JPS6174222A - vacuum circuit breaker - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a vacuum circuit breaker, and particularly to the configuration of its electrodes.

[Background of the invention]

As shown in FIG. 2, a conventional vacuum circuit breaker includes a vacuum vessel 1 consisting of an insulating cylinder 2 and end plates 3, 4, and conductive rods 6, 7 passing through the end plates 3, 4. A pair of electrodes 8 and 9 are connected to conductive rods 6 and 7 within the vacuum chamber.
It is configured by being fixed to. One conductive rod 7 is hermetically sealed to the end plate 4 via a bellows 10. The conductive rod 6 is directly attached to the end plate 3 and hermetically sealed.

A cylindrical metal vapor shield 11 is disposed around the outer periphery of the electrodes 8.9 and is attached to the middle part of the insulating cylinder 12 by a shield support 12. When the conductive rod 7 is driven upward in the axial direction by an operating mechanism (not shown), the electrodes 8 and 9 come into contact, and the vacuum circuit breaker is brought into a closed state. Further, by driving the conductive rod 7 downward in the axial direction, the vacuum circuit breaker shifts to the open state.

As disclosed in Japanese Unexamined Patent Publication No. 57-9019, electrode materials containing low melting point metals such as Bi, Pb, Te, and Se are used as electrodes for vacuum circuit breakers. The main components of the electrode material are Cur Ag and CO.

Although Cr and the like are used, Bi, Pb, etc. do not form a solid solution with these and precipitate at grain boundaries. Therefore, Hi and PB ooze out during brazing during the manufacture of vacuum circuit breakers and during heating and exhausting, resulting in a disadvantage that the withstand voltage performance of the electrodes is reduced. In addition, Se and Te form intermetallic compounds with the main component materials, but there is a peculiar phenomenon in which the main component materials become liberated near 500C, and the main component materials appear on the electrode surface in the form of whiskers. This also lowers the withstand voltage performance of the electrode.

As described above, in the conventional technology, it is difficult to bring out the inherent voltage resistance performance of the electrode.

[Purpose of the invention]

An object of the present invention is to provide a vacuum circuit breaker with good voltage resistance performance.

[Summary of the invention]

The electrode of the present invention forms a dense film of high melting point metal on the electrode surface that does not react with low melting point metal, so that the low melting point metal does not seep onto the electrode surface during the manufacture of vacuum circuit breakers, and whiskers are generated in the electrode main component material. prevent.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIG.

The conductor te7, the electrode 9 fixed to the conductive rod 7, is connected to the CO-
-3e alloy, and C' is vapor-deposited on its surface to form a dense film 13. Cr, Co, A
Since it only reacts with g+Se, the Ag whiskers produced from CO-g-F3e are shielded by a dense Cr film and do not protrude to the electrode surface. As a result, the conventional drawback of a drop in withstand voltage between the electrodes is solved, and a vacuum circuit breaker with good withstand voltage performance can be provided.

As an electrode material for vacuum circuit breakers, Cu −? The present invention can also be easily applied to metals containing Ag as the main component, to which Bi and Pb are added. That is, with these materials, Bi and PB ooze out during brazing and heating, but this can also be blocked by the vapor deposited film of C.

In these cases, the film material is (:, o
, Ni, Fe and other iron elements, as well as Ta and Me.

Refractory metals such as W exhibit high withstand voltage characteristics and are effective.

Furthermore, in the embodiment shown in FIG. 1, a material containing 3e has been described, but the present invention can also be applied to a material containing Te instead of se.

By the way, the characteristics of the film need to be dense, and a film formed by plating is porous and may not be able to fully achieve the effects of the present invention. A method using sputtering is suitable.

〔Effect of the invention〕

As explained above, in short, the present invention is an electrode containing a low melting point metal, in which a high melting point metal film is formed on the electrode surface, so that the low melting point metal oozes out and is repaired.
Since this film prevents the generation of whiskers of the main component metal, a vacuum circuit breaker with good withstand voltage can be provided.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a conventional vacuum circuit breaker. 1... Vacuum container, 6, 7... Conductive rod, 8, 9...
Electrode, 1st brother 2nd prisoner

Claims (1)

[Claims] 1. At least one integrated electrode is provided in a vacuum container so as to be openable and closable, and is attached to a conductive rod, and at least one of the electrodes has Cu, Ag, etc. as a main component, A vacuum circuit breaker composed of a low melting point metal such as Bi, Pb, Te, Se, etc., in which a film of a metal with a higher melting point than the main component material such as Cu, Ag, etc. is formed on the surface of the electrode. A vacuum circuit breaker with the following characteristics. 2. Co, Fe, Ni, Cr, Mn on the surface of the above electrode
2. The vacuum circuit breaker according to claim 1, characterized in that the vacuum circuit breaker is formed by forming a film of any one of , Ta, Mo, and W. 3. Co, Fe, Ni, Cr, Mn,
The vacuum circuit breaker according to claim 1, characterized in that a film of any one of Ta, Mo, and W is formed by vapor deposition or sputtering.