US2019348A

US2019348A - Electric circuit interrupter

Info

Publication number: US2019348A
Application number: US743109A
Authority: US
Inventors: Leland S Hobson
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1934-09-07
Filing date: 1934-09-07
Publication date: 1935-10-29
Anticipated expiration: 1952-10-29
Also published as: GB462137A

Description

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Patented Oct. 29, 1935 PATENT OFFICE 2,019,348 ELECTRIC CIRCUIT INTERRUPTER Leland S. Hobson, Yeadon, Pa., assignor to General Electric Company, a corporation of New York Application September I, 1934, Serial No. 743,109

6 Claims.

My invention relates to electric circuit interrupters of the fluid-blast type and has for its principal object the provision of an improved circuit interrupter of the aforesaid type particularly adapted to the use of an arc-extinguishing liquid, as water, which is partially conducting as contrasted with the usual circuit breaker oil.

The use of a readily vaporizable and non-inflammable arc-extinguishing liquid, as water, in

electric circuit interrupters has a number of advantages including practically instantaneous generation of adequate blast pressure upon opening of the circuit, elimination of fire hazard and decreased cost. In accordance with my invention,

an electric circuit interrupter is provided with an explosion pot containing an arc-extinguishing liquid of the character above referred to, and the explosion pct which forms a part of the movable contact structure is positioned above the level of a. separate body of similar arc-extinguishing liquid in the closed circuit position and arranged to be lowered into said liquid for refilling by and in accordance with the circuit opening operation.

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to 80' and forming a part of this specification.

Referring to the drawing, the single figure thereof is an elevational view, partly in section, of an electric circuit interrupter of the fluidblast type embodying my invention.

35 The circuit interrupter illustrated comprises a main tank or casing I containing a suitable arcextinguishing liquid 2, as water. Relative-1y movable contact structure for interrupting the circuit is disposed within the tank and in the closed circuit position shown is disposed in the gas or air space above the level of the liquid 2.

The aforesaid contact structure comprises a pair of fixed contacts 3 mounted at the lower ends 45 0f the conventional lead-in bushings 4 and a conducting bridging member 5 arranged to engage and interconnect the fixed contacts 3 in the closed circuit position.

The movable contact structure, in addition to 50 the bridging member 5, comprises an explosion pot 6 of insulating material formed in the present instance as a cylinder or tube closed at its opposite ends and enclosing the bridging member 5. The explosion pot 6 is provided at its upper 85 side with apertures 1 for receiving the fixed con tacts 3 and for serving as the usual blast openings during circuit interruption.

The explosion pot 6 when in the closed circuit position shown likewise contains an arc-extinguishing liquid 2' similar to that in the tank 5' so that upon lowering of the movable contact structure, as by the usual operating or lift rod 8, the arcs formed on separation of the contacts 3 and 5 instantly vaporize a portion of the liquid and generate high pressure within the explosion i pot. As the contacts 3 pass through the exhaust openings 1 the pressure within the explosion pot is effective to direct arc-extinguishing blasts of steam and of liquid through the arcs, causing interruption of the same. 15

In operation, the circuit is opened by lowering of the movable contact structure into the liquid 2 at the lower part of the main tank. Arcing is interrupted by the explosion chamber effect above described. After a single circuit interrupting 20 operation, particularly in case of currents of larger magnitude, an appreciable part of the arc-extinguishing liquid within the explosion pot 6 has been ejected in the form of vapor and atomized liquid. By immersing the explosion 25 pct 6 within the liquid 2 at the end of each circuit opening operation, the explosion pot is automatically refilled so as to be in readiness for another circuit interrupting operation immediately after reclosure.

For the purpose of limiting the arcing pressure within the explosion pot, as during'the interruption of short circuit currents, pressure relief means may be provided. In the arrangement shown the opposite ends of the explosion pot 6 are normally closed by valves 9 biased into seating engagement with the ends of the insulating cylinder by springs l0. Each spring Ill is mounted on a valve guide rod l I secured at one end, as at I2, to the bridging member 6 and having at its 40 free end an adjusting nut l3 for determining the opening pressure of the valve.

