JPH01206521A - Arc-extinguishing device - Google Patents

Abstract

PURPOSE:To improve arc-extinguishing property with a small size by coating the inner surface of a magnetic substance magnetically attracting an arc with an insulator generating a pyrolytic gas by the heat of the arc. CONSTITUTION:When an excessive electric current such as short-circuit current is passed through a contact point part 6, wherein a movable contact 10 is opened, for example, by tripping means of a circuit breaker, an arc 5 is generated between a fixed contact point 7 and a movable contact point 9. An insulator 4 is heated by the arc 5 to generate a pyrolytic gas, as the arc enters between the side plates 1 of a magnetic substance 3. This gas is mainly composed of hydrogen gas, which has an effect of cooling the arc 5 because of its high heat conductivity. Hence, a high arc voltage can be obtained to improve the arc-extinguishing property.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an arc extinguishing device applied to circuit breakers, electromagnetic contactors, and the like.

[Conventional technology]

An arc extinguishing device as shown in FIG. 4 has been proposed.

Does this arc extinguishing device have a U-shaped or ■-shaped notch 30? 3i number of magnetic plates 31 are laminated at intervals. 32 is a contact portion where an arc 33 is generated. The induction Ef generated by the arc 33 and flowing to the main character 31
The arc 33 is attracted to the notch 30 by the A field, and the magnetic plate 3
1, the arc 33 is cooled by heat transfer, or the arc 33 is divided by the fn temporary 31, and a cathode drop voltage is generated in each of the divided arcs 33. The voltage is increasing.

[Problem to be solved by the invention]

However, this arc extinguishing device has the disadvantage that it is necessary to increase the number of magnetic plates in order to obtain a high arc voltage, resulting in a complicated structure, an increase in size, and an increase in cost.

Therefore, an object of the present invention is to provide an arc extinguishing device that has a simple structure, can be made small, and can maintain high current limiting performance.

[Means to solve the problem]

The arc extinguishing device of the present invention includes a magnetic body that is formed into a substantially U-shape by a pair of side plates and a back plate and magnetically attracts an arc located between the pair of side plates parallel to the side plates to the back plate side; An insulator is provided on the inner surface of the magnetic material to generate pyrolysis gas by the heat of the arc.

[Effect]

According to the configuration of this invention, pyrolysis gas is generated from the insulator due to the heat of the arc attracted by the magnetic material, and the pyrolysis gas cools the arc, resulting in a high arc voltage and improved arc extinguishing performance. .

- [Example] A first example of the present invention will be described based on FIGS. 1 and 2. That is, this arc extinguishing device has a pair of side plates 1
and the back plate 2 to form a substantially U-shape, and magnetically attract the arc 5 located between the pair of side plates 1 parallel to the side plates 1 to the back plate 2 side, and a magnetic body 3 on the inner surface of the magnetic body 3. The insulator 4 is coated with an insulator 4 and generates pyrolysis gas by the heat of the arc 5.

In an embodiment, the n-type body 3 is made of a metal such as an iron plate. A contact portion 6 is provided in the opening of the cn-type body 3.

The contact part 6 consists of a fixed welder 8 having a fixed contact 7 and a movable contact 10 having a movable contact 9 that comes into contact with and separates from the fixed contact 7, and the opening/closing direction of the movable contact 10 is perpendicular to the back plate 2. It has become. When an excessive current such as a short-circuit current flows through the contact portion 6 and the movable contact lO opens, for example, due to a tripping means (not shown) of a circuit breaker, a voltage may be generated between the fixed contact 7 and the movable contact 9. Arc 5 occurs. The arc 5 generates a self-induced magnetic flux around the arc 5, and this self-induced magnetic flux flows into the magnetic body 3 and flows between the side plates 1 so as to interlink with the arc 5. Therefore, the arc 5 is magnetically attracted toward the back plate 2 by the Lorentz force. This allows arc 5
is stretched and the arc voltage increases.

