JPH05805B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power switchgear, and particularly to an improvement of a commutator plate.

A conventional power switchgear is constructed as shown in FIGS. 1, 2, and 3.

In the figure, reference numeral 1 denotes an arc extinguishing arc box made of a heat-resistant material, in which a grid 2 and a commutation plate 3 made of magnetic metal are arranged and fixed in accordance with the number of phases of the electrical circuit to be opened and closed. 4 is a cross bar, 5 is a movable contact, 6 is a movable contact attached to both ends of the movable contact 5, 7 is a movable contact holder, 8
9 is a contact spring, and 10 is a stopper. The contact spring 9 is a stopper 10
is compressed and fixed between the lower part of the presser spring support 8 and the lower end of the presser spring support 8. It is assembled in contact with the

The movable contact is connected to a built-in well-known electromagnetic drive device via a contact spring 9.

Such contact mechanisms are provided symmetrically with respect to the A-A cross section, and are arranged corresponding to the number of phases of the electrical circuits that open and close in a direction perpendicular to the plane of the paper.

FIG. 2 is a perspective view schematically showing the current plate 3, movable contact 5, and movable contact 6, which are the main parts of FIG. When the part is enlarged, it looks like Figure 3 a and b.

In such a power switchgear, when the fixed contact 14 and the movable contact 6 are opened, one end of the arc generated between the two contacts is transferred from the movable contact 6 to the commutation plate 3, while the other end is transferred from the fixed contact to the commutator plate 3. Transfer from 14 to arc runner 15. The other end of the transferred arc moves toward the end on the arc runner 15, and finally the arc is extinguished between the vertical portion of the arc runner 15 and the commutator plate 3 facing thereto.

By the way, in the above-mentioned conventional power switchgear, when the opening/closing operation is repeated many times, the commutator plate 3 bends in the direction of the arrow shown in FIG. 2 due to thermal stress caused by arc heat. This phenomenon occurs because one end of the arc exists only on the side of the commutation plate 3 that faces the grid 2, and this side of the commutation plate 3 is strongly affected by the arc heat. It is thought that stress is generated and the commutation plate 3 is deformed in the direction of the arrow in the figure.

For this reason, if the deformation progresses beyond the gap between the commutation plate 3 and the grid 2, the commutation plate 3 will come into contact with the grid 2, causing a short circuit between the two, and the power switchgear will no longer be able to operate. There were flaws.

Therefore, an object of the present invention is to provide a power switchgear having a commutation plate structure that does not undergo thermal deformation.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 4 shows a heat-resistant thermal insulator 18 used as an embodiment of the present invention, and FIG. 5 is a configuration diagram showing a state in which the heat-resistant thermal insulator 18 of FIG. 4 is incorporated into a power switchgear. be.

In FIG. 5, 18 is a heat-resistant thermal insulator. A thermal insulator 18 is fixed to the arc box 1 between the commutator plate 3 and the grid 2, as shown in FIG.

With this configuration, even if thermal stress due to arc heat is generated in the commutator plate 3 due to repeated opening and closing of the power switchgear many times, the stress will not be applied to the portion of the arc box 1 between the tip of the commutator plate 3 and the grid 2. Since the heat-resistant thermal insulator 18 is fixed, deformation of the commutation plate 3 due to thermal stress will not occur.

In addition, in the above embodiment, an example is given in which the heat-resistant thermal insulator 18 is fixed to the arc box 1 between the tip of the commutation plate 3 and the grid 2.
However, the present invention is not limited to this, and for example, a heat-resistant thermal insulator integrated with the arc box may be provided between the commutation plate and the grid.

According to the invention described above, the heat-resistant thermal insulator 18 is fixed to the arc box 1 between the commutation plate 3 and the grid 2, thereby eliminating the inability to shatter due to deformation of the commutation plate. can do.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a partial cross section of a conventional power switchgear, Figs. 2 and 3 a are perspective views schematically showing a part of Fig. 1, and Fig. 3 b is a schematic diagram showing a part of Fig. 3 a. 4 and 5 are configuration diagrams showing an embodiment of the present invention. In the figure, 1 is an arc box, 3 is a commutation plate, 5 is a movable contact, and 6 is a fixed contact. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A grid that extinguishes an arc, one end close to the grid forms a free end, and the other end is fixed to an arc box and extinguishes the arc generated at the movable contact. In a power switchgear having at least a commutator plate that transfers the current to the grid, a heat-resistant thermal insulator is fixed to the arc box portion between the free end of the commutator plate and the grid facing the free end. A power switchgear characterized by: