JPH0927252A - Gas-blast circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-blast circuit breaker which can be prevented from being degraded in breaking performance and withstand voltage performance by causing melting of a fixed contact support and which can be miniaturized. SOLUTION: This gas-blast circuit breaker has a fixed contact 23 supported against a fixed contact support 11 at its first end, a movable contact 4 which makes and breaks contact with the fixed contact 23, and an insulating nozzle 9 provided in such a way as to surround the movable contact 4; after an arc 10 generated between both contacts 23, 4 when current is cut off is supplied with an arc-extinguishing gas 1 via the insulating nozzle 9, a high-temperature thermal gas 13 generated at the extinction of the arc is exhausted from an exhaust hole 12 provided in the fixed contact support 11. In the gas-blast circuit breaker, the portion of the fixed contact support 11 against which the thermal gas 13 blows is covered with a cover 20 made of a heat resistant material. The cover 20 is provided with an inclined portion which guides the thermal gas 13 to the exhaust hole 12.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a gas circuit breaker.

[0002]

2. Description of the Related Art FIG. 2 is a cross-sectional view showing a state in which a conventional gas circuit breaker is interrupting current. A closed container 2 filled with an arc extinguishing gas 1 is provided with a fixed contact 3 for interrupting an arc. A movable contactor 4 that can be brought into contact with and separated from the fixed contactor 3 is provided. The puffer device 5 is composed of a cylinder 7 having an outlet 6, and a piston 8 which is fixedly formed and can slide on the inner surface of the cylinder 7. The insulating nozzle 9 is fixed to the cylinder 7 and is formed so as to surround the movable contactor 4. Reference numeral 12 denotes an outlet for hot gas 13 generated during arc extinction, which is formed in the fixed contact support 11. Although not shown, the main fixed contactor and the main movable contactor, which serve as a current-carrying path, are attached to the fixed contactor support 11 and the cylinder 7 separately from the fixed contactor 3 and the movable contactor 4, respectively. There is.

When the movable contactor 4 is moved to the right by an operation mechanism (not shown), the movable contactor 4 is separated from the fixed contactor 3 as shown in FIG. An arc 10 is generated between the movable contact 4 and the fixed contact 3. On the other hand, as the movable contact 4 moves to the right, the cylinder 7 integrally moves to the right, and the piston 8 compresses the arc-extinguishing gas 1 in the cylinder 7. The compressed arc-extinguishing gas 1 is blown out 6
Flowing out of the arc, is guided by the insulating nozzle 9, and is blown to the arc 10 generated between the fixed contact 3 and the movable contact 4 to extinguish the arc 10. At this time, the arc-extinguishing gas 1 sprayed on the arc 10 becomes high-temperature hot gas 13,
It flows into the fixed contact support 11 via the periphery of the fixed contact 3 and is discharged from the discharge port 12.

[0004]

In the conventional gas circuit breaker described above, hot gas 13 of high temperature generated at the time of extinguishing arc is blown to the fixed contact 3 and the fixed contact support 11.
In this case, since the fixed contactor 3 is for arc interruption, it is usually formed of arc-resistant metal, and will not melt even if the hot gas 13 of high temperature is blown. However, since the fixed contact support 11 becomes a current-carrying path through the main movable contact and the main fixed contact when the gas circuit breaker is turned on,
It is made of a material with good conductivity. Therefore, hot gas 1
Due to the high temperature at the time of spraying No. 3, the fixed contact support 11 may be melted and scattered, and the melted material may deteriorate the breaking performance and the withstand voltage performance of the gas circuit breaker. Therefore, the distance L from the part where the hot gas 13 is generated by the arc 10 to the part where the hot gas 13 of the fixed contact support 11 is blown must be increased to the distance required for cooling the hot gas 13. This is one of the factors that make the gas circuit breaker longer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gas circuit breaker capable of preventing the breaking performance and the withstanding voltage performance from being deteriorated due to the melting of the fixed contact support, and the miniaturization.

