US2282154A - Circuit interrupter - Google Patents

Description

May 5l 1942- A. H. BAKKEN 2,282,154

CIRCUIT INTERRUPTER Filed Jan. l5, 1940 2 Sheets-Sheenl 2 67 69 w l l/ n WITNEssEs: n, uw INVENTOR d a/rew/Xa/Aen mm 4 Patented May 5,

* i UNITED STAT ES PATENT- OFFICE Andrew il. Bakken, Edgewood,v ia., assigner to Westinghouse Electric Manufacturing (him pany, East Pittsburgh,A Pa..- acorporation of Pennsylvania l musicaon new', 1s, im, serai 10.313345 (ci. zoo-lis) 13 Claims.

This invention relates to improvements in circuit interrupters and, more particularly, tc circuit breakers of the gas blast type. In the ap f plication of J. B. MacNeill et al.. Serial No.

aforesaid .type by the provision of a contact structure that is simple in design, easy to operate and which enables an arc to be established directly across the discharge end of the hollow insulator utilized in supporting the arc extinguishing unit, thereby 'eliminating bends in the gas supply line from tile pressure tank to the arc extinguishing. unit and a loss of pressure.

It is a further object of the invention to provide a gas blast circuit breaker with a direct and substantially straight path for the blast of gas from `the tank through the arc at substantially right angles thereto and without restrictions which would prevent the full flow of the blast of gas through the arc, and thereby make possible the use of as low a gas pressure in the tank as possible.

A more specinc object of the invention resides in the provision of a hinged type moving contact structure for a breaker of the aforesaid type which provides a low resistance conducting path free of exible shunts or sliding contacts.

Another object 'of my invention is to provide an arc extinguishing structure in -the form of an parc chute for a gas blast .type ot circuit interrupter that is so arranged with respect to the contact assembly and the gas supply means thereto that the arc chute can be easily removed without disturbing the contact assembly or its operativeness for the purpose of enabling ready inspection of the condition oi' the contacts and/or making adjustments 'to the operating mechanism for the contacts.

A further object of my invention is to provide an improved pressure actuated operating mechanisxn for gas blast circuit breakers which. incorporates mechanically actuated means for oontrolling the admission of an arc extinguishing blast of gas to the arc extinguishing structure 15. prove the operation of circuit interrupters of the breaker.

of the breaker.- In this connection, it is contemplated to provide a separate gas blast control valve means for each arc extinguishing unit of a polyphase'circuit breaker so as to eliminate the diiiiculties of gas ilow normally encountered in a manifold conduit system utilizing but a single sas blast control Other objects and advantages will appear in the following description. when taken in' connec-l tion with the' accompanying drawings, in whichv Figure 1 is a front elevation view of a polyphase circuit interruptor embodying my invention,

Fig. 2 is a side elevation view of the circuit interrupter shown in Fig. l, partially in section vfor more clearly illustrating the gas blast control and the operating mechanism, and

Fig. 3 is an enlarged fragmentary view partiallyin'section 'showing a modiiied gas blast control arrangement.

Referring to the drawings. the reference nilmeral l designates a tank for storing gas, such as air, under pressure. Extending from the top of the tank l are a pluraiityof, in this instance. three flanged conduits 5. Secured to the ilanged portion of each conduit 5 is a metallic valve casing 'L Mounted upon the upper 'end of each valve casing 1 is a tubular insulator I which, in

has secured to its upper end an arc chute support Ii of insulating material. The support ii also carries a stationary contact assembly il including a plurality of spring pressed contact nngers i5. A throat-like gas passage il extends through the support ii and is preferably coextensive with the passage through the tubular insulator 9. The throat-like passage I1 discharges into an arc chute structure Il having two generally parallel sidewalls 2i and 2l. The side walls l2l and 23 are adapted to rest upona support Il and are secured thereto by a pair of transversely extending bolts 25 which are the sole means for holding the arc chute in place. Each are chute i9 is generally of the typ more fully shown and described in the application of L. R. Ludwig, et al., Serial No. 313.736, iiled January 13, 1940. and assigned to the assignee of this application, but inasmuch as the arc chute is not claimed speciiically in this application, it is deemed that a rfurther description thereof is not necessary for the understanding of the instant invention.

T'he forward side of each arc chute I! is provided with a rectangular slot 2l atthe lower end thereof tin-ouah which a blade-like movable con-V tact 2l may operate into and out of engagement valve for all phases of the terminal 31.

-with the stationary contact fingers l5. The movable contact 29 is preferably of inverted L-shaped blade construction having a bifurcated arm 3 the two legs of which are pivoted at 33 to a conducting bracket 35 clamped about the tubular insulator 9. The pivotal connection 33 is of the high pressure type so'that good electrical contact is maintained at all times between the bracket 35 and the arm 3|. The right-hand side of bracket 35 is provided with. an external circuit terminal 3l?.l The stationary contact assembly is is also provided with an externalv circuit terminal indicated at 35. Thus `when the interrupter is in the closed circuit position,l as shown,

an electrical circuit ismade therethrough from the terminal 39, stationary contact i5, moving contact 29, contact arm 3|, bracket 35, to the Movement of the contact arm 3| about the pivot 33 in a counter-clockwise direction to actuate theinterrupter to the open circuit position is accomplished by an operating mechanism generally indicated at lli. This operating mechanism is preferably of the gas pressure operated type and includes a cylinder 33, a piston therein. (not shown) providedwith a connecting rod d5 'f extending from theupper end of the cylinder.

The connecting rod is coupled by a pair oi links dl to .a crank arm 59 secured to a cross shaft 5|. journalled in suitable brackets 53 secured to the side of the pressure tank 3.

The cross shaft 5| -has mounted thereon at.

The cross. shaft 5|. for examplefmay be 15 -to rotate in the clockwise direction, depressing the valve stem 19 to cause valve 8| to emit a blast of gas from the tank 3 through the insulator 9 into the gas discharge throat |1 for extinguishing the arc formed upon separation of the Acon-- tacts l5 and 29. It will be noted that cam 1| has a :high side 83 which maintainsy the valve 8| open during a predetermined time interval while the moving contacts 29 are being moved to the open lcircuit position. As each moving' contact 29 reaches its full open circuit position, the roller 13 will have moved beyond the cam surface 38 to again permit the valve 8| to close, thus positively shutting of! the supply of gas through each interrupter.

it will be observed that the gas blast for extinguishing the `arc is directed in a substantially,

straight path from the pressure tank 3 through the tubularinsulator 9 into engagement wththe arc, thereby avoiding turbulence or eddies in'A the gas conducting system'and .a consequent loss of Y pressure. Y `i Closing movement of theinterrupter is effected by admitting compressed gas to the cylinder .43

through the valve 85, which moves the connecting rod 85 upwardly, causing the'crank arm and the cross'shaft 5| torotate in a clockwise direction as viewed in Fig. 2, andwconsequently also causing thecrank arms 55 to actuatethe operatspaced intervals three crank arms 55 which, in

turn, are coupled by an insulatingoperating rod 51 to the moving contact 'arms 3| of the respective pole units.` Gas under pressure is admitted to the cylinder 43 for actuating the interrupter to the open circuit' position by a valve 5%, the lower portion of which rests and is supported upon the flange 6| of a conduit 63, leading from the interior of the pressure tank 3. A similar control'valve 65 is used for controlling the admission of gas from the pressure tank 3 to the cylinder 43 for closing the circuit interruptor.

The valve 65 rests upon, and is supported by, a'

iiange 61 of theA conduit 59 leading into the storage tank 3.. Thyalves 59 and 65 are secured to the cylinder t3 so as to form a unit and are supported solely' by the conduits 63 and 69 carried by the tank3. Actuation of the .valves 59 and B5 may be by any suitable means, such as electromagnetic, pneumatic, or combinations of both.

Each of the crank arms 55 is provided with a cam 'il which is adapted to engage `a roller 13 carried by a bell crank 15. Thebell crank 15 is operatively coupled at 11 to the end of a valve stem 19 extending through the valve casing 1.

The lower end of the valve stem 19 carries a valve f 3| which normally seals oi the pressure tank 3 from the hollow insulator 9 and the arc chute i9. It will thus be seen that as gas under pressure is admitted to the operating cylinder 83 by the.

moving contacts 29 from the stationary contact i fingers I5. the cam 1| will have caused bell crank ing rods 51 upwardly so as to' rock the contact arms 3| to the closed circuit position. Shortly' following initiation of the closing movement, the l roller 13 will again Vbe actuated by the cam. surface 83 to cause'valve BI to be opened to cause-a blast of gas vto be directed through .the insulator 9 in the path betweenjhe` closing, contacts. This blast of gas is discontinued as soon as the moving contacts 29 make contacting engagement with the stationary contacts I5 andthe roller` 13 is again positioned asshown' in the drawings. During the closing operation of the interrupter, the crank arms 55 are rotated in a clockwise direction until they engage stop members 85 so positioned that the crank arms 55 and theirl associated operating rods 51 form a slightly overcenter toggle relation with each other, thereby maintaining the moving contacts 2a positively locked in the closed circuit' position.

In order to conserve gas during the operation of the interrupter, I have provided a modied gas blast control arrangement as shown in Fig. 3. In the arrangement shown in Fig. 3, the crank arm 55 has been replaced with an arm 81. The crank arm Blvdiiers from crank arm 55 in that the former has a collapsible cam portion 88 l whereas the cam portion 83 ci the latter is iixed.

The cam portion or member89 isl coupled to the crank arm 81 by two pairs of short links 9| and' 93 and pivot pins 35 and 91.

posed about each pivot pin 95 biases the cam member 89 in a clockwise direction with respect to. pins 95 against a stop`||l| which is in this instance an integral part of the crank arm 81.

' Thus when the cam member 89 is against the stop `|0| it is in an extended position with iespect to the shaft 5|, and operative with respect to the roller 13, against which it moves during th opening operation of y the interrupter; During the opening operation, the operating mechanism 4| causes oshaft 5| to be rotated in a counterclockwise direction to'bring cam 89 into engagement with the roller 13 so as to rock the bell crank 1.5 in a clockwise direction, thereby actuating'the valve 8| to the open position, which admits an arc-extinguishing blast of gas from the tank 3 into the tubular insulator 9. The cam member 89 is shaped similarly to cam 83, previously described, so that when the contacts 29 have reached full open circuit position. the valve 8| is permitted to close, causing discontinuance of the arc-extinguishing blast of gas.

However, during the closing operation, as crank arm 81 is rotated in a clockwise direction, the cam 89 will collapse upon being brought into forceful engagement with the roller 13 and take a position as shown in dotted lines in Fig. 3. In this position the cam 89 is ineffective to actuate the roller 13 and the bell crank 15, thereby permitting the valve 8| to remain closed during the entire circuit closing operation. Just prior to engagement ofV` the moving contacts 29 with the stationary contacts l5, the cam P89 is brought into` a position to clear the roller 13. Upon reaching this position,the springs 99 will rotate the links 9| and'93 in a clockwise direct-ion to again extend the cam 89 and bring it into engagement with the stop IUI, so that the cam will be operative to actuate the valve 8l during the next opening operation. Thus by making the cam 89 oi' collapsible form a considerable saving in compressed gas is effected in that the arc extinguishing blast is provided only during the circuit opening operation.

Although I have shown and described a particular circuit interrupting structure, it is to be understood that the same is for the purpose of illustration and that changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a gas blast circuit interrupter, a tank for storing gas under pressure, a hollow insulator supported by said tank, stationary contact means mounted on the free end of said insulator, a coacting movable contact pivotally mounted upon said insulator intermediate the ends thereof and having its contact portion movable across the free end of said insulator in a path generally at` right angles to the longitudinal axis of said insulator, operating means for moving said movable contact into and out of engagement with said stationary contact means mounted on the free end of said insulator to make and break the connected circuit, arc extinguishing means also mounted on the free end of said insulator, and

means for causing a blast of gas to flow from,

said tank through said hollow insulator during at least the opening movement of said movable contact, said blast o'f gas driving any arc formed at said Contact means into said arc extinguishing means.

2. In a gas blast circuit interrupter, a tank for storing gas under pressure, a straight hollow insulator supported upon and extending up` wardly from said tank, stationary contact means mounted upon the upper end of said insulator, a`

and across the arc drawn across the open end thereof.

3. In a gas blast. circuit interrupter, a tank for storing gas under pressure, a straight hollow insulator supported substantially vertically by said tank, stationary contact means mounted on the free end of said insulator, a coacting contact movable across the open end of said hollow in-4 sulator to establish an varc generally at right angles to the longitudinal axis of said hollow insulator, operating means for moving said mov-v able contact to open and closed circuit positions, a valve disposed at the juncture of said hollow insulator with the tank for controlling the ilow of gas thereinto from said tank, and means for operating said valve to open and closed positions.

4. In a gas blast circuit interrupter, a tank for storing gas under pressure, a straight tubular insulator mounted from said tank, a stationary contact supported bythe free end of said insulator and to one side ofthe open end thereof, a terminal member supported intermediate the ends of said insulator, a movable contact hinged to said terminal member for swinging movement A to open and closed circuit position, said moving contact having la portion movable across the open end of said insulator in a path generally perpendicular to the longitudinal axis of said insulator, means for operating said movable contact tor open circuit position to establish an arc across the open end of said insulator, and means foradmitting a blast of gas from said tank into said insulator to extinguish the arc.

5. In a gas blast circuit interrupter, a tank for storing gas under pressure, a tubular insulator mounted substantially vertically upon said tank, a stationary contact supported upon the upper end of said insulator and to one side of the open end thereof, a terminal member supported intermediate the endsr of said insulator, a movable bridging contact member hinged to said terminal member for swinging movement into and out of engagement with said stationary contact,

said bridging member having a contact portion movable across the open end of said insulator in a path at substantially a right angle to the axis of the passage through the insulator, an arc `chute vertically mounted over the free end of said tubular insulator for confining said/arc, and means for causing a blast of gas to flow from said tank through said tubular insulator to extinguish said arc, said blast of gas nowing in substantially a straight line from said tank through said tubular insulator. across the arc and into said arc chute.

