US3179775A

US3179775A - Circulating-type compressed-gas circuit interrupters with composite blast-tube extension

Info

Publication number: US3179775A
Application number: US74367A
Authority: US
Inventors: Jr Robert G Colclaser; Frank L Reese
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1960-12-07
Filing date: 1960-12-07
Publication date: 1965-04-20
Anticipated expiration: 1982-04-20

Description

April 1965 R. s. COLCLASER. JR.. ETAL 3,179,775v

CIRCULATING-TYPE COMPRESSED-GAS CIRCUIT INTERRUPTERS WITH COMPOSITE BLAST-TUBE EXTENSION Filed Dec. 7, 1960 3 Sheets-Sheet 1 Fig. IA 3| i 1 1 RELATIVELY HIGH- VALUE IMPEDANCE x x 80 i INVENTORS Roberi G. Colcloser,Jr. 8 Frank L.Reese Mam ATTORNEY Ap 0, 1965 R. e. COLCLASER. JR.. ETAL 3,179,775

CIRCULATINGTYPE COMPRESSED-GAS CIRCUIT INTERRUPTERS WITH COMPOSITE BLAST-TUBE EXTENSION Filed Dec. 7, 1960 3 Sheets-Sheet 2 Ap l 5 R. G. COLCLASER. JR; ETAL 3,179,775

CIRCULATING-TYPE COMPRESSED-GAS CIRCUIT INTERRUPTERS WITH COMPOSITE BLAST-TUBE'E'XTENSION Filed Dec. 7, 1960 3 Sheets-Sheet 3 RELATIVELY LOW VALUE IMPEDANCE Fig. 3

United States Patent i 3,179,775 CIRCULATENG-TYPE COMPRESSED-GAS CIR- CUIT INTERRUPTERS WITH COMPOSITE BLAST-TUBE EXTENSION Robert G. Colclaser, Jr., Monroeville, and Frank L. Reese, Wilkinsburg, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Dec. 7, 1960, Ser. No. 74,367 12 Claims. (Cl. 200-144) This invention relates to compressed-gas circuit interrupters and, more particularly, to structural mounting arrangements, operating mechanisms and arc-extinguishin g structures therefor.

A general object of the present invention is to provide an improved compressed-gas circuit interrupter of compact dimensions which will be highly eflicient and of very small size.

Another object of the invention is to provide an improved compressed-gas circuit interrupter involving a closed-gas system, in which a highly effective arc-extinguishing gas, such as sulfur-hexafiuoride (SP gas, or

selenium-hexafluoride (SeF gas, or mixtures of the foregoing gases, or meet the foregoing gases admixed with air, carbon dioxide, nitrogen, helium, or argon, is used as the arc-extinguishing gas. system involves a high-pressure reservoir and a low-pressure reservoir with a compressor unit interposed therebetween to extract the relatively low-pressure gas from the low-pressure reservoir and recompress it to the highpressure level for subsequent storage Within the high pressure tank.

In United States Patents 2,310,779, issued February 9, 1943 to ErilcH. Hall and Raymond H. Leitzel, and 2,272,380, issued February 10, 1942, to Leon R. Ludwig, Herbert L. Rawlins and Benjamin P. Baker, and assigned to the assignee of the instant application, there are shown and described compressed-gas circuit interrupters of the cross-blast type, utilizing compressed air as the arc-extinguishing medium, and obtaining circuit interruption by forcing a blast of high-pressure gas upwardly through a blast tube against the established arc.

It is a further object of the present invention to provide an improved compressed-gas circuit interrupter of the general type such as is taught by the aforesaid Hall et a1. and Ludwig et a1. patents in which by a novel location of the several parts, an improved contact construction is obtained with resulting improved operation.

Still a further object of the present invention is to provide an improved compressed-gas circuit interrupter, in which an air-break disconnecting gap is provided serially in the circuit of a cross-blast type of interrupter.

