US2375642A

US2375642A - Electric circuit interrupter

Info

Publication number: US2375642A
Application number: US477249A
Authority: US
Inventors: John D Gayer
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1943-02-26
Filing date: 1943-02-26
Publication date: 1945-05-08
Anticipated expiration: 1962-05-08

Description

May 8, 1945.

J. GAYER ELECTRIC CIRCUIT INTERRUPTER Filed Feb. 26. 1945 Fig. I.

2 Sheets-Sheet 1 47 32 ,x'. 52 38 j I 4a \49 23 ffi O O I O 25 O 0 2a 28 r I -lla Inventor:

John D. 6 ay fi' His Atto'rn ey.

y 1945- I J. D. (BAYER 2,375,642

ELECTRIC CIRCUIT INTERRUPTER Filed Feb. 25, 1945 2 Sheets-Sheet 2 4a Fi .3. 5% 52 4f 3a J6 g 25 .77 0 8 Z4 '23 4 f it? 2 l 4/ 5/ 2/ o O 26 14 2a Ihventor: John D. G y fi b 5. His Attorney Patented May 8, 1945 2,375,842 ELECTRIC CIRCUI'I. INTERRUPTER John D. Gayer, Springfield, Pa., aslignor to General Electric Company, a corporation of New York Application February 26, 1943, Serlal No. 477,249

13 Claims.

My invention relates to electric circuit interrupters and particularly to improvements in electric circuit breakers of the fluid blast type. Speciflcally my invention is an improvement on the invention disclosed and claimed in United States Letters Patent 2,287,578--Thumim et al., granted June 23, 1942, and assigned to the same assignee as the present application and also an improvement on the invention disclosed in copending Gayer et a1. application, Serial No, 477,247, flled concurrently with the present application.

Circuit breakers which do not utilize oil or other inflammable liquid for are extinguishing purdependently and accurately adjustable whereby an economical consumption of fluid results and the fluid storage facilities may be maintained within reasonable limits.

Still another object of my invention is to provide a new and improved fluid blast control arrangement for a fluid blast circuit breaker.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed poses, but instead employ a blast of fluid such tinguishing purposes. From a cost standpoint it' would be desirable to limit these facilities to a minimum and this can be accomplished by conserving the air required for the fluid blast. It has been discovered that during the circuit openingoperation of a fluid blast circuit breaker it is preferable for the fluid blast to be in existence at the instant the contacts separate and continue for a longer period of time than would be required during the circuit closing operation where I it is merely necessary to prevent the are from striking and not necessary to extinguish the arc. My invention is primarily concerned with new and improved means for controlling the fluid'blast of circuit breakers employing a fluid or air blast for are extinguishing purposes.

It isan object of my invention to provide a new and improved valve operating means for a fluid blast circuit breaker which will positively function on each opening stroke of the circuit breaker, whose operation shall be sufficiently freed from mechanical movement of the contacts of the circuit breaker to permit a blast of fluid to exist for arc extinguishing purposes prior to separation of the contacts, and that a deflnite and positive closing of the valvemeans is produced.

It is a further object of my invention to provide a new and improved circuit breaker of thefluid blast type in which the initiation and duration of both the opening and closing fluid blasts are inout with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to'the accompanying drawings in which Fig. 1 is a schematic diagram partl in section of a fluid blast circuit breaker embodying my invention, and Figs. 2, 3, and 4 are views of a portion of the fluid blast circuit breaker of Fig, 1, illustrating difl'erent operating positions thereof.

Although my invention is applicable to any fluid blast circuit breaker, single phase or polyphase, for purposes of clearness and simplicity in the disclosure, we have illustrated my invention schematically in Figs. 1 to 4 as applied to a fluid operated circuit breaker ID of the cross gas-blast type, comprising a stationary contact ii and a movable contact l2, arranged to be operated to draw an arc in an arc chute I3. It will be understood by those skilled in the art that contacts II and I2 which are relatively movable with respect to one another, are arranged to be .connected with suitable line terminals not shown. The stationary or fixed contact H is provided with spring pressed contact fingers I la and longer arcing contact fingers ll, while movable contact I2 is provided with an arcing tip l2 so that when the contacts separate an arc occurs between arcing tips II and I2. Immediately after separation of the contacts one terminal of the arc is transferred by a blast of fluid, such as air or any other gas issuing from conduit M which is suitably connected through blast valve IE to be described hereinafter with a source of fluid under pressure l6, from contact fingers II to the contact II" which is provided with a tip of arc resistant metal. The fluid blast from conduit it upon the opening of circuit breaker Ill drives the are into the arc chute it against the edges of a plurality of partitions ll which partitions are mounted in the arc chute l3, transverse to the arc gap and the ends of which extend close to the path of movement of the arcing tip I! of movable contact it. This circuit breaker i0 is illus.

trated by way of example only in order to aid in understanding my invention which is applied thereto. The circuit breaker described thus far is not my invention but is disclosed and claimed in United States Letters Patent 2,284,842- Prince et al., granted June 2, 1942, and assigned to the same assignee as the present application.

Any suitable means for producing relative movement between contacts II and I2 may be provided. I have chosen to illustrate this means in the drawing as comprising a fluid operated motor generally indicated at I8, having a cylinder I9 and a piston 20 which is adapted for reciprocal movement in cylinder I9. Piston 20 is operatively connected to movable contact I2 by means of a connecting rod 2 I, link 22, movable member or bell crank 23 pivotally mounted at 24, link 25, crank 26 pivotally mounted at 21, and circuit breaker operating rod 28. Straight line motion of movable contact I2 is obtained by virtue of guide means 29 provided on either side of contact l2. The solid lines in Fig. 1 indicate the closed position of operating rod 23 and contact I2 while the dotted lines indicate the open position.

In order to operate the fluid motor l8, fluid under pressure from source or tank I6 is introduced at the respective ends of cylinder I9, the movement of piston 23 depending upon the particular end of cylinder I9 at which fluid under pressure is introduced. As illustrated in the drawings, the left hand end of cylinder I9 is connected with the pressure source It through a conduit 30 and circuit breaker opening valve 3i schematically shown. The other end of cylinder I9 is connected with source I6 through conduit 32 and circuit breaker closing valve 33 also schematically shown. It will be understood that circuit breaker opening valve 3i and circuit breaker closing valve 33 are preferably of the three way type to permit venting respective ends of cylinder I9 to atmosphere when the particular valve is closed.

In order to provide high speed opening of circuit breaker In such fluid operated circuit break I ers are usually provided with dumping valves or the like to rapidly vent the closing sid of piston 20 to atmosphere thereby permitting high speed opening movement thereof. One example of such a dumping valve is disclosed and claimed in United States Letters Patent 2,292,096-Thumim et al., granted August l, 1942, and assigned to th same assignee as the present application. Accordingly, in the drawings I provide a dumping valve generally indicated at 35, whichis substantially identical with the dumping valve of Thumim et al. Patent 2,292,096. This dumping valve 35 is illustrated as comprising a relatively large valve member 36 operatively connected to a piston 31 of the same or larger diameter arranged for reciprocal movement in a cylinder 38 and normally biased by means of a spring 39 to hold dumping valve member 36 in th closed position, thereby preventing escape of fluid from the right hand end of cylinder I9 to atmosphere except through circuit breaker closing valv 33. Operatively connected with piston 31 is a second valve member 46 associated with the port M which opens into the left hand end of cylinder I9. When dumping'valve member 36 is in the closed position indicated in Fig. l, the second valve member 40 permits the port M to be open to atmosphere. At the same time the second valve member 40 closes the passageway between circuit breaker opening valve 3! and cylinder l9 so the lower end of slot 49.

that dumping valve 35 must be operated and at the same time roller 5| will raise cam 41 and blast valve 43 before any relative movement of the contacts of circuit breaker I0 can occur. When circuit breaker closing valve 33 is opened the pressures operating on piston 31 and valve member 36 are substantially equal and consequently spring member 39 holds valve member 36 i the closed position. On the other hand, when circuit breaker opening valve 3I is operated, fluid under pressure from source I6 operating against the relatively large surface of valve member 46 which also serves as a piston, overcomes the force of spring 39 and moves the entire valve assembly to the right so as to open dumping valv member 36 as indicated in Fig. 2 so that valve member or piston 40 closes the passageway between port 4! and atmosphere. By this arrangement the right hand end of cylinder I9 has the pressure therein instantaneously reduced so that rapid opening operation of circuit breaker It] may be obtained. Not until valve member 40 has moved a predetermined amount can fluid under pressure enter the left hand end of cylinder l9 to operate piston 20 to open circuit breaker I0. Blast valve I5 may comprise any suitable type of valve and is illustrated in the drawings as comprising a valve member 43 connected to a valve stem 44 which is biased by spring means 45 to normally maintain blast I5 in the closed position. A suitable roller 46 is provided at the end of valve stem 44 to be engaged by the blast valve operating means to be described hereinafter.

In order to open the valve means illustrated as blast valve I5, I provide means comprising two relatively movable members. One of these members is bell crank 23 pivotally mounted at 24. The other of these members is designated as cam means 41 which is pivotally mounted to bell crank 23 as indicated at 48. The pivotal movement of cam means 47! about pivot 48 is limited by means of a slot 49 in cam means 48 which engages with a pin coextensive with the pivot or axis of rotation 24 of bell crank 23. It will be observed that with this arrangement cam means 4'! for opening blast valve I5 is really pivotally mounted about a first axis of rotation 24 and at the same time has limited pivotal movement about a second axis of rotation 48. Except for the limited pivotal movement determined by slot 43, cam means 4'! moves as a unit with bell crank 23 in response to operation of fluid motor I8 and consequent movement of movable contact l2 of circuit breaker ill.

Cam means 4?! which has a cam face 4'5 when rotatedabout the axis of rotation 24 of bell crank 23 with the pin coextensive with axis 24 in the position relative to slot 49 indicated in Fig. 1 will not cause opening movement of blast valve I5, but roller 46 will just engage with cam face 41 throughout this movement of cam means 41..

In order to insure a blast of fluid in arc chamber or chute I3 adjacent relatively separable contacts II and I2 prior to any relative movement of these contacts, I provide an extension 50 on dumping valve 35 from which is supported a roller 5|. Upon opening of dumping valve 35 roller 5| will engage cam means 41 so as to move cam means 41 to the position indicated in Fig. 2 wherein the-pin, coextensive with pivot 24, is in This movement of cam means 41 will cause opening of blast valve I5 as is clearly indicated in Fig. 2. Furthermore,

pivot 24 with the cam face 41' maintaining blast I valve IS in the open position until the piston l8 of fluid motor l8 reaches the position indicated in Fig. 3 when roller 16 drops off the end of cam face 41' and permits closing of blast valve l5.

Fig. 3 shows the operating mechanism at the instant the fully open position of circuit breaker III has been attained, but prior to theinstant when circuit breaker opening valve 3| has been closed to permit dumping valve 35 to close. Fig. 4 shows the mechanism an instant later when dumping valve 35 has closed to release cam means 41 and permit limited relative movement of cam'means 41 about axis of rotation 48. With the arrangement described thus far, a blast of fluid is provided at the contacts before any relative separation of the contacts can occur. Furthermore, the duration ofthis blast of fluid'and the instant of closing of blast valve I5 may be controlled in any manner desired merely by shaping the face 41' of cam means 41. The lift of valve member 43 of blast valve member l5 may be controlled by the length of slot it. It has been discovered that a blast of fluid in arc chamber i3 is desired during th circuit breaker closing operation. However, this blast of fluid need have only a very short duration and furthermore, need not be as great as the opening fluid blast since its sole purpose is to prevent striking of the arc. Consequently I provide a short closing blast of fluidiin arc chamber it by providing a cam face 52 on bell crank 23. This cam face 52 is adapted to engage with roller Alb during the circuit closing operation and the magnitude of the blast and the duration thereof may be controlled by shaping cam face 52 in any manner desired. Since the opening of blast valve it during the closing operation of circuit breaker ill need not be as great as during the circuit breaker opening operation, cam face 52 will not interfere during the circuit breaker opening operation.

It will be observed that the blast valve operating means comprising relatively

movable members

47 and 23 is arranged to be rendered effective or ineffective to open the valve depending upon the position of dumping valve 35. It is furthermore observed that independently adjustable closing and opening fluid blasts are obtainable with my arrangement with a simple sturdy operating mechanism which is relatively inexpensive and which requires a minimum of space.

