and means responsive to electrical conditions for breaking one of the toggle linkageS 130 unbalance the reactive forces applied to the balancing lever 120 efiect its movement; as a unit and the movement of the toggle linkages relative to the tripping members to break all the toggle linkages and thereby separate all the cooperative switch members of the differeni; poles of the breaker.

STAN'LEY T. SCHOFIELD.

Images