JPH0677417B2 - Arc extinguishing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an arc extinguishing device applied to a circuit breaker, an electromagnetic contactor or the like.

[Background technology]

In order to guide the arc generated at the contact part to the arc-extinguishing chamber with the opening / closing operation of the contact part such as a circuit breaker, a U-shaped self-induction magnetic field normally formed by the contact and the contact of the contact part is formed. Alternatively, a blowout coil or the like is positively provided at the contact portion to magnetically drive the arc away from the contact. The extinction of the arc thus driven has been conventionally performed by the means shown in FIGS. 8 to 12.

That is, FIG. 8 shows a cooling arc extinguishing method using an insulating material, and the arc extinguishing chamber 51 adjacent to the contact portion 50 is made of an insulating material. The contact part 50 is formed in a U-shape that forms a self-induced magnetic field. 52 is an arc. In this case, the arc-extinguishing chamber 51 can be configured by a case such as a circuit breaker, which has an advantage that the configuration is extremely simple and the cost is low. However, since the magnetically driven arc is simply cooled in the arc extinguishing chamber 51, there is an advantage that the arc voltage is low and the interruption capability is low.

FIG. 9 and FIG. 10 show a cooling method using a magnetic material, in which a U-shaped magnetic material (usually an iron plate) 53 is arranged in an arc extinguishing chamber 51, and its opening side faces the contact portion 50. There is.
In this structure, the magnetic flux from the arc 52 passes through the magnetic body 53, and the magnetic flux 53 strongly attracts the arc 52, and the magnetic body 53 can rapidly cool the arc 52. Moreover, the structure is relatively simple. However, since the arc 52 is short-circuited by the magnetic material 53, the effect of extending the arc 52 (increase in positive column voltage) cannot be obtained, and a high arc voltage cannot be obtained.

FIG. 11 and FIG. 12 show a division method using a grid 56, in which a plurality of grid plates 55 each having a cutout 54 for attracting the arc 52 are stacked by a connecting plate 57 at intervals.
56 is formed, and this grid 56 is arranged in the arc-extinguishing chamber 51. This one attracts the arc 52 by the magnetic effect and divides the arc 52 by the grid plate 55 as shown in the figure, so that a high arc voltage is generated due to an increase in the cathode drop voltage due to the division. However, compared with FIGS. 9 and 10, the magnetic attraction is small, and the structure is complicated and large, and the assembly is complicated and the cost is high.

[Object of the Invention]

An object of the present invention is to provide an arc extinguishing device which is easy to assemble and which can obtain a high arc voltage.

[Disclosure of Invention]

The arc-extinguishing device of the present invention is formed in a U-shape by a plurality of flat plate-shaped magnetic bodies each having a concave portion for arc suction cut out at the front end, and a pair of side plates and a back plate to form each of the magnetic bodies. A narrow groove that is formed on the outer surface of the back plate in parallel with each other so that a plurality of cut portions to be inserted are arranged in a direction parallel to the side plate along the outer surface of the back plate and exposes a part of the magnetic body. Is formed in a direction parallel to the side plate at the center of the inner surface of the back plate, and an insulator for generating a pyrolysis gas by arc heat is provided.

According to the configuration of the present invention, since the magnetic body having the recess concentrates the magnetic flux around the arc on the magnetic body, the arc is attracted to the recess of the magnetic body and the arc is pressed against the insulator provided on the front side of the magnetic body. The arc is cooled, and at the same time, the pyrolysis gas is generated from the insulator to cool the arc. When the arc enters the narrow groove due to the attraction of the magnetic material, a large amount of pyrolysis gas is generated in the narrow groove to further increase the cooling drop, and the gas pressure in the narrow groove increases to extinguish the arc. be able to. Furthermore, because the arc is extended by attracting the magnetic material, the arc voltage is increased, and because part of the magnetic material is exposed in the narrow groove, the arc can be divided by the magnetic material, and the cathode drop voltage due to the division increases. The voltage can be further increased. The arc extinguishing ability can be improved by these actions. Moreover, since the magnetic body can be attached to the insulator by inserting the magnetic body into the cut portion of the insulator, the assembly is easy.

