US3538280A - Double-break circuit interrupter with stationary buswork structure guiding a u-shaped movable conducting bridge - Google Patents

Description

Nov. 3, 1970 c. F. CROMER ET AL 3,538,280 DOUBLE-BREAK CIRCUIT INTERRUPTER WITH STATIONARY BUSWORK STRUCTURE GUIDING A HAPED MOVABLE CONDUCTING BRID -5 Sheets-Sheet 1 Filed Dec. 2, 1966 Nov. 3, 1970 c. F. CROMER ET AL DOUBLE-BREAK CIRCUIT INTERRUPTER WITH STATIONARY BUSWORK STRUCTURE GUIDING A U-SHAPED MOVABLE CONDUCTING BRIDGE Filed Dec.

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. DOUBLE-BREAK CIRCUIT INTERRUPTER WITH STATIONARY BUSWORK STRUCTURE GUIDING A U-SHAPED MOVABLE CONDUCTING BRIDGE Filed Dec. 2. 1966 5 Sheets-Sheet 5 .i L A e BSG Z2 37' Q PRESSURE [40 42% 1/;7/ HIGH PRESSURE 6 NOV. 3, 1970 v c, RCROMER ETAL 3,538,280

DOUBLE-BREAK CIRCUIT INTERRUPTER WITH STATIONARY BUSWORK STRUCTURE GUIDING A U-SHAPED MOVABLE'CONDUCTING BRIDGE Filed Dec; 2. .1966 BSheets-Sheet 4.

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' Filed Dec. 2. 1966 llb- TO OPEN United States Patent 3,538,280 DOUBLE-BREAK CIRCUIT INTERRUPTER WITH STATIONARY BUSWORK STRUCTURE GUIDING A U-SHAPED MOVABLE CONDUCTING BRIDGE Charles F. Cromer, Tratford, and Charles B. Wolf, Irwin, Pa., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Dec. 2, 1966, Ser. No. 598,807 Int. Cl. H01h 33/80 US. Cl. 200-148 7 Claims ABSTRACT OF THE DISCLOSURE A double-break high voltage circuit interrupter is provided having tank means into which extends a pair of terminal bushings, each of which supports an exhaust chamber at the interior end thereof. A first stationary contact means is supported by and electrically connected to each of the exhaust chambers. A second stationary contact means cooperates, but is spaced from, each of the first stationary contact means and a relatively light-weight movable contact assemblage including a pair of spaced movable bridging contacts electrically interconnects each of the first and second stationary contact means in the closed circuit position of the interrupter.

According to a further feature of the invention, relatively stationary bus Work and supporting structure fixedly secures the pair of laterally spaced second stationary contact means into fixed position, and preferably, the bus work and supporting structure is attached to the inner walls of the tank structure to constitute a heat sink. A guide portion on the movable U-shaped conducting bridge is guided in its reciprocal movement by the stationary bus-work structure.

This invention relates, generally, to circuit interrupters and, more particularly, to circuit interrupters of the double-break high-speed type carrying relatively heavy current values in the closed-circuit position.

A general object of the present invention is to provide an improved and highly-efficient heavy-current-duty circuit interrupter, which will be able to transmit heavy currents therethrough, and yet is capable of high-speed operation.

A more specific object of the present invention is the provision of an improved high-speed circuit interrupter capable of heavy-current transmission, and yet having relatively light moving parts.

Still a further object of the present invention is the provision of a circuit interrupter capable of carrying heavy continuous currents, and adaptable for utilization with compressed-gas flow for eflicient arc extinction.

In order to carry heavy, or high continuous currents, without excessive temperature rise, it is necessary to use massive conductors. In this type of interrupter, the interrupting contact is also the main current-carrying contact, and if the crossarm is the only bridging member between the spaced interrupting units, it too must be massive. Therefore, the movable elements would require high accelerating and decelerating forces for opening, closing and stopping. It is, accordingly, an additional object of the present invention to provide a high-speed circuit interrupter having a relatively lightweight crossarm, or traverse member, which may actuate relatively heavy moving bridging finger clusters, but shunts the high current through stationary massive structural bus-bars, allowing the operating crossarm to be structurally strong, yet light in weight for high-speed operation.

