JPS63133420A - Arc extinguisher - 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] The present invention relates to an arc extinguishing device applied to a circuit breaker, an electromagnetic contactor, etc.

[Background technology]

In order to guide the arc generated in the contact part of a circuit breaker etc. to the arc extinguishing chamber when the contact part opens and closes, a self-induced magnetic field is usually created by the U-shaped structure made up of the contact point and the contact element of the contact part. Alternatively, a blowout coil or the like is actively provided at the contact portion to magnetically drive the arc in a direction away from the contact. Extinguishing the arc driven in this manner has conventionally been carried out by the means shown in FIGS. 4 to 8.

That is, FIG. 4 shows a cooling arc extinguishing method using an insulating material, in which an arc extinguishing chamber 51 adjacent to the contact portion 50 is made of an insulating material. The contact portion 5o forms a self-induced magnetic field.
It is structured in the form of letters. 52 is an arc. This device has the advantage that the arc extinguishing chamber 51 can be constructed from a case such as a circuit breaker, and the construction is extremely simple and the cost is low.

However, since the magnetically driven arc 52 is simply cooled in the arc extinguishing chamber 51, there is a drawback that the arc voltage is low and the breaking ability is low.

Figures 5 and 6 show a cooling method using a magnetic material, in which a U-shaped magnetic material (usually an iron plate) 53 is placed inside the arc extinguishing chamber 51, and its opening side faces the contact portion 5°. ing. In this case, the magnetic flux caused by the arc 52 passes through the magnetic body 53, the arc 52 is strongly attracted by this magnetic flux, and the arc 52 can be rapidly cooled by the magnetic body 53. Furthermore, the structure is relatively simple. However, since the arc 52 is short-circuited by the magnetic material 53, the elongation effect of the arc 52 (increase in positive column voltage) cannot be obtained, and there is a drawback that a high arc voltage cannot be obtained.

7 and 8 show a division method using an arc extinguishing grid 56, in which a plurality of grid plates 55 with cutouts 54 for attracting the arc 52 are stacked at intervals by a connecting plate 57 to form an arc extinguishing grid. 56, and this arc extinguishing grid 5
6 is arranged in the arc extinguishing chamber 51. This device attracts the arc 52 by magnetic effect and also divides the arc 52 by the grid plate 55 as shown in the figure, so that a high arc voltage is generated due to the increase in cathode drop voltage caused by the division. However, compared to FIGS. 5 and 6, the magnetic attraction force is small, and the structure is complicated and large, resulting in high cost.

[Purpose of the invention]

An object of the present invention is to provide an arc extinguishing device that has a simple structure and can obtain a high arc voltage.

[Disclosure of the invention]

The arc extinguishing device of the present invention includes a magnetic material formed in a U-shape by a back plate and a pair of side plates, and one of the pair of openings on the back plate side is an arc entry opening and the other is an exhaust opening. , an insulator that covers the inside of the magnetic material and generates pyrolysis gas by arc heat, and an exhaust hole connected to the exhaust opening on the exhaust opening side of the back plate of the magnetic material It is characterized by having a notch formed therein.

According to the configuration of this invention, the arc can be extended by attraction of the arc by the magnetic material, the arc can be cooled by pyrolysis gas from the insulator, and the exhaust opening is formed by the exhaust notch. At the same time, the evacuation area for arc gas and pyrolysis gas can be increased, so that arc expansion and cooling can be promoted. Therefore, the structure is simple and high arc voltage can be obtained.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 3. That is, this arc extinguishing device is formed into a U-shape by a back plate 1 and a pair of side plates 2.3, and one of the pair of openings on the back plate 1 side is an arc entry opening 4 and the other is an exhaust opening. 5, and an insulator 7 that covers the inside of the magnetic material 6 and generates pyrolysis gas by arc heat,
An exhaust opening 5 is provided on the exhaust opening 5 side of the back plate l of the magnetic body 6.
An exhaust notch 8 is formed which is continuous with the exhaust gas.

A contact portion 9 is disposed in the arc entry opening 4, and the contact portion 9 includes a fixed contact 11 having a fixed contact 10, and a movable contact 1 having a movable contact 12 that contacts and separates from the fixed contact IO.
It consists of 3.

The magnetic material 6 is made of metal such as iron.

The insulator 7 is made of an insulating material, particularly a polymer material, which has electrical insulation properties and generates pyrolysis gas by arc heat. Preferred examples are shown in the table below.

In this table, polymethylpentene resin, polybutylene resin, and polymethyl methacrylate resin are applicable to the present invention, and polybutylene terephthalate resin and polycarbonate resin are conventionally used as arc-extinguishing chamber materials and are used for comparison. This is shown in .

In this table, polymethylpentene resin is characterized by the structural formula (R is an alkyl group and Cn Hza*++
refers to resins with nwa 3 in n-1,2,3''・), polybutylene resins refer to resins with a structural formula characterized by n-1 of the above structural formula, and polymethyl methacrylate resins are characterized by Polybutylene terephthalate resin refers to a resin with a structural formula characterized by . Bonate resin refers to a resin with a structural formula characterized by .

Here, ΔHcpd is the sum of the energies of all the bonds constituting the compound, ΔHc is the sum of the energies of the bonds that produce carbon in the thermal decomposition reaction of the compound, ΔHvo
1 is the sum of energy of bonds that produce volatile matter (pyrolysis gas), and ΔHe-1l is the sum of energy of C-H bonds that produce hydrogen as pyrolysis gas. Also ΔHvol/
ΔHcpd indicates the ease with which volatiles are generated, and Δt(c
-w/ΔHcpd indicates the ease with which hydrogen gas is generated. As seen in this table, the polymethylpentene resin, polybutylene resin, and polymethyl methacrylate resin used in the present invention generate gases, especially hydrogen gas, as thermal decomposition products during thermal decomposition reactions, compared to conventional insulating materials. It turns out it's easy.

゛The value of binding energy (unit: Kcal/ma
t) is CC: 83, CC: 147, CH: 99
, C-N near 0, C=N: 213, C-0: 84,
C-o: 171, C-F2O3, C-(,1 near 8,
C-3t: 69, N-H: 93, O-H: l l
It is 01Q 7727.

Moreover, FIG. 3 shows the arc voltage when a short circuit test was performed using various insulating materials.The short circuit test was performed by discharging a capacitor. That is, both ends of the charged capacitor were short-circuited with a circuit breaker via a current-limiting resistor, and the arc voltage between the contacts was measured when the capacitor was cut off. In this case, the peak value of the short circuit current is IKA, and the contact material is Ag-W (W40χ
), and in the diagram 0 where the contact opening speed is 3 m/s, Q
is polymethylpentene, Qt is polymethyl methacrylate, Q3 is polybutylene terephthalate, and Q4 is ceramic. From this figure, it can be seen that the arc voltages of Q+ and Qz are high and the breaking performance is excellent.

Also, the above! When the edge material is filled with 5 to 35% by weight of glass fiber, a reinforcing effect can be obtained to prevent cracks from occurring in the insulator due to thermal deterioration caused by heating and one cycle of opening and closing of the contact portion. In addition, the glass fiber is
The reason why the content is limited to 35% by weight is because if it is less than 5% by weight, the reinforcing effect of the glass fiber will be lost, and if it is more than 35% by weight, the effect of thermal decomposition of the insulator will be reduced and the moldability of the glass fiber will be poor. This is because the damage to the mold becomes severe.

(Left below) In this arc extinguishing device, when an excessive current flows through the contact portion 9 and the movable contact 13 is disconnected by a trip mechanism of a circuit breaker, etc., the arc extinguishing device is constructed between the movable contact 12 and the fixed contact 10 as shown in Fig. 2. An arc 14 is generated as shown in FIG. Arc generated 1
4, magnetic flux generated around the arc 14 is concentrated on the magnetic body 6, and magnetic flux interlinking with the arc 14 is generated in the arc entry opening 4. This magnetic flux causes a Lorentz force to act on the arc 14, and the arc 14 is attracted to the back plate 1 side of the magnetic body 6, causing the arc 14 to expand as shown in FIG. Further, when the insulator 7 is heated by the arc 14, pyrolysis gas is generated from the insulator, and the arc 14 is cooled by the pyrolysis gas. Furthermore, the arc gas and pyrolysis gas accompanying the generation of the arc 14 are exhausted from the exhaust opening 5, but since the exhaust opening 5 has the exhaust area, the exhaust area is large, and therefore it is easy to exhaust, so that the arc 14 is effectively is stretched in the direction of
This increases the arc voltage.

According to this embodiment, the arc 14 can be extended by attraction of the arc 14 by the magnetic body 6, and the insulator 7
The arc 14 can be cooled by the pyrolysis gas from the pyrolysis gas, and since the exhaust notch 8 and the exhaust opening 5 can widen the exhaust area of the arc gas and the pyrolysis gas, the expansion and cooling of the arc 14 is facilitated. can be promoted. Therefore, the structure is simple and high arc voltage can be obtained.

〔Effect of the invention〕

According to the arc extinguishing device of the present invention, the arc can be extended by attraction of the arc by the magnetic material, and the arc can be cooled by the pyrolysis gas from the insulator. Since the exhaust area of arc gas and pyrolysis gas can be increased together with the opening, expansion and cooling of the arc can be promoted. Therefore, the structure is simple and high arc voltage can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an embodiment of the present invention, Fig. 2 is a sectional view thereof, Fig. 3 is an arc voltage characteristic diagram of various insulators, Fig. 4 is a sectional view of main parts of a conventional example, and Fig. 5 6 is a sectional view of the main part of another conventional example, FIG. 6 is a sectional view of the magnetic material, FIG. 7 is a sectional view of the main part of another conventional example, and FIG. 8 is a front view of the arc extinguishing grid. . DESCRIPTION OF SYMBOLS 1... Back plate, 2.3... Side plate, 4... Arc entry opening, 5... Exhaust opening, 6... Magnetic material, 7
...Insulator, 8...Exhaust notch Fig. 2

Claims (1)

[Claims] A magnetic body formed in a U-shape by a back plate and a pair of side plates, with one of the pair of openings on the back plate serving as an opening for arc entry and the other as an opening for exhaust, and the inside of this magnetic body being coated. and an insulator that generates pyrolysis gas by arc heat.
An arc extinguishing device characterized in that an exhaust notch that is continuous with the exhaust opening is formed on the exhaust opening side of the back plate of the magnetic material.