Embodiments A first embodiment of the present invention is shown in FIGS.
That is, this arc-extinguishing device includes a magnetic body 3 made of metal such as a plurality of flat iron plates having a recessed portion 2 for arc suction cut out at a front end thereof, a pair of side plates 13 and 14, and a back plate. A plurality of notches 16 formed in a U shape by 15 and into which the magnetic body 3 is attached are arranged parallel to each other so as to be arranged in a direction parallel to the side plates 13 and 14 along the outer surface of the back plate 15. An insulator 5 which is formed on the outer surface and which exposes a part of the magnetic material 3 in a direction parallel to the central side plates 13 and 14 of the inner surface of the back plate 15 and which generates pyrolytic gas by arc heat. It has and.

Reference numeral 1 denotes a contact portion where the arc X is generated, which is composed of a fixed contact 10 having a fixed contact 9 and a movable contact 12 having a movable contact 11, and the fixed contact 10 and the movable contact 12 face each other in parallel. As a result, a U-shaped electric path is formed, and the generated arc X is magnetically driven toward the concave portion 2 of the magnetic body 3 by the self-induction magnetic field. In this case, the fixed contact 9 and the movable contact 11 of the contact portion 1 are opened and closed in parallel with the side plates 13 and 14 of the insulator 5. As a result, the arc X enters the concave portion 2 of the magnetic body 3 in parallel with the side plates 13 and 14 by the opening / closing operation of the contact portion 1. These magnetic bodies 3 and the like are arranged in an arc extinguishing chamber (not shown).

The arc extinguishing operation of the arc extinguishing device of this embodiment will be described. An arc X is generated at the contact portion 1 by the opening / closing operation of the contact portion 1. The arc X is magnetically driven by the self-induced magnetic field of the contact portion 1 and enters between the side plates 13 and 14. A magnetic flux generated around the arc X passes through the magnetic body 3, and the magnetic flux attracts the arc X toward the back plate 15 having the recess 2. as a result,
Since the arc X extends, the voltage of the positive column increases and the arc voltage increases. Further, since the arc X is attracted to the magnetic body 3, it approaches the back plate 15. In this case, the insulator 5 may be formed of a thermoplastic resin, but it is effective because it is formed of a resin material that generates a pyrolysis gas by arc heat and the arc X is cooled and extinguished by the pyrolysis gas. Is. Also Ark X
Since the arc X is pressed against the back plate 15 by the magnetic attraction, the cooling effect is high. Further, since the arc X is pushed into the narrow groove 18 by the narrow groove 18, a large amount of pyrolyzed gas is generated in the narrow groove 18 to enhance the cooling effect, and the pressure in the narrow groove 18 increases, so that pressure extinction The effect is added. Further, since the arc X is divided by a plurality of magnetic bodies 3, a high arc voltage can be obtained due to an increase in cathode drop voltage.

The following table describes preferred examples of the insulator 5 that generates pyrolysis gas.

In this table, polymethylpentene resin is Structural formula characterized by (R is C _n H _{2n + 1} n = 1,2,3 ...)
Of polymethylmethacrylate resin, The polybutylene terephthalate resin is a structural resin characterized by Refers to a resin of the structural formula characterized by, polycarbonate resin, It refers to a resin with a structural formula characterized by.

Here, ΔHcpd is the sum of the energies of all the bonds that make up the compound, ΔHc is the sum of the energies of bonds that form carbon in the thermal decomposition reaction of the compound, and ΔHvol is the volatile matter (thermal decomposition gas). The sum of binding energies, △ H
_CH is the sum of the CH bond energies that produce hydrogen as a pyrolysis gas. Further, ΔHvol / ΔHcpd indicates the ease of generation of volatile matter, and ΔH _CH / ΔHcpd indicates the ease of generation of hydrogen gas. As can be seen from this table, the polymethylpentene resin and the polymethylmethacrylate resin used in the present invention are more likely to generate a gas, particularly hydrogen gas, as a thermal decomposition product during the thermal decomposition reaction than conventional materials. .

