JPS60198023A - Vacuum breaker - Google Patents

Abstract

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

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a vacuum circuit breaker.

[Technical background of the invention and its problems]

FIG. 1 is a sectional view of a vacuum valve of a general vacuum circuit breaker. Both ends of the insulating container 3 are closed by a fixed flange 1° and a movable flange 2 to form a vacuum container. The fixed electrode is the main electrode 8. It consists of a coil electrode 10 and is fixed to a fixed conductive rod 5. Similarly, on the movable side, the main electrode 9. Coil electrode 11
is fixed to the movable conductive rod 6 and further attached to the movable flange 2 via a bellows 7. A magnetic field 12 is generated between the coil electrodes 10° 11,
It is well known that it can even evacuate two major currents. FIG. 2 shows this electrode portion in detail. Opposing electrodes in a vacuum circuit breaker must be butt-to-edge; therefore, there is a high possibility that they will be pressed together with a strong force, or that they will be welded by a preceding arc at the time of closing or an arc caused by contact chatter.

To prevent this, the main electrode 9 is generally combined with the electrode 13 and the contact 14. This contactor 14 is
In order to make the main two contacts brittle or soft to prevent welding, an alloy containing impurities in copper is often used, for example.

Since a vacuum circuit breaker interrupts current by utilizing the excellent arc extinguishing ability of vacuum, the surface condition of the electrode has a very large effect on the interrupting performance. Contact materials generally contain impurities, and these impurities are more easily contaminated by oxygen, for example, than copper, which is the main material of the electrode, and are difficult to remove when combined with oxygen. Such contamination of the contact material greatly affects the breaking performance. For this reason, various treatments are being considered. Processing is only meaningful after the vacuum valve is assembled. That is, even if the material is treated before assembly, it will be contaminated with air before it is evacuated, so after assembly, a discharge treatment is performed by applying a voltage, or a treatment is performed by applying an electric current at °C and an arc.

However, in the vacuum circuit breaker of the present application, a magnetic field is applied to stabilize the arc and obtain high interrupting performance.

In order to make the magnetic field work effectively, there is a slit 1 in the electrode.
5 must be provided. It is difficult to remove contamination near the slit 15 or inside the slit.

Furthermore, since the area of the contact is quite large if it is the same size as the electrode, it is difficult to remove all contaminants because of increased processing time.

In addition to the above-mentioned problems with the contact, such as air contamination, there are various other problems such as surface roughness during machining, and these will be collectively referred to as contact defects. Unless these defects are removed by some kind of treatment as described above, the vacuum circuit breaker will not achieve its full performance.

One way to deal with the above defects is to reduce the total amount of defects by making the contact smaller than the t-electrode. However, the general C two contactor has a property that the arc is difficult to spread due to the impurities contained therein, and the vacuum circuit breaker electrode C2 of the present application, which utilizes a vertical magnetic field, was unsuitable.

[Purpose of the invention]

The present invention has a high withstand voltage, can cut off a large current, and has high reliability. The purpose is to provide a vacuum circuit breaker.

[Summary of the invention]

In the present invention, the outer diameter of the contact is less than 1/2 of the outer diameter of the electrode, and chromium has a vapor pressure almost the same as that of copper.

The contact material is made by alloying it with copper in any ratio.
After assembling the vacuum valve, the inside of the vacuum container is under vacuum for 100 minutes.
Arc treatment is performed with a current of 0.00 A or less to blow chrome and copper to the electrode and cover the electrode surface.
The object of the present invention is to provide a true circuit breaker characterized in that the entire electrode is equivalent to a copper-chrome contact.

[Embodiments of the invention]

The present invention will be described in detail below using the drawings.

FIG. 3 shows an embodiment of the present invention. The contactor 14, which is mainly made of steel and chrome, has a radius less than 1/2 of the electrode 13, and the Qi pole 13 is provided with a slit 15.

Such Makabe pulp is assembled once under vacuum 31 and then subjected to one near-arc treatment as shown in FIG.

In the electrode with the configuration shown in FIG. 3, there is a certain defect in the contact 14C.

Since it is less than 1/4 of the conventional method, defect processing can be reduced accordingly. However, defects also occur in the electrode 13 made of copper during assembly of the vacuum valve, and these defects must also be removed. When Jin.

Defects such as copper surface contamination are relatively easy to remove by heat treatment in a vacuum, so they can all be removed by a heating process that is performed several times during the valve assembly process. However, it is difficult to remove defects in the contactor 14 by heat treatment, especially since chromium has a strong affinity for oxygen.

Therefore, after the heat treatment, the contact portion is subjected to arc treatment. In a vacuum arc, the discharge is maintained by the metal vapor supplied from the electrodes, so a large amount of metal vapor blows out from the scratch guard and flies in all directions.

Most of this is deposited electrically. The new surface produced by vapor deposition has a clean metallic surface and is free from contamination since it is evaporated in a vacuum. Therefore, the arced □
This causes the material to spread from the contactor part to other parts.

At this time, the part of the electrode 13 other than the contactor 14 is only covered by a defect, and the defect will not disappear, but as mentioned above, if this part is made of copper, heat treatment can eliminate the defect. At the very least, it is possible to create a new surface layer without any defects.

Furthermore, since chromium has almost the same vapor pressure as copper, the vapor supplied from the cathode contains both chromium and copper, as shown in Figure 4, and the newly formed layer 17 is copper/chromium! It is composed of two parts.

If this material is another material, such as copper or tungsten, selective evaporation of only copper will occur, and the vapor 16 that will be scattered will be only copper. The new rounded layer 17 becomes a copper layer, and the original structure of copper/tungsten at the center of the electrode and copper at the periphery remains unchanged. However, in the case of copper and chrome, the entire surface is covered with a new layer of steel and chrome. Moreover, since chromium has a high withstand voltage, this treatment can produce an electrode with high withstand voltage.

In addition, by making the contactor 14 small in diameter, the contactor 14
1-, there is no need to make slits, and it is possible to eliminate slits in contacts that often have defects.

By performing the arc treatment with a current of 10,000 A (AC effective value) or less, the arc 18 is dispersed in the contact portion, so that the surface of the contact can be uniformly evaporated without causing particularly severe melting, and even newer Since almost no arc is transferred to the formed layer 17, it is possible to perform the new layer without damaging it.

Furthermore, since the contactor is arranged at the center of the electrode, the arc is generated from the center when firing, so that the near arc always ignites stably, which is convenient in terms of breaking performance.

As explained above, in the structure of this example, most of the area of the electrode is made of copper with few defects, and by arc treatment, the entire area is changed to a new layer of copper chromium with high withstand voltage. A large number of contacts can be handled. Furthermore, since the area of the contact is small, handling of defects in the contact is simple (1): quick and relatively easy (C): a highly reliable vacuum circuit breaker can be provided. Furthermore, since the electrode treated in this way is the same as one made entirely of copper and chromium, the arc spreads uniformly over the entire surface of the electrode due to the action of the vertical magnetic field, making the electrode suitable for large-capacity vacuum circuit breakers. be able to.

Furthermore, since chrome also has a high voltage resistance, the entire electrode can be made to have a high voltage resistance.

Although this arc treatment is effective no matter when it is performed after assembly, it is most effective if it is performed in the final process, before or after the vacuum valve is shut off.

Furthermore, as another example, the shape of the contact may not be circular, but may be shaped to match the slit 15 as shown in FIG. It goes without saying that the same applies to those divided into a large number of small pieces.

〔Effect of the invention〕

According to the present invention, it is possible to cut off a large amount of Wk with high withstand voltage.

A reliable vacuum circuit breaker can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional vacuum circuit breaker, FIG. 2 is a perspective view of a conventional electrode structure, and FIG. 3 is a perspective view of an electrode structure of the present invention.
FIG. 4 is an explanatory diagram of the new phenomenon, and FIG. 5 is a plan view of an electrode showing another embodiment. 9... Electrode, 13... Pa 1 pole. 14...Contact, 15...Slit. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) A pair of main electrodes disposed in a vacuum container so as to be able to come into contact with and separate from them;
In this vacuum valve having a coil electrode fixed to the back surface of the main electrode, the material of the contact fixed to the surface of the main electrode is an alloy material η) mainly composed of copper and chromium, and the contact 1. A vacuum circuit breaker, characterized in that the outer diameter of the main electrode is 1/2 or less of the outer diameter of the main electrode, and the vacuum circuit breaker is interrupted two or more times with an alternating current of 10.000 A or less. (2. In the thing described in claim 1. A vacuum circuit breaker characterized in that the contactor is circular. (3) In the thing C2 described in claim 1. Contact A vacuum circuit breaker characterized by having multiple children.