The operating means for the movable contact structure likewise includes an insulating barrier 14 which is formed as a plate of insulation suitably secured to the movable contact structure intermediate the fixed contacts 3. The insulating barrier I4 is effective to prevent arcing or flashover between the stationary contacts 3 when the circuit breaker is in open position, the stationary contacts 3 in such position being isolated in air.

In cases where infrequent operation of the circuit breaker is required, evaporation of the arc-extinguishing liquid may be substantially prevented by a, very small amount of oil on the the upward movement previously used in circuit breakers using a conducting liquid. The downbreak has the aid of gravity to accelerate the moving contact.

Furthermore, throwing of! of water or steam, which might be expected in the prior up-break types of circuit breakers using water, is here prevented by the main tankand its insulating lining which completely enclose the interrupting element.

It will be apparent that individual or separate explosion pots for each pole of the breaker may be used instead of the tubular explosion pot common to both poles, illustrated by way of example.

It should be understood that my invention is not limited to specific details 01' construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent oi the United States is:

1. An electric circuit interrupter oi the fluidblast type comprising relatively movable contact structure including a movable explosion pot containing an arc-extinguishing liquid, the arc formed upon separation of said contact structure causing an arc-extinguishing blast from said pot, and means for refilling said explosion pot with similar liquid by and in accordance with the circuit controlling operation, said contact structure arranged so that the same is spaced by air in the open circuit position.

2. An electric circuit interrupter of the fiuidblast type comprising relatively movable contact structure including a movable explosion pot containing an arc-extinguishing liquid, a tank in which said contact structure is mounted likewise containing similar liquid, said contact structure in the closed circuit position being positioned above the liquid level in said tank, and means for refilling said explosion pot with liquid from said tank by and in accordance with the circuit controlling operation.

3. An electric circuit interrupter oi the fluidblast type comprising a tank containing an arcextinguishing liquid, relatively movable contact structure for coacting above the level oi. said liquid including an explosion pot likewise containing arc-extinguishing liquid, and means for lowering said explosion pot in said tank for opening the circuit, said explosion pot being refilled with liquid from said tank by and in accordance with said circuit controlling operation.

4. An electric circuit interrupter oi the fluidblast type comprising a tank containing an arcextinguishing liquid, a pair 'of fixed contacts mounted in said tank, coacting movable contact structure including a conducting bridging member, a tubular insulating explosion pot movable with .said bridging member, said explosion pot having openings for receiving said fixed contacts and normally containing arc-extinguishing liquid, the aforesaid contact structure disposed above the level of the liquid in said tank in the closed circuit position, and means for lowering said bridging member and explosion pot for effecting the circuit opening operation, said explosion pot being immersed in the liquid in said tank in the open circuit position.

5. An electric circuit interrupter of the fiuidblast type comprising a tank containing an arcextinguishing liquid, a pair of fixed contacts mountedv in said tank, coacting movable contact structure including a conducting bridging member, a tubular explosion pot composed of insulation enclosing said bridging member, and pressure relief valves at opposite ends of said, explosion pot, said explosion pot normally filled with a similar arc-extinguishing liquid and positioned together with said fixed contacts above the level of the liquid in said tank in the closed circuit position, and operating means including an insulating barrier connected to said explosion pot between said fixed contacts for lowering saidexplosion pot and effecting a circuit opening operation, said explosion pot being immersed in the liquid in said tank so that it is refilled with liquid prior to the circuit closing operation.

6. An electric circuit interrupter comprising a tank containing a conducting arc-extinguishing liquid, fixed contact structure mounted above the level of said liquid, coacting movable contact structure including an explosion pot containing a similar liquid, and means for lowering said movable contact structure into the liquid in said tank thereby effecting the circuit opening operation.

LELAND S. HOBSON.