Yet a further object of the present invention is to provide an improved compressed-gas circuit interrupter of the cross-blast type, in which parts obtained from a compressed-air circuit interrupter of a conventional type may be employed in the novel construction of the present invention without necessitating the manufacture of peculiar and special parts. In other words, it is a distinct object of the present invention to use, as far as possible, conventional and stock items, which have previously been used with the compressed-air circuit-interrupting structure of the type shown in the Hall et al. patent.

Still a further object of the present invention is to provide an improved arc-chute construction in which the imposition of voltage across the arc chute is avoided in the fully open-circuit position of the associated contact structure. As a result, there is practically no voltage stress exerted upon the arc chute in the fully open-circuit position of the interrupter.

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

1 FIG. 1 is a fragmentary vertical sectional view of a compressed-gas circuit interrupter embodying features of the present invention and shown in the contact-closed position;

FIGURE 1A is a fragmentary detailed view taken along the line XX of the circuit interrupter of FIG. 1;

FIGURE 2 is a detailed fragmentary view of the operating mechanism for the improved circuit interrupter of the present invention; and,

FIGURE 3 is a fragmentary view of a modified type interrupter somewhat similar to the view of FIG. 1, but employing a relatively low-value resistance.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally designates a compressed-gas circuit interrupter. The circuit interrupter 1 generally includes a high-pressure storage reservoir 2, an upwardly-extending composite'blast-tube supporting portion 3 and an upper interrupting unit 4. Clamped externally of the upwardly extending insulating blast-tube portion 3 is a split clamping member 5, secured by bolts .6, and pivotally supporting, as at 7, a movable disconnecting contact 8. As shown, the rotatable movable disconnecting contact 8 is pivotally secured, as at 9, to an insulating operating rod 11, the latter being actuated by a suitable mechanism to be described hereinafter.

Constituting a rightw'ardly extending conducting terminal portion of the clamping ring 5 is a bar-shaped line terminal 13, which may be connected, as shown, to one line connection L; of the connected circuit.

It will be noted that the interrupting unit 4 includes 'a live metallic housing 14, which encloses the separable contact structure of the circuit interrupter 1. A bushing 15 extends through the right-hand wall of the housing 14 and has axially extending therethrough a terminal stud 16,.which may have clamped thereto, as by a'bolt 17, to its right-hand extremity a line connection 18 of a second line L Secured, .as by brazing, to the left-hand extremity of theconductor stud 16 is a finger-type relatively stationary contact structure, generally designated by the reference numeral 21. As shown, the relatively stationary contact structure 21 includes a plurality of spring-finger contacts 22, which engage the external sides of a bladeshaped movable contact 23, the latter being biased in a leftward opening direction bya compression spring 24. The uppermost spring-finger contact 22 has an arcing tip 22a of arc-resistant material. The compression spring 24' is mounted interiorly of a spring housing 25, disposed within the interrupter housing 14, and maintained in a fixed position by mount-ing bolts'26. The spring housing 25 registers with a cup-shaped portion 27, providing a seal 28 to prevent the entrance of gas axially along a movable disconnecting contact portion 31 of the mow-- able contact 23. As shown in FIG. 1A, the external end of the disconnecting portion 31 may be bifurcated, constituting thereby a jaw-shaped contact. The movable disconnecting contact 8 preferably has a contacting blade portion 8a, which enters between the furcations 32 of the movable disconnecting contact 31, preferably with lateral pressure therebetween.

Those skilled inthe art will realize that during the opening operation the movable contact 23 will move to the left, as urged by the spring pressure 24, until the spring seat 33 strikes a stop portion 34 associated with the seal 28. This will move the movable contact 23 to the broken-line portion 19 shown in FIG. 1. During this movement, an are, not shown, will be established between the arcing tip 22a, on the relatively stationary contact fingers 22 and the arc-resisting portion 23a of the movable contact 23. This arc, not shown, will be moved upwardly against the splitters 35 constituting integral portions of a splitter interrupter, or arc chute, generally designated by the reference numeral 36. Preferably the splitter interrupter 36 is composed of a suitable insulating material, such, for example, as polytetrafluoroethylene, which resists the action exerted by an are drawn in sulfurhexafluoride (SP gas. As shown, the polytetrafluo roethylene splitter interrupter 36 may be rotated about a pivot axis 37, provided by an upwardly extending lug 33, which may be suitably secured, as by welding, to the upper side of the spring housing 25. Secured to the right-hand extremity of the splitter interrupter 36 is a stop bracket 41, which may be fastened by a bolt 41a to a lug 39 extending inwardly from a side wall 42 of the interrupter housing 14.

The method of arc interruption is generally the same as that set forth in the aforesaid Hall et al. Patent 2,310,- 779, namely the blasting of the established arc laterally between the splitters 35 by an upwardly-flowing blast of high-pressure gas extending through the interior 43 of an interiorly disposed blast inlet tube 44. As shown, the blast inlet tube 44 extends interiorly of the outer blast-tube supporting portion 3. FIG. 1 shows the

seals

45, 46, which may be associated with

mounting flangerings

47, 48 associated with the outer blast exhaust tube 3.

With reference to FIG. 1 of the drawings, it will be observed that a lower mechanism housing 51 is provided,

which supports and encloses the high-pressure reservoir 2, and also a supporting flange 52 of the composite blasttube extension 3. In addition, an operating mechanism, generally designated by the reference numeral 53, is provided to synchronously bring about contact separating motion and blast-valve opening to insure the proper blasting of gas upwardly against the established arc.

The operating mechanism 53 generally includes a cam plate 54 fixed to, and rotatable with, a drive shaft 55.

The cam plate 54 has a boss portion 56 pivotally connected, as at 57, to a link 58. As shown in FIG. 2, the link 58 is pivotally connected, as at 59, to a piston rod 60. The piston rod 60 has attached thereto, adjacent the lower end thereof, a piston 61 reciprocally operable within a piston cylinder 62, and is moved to the open and closed positions by an opening, or trip valve 63 and a closing valve 64. The trip valve 63 and the closing valve 64 control the passage of high-pressure gas from the reservoir tank 2 through

pipes

65, 66 leading from the tank 2.

During the opening operation, the electrically-actuated magnet 63 is energized to effect opening thereof, and consequent passage of the high-pressure SP gas through the valve 63 from the pipe 65 and into the inlet region 67 of the control-valve assembly 68. The passage of this high-pressure gas into the operating cylinder 62 acts downwardly upon the upper face of the piston 61. In addition, the high-pressure gas acts downwardly on the upper surface 69 of the spool valve 70, moving the exhaust-valve portion 71 out of the exhaust opening 72. The exhaust opening 72 leads to the region 73, which, in turn, is connected by a pipe 74 to a compressor 75, diagrammatically illustrated in FIG. 2 of the drawings.

The downward opening motion of the piston 61 carries therewith the piston rod 60 and link 58 causing counterclockwise rotation of the cam plate 54 about the drive shaft 55. Through the linkage 11, the movable disconnecting contact 8 is rotated in a counterclockwise direction about pivot 7. This will permit the compression spring 24 to separate the

contact structure

21, 23 drawing an arc, which is moved laterally around the lower ends of the splitter portions 35 by the upwardly flowing gas, as indicated by the arrows 75.

With reference to FIG. 1 of the drawings, it will be observed that the initial counterclockwise rotation of the cam plate 54 will cause clockwise rotation of a thrust lever 7 6, pivotally mounted, as at 77, on a fixed pivot axis. A roller 7 8 pivotally secured, as at 79, to the rotatable thrust lever 76, will force the blast-valve stem 12 downwardly against the opposition of a compression spring 88 and the gas pressure exerted on the lower face 81 of the blast valve 82. The opening of the blast valve 82 simultaneously with separation of the

contact structure

21, 23 will permit a blast of high-pressure gas from the tank 2 to pass through the blast-valve opening 83 and upwardly through the passage 43 to the interrupting unit 4.

