JPH0230130B2 - DENRYOKUKAIHEISOCHI - Google Patents

Description

[Detailed Description of the Invention] This invention provides a power switching device that switches and closes current;
In particular, it relates to its arc extinguishing mechanism.

Main applicable switches of this invention include electromagnetic contactors, wiring switches, and disconnectors.

First, an example of a conventional electromagnetic contactor will be described with reference to FIG. Generally, an electromagnetic contactor is symmetrical, so FIG. 1 shows only one side of the contactor in cross section. In the figure, 1 is a mounting base, 2 is a fixed core that is laminated with silicon steel plates on this mount, 3 is a movable core that is placed opposite to the fixed core 2 and is also laminated with silicon steel plates, and 4 is the movable core 3 and the fixed core. 2 is an operating coil that applies a driving force to attract the magnets against a tripping spring (not shown), and 5 is a crossbar having a square window, the lower end of which holds the movable iron core 3.
6 is a movable contact inserted into a corner window of the cross bar 5 and held by a push spring 7; 6A is a movable contact provided on this movable contact 6; 8 is a movable contact facing the movable contact 6; A fixed contact 8A is provided on the fixed contact 8 and is capable of coming into contact with and separating from the movable contact 6A. 9 is a terminal screw for connecting the electromagnetic contactor main body with an external circuit, 10 is a base for attaching the fixed contact 8, 11 is an interphase barrier, 11A is a cover that covers the top surface of the contacts 6 and 8, and inside it is a Arc 12 generated between fixed contact 8A and movable contact 6A
A metal arc extinguishing plate 13 made of magnetic material is provided to extinguish the arc.
and shows the mounting state of the fixed contact 8A. This metal arc-extinguishing plate 13 is configured as a U-shaped frame that covers the fixed contact 8A and is erected in parallel to the contact and separation direction of both contacts 6A and 8A, and is inserted into a portion close to the fixed contact 8. A notch is provided to allow the
4 is the tip of this notch.

Next, the operation will be explained. When the operating coil 4 is demagnetized, the movable core 3 is separated from the fixed core 2 by a tripping spring (not shown), the crossbar 5 also assumes the state shown in FIG. 1, and the fixed contact 8A and the movable contact 6A are separated and both Arc 1 between contacts 6A and 8A
2 occurs, but this arc 12 is caused by the metal arc extinguishing plate 13
As a result, the arc is extinguished at the current zero point, and the current is suddenly cut off.

The arc extinguishing process of the arc 12 in this conventional electromagnetic contactor will be explained in more detail with reference to FIG. 3, which shows a cross section of the arc extinguishing chamber.

The arc 12 generated between the movable contact 6A and the fixed contact 8A is attracted by the magnetic metal arc-extinguishing plate 13 and is elongated into an extended arc 12A.
When the arc is stretched like this extended arc 12A, the arc voltage increases, so dielectric breakdown occurs between the movable contact 6A and the metal arc-extinguishing plate 13, and between the metal arc-extinguishing plate 13 and the fixed contact 8. And arc 1
2A is divided into two arcs 12B and 12C,
These two arcs 12B, 12 at the current zero point
C is extinguished.

In a conventional electromagnetic contactor that extinguishes the arc by such a process, the arc voltage is low because the extension of the arc 12A is restricted by the presence of the metal arc extinguishing plate 13, and therefore the arc voltage is low. Dielectric breakdown was less likely to occur between the metal arc extinguishing plate 13 and the fixed contact 8, and the arc 12A was less likely to be divided into two arcs 12B and 12C. As described above, in the conventional electromagnetic contactor, it is difficult to break the arc 12, so it is not possible to obtain excellent cutting performance.Furthermore, electric field concentration occurs in the metal arc extinguishing plate 13, and the tip portion 14 has poor thermal conductivity. Since arc 12C is generated in the process, these arcs have become the main cause of further deterioration of the shear cutting performance.

In order to eliminate the above-mentioned drawbacks and improve the shearing performance, a power switchgear according to a prior invention has been proposed. According to this, a U-shaped projection is formed at a portion of the metal arc-extinguishing plate adjacent to the fixed contact, and this U-shaped projection is made to protrude oppositely into the contact/separation space of the contact.
This prior invention will be explained below based on the drawings. Fourth
In the figures to FIG. 6, 13A is a U-shaped protrusion provided on the metal arc-extinguishing plate 13. Figures 5 and 6
As shown in the figure, the arc 12 is connected to the fixed contact 8A and the movable contact 6.
To explain the process from when the arc is generated between the contacts 6A and 8A until it is extinguished, the arc 12 generated between the contacts 6A and 8A is first attracted to the magnetic metal arc extinguishing plate 13, and the state of the arc 12A is and then the U-shaped protrusion 13 of the metal arc extinguishing plate 13 as shown in the arc 12D.
It is curved and extended along A, and the arc voltage is increased. Furthermore, dielectric breakdown occurs between the movable contact 6A and the U-shaped protrusion 13A of the metal arc-extinguishing plate 13, and between the U-shaped protrusion 13A of the metal arc-extinguishing plate 13 and the fixed contact 8. As shown in FIG. 6, it is divided into two arcs 12E and 12F. When the arc 12 is divided into two in this way, a current flows through the U-shaped protrusion 13A of the metal arc-extinguishing plate 13.
The divided arcs 12E, 12F are further driven by the magnetic field created by this current, and the arcs 12G, 12F are further driven by the magnetic field created by this current.
It is extended outward like 2H, and the arc is extinguished at the current zero point.

However, in the preceding power switchgear as described above, the driving force of the arc 12 is insufficient, so
Due to the long time required for the arc 12 generated between both contacts 6A and 8A to be divided into two arcs 12E and 15F, and the small number of divided arcs 12, it is difficult to improve the shearing performance too much. I couldn't do it.

This invention was made in order to eliminate the drawbacks of the conventional and preceding ones as described above, and includes a fixed contact, a fixed contact joined to the fixed contact, and a fixed contact provided opposite to the fixed contact. a movable contact joined to the movable contact and capable of coming into contact with and separating from the fixed contact; A first metal arc-extinguishing plate made of a magnetic material and having a U-shaped protrusion protruding opposite to the contact/separation space, and a magnetic It is an object of the present invention to provide a power switchgear with excellent shearing performance by including a second metal arc-extinguishing plate made of a metal arc-extinguishing plate.

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

FIG. 7 is a perspective view showing a metal arc-extinguishing plate according to an embodiment of the present invention. A first metal arc-extinguishing plate made of a magnetic material has a U-shaped protrusion 13A protruding opposite to the space near the space, and 15 is in movable contact with the first metal arc-extinguishing plate 13. This is a second metal arc extinguishing plate made of a magnetic material and provided between the second metal arc extinguishing plate and the second metal arc extinguishing plate.

Next, the process from when the arc 12 is generated between the contacts 6A and 8A until it is extinguished will be explained with reference to FIGS. 8 and 9. As in the case of the previous example, the arc 12 generated between the fixed contact 8A and the movable contact 6A is first attracted to the first metal arc-extinguishing plate 13 made of a magnetic material, passes through the state of the arc 12A, and then U of the first metal arc extinguishing plate 13 like the arc 12D
It is curved and stretched along the letter-shaped protrusion 13A, and the arc voltage is increased. In the case of this invention, due to the presence of the magnetic second metal arc extinguishing plate 15, the arc
Since D is strongly attracted to this second metal arc-extinguishing plate 15, the arc voltage becomes higher than in the case of the preceding example. Furthermore, dielectric breakdown occurs between the movable contact 6A and the U-shaped protrusion 13A of the first metal arc extinguishing plate 13, and between the U-shaped protrusion 13A and the fixed contact 8. As shown in the figure, it is divided into two arcs 12E and 12F. When the arc 12 is divided into two in this way, the first metal arc extinguishing plate 1
Since a current flows through the U-shaped protrusion 13A of No. 3, the divided arcs 12E and 12F are further driven by the magnetic field created by this current, and the arcs 12G and 12
The arc 12G is extended outward like H, and the arc 12G is the second
Two more arcs 12 are caused by the metal arc extinguishing plate 15.
I, 12J, the arc is extinguished at the current zero point, and the current is briefly cut off.