It is an additional object of the present invention to provide an improved circuit-interrupter construction in ice which heat sinks are provided, and therefore provide large surface areas for cooling of the contact elements.

Still a further object of the present invention is to provide an improved double-break circuit interrupter in which the structural members not only serve the purpose of supporting the contact assemblies, but additionally act as current-carrying bus-bars, and moreover provide heat sinks to provide thereby a considerable cooling function.

In accordance with a preferred embodiment of the invention, there is provided a pair of stationary currentcollector assemblies, which are structurally supported by bus-bar structural elements with attachment to the surrounding metallic tank structure, so that large areas for cooling are provided. A relatively lightweight movable cross-arm actuates a pair of serially-related moving bridging contact assemblies, which serve the function of establishing two arcs and effecting their extinction. The bus-bar construction preferably employs a pair of stationary laterally-spaced conducting bus-bar members, which are clamped and structurally support the two stationary current-collector assemblies, so that the entire arrangement is adaptable for heavy continuous current-carrying duty, yet is lightweight for high-speed interrupting duty.

Further objects and advantages will readily become apparent upon reading the following specification taken in conjunction with the drawings, in which:

FIG. 1 is a side elevational view of a three-phase dualpressure type of compressed-gas circuit interrupter embodying principles of the present invention;

FIG. 2 is an end elevational view of the three-phase compressed-gas circuit interrupter of FIG. 1;

FIG. 3 is a vertical sectional view taken along the line IIIIII of one of the modular compressed-gas units of FIGS. 1 and 2, the left-hand unit being shown partially in section, and the contact structure of both units being indicated in the closed-circuit postion;

FIG. 4 is a vertical sectional view taken substantially along the line 'IV1V of FIG. 3, again the contact structure being illustrated in the closed-circuit position;

FIG. 5 is an enlarged fragmentary vertical sectional view taken through the separable contact structure of one of the arc-extinguishing units of the arc-extinguishing assemblage of FIGS. 3 and 4, the contact structure being illustrated in the closed-circuit position;

FIG. 6 is a view similar to that of FIG. 5, but illustrating the conditions during the arcing period, while the guide-slow insulating member conducting gas flow is retained in its upward extended position due to the differential gas pressure;

FIG. 7 is a view similar to that of FIGS. 5 and 6, but illustrating the disposition of the several parts in the fully open-circuit position;

FIG. 8 is a detailed sectional view of the moving bridging contact structure taken substantially along the line VlII-VIII of FIG. 7; and,

FIG. 9 is a considerably enlarged fragmentary view indicating the blast-valve operating linkage, the blast-valve linkage and the contact-operating rod being illustrated in the closed-circuit position with the blast valve closed.

Referring to the drawings, and more particularly to FIGS. 1 and 2 thereof, the reference numeral 1 generally designates a three-phase dual-pressure type of compressedgas circuit interrupter. As shown, the circuit interrupter 1 comprises three modular units 2 for each phase, such units being electrically connected in series by connectors 3. Electrostatic rings 4 may be used for the prevention of high electrical stresses adjacent the confronting ends of the terminal bushings 5 of the units 2.

If desired, a suitable current-transformer structure 6 may be employed for measurement of the current passing through the interrupter 1 and for relaying purposes.

Supporting the modular units 2 in an upstanding relation at the upper ends of insulating supporting column 8 is frame support 9, to which is secured a mechanism housing 10. Disposed interiorly of the mechanism housing 10 is a suitable operating mechanism, which may be of the conventional type, and functioning to synchronize the operation of operating rods 11 extending upwardly within each of the supporting insulating columns 8. Reference may be had to the linkage set forth in US. patent application filed Iune 12, 1964, Ser. No. 374,708, now US. Pat. 3,291,947, issued Dec. 13, 1966 to Roswell C. Van Sickle, and assigned to the assignee of the instant invention, for a possible type of linkage construction. Such linkage, however, per se constitutes no part of the present invention. With reference to FIG. 2 of the drawings, it will be noted that assisting in the upward rigid support of the several modular units 2 are diagonally extending insulating support rods 13, which provide a desirable bracing construction.