The value of the binding energy (unit: Kcal / mol) is CC:
83, C = C: 147, CH: 99, CN: 70, C = N: 213, CO: 84,
C = O: 171, CF: 105, C-Cl: 78, C-Si: 69, NH: 93, OH:
110, Si-O: 88, And

Further, FIG. 4 shows arc voltages of various insulators 5. In the figure, Q ₁ is polymethylpentene, Q ₂ is polymethylmethacrylate, Q ₃ is polybutylene terephthalate, and Q ₄ is a comparative ceramic. In addition, 1KA peak, A
g-W 40%, 3m / s, 2K Gauss. It can be seen that the arc voltage of Q _1, Q ₂ is superior high cut off performance from FIG.

In this embodiment, the number of magnetic bodies 3 may be one.

A second embodiment of the present invention is shown in FIGS. 5 and 6.
That is, in this arc extinguishing device, the exhaust hole 17 is formed in the narrow groove 18 in the second embodiment.

By forming the exhaust hole 17, the arc gas is
Since it is exhausted more, the arc X is further propelled in the traveling direction by the pressure difference between the inside and the outside of the narrow groove 18, and the arc X is moved toward the narrow groove 18
The cooling effect can be further enhanced by pressing it to the deepest part.

FIG. 7 shows a modified example in which a plurality of exhaust holes 17 are formed in a staggered arrangement.

In the present invention, the contact portion 1 may be provided with an arc traveling plate that drives the arc X so as to approach the magnetic body 3. Further, the arc extinguishing performance can be further improved by selecting the insulator 5 that generates a large amount of pyrolysis gas and has excellent insulating performance.

〔The invention's effect〕

According to the arc-extinguishing device of the present invention, since the magnetic material having the recess concentrates the magnetic flux around the arc on the magnetic material, the arc is attracted to the recess of the magnetic material and the arc is provided on the front side of the magnetic material. The arc is cooled by pressing against the arc, and the pyrolysis gas is generated from the insulator to cool the arc. When the arc enters the narrow groove due to the attraction of the magnetic material, a large amount of pyrolysis gas is generated in the narrow groove to further enhance the cooling effect, and the gas pressure in the narrow groove increases to extinguish the arc by pressure. be able to. Furthermore, because the arc is extended by attracting the magnetic material, the arc voltage is increased, and because part of the magnetic material is exposed in the narrow groove, the arc can be divided by the magnetic material, and the cathode drop voltage due to that division becomes large. The voltage can be further increased. The arc extinguishing ability can be improved by these actions. Further, since the magnetic body can be attached to the insulator by inserting the magnetic body into the cut portion of the insulator, there is an effect that the assembly is easy.

[Brief description of drawings]

FIG. 1 is a perspective view of the first embodiment of the present invention with a magnetic body removed, FIG. 2 is a cross-sectional view thereof, FIG. 3 is a cutaway perspective view, and FIG. 4 is arc voltage of various insulators. Fig. 5 is a characteristic view, Fig. 5 is a perspective view of the second embodiment with the magnetic material removed, Fig. 6 is its rear view, Fig. 7 is a rear view of its modification, and Fig. 8 is a cross section of a conventional example. FIG. 9 is a sectional view of another conventional example, FIG. 10 is a sectional view of the magnetic substance, FIG. 11 is a sectional view of yet another embodiment, and FIG. 12 is a side view of the grid. DESCRIPTION OF SYMBOLS 1 ... Contact part, 2 ... Recessed part, 3 ... Magnetic material, 4 ... Part, 5 ... Insulator, 13,14 ... Side plate, 15 ... Back plate, 16 ... Notch part, 18 ... Fine groove

Claims (2)

[Claims] 1. A U-shaped member composed of a plurality of flat plate-shaped magnetic members each having a recess for arc suction formed in a notch at a front end thereof, and a pair of side plates and a back plate, into which each of the magnetic members is inserted. A plurality of notches are formed on the outer surface of the back plate parallel to each other so as to be aligned in a direction parallel to the side plate along the outer surface of the back plate, and a narrow groove exposing a part of the magnetic body is formed on the back plate. An arc extinguishing device, comprising: an insulator formed at a center of an inner surface of the plate in a direction parallel to the side plate and generating a pyrolytic gas by arc heat. 2. The arc-extinguishing device according to claim 1, wherein the insulator has an exhaust hole penetrating from a bottom portion of the narrow groove to a back surface of the back plate.