The passage of high-pressure gas upwardly through the insulating blast tube 44 will cause the established are, not shown, to be moved about the splitter portions 35 of the splitter interrupter 36 quickly effecting the extinclion thereof. When the movable contact 23 has reached its fully-open position, as indicated by the dotted lines 19, the movable disconnecting contact 31 will be halted at this time. Continued opening counterclockwise travel of the movable disconnecting blade 8 will consequently elfect an isolating gap between the

contact structure

8a, 32 to effect an isolating break in free air externally of the interrupting unit 4. This isolating break will assist in holding voltage across the interrupter 1 in the fully open-circuit position.

A high-value ohmic resistor, or capacitor 91 is used for voltage grading purposes. It is connected between the lead 16 and the housing 14. When the disconnect gap at 8a and 32 is formed, this resistor 91 brings the potential of the housing 14 to the same potential as the lead 16, removing all voltage from the splitter assembly, or are chute 36. The recovery voltage is then maintained by the air gap 8a to 32.

Referring to FIG. 2, during the closing operation, the electromagnetically-actuated closing valve 64 is energized by suitable means, not shown. This will open the closing valve and provide the passage of high-pressure SP gas from the pipe 66 through the valve 64 and into the inlet region 84 of the control-valve assembly 68.

The presence of high-pressure gas within the region 84 will act upwardly on the lower surface 85 of the spool valve 76, forcing the latter quickly upwardly. This will open up the passage 86 and close off the exhaust passage 72. The passage of high-pressure gas into the region 87 on the lower surface 88 of the piston 61 will cause upward travel thereof, with consequent closing of the circuitinterrupting structure 1. During this upward movement of the piston 61, the high-pressure gas on the top side of the piston 61 is exhausted through the opening 89 by upward movement of the exhaust valve 96 of control spool valve 70. As a result, the opening and closing operations of the piston 61 are not adversely affected by the presence of gas on the opposite faces of the piston 61.

As will be obvious to those skilled in the art, closing motion of the circuit interrupter 1 will be accompanied by clockwise rotative motion of the movable disconnecting contact 8. The contacting portion 8a of the movable disconnecting contact 8 will strike the bifurcated portion 32 of movable contact 23, forcing the latter toward the right and into contacting engagement with the contact fingers 22 thereby compressing the compression spring 24. The several parts will then appear as they are shown in FIG. 1 of the drawings, and the circuit L L will be completed through the circuit interrupter 1.

During the closing operation, the clockwise rotation of the cam plate 54 will rotate the latch lever 98 in a counterclockwise direction about its pivot 92 thereby rendering the thrust lever 76 inoperable during the closing stroke of the interrupter. This is desirable to prevent the loss of high-pressure gas during a closing operation, when such a blast of gas may not be necessary. However, for certain applications, it may be desirable to utilize a blast of gas during the closing operation to minimize pro-striking across the separated contacts, as they near one another during the closing stroke. In such an eventuality, the oneway-acting latch lever 98 may be dispensed with, and a suitable valve mechanism such' as set forth in United States Patent 2,282,154, issued May 5, 1942 to Andrew H. Bakken and assigned to assignee of the instant invention, may be employed to effect a blast of high-pressure gas during both the opening and closing operations.

As shown in the modified interrupting structure 92 of FIG. 3, a relatively low-valve resistor or impedance 93 may be connected from the terminal 16 to the housing 14. During an opening operation this low ohmic resistor 93 shunts the interrupting

break

21, 23 reducing the severity of the recovery voltage at the

main break

21, 23. The resistor current is, in turn, interrupted by the separation of the

contacts

8a and 32, when the breaker is in the open position. The resistor forces the housing 14 to the same potential as the terminal 16. The voltage is then held by the air gap between 811 and 32. This removes the voltage from the splitter assembly, or arc chute 36.

From the foregoing description of the present invention,

it Will be apparent'that there is shown a closed-gas system associated with a compressed-gas type of circuit interrupter, in which the gas is highly effective, and may be used over and over again. Operation of the compressor 75 which may be a function of the pressure within the exhaust tank 14 will ensure that a suitably high pressure, say for instance 250 p.s.i., may be present within the highpressure reservoir tank 2.

By having the composite blast-tube structure 3 extending upwardly, and having the clamping structure 5 associated with the terminal bushing 15 in the manner indicated, an interrupter of compact dimensions is obtained. In addition, the maintenance of the potential of the splitter interrupter, or are chute 36 at the potential of the moving contact 23 prevents impressing voltage across the insulating splitter interrupter 36 in the fully open-circuit position of the interrupter, As a result, there is no voltage stress exerted upon the interrupting unit 36. The employment of an external isolating gap at the disconnecting

contacts

8a, 32 additionally insures that the circuit will be maintained open in'the open-circuit position, even though voltage surges may be present upon the line L L Although there has been illustrated and described specific interrupting structures embodying features of the invention, 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. An arc chute for a circuit interrupter having insulating portions and including conducting bracket means adjacent opposite ends thereof, a pair of relatively movable contacts to establish an arc, and both said conducting bracket means being .connected to one of said contacts to eliminate voltage stress on the arc chute in the fully opencircuit position of the interrupter.

2. The combination in a compressed-gas circuit interrupter of a cross-blast type are chute having a plurality of splitter portions associated therewith, separable contact means including a separable pair of contacts for establishing an arc across one side of the arc chute, means for releasing a blast of high-pressure gas transversely across the established arc to force the same laterally into the splitter portions of the arc chute, and conducting means electrically paralleling the arc chute connected only to one of said contacts for eliminating voltage stress across the arc chute in the fully open-circuit position of the interrupter.

3. The combination in a compressed-gas circuit interrupter of a grounded high-pressure storage tank, an upstanding composite insulating blast-tube support, the composite blast-tube support including concentric blast inlet and blast exhaust tubes, an interrupting structure disposed at the upper end of the composite blast-tube support and at least partially supported by the same, said interrupting structure including a conducting exhaust housing, an arcchute disposed within said conducting exhaust housing, a bushing extending through one wall of said housing and supporting a relatively stationary contact, a movable con tact cooperable with said relatively stationary contact to establish an are adjacent said are chute, said movable contact having an extension protruding through the wall of said housing, and a movable disconnecting contact cooperable with said extension externally of said housing.

4. The combination in a compressed-gas circuit interrupter of a grounded high-pressure storage tank, an upstanding composite insulating blast-tube support, the composite blast-tube support including concentric blast inlet and blast exhaust tubes, an interrupting structure disposed at the upper end of the composite blast-tube support and at least partially supported by the same, said interrupting structure including a conducting exhaust housing, an arc chute disposed within said conducting exhaust housing, a bushing extending through one wall of said housing and supporting a relatively stationary contact, a movable contact cooperable with said relatively stationary contact to establish an are adjacent said are chute, said movable contact having an extension protruding through the wall of said housing, a movable disconnecting contact cooperable with said extension externally of said housing, and terminal clamping means clamped to saidupstanding composite insulating blast-tube support intermediate the ends thereof for pivotally supporting said movable disconnecting contact.

5. The combination in a compressed-gas circuit interrupter of a grounded high-pressure storage tank, an upstanding composite insulating blast-tube support, the composite blast-tube support including concentric blast inlet and blast exhaust tubes, an interrupting structure disposed at the upper end of the composite blast-tube support and at least partially supported by the same, said interrupting structure including a conducting exhaust housingat relatively low pressure to form a part of a closed recirculatory gas system, an arc chute disposed within said conducting exhaust housing, a bushing extending through one wall of said housing and supporting a relatively stationary contact, a movable contact cooperable with said relatively stationary contact to establish an are adjacent said are chute, said movable contact having an extension protruding through the Wall of said housing, a movable disconnecting contact cooperable with said extension externally of said housing, terminal clamping means clamped to said upstanding composite insulating blast-tube support intermediate the ends thereof for pivotally supporting said movable disconnecting contact, and operating means operated with compressed gas from said grounded highpressure storage tank for eifecting opening and closing motion of said movable disconnecting contact.