The insulator 4 may be molded and fixed to the inner surface of the magnetic body 3 by mechanical means such as caulking or fitting, or may be heated by coating or vapor depositing an insulating material.

It is integrated into the magnetic body 3 by electrical or chemical means.

As the arc 5 enters between the side plates 1 of the magnetic body 3, the insulator 4 is heated by the arc 5 and generates pyrolysis gas. The main component of this pyrolysis gas is hydrogen gas, and since hydrogen gas has high thermal conductivity, it has the effect of cooling the arc 5. For this reason, the arc 5 increases the arc voltage by cooling, and the cross-sectional area of the arc decreases due to the thermal pinch effect, so the Lorentz force acting on the arc 5 becomes stronger, and the arc 5 further expands and presses the insulator 4. It will be done. By this pressing of the arc 5, the heat of the arc 5 is transferred to the insulator 4, and the arc 5 is cooled.

The insulator 5 is preferably an insulating material that generates as much hydrogen gas as possible when thermally decomposed by the heat of the arc 5 or the like. The table shows the amount of hydrogen gas generated when each insulating material is subjected to high frequency heating for about 1 second in a nitrogen gas atmosphere.

(Left below) The analysis method was to pass the thermally decomposed gas using a Curipoint pyrolyzer through gas chromatography. The sample amount was 0.1 cm, the thermal decomposition temperature was 764°C, and the thermal decomposition atmosphere was nitrogen gas. The analysis conditions were as follows: column: 1,000-nilar sieve-5A, column temperature: 50°C, detector: thermal conduction detector (TCD), sample vaporization chamber temperature: 100°C, detector temperature: 100°C, carrier gas: nitrogen gas. .

The table shows that melamine resin generates more hydrogen during thermal decomposition than other resins. Therefore, when melamine resin is used for the insulator 4, the amount of hydrogen gas generated by thermal decomposition of the insulator 4 is large, so the arc 5 can be effectively cooled and extinguished. For this reason,
A high arc voltage can be obtained with a simple configuration.

A second embodiment of the invention is shown in FIG. That is, in this arc extinguishing device, the opening/closing direction of the contact portion 6 is determined by the back plate 2 of the magnetic body 3.
It is parallel to The rest is the same as the first embodiment.

A third embodiment of the invention is shown in FIG. That is, in this arc extinguishing device, the back plate 2 of the substantially U-shaped magnetic body 3 is formed into a substantially square square shape. Therefore, there is an effect that the suction force acting on the arc 5 is strong (and a large amount of pyrolysis gas can be generated).

In addition, in each of the above embodiments, by forming one or more grooves intersecting the arc 5 on the surface of the insulator 4, the arc 5 extends along the grooves, so that the arc voltage is further increased due to the elongation effect. I can do things.

It is also conceivable to provide the back plate 2 with one or more arc gas exhaust ports formed through the insulator 4.

〔Effect of the invention〕

According to the arc extinguishing device of the present invention, pyrolysis gas is generated from the insulator due to the heat of the arc attracted by the magnetic material, and the arc is cooled by the pyrolysis gas, resulting in a high arc voltage and improved arc extinguishing performance. It has the effect of improving.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the first embodiment of the invention, FIG. 2 is a perspective view of the second embodiment, and FIG. 3 is a perspective view of the third embodiment.
FIG. 4 is a perspective view of a proposed example. 1... Side plate, 2... Back plate, 3... Magnetic material, 4...
・Insulator, 5... Arc, 6... Contact part Fig. 1 1! 2 Fig. 3 Fig. 4

Claims (2)

[Claims] (1) A magnetic body that is formed into a substantially U-shape by a pair of side plates and a back plate and magnetically attracts an arc located between the pair of side plates parallel to the side plates to the back plate side, and an inner side of the magnetic body. an insulator that is coated on the surface of the insulator and generates pyrolysis gas by the heat of the arc. (2) The arc extinguishing device according to claim (1), wherein the material of the insulator is melamine resin.