US2374058A - Circuit breaker - Google Patents

Description

Apnl 17, 1945. H. J. WEBB ET AL 2,374,058 CIRCUIT BREAKER Filed July 29, 1945 4 Sheets-Sheet 1 INVENTORS WITNESSES:

flanjamz'n PBa/rar; Herbs/v.1 Webb April 17, 1945. H. J. WEBB ET AL C IRCUIT BREAKER Filed July 29, 1943 4 Sheets-Sheet 3 INVENTORS and A rl/Zur M Wa/zl.

BenjammPBc kar; Herbs/"z JWaZab ATTO Patented Apr. 17, 1945 CIRCUIT BREAKER Herbert J. Webb, Forest Hills, Benjamin .P. Baker,

Turtle Creek,. and Arthur M. Wahl, Wilkinsburg, Pa., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 29, 1943, Serial No. 496,576

11 Claims.

The invention relates to high-voltage circuit breakers and, more particularly, to high-voltage circuit breakers of the compressed gas type in which at least some of the parts are supported by porcelain insulators.

The 'pole'units of high-voltage circuit breakers of the compressed gas type are usually rigidly supported 'by one or more rigidly-mounted hollow porcelain insulators, and the moving contact or contacts are operated at high-speed by compressed gas-motor means which in some cases is mounted in a housing supported on the insulator means. Upon operation of the circuit breaker, very high impact forces, and vibrations or oscillations are produced which set up high stresses in the rigidly-mounted insulators, despite the provision of shock absorbers in the motor means. The impact forces and oscillations resulting from impact of the contact means and moving parts may be augmented by those resulting from rebound of the moving parts and also by the transient vibrations set up by the sudden initial application of compressed gas for operating the breaker. If the circuit breaker embodies a vertically movable interrupting contact and driving piston therefor, and a disconnecting con-tact member and driving piston therefor disposed at an angle to the vertical axis, the impact "forces and oscillations will be both vertical and horizontal and corresponding stresses will be set up in the supporting insulators. The high stresses set up in the insulators have in a number of cases resulted in breakage of the insulators.

The provision of ordinary resilient washers between "the end'sof the insulators and the parts to which the insulators are bolted does not solve the problem of preventing excessive stressing of the insulators assuch an arrangement only allows freedom of movement of the insulator in one direction to take up the shocks and oscillations, namely in the direction which compresses the washer. In such an arrangement, the bolts do not allow movement-Lin the opposite direction nor tilting or pivoting movement for the horizontal components of impact and oscillation.

An object of the invention is the provision of a circuit breaker of the type having parts supported "by one or more porcelain insulators with a novel resilient mounting arrangement for the insulators to materially reduce the stresses in the insulators resulting from impact forces and oscillations produced upon operation of the breaker. I

Another object of the invention is the provision of a circuit breaker having parts supported by porcelain insulators with flexible or resilient supports for either one or both ends of the insulators to absorb the impact forces and oscillations resulting from operation of the breaker without overstressing the insulators.

Another object of the invention is the provision of a circuit breaker comprising a' supporting insulator with a resilient shock-absorbing connection between the insulator and the part supported thereby or between the insulator and the part on which it is supported or between the insulator and both parts, to provide flexibility and absorb the impact forces and oscillation forces resulting from operation of the breaker without overstressing the insulator.

Another object of'the invention is the provision of a circuit breaker of the type having one more porcelain supporting insulators with means for resiliently supporting or securing the insulators to perm-it both horizontal and vertical oscillations of the structure to prevent excessive stresses in the insulators.

Another object of the invention is the provision of a circuit breaker of the compressed gas type having a vertically movable interrupting contact and a movable disconnecting contact disposed for movement at an angle to the vertical axis, both supported by porcelain insulators, with resilient supports for the insulators to provide for vertical and horizontal oscillations of the structure and absorption of the impact and oscillation forces without overstressing the insulators.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself both as to structure and operation, together with additional objects and advantages thereof will be best understood from the following detailed description of several embodiments thereof when read in conjunction with the accompanying drawings, in which:

Figure l is a side elevational view partly in section, showing a compressed gas circuit breaker to which the invention is applied;

Fig. '2 is an enlarged fragmentary sectional view illustrating the resilient mounting of one of the porcelain insulators on the base or frame;

Fig, 3 is -an enlarged fragmentary sectional view showing a modification of the resilient mounting of the supporting insulator;

Fig. 4 is an enlarged fragmentary view, partly in section, showing the operating mechanism casting of a circuit breaker with the insulators resiliently secured thereto in "accordance with a further modification of the invention, and

,sulating material such as porcelain.

