US3603753A

US3603753A - Metalclad switchgear using vacuum interrupter elements

Info

Publication number: US3603753A
Application number: US709013A
Authority: US
Inventors: Russell E Frink
Original assignee: Westinghouse Electric Corp
Current assignee: Westinghouse Electric Corp
Priority date: 1968-02-28
Filing date: 1968-02-28
Publication date: 1971-09-07
Anticipated expiration: 1988-09-07
Also published as: FR2002832A1; ES363978A1; BE728927A; US3529111A; GB1250954A

Abstract

A circuit breaker for metalclad switchgear use is provided using vacuum-interrupter elements in substitution of the usually provided magnetic and insulating plate structures, customarily employed. A resilient mounting for the interrupter elements is provided, together with massive end contact blocks for heat dissipation generated within the vacuum-interrupter elements. A pivoted operating lever, connected to the massive contact block secured to the moving contact of the vacuum-interrupter, is operated by a resilient connection to the insulating operating rod of the circuit breaker. Because of the reduced dimensions, the cubicle dimensions may be drastically reduced, if desired.

Description

United States Patent (72] Inventor Russell E. Frlnk Forest Hllls, Plttsburgh, Pa.

(2H Appl. No. 709,013

[22] Filed Feb. 28, I968 [45] Patented Sept. 7, I97] 1 73 I Ansignee Westlnghouse Electric Corporation Pittsburgh, Pa.

[54] METALCLAD SWITCHGEAR USING VACUUM INTERRUPTER ELEMENTS 8 Claims, 6 Drawing Figs.

{52] US. Cl 200/[44 B, 200/50 AA {51] lnLCL .i...H0lh33/66 [50] Field at Search 200/50 AA, [44 B [56] References Cited UNITED STATES PATENTS 3,30S 65 7 2/l967 Roxburgh et al. 200/5015 X 3,397,293 8/1968 Darrow et 200/5015 FOREIGN PATENTS l,260,754 4/I96l France a, 200150.15

966,538 9/1967 Germany 200/50. l 5

Primary Examiner Robe rt St Macon Attorneys-A. T. Stratton. Clement L. McHale and Willard R,

Crout ABSTRACT: A circuit breaker for metalclad switchgear use is provided using vacuuminterrupter elements in substitution of the usually provided magnetic and insulating plate structures. customarily employed A resilient mounting for the inter rupter elements is provided, together with massive end con tact blocks for heat dissipation generated within the vacuuminterrupter elements. A pivoted operating lever, connected to the massive contact block secured to the moving contact of the vacuum-interrupter, is operated by a resilient connection to the insulating operating rod of the circuit breaker. Because of the reduced dimensions, the cubicle dimensions may be drastically reduced, if desired.

PATENTEB SEP 7 ISH SHEET 2 0F 3 FIG.3.

PATENTEUSEP 7l97i 3503753 SHEEI 3 [1F 3 i iL.JL.J 50 CONTROL, r MODULE j L1 V CONTROL I MODULE r 5 s| L T I I I l BREAKER- I AND LINE BUS l MODULE --9 6 MODULE I: 1 j H I L I fifiofifiE \LINE PRI A T PRIQR RT MODULE FIGS.

FIG.4.

s2 L l L Q I I l BREAKER I LINE fi s MODULE MODULE i j 1 I l i iHL BREAKER AND BUS MODULE LINE MODULE FIG.6.

METALCLAD SWITCIIGEAR USING VACUUM INTERRUPTER ELEMENTS CROSS-REFERENCES TO RELATED APPLICATIONS Applicant is not aware of any related patent applications pertinent to the present invention.

BACKGROUND OF TH E INV ENTION As well known by those skilled in the art metalclad switchgear his achieved extensive use within the industry. Customarily, magnetic air-break arc-chute structures have been employed, such as set forth in U.S. Pat. 3,307,004, issued Feb. 28, 1967, to Samuel A Bottonari, and assigned to the assignee of the instant application. Such magnetic air-break circuit interrupters are rolled on a movable truck into a cubicle, or metalclad switchgear enclosure, for either indoor or outdoor use, and the surrounding grounded housing provides protection to operating personnel.

Vacuum-type circuit interrupters have developed, and are, at the present time, of considerable reliability. It is desirable, therefore, to utilize the new type vacuum-interrupter units, of proven integrity, in the metalclad switchgear industry to take advantage of their small size and efficient operation.

It is, accordingly, an object of the present invention to utilize the improved construction of present-day vacuum-interrupter units within metalclad switchgear, and to provide the requisite additional components to render their operation reliable and trouble-free.

SUMMARY OF THE INVENTION According to a preferred embodiment of the present invention, there is provided a truck-mounted switchgear unit incorporating vacuum-type interrupter elements so that a threephase interrupter may be rolled into the cubicle, or metalclad switchgear housing, with the mounting being sufficiently resilient, and provision made for heat conduction from within the interior of the vacuum-interrupter envelopes, so that reliable operation is achieved. According to the invention, the interrupter elements are resiliently supported by a plurality of conducting straps constituting leaf springs, and heat conduction from the evacuated interior of the interrupter elements is transmitted by the utilization of relatively massive split contact blocks clamped to the vacuum-interrupter contacts, so that reliable operation is achieved at a relatively low tempera ture.

A contact finger arrangement is used to achieve current conduction between the contact block, clamped to the movable contact rod, and the terminal-bushing termination with contact finger springs so supplied as to efi'ect both adequate contact pressure at the termination, and also at the movable contact block secured to the moving contact rod of the vacuum interrupter element.

It is, accordingly, a general object of the present invention to provide an improved metalclad switchgear structure utilizing vacuum-interrupter elements in place of the customarily provided magnetic air-break arc chutes.

Still a further object of the present invention is the provision of an improved vacuum-type circuit breaker in which provision is made for a resilient and flexible mounting of the vacuuminterrupter elements, and also provision is additionally provided for the heat generated within the vacuum-interrupted units during circuit interruption.

Still a further object of the present invention is the provision of an improved current-transfer arrangement between the moving contact of the vacuum-interrupter and the terminal of the associated bushing structure.

Another object of the present invention is the provision of an improved resilient mounting for a vacuum-interrupter unit utilizing a novel resilient contact compression spring between the insulating operating rod and the pivoted actuating lever for the movable contact rod of the vacuum-interrupter.

Yet a further object of the present invention is the provision of an improved resilient mounting for a vacuum-interrupter unit to lower the impact forces encountered during the opening and closing operations by a multiple-leaf spring construction, without unnecessarily increasing the number of com ponent parts associated with the vacuum-type circuit interrupter.

Further objects and advantages will readily become apparent upon reading the following specification, taken in con' junction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a truck-mounted mctalclad type of switchgear breaker incorporating vacuum-type inter rupting elements, with the breaker shown in the closed circuit position;

FIG. 2 is an enlarged fragmentary side elevational view, par tially in vertical section, of the vacuum-type switchgear structure of FIG. I, the contacts being illustrated in the opencircuit position;

FIG. 3 is an enlarged side elevational view of the resilient mounting for the vacuum-interrupter element, together with a showing of the resilient interconnection between the operating rod and the pivoted operating lever, the contact structure being illustrated in the closed-circuit position;

FIG. 4 is a diagrammatic view of a prior art type of metalclad switchgear structure using magnetic air-type arc chutes, and illustrating the space required, with the circuit breaker being indicated in the operating and test positions;

FIG. 5 is a perspective view of a prior art type of metalclad switchgear structure illustrating the considerable space required; and,

FIG. 6 is a diagrammatic view illustrating the saving contact finger space obtained by the use of vacuum-interrupter elements in place of the customarily employed magnetic-type arc-chute structures.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral I generally designates a truck mounted three-phase metalclad type of circuit breaker. As shown, the three-phase circuit-interrupter unit comprises three vacuum-type circuit-

interrupter elements

2, 3 and 4 positioned generally vertically between pairs of horizontally extending terminal bushings 5, 6 the latter being supported by insulating pole supports 7. The pole supports 7 may be formed of porcelain, as set forth and described in U.S. Pat. applica tion, Ser. No. 433,529, filed Jan. 26, l965, by James R. Gamble, entitled Joint Constructions," and assigned to the assignee of the instant application.