6. The combination in a compressed-gas circuit interrupter of a grounded high-pressure storage tank, an upstanding composite insulating blast-tube support, an interrupting structure disposed at the upper end of the composite blast-tube support and at least partially supported by the same, a terminal clamp clamped to said upstanding composite insulating blast-tube support intermediate the ends thereof, a hook-shaped movable disconnecting contact, a movable intermediate contact, a relatively stationary contact, the relatively stationary contact and the intermediate contact being cooperable to establish an are within said interrupting structure, said composite blasttube support including a blast-tube leading from said tank and an exhaust return tube at relatively low pressure leading from said interrupting structure to the region adjacent said tank to form a closed recirculating gas system, blast-valve means for controlling a blast of highpressure gas from said high-pressure storage tank through the blast-tube to the interrupting structure, and a relatively low-value impedance connected between the relatively stationary contact and the intermediate contact.

7. An interrupting element for a compressed-gas circuit interrupter including a conducting exhaust housing, an

insulating arc-chute disposed within said conducting exhaust housing, a bushing extending through one Wall of said housing and supporting a relatively stationary contact, a movable contact cooperable with said relatively stationary contact to establish an are adjacent said are chute, said movable contact having an extension protruding through the wall of said housing, and a relatively lowvalve impedance connected between the relatively stationary contact and said conducting exhaust housing for eliminating voltage stress on the insulating arc chute in the open-circuit position of the interrupter.

8. The combination in a compressed-gas circuit interrupter of a grounded high-pressure storage tank, an upstanding composite insulating blast-tube support, the composite blast-tube support including concentric blast inlet and blast exhaust tubes, an interrupting structure disposed at the upper end of the composite blast-tube support and at least partially supported by the same, said interrupting structure including a conducting exhaust housing, an insulating arc-chute structure disposed within said conducting exhaust housing, a bushing extending through one wall of said housing and supporting a relatively stationary contact, a movable contact cooperable with said relatively stationary contact to establish an are adjacent said arc chute, said movable contact having an extension protruding through the wall of said housing, and a relatively low-value impedance connected between the relatively stationary contact and said conducting exhaust housing for eliminating voltage stress on the insulating arc chute in the open-circuit position of the interrupter.

9. The combination in a compressed-gas circuit interrupter of a grounded high-pressure storage tank, an upstanding composite insulating blast-tube support, the composite blast-tube support including concentric blast inlet and blast exhaust tubes, an interrupting structure disposed at the upper end of the composite blast-tube support and at least partially supported by the same, said interrupting structure including a conducting exhaust housing, an insulating arc chute structure disposed within said conducting exhaust housing, a bushing extending through one wall of said housing and supporting a relatively stationary contact, a movable contact cooperable with said relatively stationary contact to establish an arc adjacent said are chute, said movable contact having an extension protruding through the wall of said housing, a movable disconnecting contact cooperable with said extension externally of said housing, and a relatively high-value impedance connected between the relatively stationary contact and the conducting exhaust housing for eliminating voltage stress on the insulating arc chute in the open-circuit position of the interrupter.

10. A circuit interrupter including a pair of relatively movable contacts to establish an arc, an arc chute for extinguishing said are having insulating portions, and conducting means electrically paralleling the arc chute and connected only to one of said contacts for eliminating voltage stress across the are chute in the fully open-circuit position of the interrupter.

11. The combination according to claim 10, wherein the conducting means includes a metallic housing member at least partially enclosing the arc chute.

12. The combination according to claim 11, wherein the metallic housing member constitutes an exhaust chamber for confining and effecting recirculation of an arc-extinguishing gas.

Reterences tilted by the Examiner UNITED STATES PATENTS BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAFFER, Examiner.

Claims

10. A CIRCUIT INTERRUPTER INCLUDING A PAIR OF RELATIVELY MOVABLE CONTACTS TO ESTABLISH AN ARC, AN ARC CHUTE FOR EXTINGUISHING SAID ARC HAVING INSULATING PORTIONS, AND CONDUCTING MEANS ELECTRICALLY PARALLELING THE ARC CHUTE AND CONNECTED ONLY TO ONE OF SAID CONTACTS FOR ELIMINATING VOLTAGE STRESS ACROSS THE ARC CHUTE IN THE FULLY OPEN-CIRCUIT POSITION OF THE INTERRUPTER.