JPS63276841A - Electrode for vacuum circuit breaker - Google Patents

Abstract

PURPOSE:To increase withstand voltage between electrode shields so as to improve withstand characteristics by controlling the route of magnetic field produced at a coil electrode so as to control charged particles not to flow into the area with strong electric field. CONSTITUTION:Electrodes 4a, 4b are of the same structure. For the lower electrode 4b, a coil electrode 42 is disposed on the back of a main electrode 43, and on the back of the coil electrode is applied a disc-like conductor 12 of copper, silver or alloy including copper or silver of which conductivity is good is applied. Eddy current 13 flows in a large quantity to the disc-like conductor by magnetic field produced at the electrode 42, and the produced magnetic field becomes very small, while most magnetic field takes the route of passing along the surface of the disc-like conductor 12 to return. As a result, charged particles 11 do not reach a shield end where electric field is strong, discharge at the shield end is eliminated, deviation of arc from the space between electrodes is eliminated, and circuit breaking performance is greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum circuit breaker, and more particularly to an electrode structure provided with means for generating a magnetic field parallel to the interrupting mark.

[Conventional technology]

As shown in FIG. 2, the vacuum circuit breaker includes a pair of end plates 2a,
2b, and a pair of relatively movable electrodes 4a, 4b arranged in a vacuum container made of an insulating cylinder 1 made of glass or the like. Electrodes 4a and 4b are fixed to conductive rods 3a and 3b, respectively, conductive rod 3a is fixed through end plate 2a, and conductive rod 3b is axially movable through bellows 7 through end plate 2b. and hermetically sealed. Around the electrodes 4a and 4b, a metal shield 5 is installed with a shield support 6 to prevent metal vapor diffused from the arc ignited between the electrodes 4a and 4b from adhering to the inner wall of the insulator cylinder 1. Cylinder 1
is attached to the inner wall of the Incidentally, in order to interrupt large currents, vacuum circuit breakers employ a method of applying a magnetic field parallel to the arc to confine the arc within the electrode space. As a conventional example of this system, an electrode as shown in Japanese Patent Publication No. 54-22813 is generally used. That is, FIG. 3 shows an electrode 4b of this type, where 42 is a coil electrode, and 43 is a main electrode provided on the front side of this coil electrode 42 so as to overlap. Coil electrode 42
is a disk-shaped mounting base 42a that is attached to the conductive rod 3b.
A plurality of arms 42b of the same length extend at equal intervals in the radial direction around The arcuate portions 42c each draw an arc in the same direction, and the protrusion portions 42d that protrude toward the main electrode 43 from the tip of each of the arcuate portions 42c are electrically connected so as to maintain an appropriate gap from the protruding end. It is formed integrally with the As a result, the current 8 from the main electrode 43 is 42d→42c→42
The current flowing through path a and 42c will generate an axial magnetic field equivalent to the current flowing through exactly one turn of the coil.

However, this electrode has the following drawbacks.

That is, the magnetic field 10 generated between the electrodes follows a path that goes around the back sides of the electrodes 4a, 4b and returns, as shown in FIG. For this reason, the valence particles 11 generated with the generation of the arc drift along the lines of magnetic force toward the end of the shield 5 while performing rotational motion due to the magnetic field 1o, and discharge 12 at the portion of the shield end where the electric field is strong. happens. Due to this discharge, the arc 9 is transferred to the shield 5, causing an inability to interrupt the shield and impairing performance. To prevent this, the shield can be made longer and the distance between the corner on the back side of the coil electrode and the end of the shield can be increased. However, this method increases the size of the vacuum circuit breaker and is economically disadvantageous.

[Means for solving problems]

The above purpose is to control the path of the magnetic field generated by the coil electrode,
This is achieved by controlling valence particles so that they do not flow into areas where the electric field is strong.

[Effect]

In the present invention, in order to eliminate the drawbacks of the above-mentioned prior art,
A disk-shaped conductor with good conductivity is provided on the back side of the coil electrode,
The eddy current flowing through the disc-shaped conductor is used to weaken the magnetic field on the back side of the coil electrode, preventing valence particles generated between the electrodes from flowing to the back side of the coil electrode near the shield end. Discharge at the end is eliminated.

〔Example〕

The present invention will be explained in detail with reference to the embodiment shown in FIG.

In FIG. 1, the electrodes 4a and 4b are the same, so the electrode configuration will be explained with reference to the lower electrode 4b. A coil electrode 42 is arranged on the back side of the main electrode 43, and a disk-shaped conductor 12 made of copper, silver, or an alloy containing copper, silver, etc. and having good conductivity is attached to the back side of the coil electrode. When a disk-shaped conductor with good electrical conductivity is arranged on the back side of the coil electrode in this way, a large amount of eddy current 13 flows through the disk-shaped conductor due to the magnetic field generated by the coil electrode 42, and the magnetic field generated by this eddy current Since the direction is opposite to the direction of the magnetic field generated by the electrodes, the magnetic field 1o is canceled out in the disc-shaped conductor 12, and the magnetic field transmitted to the back side of the disc-shaped conductor is very small. As shown in FIG. 1, the path returns through the surface of the disc-shaped conductor 12. As a result, charged particles 11
The arc no longer reaches the edge of the shield where the electric field is strong, there is no discharge at the edge of the shield, the phenomenon of the arc deviating from the interelectrode space is eliminated, and the interrupting performance is greatly improved.

FIG. 5 shows another embodiment of the present invention, which has a structure in which a cylindrical coil electrode 44 is arranged on the back side of the main electrode 43 and a disc-shaped conductor 12 is arranged on the back side. The current 8 from 43 is 42d→42c→42d→disk-shaped conductor 12→
The current flowing in the path of the conductive rod 3b and flowing through 42c is exactly 1
An axial magnetic field equivalent to the current flowing through the coil of the turn is generated, and this magnetic field causes an eddy current to flow through the disc-shaped conductor 12, producing the same effect as the embodiment shown in FIG.

〔Effect of the invention〕

According to the present invention, the withstand voltage between the electrode and the shield is improved,
The phenomenon of the arc deviating from the inter-electrode space is eliminated, and the interrupting performance is improved.

[Brief explanation of the drawing]

Claims (1)

[Scope of Claims] 1. In a vacuum container consisting of at least one pair of end plates and an insulating cylinder, respective conductive rods are provided in a relatively movable state through the end plates, and each of the conductive rods In a vacuum circuit breaker electrode in which a main electrode and a coil electrode that generates an axial magnetic field are inserted at the tip of a rod, a disk made of copper, silver, or an alloy containing these with good conductivity is placed on the back side of the coil electrode. An electrode for a vacuum circuit breaker characterized by having a shaped conductor arranged thereon.