JPS6367724B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode for a vacuum breaker and, more particularly, to an electrode for a vacuum breaker which can be easily tripped.

Generally, Cu or Cu alloy, which has good conductivity, is used as the electrode in vacuum shields and disconnectors.

However, although Cu or Cu alloys have excellent electrical conductivity, they have problems with withstand voltage characteristics, making them unsuitable for interrupting high-voltage currents. In order to eliminate this drawback, so-called Fe alloys, which have excellent withstand voltage characteristics, are used for these fixed electrodes and movable electrodes. However, although fixed electrodes and movable electrodes made of such Fe alloys have voltage resistance characteristics and are suitable for cutting off high-voltage currents, part of the contact surface of the electrodes rises to abnormal temperatures due to arcs generated when they open and close. A welding phenomenon occurs in which parts are partially melted and fused together. This phenomenon affects repulsive force due to current concentration, reduction in contact force due to electromagnetic force, and wear and tear on the contact surface due to chattering during closing. After the electrodes are welded, their tensile strength is so high that they cannot be removed using conventional operating mechanisms, which necessitates a large operating mechanism, leading to the problem of increasing the size of the vacuum shield and disconnector. It was hot.

The present invention was made in view of the above problems, and
The purpose of this invention is to provide an electrode for a vacuum shield or disconnector, which uses an Fe alloy with low tensile strength to construct the electrode, and can easily cut off current even when the electrode is welded.

Hereinafter, the present invention will be explained in detail with reference to the drawings showing one embodiment thereof.

Reference numeral 1 shown in FIG. 1 is a vacuum container made of an insulating material. This vacuum vessel 1 houses a fixed rod 3 provided with a fixed electrode 2 and a movable rod 5 having a movable electrode 4 that can be moved up and down via a bellows 8, thereby forming the electrodes of the vacuum chamber and disconnector. There is. fixed electrode 2,
The movable electrode 4 includes disc-shaped arc drive parts 6, 6, and concentric disc-shaped contact parts 7, 7 protruding from approximately the center of the arc drive parts 6, 6.

Fig. 2 shows the electrodes of a vacuum chamber disconnector with a simplified electrode configuration.A fixed electrode 2 and a movable electrode 4 are configured in the shape of a disk, and are installed on a fixed rod 3 and a movable rod 5, and are connected to a vacuum vessel 1. will be stored in.

The movable rod 5 provided with the movable electrode 4 is housed via a bellows 8 so as to be vertically movable.

Furthermore, the configurations of the fixed electrode 2 and the movable electrode 4 can be selected depending on the purpose of use.

By the way, in order to reduce the tensile strength of the contact parts 7, 7, the fixed electrode 2, and the movable electrode 4, one or all of them may be made of, for example, Fe,
It is an Fe alloy whose main components are at least two of Cr, Ni, and Mn, and is formed by press-molding and sintering a metal powder that partially or completely has an austenitic structure at room temperature.

When the metal powder is, for example, austenitic stainless steel made of Fe, Ni, and Cr, it is possible to form an Fe alloy that is particularly non-magnetic and has good voltage resistance.

Pressure forming and sintering of metal powder has a great effect on the tensile strength, so as shown in Figures 3 and 4, the density is 6.2 g/cm ³ or less and the pressure is 4.5 t/cm ² . and mold it. This makes its tensile strength
25Kg/ ^mm2 or less. Moreover, this pressure forming eliminates the need for post-pressing after sintering.

Sintering after forming is carried out in one or both of the following atmospheres: vacuum, which is advantageous for degassing, hydrogen, which is advantageous for reduction, and decomposed ammonia.
Perform at a temperature of ℃ or higher and a holding time of 10 minutes or more. From the viewpoint of yield, this sintering condition is, for example,
It is desirable to shorten the holding time by increasing the temperature, such as holding it at 1000°C for 5 minutes, but this requires a high-temperature furnace, so the temperature is generally about 2/3 of the melting point.

As shown in FIG. 5, the contact parts 7, 7, fixed electrodes 2, and movable electrodes 4 constructed in this way have a tensile strength of less than half of the conventional tensile strength of 50 Kg/mm ² , that is, 25 Kg/mm ² or less. becomes. As a result, even if welding occurs between the contact parts 7 and 7 or between the electrodes 2 and 4, these welds can be cut extremely easily using a conventional operating device (not shown), and can be done in a vacuum. It is possible to reduce the size of the disconnector.