Fig. is a sectional view taken on the line- VV of Fig. 4 showing the manner of attachment of the casting and lower insulators to the resilient mounting plate between the casting and the supporting insulators.

The features of the present invention are illustrated as applied to a compressed gas circuit breaker similar to that disclosed in the copending application of L. R. Ludwig, et al., Serial No. 431,394, filed February 18, 1942, and assigned tothe assignee of the present application. Only as much of the circuit breaker structure is shown in the drawings of this application and described herein as is deemed necessary for a complete understanding of the present invention. For other details of the circuit breaker, reference may be had to the aforementioned copending application Serial No. 431,394. While the present invention is illustrated as applied to a particular circuit breaker, it is to be understood that the invention is also applicable to other circuit breaker structures embodying porcelain supporting insulators.

Referring to Fig. 1 of the drawings, the reference numeral designates a base or frame fabricated of structural steel or other suitable material. Rising from the left-hand end of the base. H are a plurality of columns of tubular supporting insulators i3 and I5 of vitreous in- A third supporting insulator column, not visible in the drawings, but similar to the column I5, is dis posed in back of the column l5. Each of the insulator columns l3 and l5 in the embodiment shown consists of a stack of two standard porcelain insulators secured together, and the three supporting columns are connected together by a bracing plate l8. The size of the insulators, the number in each column, and the number of supporting columns willof course depend upon the voltage and strength requirements.

Supported on the upper end of the plurality of the supporting insulators is an operating mechanism housing or casting IS on which is supported a hollow porcelain supporting insulator 2| which, in turn, supports a circuit interrupting element 23. A hollow porcelain insulator 25 extends upwardly from the element 23 and has a metallic terminal cap 21 secured on its upper end. i a

Each-of the insulators I3, l5, 2| and 25 is of conventional construction having flanged metallic end fittings 20 rigidly secured to each end thereof for securing the insulator. I

A stationary contact 29 extends downwardly from the cap 21 into the chamber of the circuit interrupting element 23. A movable contact member 3! cooperates with the stationary contact 29 and extends downwardly through the element 23 and hollow insulator 2|. The lower end of the movable contact member 3| extends into the housing l5 and is connected to an actuating piston 33 movable in a cylinder 35 mounted in the housing It, The piston 33 is. adapted to be operated by compressed gas to actuate the movable contact 3| to open and to closed circuit position. 1

The contacts 29-3| form the current interrupting or arcing contacts of the breakerand are electrically connected in series with a pair of disconnect contacts which are arranged to be opened. after the arcing contacts during a circuit opening operation of the breaker and'closed after the arcing contacts have closed during a closing at o 'y heb ea i rh 1 591 55. 7

tacts comprise a relatively stationary disconnect contact 37 mounted on a terminal cap 39 secured to the upper end of a hollow porcelain insulator 4| on the right-hand end of the base, and a cooperating movable disconnect contact member 43 in the form of a rod which is mounted in bearing means on the housing IQ for straight-line movement into and out of engagement with the staits actuating piston is at an angle to the axis of movement of themovable arcing contact 3|. The inner end of the movable disconnect contact member 43 is connected to an operating pisten 45 which moves in a cylinder 41 mounted in the housin 19. The piston 45 is adapted to be operated by compressed gas to actuate the disconnect contact member to open and to closed circuit position.

' The movable arcing contact member 3| and the movable disconnect contact member 43 are elect'rically connected in series by electrical connections including finger contacts slideably engaged by the contact members 3| and 43. The hollow insulator 4| serves as a housing for transformers and other suitable electrical instrumentalities necessary for the control of the circuit breaker. External circuit connections to the circuit breaker are made to terminals 43 and 5| on the terminal caps 21 and 39. When the circuit breaker is in closed position, current flows through the breaker from the terminal cap 21 through the stationary contact 29, movable arcing contact 3|, through electrical connections to the movable disconnect contact member 43, to the stationary contact 31 and terminal cap 33. Extinction of the are drawn by the movable arcing contact member 3| upon interruption of the circuit is accomplished by a blast of compressed gas or air directed to the chamber of the interrupting element 23.