It will be noted that each modular unit 2 comprises a generally spherical live metallic tank 14 at live potential having preferably only a single access manhole 15 associated with a hinged door 16, by means of which access may be obtained interiorly of each tank structure 14.

To assist in dividing the voltage equally between the several modular units 2, and also providing a certain amount of support, is serially-related impedance sections 17, which may comprise resistance or capacitance elements, such as are of the type set forth in US. Pat. 2,748,- 226, issued May 29, 1956, to MacNeill et al., and assigned to the assignee of the instant application.

With particular attention being directed to FIG. 3 of the drawings, it will be noted that the spherical tank 14 has circular apertures 18 burned, or otherwise cut thereout of, and having welded thereto flange collars 19. Each flange collar 19 has fixedly secured thereto, by means of mounting bolts 20, a flanged cylindrical support member 21, to the outer end of which is fixedly mounted the terminal bushing by means of the support ring 22.

In more detail, the terminal bushing 5 comprises a pair of insulating shells 5a, 5b having interposed therebetween the supporting ring 22 having a smoothly curved inner periphery, as shown at 22a (FIG. 3). Extending axially through the terminal bushing 5, and serving the function of carrying the current interiorly of the tank structure 14, and also supporting a stationary contact assembly 26, is a tubular conductor stud 27. The conductor stud 27 may have associated therewith a suitable biasing-spring construction, not shown, and an outer cap structure 28.

Fixedly secured, as by a threading and clamping arrangement, to the interior end 27a of the terminal stud 27 is an apertured support casting 29 having fixedly secured thereto an exhaust chamber 30. As shown, the exhaust chamber 30 includes a lower metallic orifice plate 31 making contacting engagement with a movable bridging contact assembly, generally designated by the reference numeral 33'.

It will be observed that the two laterally spaced exhaust chambers 30 with the lower-disposed stationary contacts 31 constitute a pair of spaced stationary first contact means, generally designated by the reference numeral 32.

FIGS. 58 may be referred to for a more detailed description of the moving bridging contact assembladges 33.

With particular reference being directed to FIG. 5 of the drawings, the moving bridging contact assemblages 33 comprises a plurality of circumferentially disposed doubleended contact fingers 35 having an inwardly extending, generally T-shaped retaining member 35a. The T-shaped retaining portion 35a is somewhat resiliently secured within an enlarged aperture 37 formed by the mating of a pair of complementary-slotted spring cups 38 having central apertures 38a provided therethrough, A rod-shaped arcinghorn 40 having an arc-resisting tip portion 40a is provided extending through the pairof apertures 38a and fixedly secured to the upper end of an operating rod 42. Extending laterally through the metallic operating rod 42 is an abutment pin 43, which serves, during the closing operation, to pick up a cross-bar 44, generally of channel'- shaped configuration. Fixedly secured to the ends of the cross-bar 44 is a pair of metallic push rods 46, which extend through apertures 47 provided through a generally annular cup-shaped casting member 48 defining a gasentrance chamber 49. Interposed between the base portion 38b of the lower slotted spring assembly 38 and the crossbar 44 is a compression retrieving spring 50, the function for which will be more clearly apparent hereinafter.

As shown more clearly in FIG. 5, the lower ends 35b of the several spring fingers 35 make sliding contacting engagement with the inner surface 48a of the annular stationary cup-shaped member 48 and serve to transmit current therethrough in the closed-circuit position, as shown in FIG. 5. The two laterally spaced cup-shaped conducting members 48 constitute a pair of laterallyspaced stationary second contact means, which are electrically connected with the pair of laterally-spaced first contact means 32 by the two moving bridging contact assemblies 33, as shown in FIGS. 3 and 5 of the drawings.

Disposed at the upper ends of the two diametricallylocated push-rods 46 is a retaining ring 53 fixedly secured to a fluid-directing nozzle member 54 defining an outlet orifice 54a. It is desirable to position the gas-flow fluiddirecting member 54 in an upper extended position in the closed-circuit position of the interrupter, as illustrated in FIG. 5 of the drawings. By suitable means, more clearly described hereinafter, gas is caused to enter within the gas entrance region 49, and this high-pressure gas is driven upwardly through the orifice 54a of the fluid-directing member 54 in the direction of the arrows 56, (FIG. 6) and through the orifice member 31 into the interior 58 of the exhaust member 30. This will serve to extinguish the established are 57 (FIG. 6), which is drawn between the arcing horn 40 and the stationary orifice contact 59 composed of arc-resisting material, which constitutes the inner periphery of the orifice 55 through the Stationary orifice contact 31. The exhausted gas is forced through the interior 27a (FIG. 3) of the terminal stud 27, and by suitable openings, not shown, is forced to return downwardly, as indicated by the arrows 60 of FIG. 3, and through the apertures 29a of the supporting casting 29 to the region 62 interiorly of the tank structures 14.

To assist in the extinction of the arcs 57 established within the interrupting units 70 connected in series by a conducting bus-car structure, or means 71 is a resistance means, generally designated by the reference numeral 72, and comprising a pair of electrically-parallel wire-wound resistance elements 73, wound around laterally off-jutting insulating sleeves 74, and electrically connected between the central exhaust chamber 30 and the centrally-located stationary arcing horn 76.

The blast of gas passing radially inwardly through the fluid-directing member 54 carries the initially established arc, drawn between the contacts 59, 35, to the arcing horns 40, 76 with the two resistor elements 73 electrically in parallel. The reduced current amperage and the improved power factor facilitates the interruption of the are 78 (indicated by dotted lines of FIG. 6) drawn within each of the arc-interrupting units 70.

To synchronize the opening and closing movements of the two operating rods 42, there is provided a relatively lightweight horizontally-disposed cross-bar 77, fixedly secured to the upper ends of the insulating operating rods 11. Preferably, the upper ends of the operating rods 11 are joined, as at 11a, and provided a guide extension 1112,

which may be guided within a suitable guide aperture provided by the conducting bus-bar construction 71.

It will be noted that the stationary conducting bus-Work means 71, comprising a pair of laterally-spaced conducting bars 71a secured, as by welding, to support brackets 71b secured to the metallic tank 14, rigidly supports the spaced stationary second contact means in a rigid position, and eliminates the necessity of the movable traverse 77 carrying the series line current in the closed-circuit position of the device, as shown in FIG. 3. This reduces the mass of the moving system and enables an increase of speed.

To control the admission of a high-pressure blast of SF gas from the high-pressure region 90 (FIG. 3), there is provided a blast-valve assembly, generally designated by the reference numeral 91 (FIG. 9), and including a pair of pivotally-mounted blast valve levers 92, pivotally mounted about a stationary pivot pin 93. Each blast-valve lever 92 has an elongated slot 94 provided therethrough, within which, slides a roller assembly 95. The roller assembly 95 is biased by springs, not shown, to a roller pin 96, about which is encircled a roller 97, which makes abutment with the valve stem 98 of a blast valve 99. It will, therefore, be apparent that rightward opening movement of blast-valve stem 98 will cause opening of the blast valve 99 and permit the exhausting of a blast of high-pressure gas through a conduit structure 100 and into the two gas-entrance regions 49 of the two arc-extinguishing units 70.

During the closing operation, the cam portion 105 (FIG. 9), which previously caused opening counterclockwise rotation of the blast-valve lever assembly 92, will cause the roller assembly 95 to move to an inoperative position, that is being moved laterally upwardly along the slots 94 against the spring tension of the biasing spring (not known). The result will be that there will be no blast occurring during the closing stroke.

Certain features of the fluid-director nozzle construction 54 are set forth and claimed in U.S. patent application filed Dec. 2, 1966 Ser. No. 598,761, by Albert P. Strorn and Charles F. Cromer and assigned to the assignee of the instant application. Certain features of the tank configuration are set forth and claimed in US. patent application filed Dec. 2, 1966, Ser. No. 598,856, by Winthrop M. Leeds and Albert P. Strorn, and assigned to the same assignee.

It may be convenient to weld a steel pipe 119 through the top and bottom ends of the high-pressure chamber 90, preferably on the central axis for two purposes. One is to provide a duct for leading low-pressure gas from the main tank 14 to the porcelain supporting column 8 and then to ground. A connection to a gas compressor allows this gas to be raised to a high pressure and stored, first in a reservoir at ground potential, and then carried up through an insulated pipe, as needed, to the reservoir 90, at high potential.

By way of recapitulation, during the opening operation, the operating rods 11, extending upwardly within the insulating columns 8, are forcibly moved downwardly by a suitable mechanism disposed interiorly within the operating housing 10. The downward opening movement of the operating rods 11 causes simultaneous downward opening movement of the cross-bars or traverse members 77 and the bridging contact structures 33. The camming action of the cam 105 (FIG. 9) secured to the operating rods 11 effects opening of the blast-valve structure 91 and causes the entrance of high-pressure gas into the gasentrance chamber 49. This will maintain the fluid-directing orifice members 54 in their upper position, as illustrated in FIG. 6, despite the fact that the bridging members 33 will be forcibly moved downwardly causing separation between the pickup pin 43 and the cross-bar 44. The gas pressure within the region 49 will be greater than the spring pressure exerted by the compression spring 50. The net result is that the fluid-directing nozzle member 54 will be maintained in its upper extended position during arc interruption, as shown more clearly in FIG. 6 of the drawings.

The downward movement of the bridging contact assembly 33 will initially draw an are between the contact portions 35b and 59. The upwardly flowing high-pressure gas flowing through the orifice opening 55 and into the exhaust chamber 58 will effect are transfer from the separating contacts 35b, 59 to the arc horns 40, 76, thereby inserting the two resistor elements 73 into series circuit, thus reducing the amperage of the current being interrupted. The residual-current arc is established between the arcing contacts 40, 76 and the longitudinal passage of the high-pressure gas into the exhaust region 58, as indicated by the arrows in FIG. 6, will quickly effect extinction of this residual-current arc. Further downward opening movement of the operating rods 11 will cause the cam 105 to ride off of the blast-valve roller 95, thereby permitting the compression spring 89 to effect reclosure of the blast valve 99.

The reduction of the pressure within the entrance region 49, resulting from reclosure of the blast valve 99, will permit the retrieving compression spring 50 to effect downward retracting motion of the fluid guide 54 to a position illustrated in FIG. 7 of the drawings. The interrupter 1 is now in the open-circuit position with the fluid director 54 in its lowered position improving the dielectric conditions at the contact gap.

During the closing operation, suitable mechanism disposed interiorly of the mechanism housing 10', will be effective to cause upward closing motion of the several operating rods 11. The upward closing motion of the operating rods 11 will effect, through the cross-bars 77, upward movement of the operating rods 42. This motion will continue until the pickup pin, or abutment 43, strikes the cross-bar thereby causing the fluid director 54 to move upwardly with the bridging contact structure 33 as a unit. Such closing motion continues until the bridging contacts 33 assume the position illustrated in FIG. 5 of the drawings.

For replenishment of the high-pressure gas within the hlgh-pressure reservoir 90 there is preferably provided a compressor, as previously mentioned, and a suitable lnsulating feed conduit, which extends upwardly within the insulating column 8 of each unit 2.

From the foregoing description it will be apparent that there 1s provided an improved compressed-gas circuit interrupter having an improved structure, for carrying heavy currents continuously, yet is high-speed in operation. In addition, the construction is suitable for multiple units in series for the higher voltage applications. For example, for 500 kv. application, three units, such as illustrated in FIG. 1, would be required. For a lower-voltage rating, of course, the number of units could be reduced.

The provision of the pair of horizontally-spaced conducting bus-bar straps 71a secured by the angle brackets 71b to the metallic tank 14, and fixedly supporting the pair of laterally-spaced stationary second contact means 48 contributes appreciably to the reduction of the mass of the moving system, and thereby enables the circuit interrupter 1 to be extremely high speed in operation. This results since the moving traverse member, or bridging member 77, may be of relatively lightweight in construction. Since the moving elements require high accelerating and decelerating forces for the opening, closing and stopping movements, it is a considerable advantage to have lightweight moving parts, and the stationary bus work supporting and conducting structure 71 supplies this requirement. As a result, the only parts which move are the bridging contact assemblies 33, their operating rods 42, and the horizontally-extending traverse member 77, all of which have a relatively low mass. High-speed operating movement thereby results.