Although the embodiment in which the contact portions 7, 7 or the electrodes 2, 4 are made of an Fe alloy having an austenitic structure has been described above, the present invention is not limited thereto, and the second embodiment described below It can also be configured.

In this second embodiment, in order to reduce the tensile strength of the contact portions 7, 7, fixed electrode 2, and movable electrode 4, one or all of them may be
An Fe alloy whose main components are at least two or more of Fe, Cr, Mn, Al, S, and Se, and a metal powder whose part or all has a ferrite structure at room temperature is press-formed under specified conditions. Moreover, it is constructed by sintering. In this case, for example, if a metal powder of ferritic stainless steel made of Fe and Cr is pressure-formed and sintered, it is a magnetic material and is suitable as the contact parts 3, 3 or electrodes 2, 4 for the vertical magnetic field, and the first embodiment It is possible to construct a material with better electrical conductivity than the austenitic stainless steel mentioned above.

In this second example, the predetermined conditions regarding pressure forming and sintering of the metal powder are the same as those in the first example described above, and the conditions are similar to those shown in FIGS. 3 and 4. .

As shown in FIG. 6, the contact parts 7, 7 or electrodes 2, 4 constructed in this manner have a tensile strength of 25 Kg/mm 2 or ^{less, compared to 45 Kg/mm 2 in} the prior art. Therefore, the contact portions 7, 7 or the electrodes 2, 4 which are suitable for longitudinal magnetic fields and have good conductivity can be formed of a magnetic material, and these contact portions 7,
7 or the electrodes 2 and 4 have the same effects as those described in the first embodiment.

As described above, the present invention provides an electrode for a vacuum shield breaker in which a fixed electrode and a movable electrode are housed in a vacuum container so as to be able to be freely approached and separated, and in which the fixed electrode and the movable electrode have an austenite structure or a ferrite structure. Made by pressure forming and sintering metal powder
Since the electrode is made of Fe alloy into a predetermined shape and used as a vacuum shield or disconnector, it is easy to manufacture an electrode with low tensile strength and no post-processing is required after sintering, which causes welding between the electrodes. Even in such cases, the current can be turned on and off very easily using a conventional operating device without the need for a powerful and large operating device. Therefore, it is possible to downsize the vacuum shield and disconnector. Moreover, in the second invention, it is possible to construct an electrode according to the purpose of use, such as an electrode for a vertical magnetic field, using a magnetic material with good electrical conductivity.

[Brief explanation of drawings]

1, 2, 3, 4, 5, and 6 show an embodiment of the present invention, and FIGS. 1 and 2 are cutaway front views showing essential parts, and FIG. Figure 3 shows the relationship between the density and tensile strength of Fe alloys, and Figure 4 shows the relationship between Fe alloy density and tensile strength.
Drawing showing the relationship between alloy density and forming pressure, No. 5
6 are drawings showing the results of a tensile test. 1... Vacuum vessel, 2... Fixed electrode, 3... Fixed rod, 4... Movable electrode, 5... Movable rod, 6
...Arc drive part, 7...Contact part, 8...Bellows.

Claims (1)

[Scope of Claims] 1. In an electrode for a vacuum shield breaker in which a fixed electrode and a movable electrode are housed in a vacuum container so as to be able to be freely approached and separated, the fixed electrode and the movable electrode are selected from Fe, Cr, Ni, and Mn. A metal powder having an austenitic structure consisting of one or more of
Made of Fe alloy and has a density before sintering of 6.2
An electrode for a vacuum breaker, characterized in that it is less than g/cm ³ . 2. In the electrode of a vacuum shield and disconnector in which a fixed electrode and a movable electrode are housed in a vacuum container so as to be able to be freely approached and separated, the fixed electrode and the movable electrode are made of Fe, Cr, Mn, Al,
Constructed from an Fe alloy obtained by pressure forming and sintering a metal powder having a ferrite structure consisting of one or more selected from S and Se, and having a density before sintering of 6.2 g/cm ³ or less. Electrodes for vacuum shields and disconnectors featuring: