JPS585929A - Electrode for 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 The present invention relates to an electrode for a vacuum breaker, and particularly to an electrode structure suitable for improving current carrying performance and preventing welding during short-time current passing.

The vacuum breaker V shown in FIG. 1 is made into a vacuum container IA' with terminal plates 3 and 4, an insulating tube 2, and a bellows 5, and inside it is a fixed electrode 6 fixed to a fixed holder 7 and a movable holder 9.
A movable electrode 8 and an intermediate shield 10 are provided which are fixed to the.

In order to improve the breaking performance of these electrodes, parallel magnetic field type electrodes that generate a magnetic field parallel to the arc are increasingly used. As shown in Fig. 2, its structure includes an arc electrode 11 that generates and extinguishes an arc, a reinforcing plate 12 that increases the mechanical strength of the arc electrode 11, a coil electrode 13 that allows current to flow in the circumferential direction, and a reinforcing plate 12. A resistor 14 that supports the holder 9 and limits the current flowing from the holder 9 to the arc electrode 11.
It consists of The structure shown in FIG. 2 is obtained by overlapping each of these parts in the direction of arrow 15 in FIG. 3 and joining their contact parts.

As shown in FIG. 3, the electric current flowing through each part flows from the holder 9 to the center of the coil electrode 13, flows around the circumference of the coil electrode 13, and flows from the protrusion 13b to the arc electrode 13.
Flows into 1. Since the arc electrode 11 is restricted by the grooves 188 to 18d, it flows only in the radial direction and reaches the contact portion 11a. When viewed from the arc electrode 11 side, the current path at this time is as shown by the dotted line in FIG. 4, and a magnetic field H parallel to the arc is generated on the surface of the arc electrode 11 in four areas. When an arc 16 is generated in the contact portion 11a, it spreads from near the center where the magnetic field is very weak to four areas where the magnetic field is strong, as shown in FIG. 4, and is extinguished there.

As mentioned above, parallel magnetic field type electrodes spread the arc over the entire surface of the electrode to prevent local melting and improve the breaking performance, but even with such electrodes, the performance is affected by the material used. is unavoidable. In other words, if a CLl-Pb alloy or a CLI-Br alloy is used as the material for the arc electrode 11, since these alloys are relatively soft materials when current is applied, there will be no contact at the electrode contact portion 11a. Because it is easy to use and has high conductivity, it has excellent current carrying performance. However, since these alloys have low melting points, when an arc occurs, the electrode surface melts and a large amount of metal vapor is generated, making it difficult to shut off. Also, the material is Cu-pe,
When made into alloys such as Cu-co, these materials have excellent arc resistance and withstand voltage performance, so
Although large currents such as A can be interrupted, these materials are hard, so if there is a slight eccentricity, they will not easily deform even if a large contact force is applied, resulting in uneven contact, and the electrode contact part 1
1a tends to cause point contact, and these alloys also have relatively low electrical conductivity, so in line with performance test standards, 40 kA and 6
When a large current such as 3kA is applied, heat generation is significant.
In the worst case, a phenomenon occurs in which the contact portion 11a melts and welds, and the movable electrode 8 becomes unable to separate from the fixed electrode 6. Therefore, there is no problem if there is a material that is as soft as CLJ-pb and has similar arc resistance (:' u -CO alloy, but in reality there is no material that satisfies both.
It was not possible to fully satisfy both current carrying performance and breaking performance at the same time.

An object of the present invention is to provide an electrode for a vacuum breaker that is excellent in both current carrying performance and breaking performance.

In order to improve the breaking performance of the electrode of the present invention, a material with a high melting point such as a Cu-Co alloy is used for the arc electrode, but these materials are hard and cause uneven contact at the contact part of the arc electrode. Point contact is likely to occur. In order to obtain a state close to surface contact at the contact portion, the contact portion or other portions may be deformed so as to obtain a state close to surface contact.

Therefore, the above problem can be solved by using a soft and easily deformable material on the back side of the contact portion.

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

FIG. 5 shows the movable electrode 19, the arc electrode 20 and the contact part 20.
A is made of a material with excellent arc resistance such as a Cu-Co alloy between the arc electrode 20 and the contact part 20a (:
A damper electrode 21 that is soft and has high conductivity, such as a u-pb alloy or an Ag alloy, is arranged.

If the damper electrode 21 is placed, the contact portion 20
Even if a causes uneven contact, the arc electrode 20 and the contact part 20
The damper electrode 21 sandwiched between the contact portion 20a and the contact portion 20a is deformed, and a state close to surface contact is obtained at the contact portion 20a. Therefore, even if the contact part 20a is made of a material that is hard and has a slightly low conductivity, the contact part 20a forms a surface contact, so the current-carrying area becomes large, and the temperature rise at the contact part 20a is alleviated.
There is no chance of the contact parts melting or welding when energized. In this way, by providing the damper electrode 21 on the back side of the contact part 20a, the contact part 20a can always maintain surface contact, so it has good current carrying performance, and the electrode material is made of a material with good arc resistance. Since it can be used, it is possible to improve both the current conduction and cutoff performance.

In the above description, it is assumed that the diameter of the contact portion 20a and the diameter of the damper electrode are the same, but they do not necessarily have to be the same, and even if the diameter of the damper electrode is made smaller as shown in FIG. Damper electrode 21 or damper electrode 2 as in
The same effect as described above can also be obtained by providing a plurality of grooves 22 on both the blades of the contact portion 1 and the contact portion 20a.

As described above, according to the present invention, by arranging the damper electrode made of an easily deformable material on the back side of the contact part, the damper electrode is deformed even if uneven contact occurs, and the contact part is always Since it is possible to obtain a state close to surface contact, there is no local melting, and welding resistance can be obtained. Therefore, it is possible to provide an electrode with excellent current conduction performance and cutoff performance.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of a conventional vacuum breaker, Fig. 2 is a side sectional view of a conventional electrode, Fig. 3 is an exploded perspective view thereof, Fig. 4 is an explanatory diagram of the state of the magnetic field, and Fig. 5 is a booklet. A side sectional view of the electrode of the invention,
FIG. 6 is a side sectional view of an arc electrode portion showing another embodiment of the invention, and FIGS. 7 and 8 are perspective views of electrodes shown as other embodiments of the invention. 20... Arc electrode, 21... Contact portion, 21... Damper electrode, 22a to 22h... Groove. Horse II! I also 3rd mouth 5th mouth "mouth plan, 7'Jj, 8th mouth"

Claims (1)

[Claims] 1. A vacuum breaker consisting of a pair of electrodes that are housed in a vacuum container and have a holder that extends to the outside and that can be freely brought into and out of contact with the other electrode, and a contact portion that protrudes from the corresponding surface of the electrode toward the other electrode, in which the contact portion and An electrode for a vacuum breaker, characterized in that a damper electrode is provided between the electrode and the damper electrode.