In view of the detailed description included above, the operation of the circuit breaker heretofore described will be obvious to those skilled in the art. Whenever circuit breaker opening valve 3| is opened, dumping. valve 35 is immediately operated and consequently valve opening means comprising

members

23 and 41 is rendered effective to open blast valve I5 prior to any movement of contact 12 and furthermore to control the opening fluid blast thereafterin response to the opening movement of circuit breaker Hi.

It will be apparent to those skilled in the art that my invention is not limited t the particular constructions shown but that changes and modifications may be made without departing from the spirit and scope of my invention and I aim in the of fluid adjacent said contacts during the circuitappended claims to cover all such changes and modifications.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an electric circuit breaker of the fluidblast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including valve means assoclated with said source for producing a blast interrupting operation of said circuit breaker, means for opening said valve means comprising two relatively movable members, means for moving one of said members relative to the other to open said valve means prior to any relative separation of said contacts, and means for subsequently rotating said two members as a unit in response to opening of said circuit breaker to control the duration of the period that said valve means is maintained in the open position.

2. In an electric circuit breaker of the fluidblast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including valve means associated with said source for producing-a blast of fluid adjacent said contacts during the circuitinterrupting operation of said circuit breaker, a cam means for opening said valve means pivotally mounted about a first axis of rotation but having limited pivotal movement about a second axis of rotation, means for causing limited pivotal 1 movement about said second axis to open said valve means prior to any relative separation of said contacts, and means for rotating said cam about said first axis in response to relative separation of said contacts to control the duration of the period that said valve means is maintained in the open position.

3. In an electric circuit breaker oi the fluidblast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including a valve associated with said source for producing a blast of fluid adjacent said contacts during the circuit interrupting operation of.said circuit breaker, means movable in response to relative separation of said contacts, said last mentioned means being arranged to be rendered effective or ineffective to open saidivalve, and. means for rendering said last mentioned means-effective to open said valve prior to any relative separation of said contacts to produce a blast of fluid in said are chamber for are extinguishing purposes.

4. In an electric circuit breaker of the fluidblast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including valve means associated with said source for producing a blast of fluid adjacent said contacts during the circuitinterrupting operation of said circuit breaker, means for opening said valve means comprising two relatively movable members, fluid operated means for moving one of said members relative to the other to open said valve means prior to any relative separation of said contacts, and means for subsequently moving said two members as a unit in response to opening of said circuit breaker to control the duration of the period that said valve means is maintained in the open position.

5. In an electric circuit breaker of the fluidblast type comprising a plurality of relatively movement between said contacts, a source of fluid under pressure, means including valve means associated with said source for producing a blast of fluid adjacent said contacts during the circuitinterrupting operation of said circuit breaker, means for opening said valve means comprising two relatively movable members, fluid operated means for moving'one of said members relative to the other to open said valve means prior to any relative separation of said contacts, means for subsequently moving said two members as a unit in response to opening of said circuit breaker to control the-duration of the period that said valve means is maintained in the open position, and independent means for controlling the opening of said valve means during the circuit closing operation.

6. In an electric circuit breaker of the fluidblast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including valve means associated with said source for producing a blast of fluid adjacent said contacts during the circuitinterrupting operation of said circuit breaker, a cam means for opening said valve means pivotally mounted about a first axis of rotation but having limited pivotal movement about a second axis of rotation, fluid-operated means for causing limited pivotal movement about said second axis to open said valve means prior to any relative separation of said contacts, and means for rotating said cam about said first axis in response to relative separation of said contacts to control the duration of the period that said valve meansis maintained in the open position.

7. In an electric circuit breaker of the fluidblast type comprising a plurality of relatively movable contacts, means for producing relative movement between said contacts, a source of fluid under pressure, means including valve means associated with said source for producing a blast of fluid adjacent said contacts durin the circuit-interrupting operation of said circuit breaker, a cam means for opening said valve means pivotally mounted about a first axis of rotation but having limited pivotal movement about a second axis of rotation, fluid operated means for causing limited pivotal movement about said second axis to open said valve means prior to any relative separation of said contacts, means for rotating said cam about said first axis in response to relative separation of said contacts to control the duration of the period that said valve means is maintained in the open position, and independent means for controlling the opening of said valve means durin the circuit closing operation.