It will be noted that the three insulating pole supports 7 are bolted, as at 8, to a lower metallic frame support 9, mounted upon wheels 10, and adaptable for insertion and withdrawal within metalclad switchgear cell structure I], as illustrated in FIGS. 5 and 6 of the drawings. A solenoid-operating mechanism, or a stored-energy operating mechanism I3 may be provided within the lower framework 9 of the circuit breaker l, the construction of which constitutes no part of the present invention. Reference may be had to U.S. Pat 3,183,332 issued May 22, l965 to Funk et al. for a typical stored-energy operating mechanism 13, which may be u used, ifdesired,

FIG, 2 more clearly illustrates the internal construction of the vacuum-interrupter elements, showing the separable con tacts l4, 15 the upper contact 14 being a stationary contact and supported upon a stationary contact rod I6 extending upwardly through the upper end 17 of the vacuum interrupter element and clamped within a relatively massive contact block 18. Clamping bolts I9 may be employed to effect a secure clamping engagement between the contact block 18 and the stationary contact rod extension I6. As shown, the relatively massive split contact block I8 is secured, as by brazing,

between a pair of laterally extending

contact straps

20, 21, which, for example, may be made of hard copper or chrome copper, so as to be somewhat resilient. The lower contact strip 21 may have apertures provided therethrough to accommodate mounting studs 22, which may be provided by the manufacturer of the vacuum-interrupter element. Consequently, the mounting nuts 23, secured to the interrupter element mounting studs 22, if provided, together with the secure clamping of the contact block I8 to the upper end portion of the stationary contact rod [6, provides a secure attachment of the interrupter element to the terminal 24 of the upper terminal bushing 25, the latter extending through the upper end of the insulating pole support 7.

In vacuum-type circuit interrupters, there is no internal convective cooling; and cooling by radiation is very slight because the metal condensing shield 26 also acts as a radiation shield. This means that practically all of the heat generated interiorly of the vacuum-interrupter element must be taken out through the terminals and dissipated externally. The provision of the relatively massive split contact block 18, which may be of copper, adequately provides a heat sink for the storage of heat generated within the vacuum interrupter element.

The lower terminal bushing 27 has a terminal member, designated by the reference numeral 28, and to this is bolted, as at 29, a wide flat supporting member 30, made of a conducting resilient material, such as silicon bronze, for example. As shown in FIG. 3, the fiat support member 30 may be secured to the vacuum-interrupter element by mounting studs 3! supplied with the interrupter element by the manufacturer, and these mounting studs 3I may extend through registering apertures provided in the flat supporting strip 30 and secured thereto by suitable mounting nuts 32.

The vacuum-interrupter element itself has simple butt con tacts I4, I5, and they are closed at high speeds. In order to reduce the rebound of these contacts, a certain amount of resiliency must be provided in the interrupter mounting. It will be noticed, in this connection, that the

elements

20, 21, and 30 act as leaf springs to provide this resiliency.

Bolted to the lower movable contact rod 33 of the vacuumtype interrupter element 4, which moves in a reciprocally vertical direction, is a split relatively massive contact block 34, which is conductively connected to the lower bushing foot, or terminal 35, by a multiplicity of contact fingers 36. Contact pressure between these contact fingers 36 and the contact block 34 and end terminal 35 of the bushing 27 is provided by compression springs 37 The interrupting device, as shown in FIG. 3, is in the closed position, and operation between the open and closed positions is effected by the bifurcated operating lever 38. The operating lever 38 is pivoted about a fixed support pin 39, and is connected to the contact lock 34, and moving contact rod 33 by the moving pin 40. The end of the operating lever 38 is rotatably operated by the insulating operating rod 42. In the closed position, as shown in FIG. 3, the insulating rod 42 has compressed the contact compression springs 43, which bias the operating lever 38 in a counterclockwise direction about the fixed mounting pin 39, and, through the pin 40, holds the interrupter contacts I4, I closed with the required force.

When the circuit breaker mechanism 13 is tripped, the insulating operating rod 42 moves downwardly gathering momen' tum, until the nut 44 at its upper extremity strikes the top 380 of the forked operating lever 38. This opens the interrupter contacts with an impact force, which breaks loose any welds, which may have formed and separates the contacts 14, IS with an initial velocity. The travel of the insulating operating rod 42 is stopped when the required contact separation is reached. During the closing operation, the operating rod 42 is moved upwardly, and the butt contacts within the interrupter strike together with an impact, which is cushioned by the resiliency of the leaf members 20, ZI and 3t) and by the contact compression spring 43. The operating rod 42 continues to move until it reaches the position shown in FIG. 3.

FIGS. 4 and 5 diagrammatically illustrate a conventional magnetic air-break circuit interrupter, and the necessity for providing adequate space for the exhaust gases generated within the magnetic-type air-break arc chute 46. Reference may be had to U.S. Pat. 3,307,004 for a typical arc-chute structure. Also reference may be had to U.S. Pat. application filed July ll, I967 Ser. No. 652,526 by Samuel A. Bottonari, now U.S. Pat. No. 3,538,279 issued Nov. 3, I970 assignee of the instant application, for a description of a typical type of air-break arc chute structure 46, and the description of the concomitantly generated arc-chute gases. Provision must be made, of course, for the cooling of such generated gases; and the space 48 in FIG. 4 is requisite for such accommodation.

It will be noted, however, that due to the small size of the

interrupter elements

2, 3, 4, and the fact that no exhaust gases are generated, leads to drastically reduced dimensions. FIG. 6 illustrates an outline of the circuit breaker of the present invention as positioned within a metalclad cell 11. With a conventional type of magnetic air-break circuit interrupter 46, the breaker completely fills the space, and expansion space for the exhaust gases is provided for in the control module 50 (FIG. 5), which is mounted on top of the breaker module SIv The vacuum breaker, however, is considerably smaller thin a con ventional type of magnetic air-break circuit interrupter 46, and surplus space 52, as shown by the crosshatched area, is available to be used for instruments and control. This eliminates the necessity for providing a control module 50, such as illustrated in FIG. 5, and results in a substantial cost improvement.

If it is desired to make the vacuum breakers of the present invention interchangeable with olderstyle magnetic air-break circuit interrupters, such as the type known as DH-P," it is only necessary to equip the vacuum breaker with an in' terphase barrier of the same physical size as that used for the type 5H4 breakers, and provide standard DH-P cells. The breakers are then perfectly interchangeable.

From the foregoing description it will be apparent that there has been provided an improved metalclad type of switchgear utilizing vacuum-

type interrupter elements

2, 3, 4 in place of the ordinarily utilized magnetic-type air-break arc-chute structures 46. In addition, a resilient mounting 54 for such vacuum interrupter elements has been supplied by the use ola leaf-spring construction, and the dissipation of heat generated within the vacuum interrupter envelopes has been provided by the use of heat sinks S5, or relatively massive contact blocks 18, 34, which are secured to the stationary and movable con tact elements of the vacuumtype circuit interrupter.

It will, additionally, be noted that a relatively simple contact finger arrangement 36 has been provided between the lower movable contact block 34 and the terminal-bushing end terminal member 35 by a relatively simple contact finger construction 36 suitably biased by contact compression springs 37. Finally, the interposition of the contact compression springs 43 between the movable operating rod 42 and the movable operating lever 38 provide a desired resilient and cushioning action during the closing operation with the additional provision of a shock opening force during the opening operation to break any welds, which may have formed between the separable contacts I4, 15.

Although there has been illustrated and described a specific structure, it is to be clearly understood that the same was mereiy 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.

I claim:

1. A truck-mounted multipole vacuum-type circuit interrupter including, in combination:

a. a wheeled truck carrying a plurality of side-byside vertically disposed vacuum-interrupter units;

bv the upper and lower terminal ends of each vertically disposed vacuum-interrupter unit being electrically con nected to upper and lower spaced horizontally disposed terminal bushings,

the truck additionally carrying an operating mechanism for the simultaneous operation of all the vertically disposed vacuum'type interrupter units; and,

a flexible mounting means being provided for each vacuumtype interrupter unit including at least one flexible conducting strap interposed between the terminal of one of the terminal bushing for each unit and one of the ends of said respective unit.

2. The truck-mounted multipole vacuum-type circuit interrupter ofclaim 1, including;

a pivotally mounted operating lever connected to the movable vertically actuable contact of each vacuum-interrupter unit; and,

an insulating operating rod mechanically connected between the free end of the respective operating lever and the operating mechanism.

3. The combination according to claim 1 wherein each vacuumtype circuit-interrupter element includes a pair of separable contacts separated within an evacuated enclosure, at least one contact rod supporting one of said contacts extending externally of the evacuated enclosure, and a heat sink comprising a relatively massive contact block secured to the external end of said contact rod.

4. The combination according to claim 3, wherein the contact block is split and adapted for clamping action.

5. The combination according to claim I, wherein the flexible mounting means includes a plurality of laterally extending flexible conducting straps interposed between the terminals ol the two terminal bushings of each interrupter unit and the ends of said respective interrupter unit.

6. At the combination according to claim 1, wherein each vacuum-type circuit interrupter element includes a pair of separable contacts separated within an evacuated enclosure. stationary and movable contact rods extending externally of the evacuated enclosure, and a pair of heat sinks comprising relatively massive contact blocks secured to the external ends of said contact rods.

7. The combination according to claim I, wherein the upper end of each of the vacuum-type interrupter units includes as a part of said flexible mounting means a pair of laterally extending flexible conducting straps extending between the upper end of the respective unit and the terminal of the upper terminal bushing for said respective unit.

8. The combination according to claim 3, wherein the flexible mounting means for each unit includes a pair of straps disposed on opposite sides of said heat sink.

Claims

1. A truck-mounted multipole vacuum-type circuit interrupter including, in combination: a. a wheeled truck carrying a plurality of side-by-side vertically disposed vacuum-interrupter units; b. the upper and lower terminal ends of each vertically disposed vacuum-interrupter unit being electrically connected to upper and lower spaced horizontally disposed terminal bushings; the truck additionally carrying an operating mechanism for the simultaneous operation of all the vertically disposed vacuumtype interrupter units; and, a flexible mounting means being provided for each vacuum-type interrupter unit including at least one flexible conducting strap interposed between the terminal of one of the terminal bushing for each unit and one of the ends of said respective unit.

2. The truck-mounted multipole vacuum-type circuit interrupter of claim 1, including: a pivotally mounted operating lever connected to the movable vertically actuable contact of each vacuum-interrupter unit; and, an insulating operating rod mechanically connected between the free end of the respective operating lever and the operating mechanism.

3. The combination according to claim 1 wherein each vacuum-type circuit-interrupter element includes a pair of separable contacts separated within an evacuated enclosure, at least one contact rod supporting one of said contacts extending externally of the evacuated enclosure, and a heat sink comprising a relatively massive contact block secured to the external end of said contact rod.

5. The combination according to claim 1, wherein the flexible mounting means includes a plurality of laterally extending flexible conducting straps interposed between the terminals of the two terminal bushings of each interrupter unit and the ends of said respective interrupter unit.

6. At the combination according to claim 1, wherein each vacuum-type circuit interrupter element includes a pair of separable contacts separated within an evacuated enclosure, stationary and movable contact rods extending externally of the evacuated enclosure, and a pair of heat sinks comprising relatively massive contact blocks secured to the external ends of said contact rods.

7. The combination according to claim 1, wherein the upper end of each of the vacuum-type interrupter units includes as a part of said flexible mounting means a pair of laterally extending flexible conducting straps extending between the upper end of the respective unit and the terminal of the upper terminal bushing for said respective unit.