Fluid under pressure, inthis instance compressed air, for extinguishing the arc and also for operating the movable contacts 3| and is stored in a tank 53 mounted within the frame or base I Extending from the left-hand end of the air-storage tank 53 is a pipe 55 which has mounted thereon and in communication therewith a blast valve 51. The blast valve when opened admits a blast of compressed air from the tank 53 through the passage of the supporting insulator column I 3 and through a pipe 59 and the passage of insulator 2| to the interrupting element 23 where it serves to quickly extinguish the are drawn by the opening of the arcing contacts.

Closing operation of the circuit breaker is controlled by a closing control valve. Bl connected to the pipe 55. When the valve BI is op-, eratedto open position upon energization of its control electromagnet, compressed air is admitted from the tank 53 and supply pipe 55 through a pipe 63 and the passage through the insulator column l5 and a pipe 55 into the lower end of the cylinder 35. The piston 33 is driven upwardly by the compressed air thereby actuating the arcing contact 3| to closed position. As the piston 33 moves upwardly it uncovers a port in the side of the cylinder 35 whereupon compressed air i admitted through a pipe 61 into the lower end of the disconnect cylinder 41, causing the piston 45 to move the movable disconnect contact member 43 to closed circuit position completing the circuit through the breaker.

Opening operationof the circuit breaker is controlled by an opening control valve not visible in the drawings but disposed in back of the valve BI and connected to the common supply pipe 55. When the opening control valve is opened upon energization of its control electromagnet, compressed air is admitted from the supply pipe 55 through the valve and through a pipe (not shown) and the passage of the other supporting insulator column behind the column and through a pipe H into the upper end of the arcing contact operating cylinder 35. The compressed air drives the piston 33 downwardly to the bottom of the cylinder and thereby actuating the movable arcing contact 3| to open circuit position. As the piston 33 moves downwardly, it uncovers a port in theside of the cylinder 35 whereupon compressed air is admitted from the cylinder 35 through a pipe connection 73 into the upper end of the disconnect cylinder 41 causing the disconnect piston -to be moved to the lower end of the cylinder ll, thereby actuating the disconnect contact member 43 to the open-circuit position shown.

The control electro magnet for the blast valve 51 and the control eleotromagnet for the circuit breaker opening valve are arranged to be energized simultaneously to initiate opening operation of the circuit breaker so that a blast of compressed air will be directed to the arcing contacts simultaneously with the opening movement thereof. a

Shock absorbing means (not shown) are provided for each of the operating pistons 33- and 45 as disclosed in the aforementioned copending application Serial No. 431,394, although other forms of shock absorbing means for the erating pistons 33 and 45 are operated at very high speeds, and although some of the kinetic energy of the moving parts is absorbed by the mechanism housing and the shock-absorbing means for the operating pistons, the entire pole unit mechanism above the insulators l3 and I5 is forced into oscillation. The oscillations produced by the operation of the arcing contact 3| and its operating piston 35 are .in a Vertical direction whereas the oscillations produced by the operation of the disconnect contact 43 and its piston 45 have both a vertical. and a horizontal component. These impact and oscillation forces may be augmented by the transient vibration. produced by the sudden application of compressed air to the operating. pistons. If the supporting insulators are rigidly supported and secured in the usual manner, the impact forces and oscillation resulting from the operation of the circuit breaker are very apt to break the insulators, and in fact breakage of the insulators has occurred in a number of casesfrom this cause.

- In accordance with the present invention,

means are provided for resiliently mounting or securing the supporting insulators at one or both ends to permit both vertical and horizontal oscillaticns of structure to absorb the impact and oscillation forces and prevent excessive stressing of the insulators.

Referring to Figs. 1 and 2, the lower insulator units l3 and I5 of each of the plurality of supporting columns are mounted on the top plate of the base II by means of a plurality of bolts or cap screws 11 which extend through holes '19 provided therefor in the flange of the metal end fitting 20 of the insulator and thread into the top plate of the base I l. The bolt holes 79 in the insulator fiange are of larger diameter than that of the bolts or screws 11 so as to permit up and down movement and rocking movement of the insulator relative to the top plate of the base H and the bolts '11. A washer 8| of resilient material such as rubber, neoprene, thiacol, cork or other suitable resilient material is disposed between the metal end fitting 20 of the insulator and-the top plate of the base I I. An annular gasket 83 of resilient material seated in an annular recess in the top plate of the base H and disposed between the washer BI and the top plate of the base may also be provided. This gasket 83 assists the washer 8| in making the joint between the insulator fitting 2D and the top plate of base ll gas-tight to prevent leakage of compressed air through this joint. Encircling each of the bolts 11 and disposed between the head of the bolt and the flange of the insulator fitting 20 is a resilient spring means consisting of a plurality of convex shaped spring washers 85 arranged in alternating fashion one washer with its convex side up and the next adjacent washer having its convex side down.

A fiat metal retaining ring 86 is disposed around the outside edge of the resilient washer 8! between the flange of the insulator fitting 20 and the top plate of the base. The bolts Tl pass thru openings in this retaining ring to hold it in position. The ring 86 serves to prevent the edge portion of the resilient washer 8| from bulging out in the spaces between the bolts 11.

In tightening the bolts 11, the metal end fitting of the insulator comes down securely on the resilient washer 8| and the spring washers 85 are compressed or deflected a predetermined amount. With this resilient mounting arrangement it is evident that for vertical oscillations of the supporting insulator and structure above it the insulator is floated between the resilient washer -81 and the spring washers 85, these resilient elements permitting up and down oscillations of the insulator relative to the base H. For horizontal or rocking oscillations of the mechanism housing 49 and supporting insulators l3 and I5, the supporting insulators can rock Or pivot relative to the base H, compressing the resilient washers 8| on one side and compressing the spring washers 85 on the other side and vice versa as the structure rocks. The resilient washers 8! and spring washers 85 provide suiiicient flexibility to absorb the shock forces and oscillation forces resulting from the operation of the breaker without overstressing the porcelain supporting insulators.

The upper metal end fittings of the upper porcelain supporting insulators l3 and I5 of each supporting column may also be, and preferably are, resiliently secured to the bottom wall of the mechanism housing l9 in the same way that the lower supporting insulators are resiliently mounted on the base H as described above and shown in- Fig. 2. With the upper insulators l3 and I5 I resiliently secured to the bottom wall of the mechanism housing I9, the mechanism housing l9 and structure carried thereby can oscillate up and down and also pivot or rock relative to the supporting insulators l3 and I5 so as to absorb the shock and oscillation forces without overstressing the insulators.

The method of resiliently mounting or securing the supporting insulators not only provides sufficient flexibility. to permit horizontal and verfaces of their metal end fittings all in exactly the same plane." The parts can be easily assembled without danger of straining the insulators despite variations of manufacture. A good gas-tight joint is also obtained by the resilient mounting arrangement. T

The hollow insulator 2 l, which supports the in- 4 terrupting element 23 and the structure above it, may also be, and preferably is, resiliently mounted on the top wall of the mechanism housing [9 in the same way that the lower supporting insulators are resiliently mounted onthe base II as has been previously described and shown in Fig. 2. This will enable theinsulator 2| and the structure carried thereby to oscillate up and down and rockor pivot relative to the mechanism housing l9 thus providing suificient flexibility to absorb the shock forces and oscillation forces without overstressing the insulator.

