JPH11329166A - Gas-blast circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas-blast circuit breaker having a fixed main contact prevented from forming a rough surface, by protecting the fixed main contact from arc heat. SOLUTION: This gas-blast circuit breaker is equipped with a container 20 filled with arc-extinguishing gas, a fixed electrode 21 having a fixed main contact 22 and a fixed arc contact 23 mounted to the container 20, a movable electrode 24 having a movable main contact 25 and a movable arc contact 26 supported on the container 20, and a cylindrical body 27 of conductive material, which is mounted to the fixed electrode 21, has an arc runner 28 on its inner periphery and has an arc driving coil 29 on its outer periphery. In this case, one end of a shielding material 1 with another and fixed to the arc runner 28 is placed between the movable arc contact 26 and the fixed main contact 22, and a thermal spray film is formed on the surface of the shielding material 1 facing the movable arc contact 26 by thermally spraying arc resistant material or insulating material. Accordingly, since arc heat is not applied on the fixed main contact 22, projecting and recessed parts caused by fusion are not produced on the surface of the fixed main contact 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas circuit breaker for extinguishing an arc in an arc-extinguishing gas.

[0002]

2. Description of the Related Art A conventional gas circuit breaker is configured as shown in FIG. In the figure, reference numeral 20 denotes a container made of an insulating material, and a fixed electrode 21 is attached to the top of the container 20. A fixed main contact 22 and a fixed arc contact 23 are attached to the fixed electrode 21. Reference numeral 24 denotes a movable electrode attached to the container 20 via a support member (not shown). The movable electrode 24 is provided with a movable main contact 25 that comes into contact with the fixed main contact 22 and a movable arc contact 26 that comes into contact with and separates from the fixed arc contact 23. . Reference numeral 27 denotes a cylindrical body made of a conductive material attached to the fixed electrode 21. An arc runner 28 is provided at an end of the cylindrical body 27. An arc drive coil 29 is wound around the outer periphery of the cylindrical body 27. One end is connected to the fixed electrode 21 via the cylindrical body 27, and the other end is connected to the arc runner 28. Reference numeral 30 denotes an arc-extinguishing gas sealed in a container. Next, the switching operation of the gas circuit breaker will be described. FIG. 2 shows a state in which the gas circuit breaker is open. When the movable electrode 24 is actuated in the direction of arrow B by operating an operating mechanism (not shown) from this state, the movable arc contact 26 becomes the fixed arc contact 23. , The movable main contact 25 comes into contact with the fixed main contact 22, and current flows through the movable main contact 2 of the movable electrode 24.
5 flows to the fixed main contact 22 of the fixed electrode 21 to close the electric circuit. When the movable electrode 24 is actuated in the direction opposite to the direction of arrow B from this state, the movable main contact 25 is separated from the fixed main contact 22 and then the movable arc contact 26 is moved to the fixed arc contact 2.
3, an arc is generated between the movable arc contact 26 and the fixed arc contact 23. Further, the movable electrode 24
Is actuated in the direction opposite to the direction of arrow B, the arc foot on the fixed arc contact 23 moves onto the arc runner 28. The arc current at this time is applied to the movable arc contact 26 of the movable electrode 24.
Flows through the arc extinguishing gas 30 to the arc runner 28.
The arc current that has flowed through the arcrunner 28 flows through the cylindrical body 27 through the arc driving coil 29 to the fixed electrode 21.
The arc drive coil 29 generates a magnetic flux by the arc current flowing through the arc drive coil 29. This magnetic flux causes the arc between the arc runner 28 and the movable arc contact 26 to rotate in an arc-extinguishing gas atmosphere to extinguish the arc.

[0003]

However, in the conventional gas circuit breaker, the heat of the arc rotating between the movable arc contact 26 and the arc runner 28 is transferred to the fixed main contact 22.
Irradiates the surface of the fixed main contact 22 made of a material having a low melting point, such as silver, in some cases. As a result, the surface of the fixed main contact 22 becomes uneven, and the surface thereof becomes rough.
And the contact resistance between them has increased, and the conductivity has deteriorated. Therefore, an object of the present invention is to provide a gas circuit breaker that protects a fixed main contact from heat of an arc and prevents the fixed main contact from being roughened.