[0006]

According to the present invention, a fixed contact whose base end is supported by a fixed contact support, a movable contact that comes in contact with and separates from the fixed contact, and the movable contact is surrounded. With an insulating nozzle provided in such a manner, after blowing an arc extinguishing gas through the insulating nozzle to the arc generated between the two contacts at the time of current interruption, the high-temperature hot gas generated during arc extinguishing In a gas circuit breaker for discharging from a discharge port provided in the fixed contact support, a portion of the fixed contact support to which the hot gas is blown is covered with a cover formed of a heat resistant material. To do. Further, it is preferable that the cover is provided between the fixed contact and the fixed contact support, and has an inclined portion for guiding the hot gas to the discharge port.

[0007]

In the gas circuit breaker of the present invention, the hot gas is blown onto the cover made of a heat-resistant material, so that the fixed contactor support is not exposed to the high temperature due to the hot gas. Therefore, the distance from the portion where the hot gas is generated by the arc of the fixed contact to the portion where the hot gas is blown can be shortened, and the size can be reduced. Further, by providing the cover with the inclined portion for guiding the hot gas to the discharge port, the hot gas is smoothly discharged, and the breaking performance of the gas circuit breaker can be improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the gas circuit breaker of the present invention is shown in FIG.
It will be described in detail based on. FIG. 1 is a cross-sectional view showing a state in which the current is cut off. The base end of the fixed contact 23 and the fixed contact support 11 cover the fixed contact 23 of the fixed contact support 11 and the discharge port 12. As described above, the cover 20 is made of a heat-resistant material such as arc-resistant metal.
Is provided. Further, the cover 20 is provided with an inclined portion that guides the hot gas 13 to the discharge port 12 of the fixed contact support 11.

In such a gas circuit breaker, the high temperature hot gas 13 generated at the time of arc extinguishing is sprayed on the heat resistant cover 20, and the fixed contact support 11 made of a material having good conductivity is formed by the hot gas 13. It is not directly exposed to high temperatures. Therefore, it is possible to prevent the fixed contact support 11 from being melted and damaged by the hot gas 13, so that the distance L ′ from the part where the hot gas 13 is generated by the arc 10 to the part of the fixed contact support 11 to which the hot gas 13 is sprayed is It can be made smaller than the distance L in the conventional gas circuit breaker.

Further, the inclined portion of the cover 20 which guides the hot gas 13 to the discharge port 12 allows the hot gas 13 to be smoothly discharged.
Therefore, the breaking performance of the gas circuit breaker can be improved.

[0011]

As described above, according to the present invention, the hot gas is sprayed on the cover formed of the heat resistant material,
Since the fixed contact support is not exposed to high temperature due to hot gas,
Since there is no melting damage, it is possible to provide a small-sized and highly reliable gas circuit breaker without lowering the breaking performance and the withstand voltage performance.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a gas circuit breaker of the present invention.

FIG. 2 is a sectional view showing an example of a conventional gas circuit breaker.

[Explanation of symbols]

 1 Arc-Extinguishing Gas 2 Airtight Container 4 Movable Contact 5 Puffer Device 6 Blowout Port 7 Cylinder 8 Piston 9 Insulation Nozzle 10 Arc 11 Fixed Contact Support 12 Discharge Port 13 Hot Gas 20 Cover 23 Fixed Contact

Claims (2)

[Claims] 1. A fixed contactor whose base end is supported by a fixed contactor support, and a movable contactor which comes into contact with and separates from the fixed contactor.
An insulating nozzle provided so as to surround the movable contactor, and after extinguishing an arc-extinguishing gas through the insulating nozzle to an arc generated between the contacts when the current is cut off, at the time of extinguishing the arc. In a gas circuit breaker that discharges the generated high-temperature hot gas from an outlet provided in the fixed contact support, a portion of the fixed contact support to which the hot gas is blown is formed of a heat-resistant material. A gas circuit breaker characterized by being covered with a cover. 2. The cover is arranged between the fixed contact and the fixed contact support, and is provided with an inclined portion for guiding the hot gas to the discharge port. The gas circuit breaker described.