Since the arc is extinguished as described above, in the electromagnetic contactor according to the present invention, the arc 12 is easily divided at the U-shaped protrusion 13A of the first metal arc extinguishing plate 13, and after being divided, U-shaped protrusion 13A
The first metal arc extinguishing plate 13 is driven at high speed by the magnetic field created by the current flowing through the arc, and is ultimately divided into three arcs 12I, 12J, and 12H, which can be quickly extinguished. can. Moreover, at this time, electric field concentration on the first metal arc-extinguishing plate 13 does not occur as in the conventional example shown in FIG. , because the arc voltage of the arc 12D increases due to the presence of the second metal arc-extinguishing plate 15 having magnetism, this arc 12D becomes two arcs 12E,
The time required to separate into 12F is shortened, and extremely excellent shear cutting performance can be exhibited.

The present invention is also applicable to a fixed contact 8 having a different shape as shown in FIG. 10. In this case, since the fixed contact 8 is U-shaped, both contacts 6A, Arc 12 generated between 8A
The magnetic driving force is strengthened, and the shearing performance is further improved.

Further, even if the second metal arc-extinguishing plate 15 having a shape as shown in FIG. 11 is used, the same effect as that in FIG. 7 can be expected.

In this case, there is a feature that thermal damage to the interphase barrier 11 due to the arc 12 can be reduced.

Furthermore, when the fixed contact 8 is provided with the protrusion 8B as shown in FIG. Since the distance between the fixed contact 8 and the non-protruding part of the fixed contact 8 is smaller than the distance between the fixed contact 8 and the non-protruding part, the probability that the arc 12 will occur on the fixed contact 8 is increased, and the interphase barrier 1
Thermal damage of No. 1 can be further reduced. Note that the shape of the protrusion 8B does not have to be cylindrical as shown in FIG. 12, and may be, for example, prismatic or hemispherical.

In addition, in the above explanation, only an example is described in which the present invention is applied to a power switching device that uses magnets to open and close contacts, that is, an electromagnetic contactor. It is obvious that it can also be applied to other power switchgear.

As described above, according to the present invention, there is a fixed contact, a fixed contact joined to the fixed contact, a movable contact provided opposite to the fixed contact, and a fixed contact joined to the movable contact. , a movable contact that can come into contact with and separate from the fixed contact, and a U-shape that is erected in parallel to the contact and separation direction of both of the contacts and protrudes opposite to the contact and separation space at a portion adjacent to the fixed contact. A first metal arc-extinguishing plate having a shaped protrusion and made of a magnetic material, and a second metal arc-extinguishing plate made of a magnetic material and provided between the first metal arc-extinguishing plate and the movable contact. This has the effect of providing a power switchgear with excellent shearing performance.

[Brief explanation of drawings]

Figure 1 is a partial sectional view showing a conventional electromagnetic contactor.
Fig. 2 is an enlarged perspective view of the metal arc-extinguishing plate and fixed contact shown in Fig. 1, Fig. 3 is an explanatory diagram for explaining the arc-extinguishing process in a conventional electromagnetic contactor, and Fig. 4
The figure is a perspective view showing a metal arc-extinguishing plate according to a prior example, FIGS. 5 and 6 are explanatory diagrams for explaining the arc-extinguishing process in the prior example, and FIG. 1. A perspective view showing the second metal arc-extinguishing plate; FIGS. 8 and 9 are explanatory diagrams for explaining the arc-extinguishing process in the electromagnetic contactor using the metal arc-extinguishing plate of FIG. 7; 11 is a block diagram showing the main parts of an electromagnetic contactor according to another embodiment of the present invention; FIG. 11 is a perspective view showing first and second metal arc-extinguishing plates according to another embodiment of the present invention; FIG. 12 is a perspective view showing a fixed contact according to another embodiment of the invention. In the figure, 6 is a movable contact, 6A is a movable contact, 8 is a fixed contact, 8A is a fixed contact, 12, 1
2A to 12J are arcs, 13 is a first metal arc-extinguishing plate, 13A is a U-shaped projection, and 15 is a second metal arc-extinguishing plate. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A fixed contact, a fixed contact connected to the fixed contact, a movable contact provided opposite the fixed contact, and a fixed contact connected to the movable contact and capable of coming into contact with and separating from the fixed contact. A movable contact and a U that is erected in parallel with the direction of contact and separation between the two contacts and protrudes from the contact and separation space at a portion adjacent to the fixed contact.
A first metal arc-extinguishing plate made of a magnetic material and having a letter-shaped projection, and a second metal arc-extinguishing plate made of a magnetic material provided between the first metal arc-extinguishing plate and the movable contact. Power switch equipped with.