[0004]

In order to solve the above problems, the present invention provides a container filled with an arc-extinguishing gas, a fixed electrode having a fixed main contact and a fixed arc contact attached to the container, A movable electrode supported by the container and having a movable main contact and a movable arc contact, and attached to the fixed electrode;
In a gas circuit breaker having an arc runner on the inner periphery and a cylindrical body made of a conductive material having an arc driving coil attached on the outer periphery, the other end of the shielding member having one end attached to the arc runner is connected to the movable arc contact and the movable arc contact. A sprayed film formed by spraying an arc-resistant material or an insulating material is formed on a surface of the shielding member facing the movable arc contact, which is disposed between the fixed main contact and the movable arc contact.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view showing a main part of a gas circuit breaker according to an embodiment of the present invention. The same parts as those in FIG. 2 are denoted by the same reference numerals, and detailed description is omitted. Reference numeral 1 denotes a shielding material formed in a mortar shape. One end is attached to the arc runner 29 and the other end is disposed between the movable arc contact 25 and the fixed main contact 22. A sprayed film formed by spraying an arc-resistant material such as tungsten carbide or an insulating material such as white alumina is applied to a surface of the shielding member 1 facing the movable arc contact 25. Next, the switching operation of the gas circuit breaker thus configured will be described. FIG. 1 shows a state in which the gas circuit breaker is open. When the movable electrode 24 is actuated in the direction of arrow A by operating an operation mechanism (not shown) from this state, the movable arc contact 26 becomes a fixed arc contact. 23, the movable main contact 25 contacts the fixed main contact 22,
The current flows from the movable main contact 25 of the movable electrode 24 to the fixed electrode 21.
Flows through the fixed main contact 22 to close the electric circuit. When the movable electrode 24 is operated in the direction opposite to the direction of the arrow A from this state,
After the movable main contact 25 is separated from the fixed main contact 22, the movable arc contact 26 is separated from the fixed arc contact 23, and an arc is generated between the movable arc contact 26 and the fixed arc contact 23. Further, when the movable electrode 24 is operated in the direction opposite to the direction of the arrow A, the arc foot on the fixed arc contact 23 moves onto the arc runner 28. The arc current at this time flows from the movable arc contact 26 of the movable electrode 24 through the arc-extinguishing gas 30 to the arc runner 28. Arcranna 2
The arc current that has flowed through 8 passes through the cylindrical body 27 and flows through the arc drive coil 29 to the fixed electrode 21. The arc drive coil 29 generates a magnetic flux by the arc current flowing through the arc drive coil 29. This magnetic flux is applied to the arc runner 2
The arc between the movable arc contact 8 and the movable arc contact 26 is rotated in an arc-extinguishing gas atmosphere to extinguish the arc. In this case, since the fixed main contact 22 is shielded from the arc by providing the shielding material 1, the heat of the arc is not irradiated to the fixed main contact. Therefore, the surface of the fixed main contact is not melted by the arc heat and does not become rough, so that the contact resistance between the fixed main contact 22 and the movable main contact 25 does not increase.

[0006]

As described above, according to the present invention, since the surface of the fixed main contact is protected from the arc by the shielding material attached to the arc runner, the surface of the fixed main contact does not become rough.

[Brief description of the drawings]

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

FIG. 2 is a side sectional view of an upper half of a conventional gas circuit breaker.

[Explanation of symbols]

Reference Signs List 1 shielding material, 20 container, 21 fixed electrode, 22
Fixed main contact, 23 fixed arc contact, 24 movable electrode, 25 movable main contact, 26 movable arc contact, 2
7 cylindrical body, 28 arcrunner, 29 arc drive coil, 30 arc-extinguishing gas

Claims (1)

[Claims] 1. A container filled with an arc-extinguishing gas, a fixed electrode having a fixed main contact and a fixed arc contact attached to the container, a movable electrode supported by the container and having a movable main contact and a movable arc contact. Attached to the fixed electrode,
A gas circuit breaker having an arc runner on the inner periphery and a cylindrical body made of a conductive material having an arc driving coil attached on the outer periphery, wherein the movable arc contact and the other end of the shielding member having one end attached to the arc runner; A gas circuit breaker which is disposed between a fixed main contact and a sprayed film formed by spraying an arc-resistant material or an insulating material on a surface of the shielding material facing the movable arc contact.