' A modification of the resilient mounting or securing arrangement for the supporting insulators is shown in Fig. 3; Each of the lower supporting insulators of the plurality of supporting columns mounted on the topof the base 'I l in the manner shown in Fig. 3. In this figure of the drawings, 89 designates the top plate of the circuit breaker base II. The lower end of each of the lower supporting insulators has a metal fittingSl rigidly secured thereto. An annular relatively thin plate 93 of spring steel or other strong resilient metal is secured at its central portion to the bottom of metal fitting 9! by welding or other suitable securing means. The spring plate 93 is of slight- 1y convex shape as shown in Fig. 3 so that its center portion is spaced above the base plate 89. Adjacent its outer peripheral edge the spring plate is secured to the base plate 89 by a plurality of cap screws or bolts 95, the bolts being arranged in spaced relation in a circle adjacent the outer edge of the spring plate 93. An opening 94 in the base plate 89 and the center opening 96 in the spring plate 93 are aligned with the passage through the insulator to permit the passage of compressed air through the insulator, and

the outer edge portion of the spring plate is cemented to the base plate 89 to prevent leakage 91, and a resilient gasket Hill is disposed between the houlder on the conduit 98 and the under side of the ring '91.. tion between the conduit and the ring permits oscillating and tilting movement of the insulator relative'to the conduit 98, and the gasket makes the joint gas-tight despite relative movement between the parts.

The resiliency of the spring plate 93 permits the supporting insulator to oscillate up and down and also to rock relative to the base plate 89, and

The loose slideable connec the shock forces and oscillation force resulting from operation of the breaker are thereby absorbed without excessively stressing the supporting insulator.

The upper end of each of the supporting insulator columns which support the operating mechanism housing I9 of the circuit breaker can also be resiliently secured to the bottom wall of the mechanism housing 19 by a spring plate in the same manner as shown in Fig. 3. This will permit the mechanism housing l9 and the structure supported thereby to oscillate-up and down to rock relative to the supporting insulators and the spring plates will thereby absorb the shock forces and oscillation forces without overstressing the insulators.

The insulator 2| of the circuit breaker may also be resiliently mounted on the upper wall of the mechanism housing 19 by a spring plate mounting similar to that shown in Fig. 3 to provide flexibility for this insulator so that it will not be excessively stressed by the shock and oscillation forces resulting from operation of the circuit breaker.

Another modification of the invention is shown in'Figs. 4 and 5. Referring to Fig. 4, the operating cylinder 35 for the movable arcing contact 3| and the operating cylinder 41' forthe movable disconnect contact 43 are mounted on a metal casting IBI which corresponds to the mechanism housing l9 shown'in Fig. 1. The arcing contact 3| is operated to'open and closed position by a piston 33 in the cylinder 35, and the movable disconnecting contact 43 is operated to open and to closed position by a piston 45 in the same manner as previously described in connection with the Fig. 1 embodiment. The casting I0! is formed to provide a conduit 13 which .communicates with the blast air passages of the each supporting column l3 and 15 is secured to the resilient plate by a plurality of bolts or cap screws I09 which extend through the resilient plate and thread into the flange of the insulator fitting 20. The bolts 109 for securin each insulator to the plate I05 are arranged in a circle which is of considerably larger diameter than the circleof the bolts I01 thus leaving a section of the plate I05 between the concentric circles of bolts I01 and I09 to provide flexibility between the mechanism casting llll and each supporting'insulator l3 or IS. The resiliency of this section of the plate I05 permits the mechanism castin Hll to oscillate up and down and also to rock a limited amount relative to the supporting insulators and thereby absorb the shock forces and oscillation forces resulting from operation of the circuit breaker without overstressing the supporting insulators. The lower end of the supporting insulators l3 and I5 of each column may be resiliently mounted onthe base or frame ll of the circuit breaker either in the manner shown in Fig. 2 min the manner shown in Fig. 3. 4 v

The upper end of the mechanism casting IOI is provided with a relatively thin circular flange H l and the flange'o't the lower end fitting 20 of the hollow insulator 2'! is secured to'the flange HI by'a plurality of cap screws H3. The casting is made of a suitable resilient metal, and the thin flange portion Hl' thereof provides a resilient mounting for the upper insulator 21' to permit oscillation of the insulator 2i and structure carried thereby and absorb the shock forces and oscillation forces without overstressing the insulator.

The remaining structure of the circuit breaker is the same as that shown in Fig. 1 and described in connection therewith.

While several embodiments of the invention have been disclosed in accordance with the patent statutes, it is to be understood that various changes in the structure and arrangement of parts may be made without departing from some of the essential features of the invention.

We claim as our invention:

1. In a high-voltage electrical circuit breaker structure, circuit interruptin mechanism, tubular porcelain insulator means for supporting said circuit interrupting mechanism, and means re siliently securing said insulator means to a part of said circuit breaker structure for permitting Vertical and horizontal oscillation of said insu lator means relative to said part for preventing excessive stressing of said insulator means 2. In an electrical circuit breaker, circuit interrupting mechanism, high-voltage insulator means supporting and bearing the weight of said circuit interrupting mechanism, and means resiliently mounting said circuit interrupting mechanism on said insulator means for permittin vertical oscillations and horizontal oscillations of said circuit interrupting mechanism relative to said insulator means in opposite directions from the normal position of said mechanism for base for preventing excessive stressing of said insulator means.

4. In an electrical circuit breaker, a base, tubular high-voltage insulator means of vitreous insulating material mounted on said base, circuit interrupting mechanism mounted on and sup- 7 ported by said insulator means, means resiliently mounting said insulator means on said base and means resiliently mounting said circuit interrupting mechanism on said insulator means for permitting vertical and horizontal oscillations of said mechanism relative to said insulator means and vertical and horizontal oscillations of said insulator means relative to said base for absorbing shock forces and preventing excessive stressing of said insulator means.

5. In a high-voltage electrical circuit breaker, a base, a plurality of high-voltage tubular supporting insulators of vitreous insulating material mounted on said base, circuit interrupting mechanism mounted on and supported by said insulators comprising a vertically movable current interrupting contact and actuating means therefor and a separate series connected movable disconnect contact member and actuating means therefor disposed for movement at an angle to means resiliently mounting said circuit interrupting mechanism on said one or more insulators for reducing shock forces and oscillation forces applied to said one or more insulators resulting from operation of the circuit breaker, said resilient mounting means comprising a washer of resilient material disposed between said mechanism structure and each supporting insulator, a plurality of bolts securing said insulator to said mechanism structure and resilient means on each bolt between the head of said bolt and said insulator.

'7. In a high-voltage electrical circuit breaker, a base, one or more insulators mounted on said base, circuit interrupting mechanism mounted on and supported by said one or more insulators, and means resiliently mounting said one or more .insulators on said base to prevent excessive stressing of said insulators, said resilient mounting means comprising a washer of resilient material disposed between each insulator and said base, a plurality of bolts securing said insulator on said base and spring means on each bolt between the head of said bolt and said insulator.

8. In an electrical circuit breaker, circuit interrupting mechanism, one or more tubular insulators of vitreous insulating material supporting and bearing the weight of said circuit interrupting mechanism, each insulator having a rigid fitting on each end thereof, means resiliently mounting said circuit interrupting mechanism on said one or more insulators to permit limited oscillation of said mechanism relative to said one or more insulators and to prevent overstressing of said one or more insulators comprising a relatively thin plate of resilient metal attached to the end fitting of each insulator and secured at a plurality of points adjacent to said circuit interrupting mechanism structure.

9. In an electrical circuit breaker, a base, one or more tubular insulators of vitreous insulating material mounted on said base, circuit interrupting mechanism mounted on'and supported by said one or more insulators, each insulator having a rigid fitting secured to each end thereof, means resiliently mounting said one or more insulators on said base for permitting oscillation of said circuit interrupting mechanism and said one or more insulators relative to said base and for preventing excessive stresses in said one or more insulators comprisin a relatively thin plate of resilient metal attached to the fitting of each insulator and secured at a plurality of points to said base.

10. In an electrical circuit breaker, a base, a plurality of insulators of vitreous insulating material mounted on said base, circuit interrupting mechanism mounted on and supported by said insulators, and means resiliently mounting said insulators on said base to permit oscillation of said mechanismand insulators relative to said base and prevent excessive stresses in said insulators comprising a separate relatively thin mounting plate attached at its central portion to the end of each insulator and secured at a plurality of points adjacent its edge to said base.

11. In an electrical circuit breaker, a plurality of supporting insulators, a metal housing mounted on said insulators having a. relatively thin circular resilient flange at its upper end, a tubular 10 insulator of vitreous insulating material having a rigid fitting on its lower end secured at a plu-

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