In addition, the provision of the stationary angle supports provides heat sinks to the large surface areas of the tank walls 14 for rapid cooling of the current-carrying parts. Thus, the bus-work means serves not only the dual purpose of structural members and acting as currentcarrying bus-bars, but by being fastened to the low-pressure metallic tank walls 14, additionally provides a readily available large heat sink.

Features of the movable bridging contacts are set forth and claimed in our copending patent application filed Dec. 2, 1966 Ser. No. 598,857, by Charles F. Cromer and Charles B. Wolf, and assigned to the foregoing assignee.

Although there has been illustrated and described specific structures, it is to be clearly understood that the same were merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the invention.

We claim as our invention:

1. A circuit interrupter comprising, in combination, a metallic tank having a pair of terminal bushings extending therewithin, each terminal bushing having a relatively stationary first contact means secured to the interior end thereof, electrically-conducting stationary bus-work and supporting structure extending across the interior of the tank and having its ends aflixed to the interior walls of the tank in good heat-transfer relationship therewith, whereby the side walls of the tank serve as heat sinks for heat generated within said bus-work structure, said electricallyconducting bus-work structure supporting a pair of spaced second stationary contact means in spaced vertical alignment with said spaced first contact means, a relatively light U-shaped movable conducting bridging member having an actuating member aflixed adjacent the mid-portion of the lower bight portion thereof to efiYect the opening and closing movements thereof, two clusters of circumferentially-disposed contact fingers afiixed to the upper free ends of the relatively light U-shaped movable conducting bridging member for electrically bridging the respective first and second stationary contact means in the closedcircuit position of the device, said relatively light movable U-shaped conducting bridging member having a guide portion to accurately guide the reciprocal vertical movement thereof, and said stationary bus-work structure additionally guiding said guide portion for the accurate guiding motion of the U-shaped bridging member, whereby the electrical current through the device in the closed-circuit position thereof is largely carried by said bus-work structure.

2. The circuit interrupter of claim 1, wherein each terminal bushing has an exhaust chamber secured thereto at the interior end thereof supporting the first stationary contact means, and gas-blast means are provided for forcing a blast of gas into each of the two arcs which are established between the first stationary contact means and the cooperating ends of the movable bridging member, and said gas exhausting into the respective exhaust chambers to become thereby cooled.

3. The circuit-interrupter combination of claim 2, wherein a gas-directing insulating nozzle member is associated with the free end of each movable bridging member to direct high-pressure gas flow into the respective exhaust chamber.

'4. The combination of claim 1, wherein the tank means is at line potential in the closed-circuit position of the interrupter, and said metallic tank means is surmounted upon an upstanding insulating column means.

5. The combination of claim 3, wherein the two gasdirecting insulating nozzle members are retracted into the pair of spaced stationary second contact means in the fully open-circuit position of the circuit interrupter.

6. The combination according to claim 2, wherein the blast-valve means is interposed between the pair of spaced stationary second contact means, and a portion of the relatively lightweight U-shaped bridging member operates the blast-valve means.

7. The combination according to claim 1, wherein the bus-work and supporting structure comprises a laterallyspaced pair of supporting members encompassing the pair of spaced stationary second contact means.

References Cited UNITED STATES PATENTS 3,052,783 9/1962 Buron "200-148 3,091,678 5/1963 Leeds 200-148 3,218,421 11/1965 Latour 200 14s 3,275,778 9/1966 Morioka 200-448 3,364,327 1/1968 Cromer 200--148 X 3,214,546 10/1965 Leeds 200148 FOREIGN PATENTS 1,168,996 4/1964 Germany.

ROBERT K. SCHAEFER, Primary Examiner R. A. VANDERHYE, Assistant Examiner US. Cl. X.R.

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