8. In an electric circuit breakerv of the fluidblast type comprising a plurality of relatively movable contacts, a source of fluid under pressure, a fluid motor for producing relative movexnent between said contacts, means including valve means associated with said source for producing a blast of fluid adjacent said contacts during the circuit interrupting operation of said circuit breaker, means arranged to be rendered eiiective or ineffective to open said valve means movable in response to relative separation of said contacts, and fluid operated means for rendering said last mentioned means effective, said fluid operated means being constructed so as to block the fluid passage between said fluid source and said fluid motor to prevent said fluid motor from being operated to open said circuit breaker until said last mentioned means has been rendered eifec'tvie to open said valve means. i

9. In an electric circuit breaker of the fluidbIast type comprising a plurality of relatively movable contacts, a source of fluid under pressure, a fluid motor for producing relative movement between said contacts, means including valve means associated with said source for producing a blast of fluid adjacent said contacts during the circuit interrupting operation of said circuit breaker, means for opening said valve means comprising two relatively movable members, a fluid operated dump valve associated with said fluid motor and including means movable therewith for moving one of said members relative to the other to open said valve means prior to any relative separation of said contacts, and means fOl subsequently moving said two members as a unit in response to opening of said circuit breaker to control the duration of the period that said valve means is maintained in the open position.

10. In an electric circuit breaker of the fluidblast type comprising a plurality of relatively movable contacts, a source of fluid under pressure, a fluid motor for producing relative movement between said contacts, means including valve means associated with said source for producing a blast of fluid adjacent said contacts during the circuit-interrupting operation of said circuit breaker, a cam for opening said valve means pivotally mounted about a first axis of r0- tation but having limited pivotal movement about a second axis of rotation, fluid operated means for causing limited pivotal movement about said second axis to open said valve means, said fluid operated means being arranged to prevent operation of said fluid motor during the circuit interrupting operation until said valve means is opened, and means for rotating said cam about said first axis in response to relative separation of said contacts to control the duration of the period that said valve means is maintained in the open position.

11. In an electric circuit breaker of the fluidblast type comprising a plurality of relatively movable contacts,'a source of fluid under pressure, a fluid motor for producing relative movement between said contacts, means including valve means associated with said source for producing a blast of fluid adjacent said contacts during the circuit interrupting operation of said circuit breaker, means for opening said valve means comprising two relatively movable members, a fluid operated dump valve associated with said fluid motor and including means for moving one of said members relative to the other to open said valve means prior to any relative separation of said contacts, means for subsequently moving said two members as a unit in response to opening of said circuit breaker to control the duration of the period that said valve means is maintained in the open position, and independent means for controlling the opening of said valve means during the circuit closing operation.

12. In an electric circuit breaker of the fluidblast type comprising a plurality of relatively movable contacts, a source offluid under pres- 'sure, a fluid motor for producing relative movement between said contacts, means including valve means associated with said source for producing a blast of fluid adjacent said contacts during the circuit-interrupting operation of said circuit breaker, a cam for opening said valve means pivotally mounted about a first axis of rotation but having limited pivotal movement about a second axis of rotation, fluid operated means for causing limited pivotal movement about said second axis to open said valve means, said fluid operated means being arranged to prevent operation of said fluid motor during this circuit interrupting operation until said valve means is opened, means for rotating said cam about said first axis in response to relative separation of said contacts to control the duration ofv the period that said valve means is main tained in the open position, and independent means for controlling the opening of said valve means during the circuit closing operation.

13. In an-electric circuit breaker of the fluid blast type comprising a plurality of relatively movable contacts, a source of fluid under pres sure, a fluid motor for producing relative movement between said contacts, a blast valve connected between said source and said contacts for controlling an arc extinguishing blast of fluid adjacent said contacts during a circuit interrupting operation of said circuit breaker, and means including a piston for causing opening of said :blast valve prior to any relative opening movement of said contacts, said last mentioned means being so constructed and arranged so that said piston blocks the fluid passage between said fluid source and said fluid motor to prevent fluid from reaching said fluid motor to operate the same to open said circuit breaker until said blast valve has been opened.

JOHN D. GAYER.