6. In a multi-phase gas blast circuitl interruptor, a tank for storing gas under pressure, a plurality of tubular insulators mounted from said tank, separable contact means for drawing an arc adjacent the open end of each of said insulators, said tubular insulators providing direct paths for the flow of individual blasts of gas from said tank to said arcs, operating means for actuating said separable contact means, individual valve means for each path, and single means for simultaneously actuating said individual valve means for controlling the flow of gas in each of saidpaths and to provide a unlform ow of gas to all of said arcs.

'1. In a multi-phase gas blast circuit interrupter, a tank for lstoring gas under pressure, a plurality of tubular insulators mounted from said tank, separable contact means for drawing an arc across the open end of each of said insulators, said tubular insulators providing straight paths for the flow of individual blasts of gas from said tank to said arcs, operating means including a rock shaft for actuating said separable contact means, said rock shaft being supported for rockgas under pressure, separable contacts for mak ing and breaking the connected circuit, a pressure actuated operating means for said contacts including a cylinder, a piston movable in said cylinder, a contact opening valve operable for admitting gas from said tank to'said cylinder to actuate said piston and cause said contacts to, be opened, a contact closing valve operable for admitting gas from said tank to said cylinder to actuate said piston and cause said contactsto be' closed, said opening and closing valves being secured to said cylinder to form a unit assembly,

and conduit means joining said' tank withsaid valves, said conduit means serving as the sole support for said unit assembly.

9.A In a gas blast circuit interrupter, a source' of gas under pressure, separable contacts for establishing .an arc, operating means for actuat- ,"'ing said contacts to open and closed circuit positions, valve means for controlling the ilow of gas from said source through the arc, and cam means'carried by said operating means and a follower movable over the face of the cam for actuating said valve means, said cam means hav- .ing said face on which the follower is movable collapsible during movement in one direction to portion to the collapsed position during movement of said contact operating means to the closed circuit position to actuate said valve means in a diierent manner.

11. In a multi-phase gas blast circuit interrupter, a plurality of pairs of separable con-l tacts, a plurality of arc chambers each of which receives the arc drawn upon separation of one of said pairs oi' contacts, a common tank for holding sas under pressure for extinguishing all ofI said arcs, a pluralityl of separate conduits each of which extends directly from said common tankto one of said aro chambers to provide an individual blast of gas from said tank to extinguish the arc drawn by one of said plurality of pairs of contacts, a plurality of blast valves each of which controls the blast of gas through one of said plurality of separate conduits, and means for jointly operating said plurality of blast valves upon separation of said plurality of pairs of contacts.

12. In a multi-phase gas blast circuit interrupter, a plurality of pairs of separable contacts, a plurality of arc chambers each of which receives the arc drawn upon separation of one of said pairs of contacts, a common tank for holding gas under pressure for extinguishing all of said arcs, a plurality of separate conduits each of which extends directly from, said common tank to one of said arc chambers to provide an individual blast of gas from said tank to extinguish the arc drawn by one of said plurality of pairs open said valve means only during the opening lish an arc, operating means for actuatingsaid contacts to open and closed circuit positions, valve means for admitting a blastl of gas from saidtank to said contacts, valve operating means associated with said contact operating means, said valve operating means including a cam having a collapsible portion and a follower movable over the face of said collapsible portion for actuating said valve means, means biasing and holding said collapmble portion in said extended position during movement of said contact operating means to the open circuit position to cause said collapsible portion to actuate said follower to open and close said valve means in a predetermined manner, said holding means vbeing arranged to permit movement of saidcollapsible of contacts, a plurality oi blast valves each of which controls the blast of sas through one of said plurality of separate conduits, a common operating device for causingV separation of all of said plurality of pairs of separable contacts, and means mechanically actuated by movement of said common operating device for jointly operating said plurality of blast valves upon separation of said plurality oi' pairs of contacts.

13. In a multi-phase gas blast circuit interrupter, tank means for storing gas under pressure, a plurality of tubular insulators extending from said tank-means. separable contact means f or drawing an arc adjacent the open end of each of said insulators, said tubular insulators providing direct paths for the iiow of individual blasts of gas from said tank means to said arcs. operating means for actuating said separable contact means, individual valve means for each p'ath, a common valve opening means mechanically driven from said operating means for siof said paths.

ANDREW H. BAKKEN,

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