JPH0445927B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to an arc extinguishing device applied to circuits, disconnectors, etc. [Background Art] An arc extinguishing device as shown in FIG. 8 has been proposed. This arc extinguishing device includes a fixed contact 51 having a fixed contact 50, a movable contact 53 having a movable contact 52 that faces the fixed contact 51 and contacts and separates from the fixed contact 50, and the fixed contact 51. is connected in series with the fixed contact 50 and the movable contact 52, and is arranged on both sides of the contact state of the fixed contact 50 and the movable contact 52, so that when an excessive current flows through the movable contact 53, the movable contact 52 is fixed immediately after the excessive current and the contact is opened. Contact 50
The movable contact 5 interlinks with the arc 54 between
3 in a direction away from the fixed contact 51, and drives the arc 54 to extend in a direction away from the movable contact 52 and the fixed contact 50.
a pair of drive coils 55 that generate a
It is equipped with This arc extinguishing device uses a magnetic flux Φ passing between the centers of the drive coil 55 to open and close the movable contact 53 at high speed just before the movable contact 53 is opened by the opening/closing/trip mechanism of the circuit and disconnector. arc 54
extends toward the arc extinguishing grid 56 side. Further, the arc extinguishing grid 56 has a structure in which a plurality of magnetic plates 58 having notched grooves 57 for attracting the arc 54 are laminated at intervals, and the synergistic effect of splitting the arc 54 and cooling by the magnetic plates 58 suppresses the arc voltage. Extinguish the arc at a high level. However, in this arc extinguishing device, the drive coil 5
The magnetic flux Φ′ flowing in the opposite direction flowing outside of the movable contact 53 and the arc 54 that have opened is interlinked with each other, thereby inhibiting the opening of the movable contact 53 and the extension of the arc 54. . In addition, the notched groove 57 of the arc extinguishing grid 56 has a weak arc attraction force, and it is necessary to increase the number of magnetic plates in order to obtain a high arc voltage, which results in a complicated structure, larger size, and higher cost. There were flaws. [Object of the Invention] The object of the invention is to promote high-speed opening of the movable contact and extension of the arc, to have a strong arc suction force, to have a simple and compact structure, and to maintain high current limiting performance. An object of the present invention is to provide an arc extinguishing device that can. [Disclosure of the Invention] The arc extinguishing device of the present invention includes a fixed contact having a fixed contact, a movable contact having a movable contact facing the fixed contact and coming into contact with and separating from the fixed contact, and the fixed contact. The movable contact is connected in series with the fixed contact and is arranged on both sides of the contact state of the fixed contact and the movable contact, so that the movable contact is linked to the excessive current flowing through the movable contact, the movable contact, and the fixed contact. a pair of drive coils that generate a magnetic flux that drives an arc away from the movable contact and the fixed contact and causes an arc between the movable contact and the fixed contact to extend in a direction perpendicular to a direction in which the movable contact and the fixed contact face each other; A pair of side plates located on the side where the movable contact opens and separates, and a back plate that connects the side of the pair of side plates away from the movable contact and the fixed contact and is parallel to the opening/closing direction of the movable contact. U
The arc-extinguishing part is provided inside the magnetic body formed in the shape of a letter and coated with an insulator that generates pyrolysis gas by the heat of the arc. According to the configuration of the present invention, the magnetic body bypasses the magnetic flux flowing outside the drive coil, so that it does not link with the separated movable contactor and the arc. Also, since the arc is attracted by the U-shaped magnetic plate, the attraction force is large. Moreover, the arc is pressed against the insulator and cooled by thermal conduction, and the arc is cooled by pyrolysis gas generated by the arc being heated by the insulator, so the arc voltage can be increased to extinguish the arc. Therefore, high-speed opening of the movable contact and expansion of the arc are promoted, the arc attraction force is strong, the structure of the arc extinguishing device is simple and compact, and high current limiting performance can be maintained. Embodiment An embodiment of the present invention will be described based on FIGS. 1 to 6. That is, this arc extinguishing device includes a fixed contact 2 having a fixed contact 1, and a movable contact 3 that faces the fixed contact 2 and approaches and separates from the fixed contact 1.
A movable contact 4 having a
The movable contact 4 is linked to the excessive current flowing through the movable contact 4, the movable contact 3, and the fixed contact 1, and the movable contact 4 is driven in the direction away from the fixed contact 2, and the movable contact 3 A pair of drive coils 6 generate a magnetic flux that extends and drives an arc 5 between the fixed contact 1 in a direction perpendicular to the facing direction of the movable contact 3 and the fixed contact 1, and the drive contacts 4 of these drive coils 6. A pair of side plates 7 located on the side to be separated
The sides of the pair of side plates 7 that are remote from the movable contact 3 and the fixed contact 1 are connected, and the movable contact 4
arc extinguishing part 1, which is covered with an insulator 10 that generates pyrolysis gas by the heat of the arc 5, inside a magnetic body 9 formed in a U shape with a back plate 8 parallel to the opening/closing direction of the arc extinguishing part 1;
1. A U-shaped slit 13 is formed in the fixed contact 2 and the conductive plate 12 at the center thereof. Further, an arc travel plate 2a is formed continuously to the fixed contact 2 on the opposite side from the fixed contact 1. A power terminal 14 is provided at the end of the conductive plate 12 . The movable contactor 4 is connected to a load terminal (not shown) via a detection unit (not shown) that detects an excessive current in a circuit or a circuit breaker. In addition, the movable contactor 4 is a circuit or disconnector opening/closing/trip mechanism (not shown).
The opening/closing/trip mechanism is opened/closed by a handle (not shown) when the opening/closing/trip mechanism is set. The drive coil 6 is formed by bending both sides of the fixed contact 1 of the conductive plate 12 into a U-shape. As shown in FIG. 5, when current flows through the fixed contact 2 and the movable contact 4 in the direction of arrow A, a magnetic flux of Φ ₁ is generated between the drive coils 6. When this magnetic flux Φ ₁ interlinks with the excessive current flowing through the movable contact 4, the movable contact 4 receives a Lorentz force in the direction of separating it from the fixed contact 2. Therefore, as shown in Fig. 3, when an excessive current flows, the movable contact 4 instantly begins to open and close, and then opens and closes.
The trip mechanism is activated to mechanically open the contacts.
Further, the arc 5 generated by the opening of the movable contact 3 is also subjected to the Lorentz force on the power terminal 14 side due to the interlinkage of the magnetic flux Φ ₁ . Therefore, the arc 5 extends in the direction of the arc extinguishing part 11. The arc-extinguishing part 11 has a notch 15 formed in the side plate 7 , and the notch 15 is engaged with the drive coil 6 .
The magnetic body 9 is an example of a metal plate such as an iron plate.
The insulator 10 is molded and fixed to the inner surface of the magnetic plate by mechanical means such as caulking or fitting, or by heat, electricity, or chemical means such as coating or vapor deposition with an insulating material. It is integrated into. As shown in FIGS. 3 and 4, the magnetic flux generated around the arc 5 approaching the arc extinguishing part 11 is concentrated on the magnetic body 9, and the back plate 8 of the side plate 7 of the magnetic body 9
Since the arc 5 interlinks with the magnetic flux passing between the side plates 7 on the opposite side, the arc 5 crosses the back plate 8 as shown in FIG.
When the arc 5 is magnetically attracted to the side and expands, the voltage of the positive column increases and the arc voltage increases.
Further, the arc 5 is pressed against the insulator 10 on the front surface of the back plate 8, whereby the heat of the arc 5 is transferred and cooled. Furthermore, by selecting the following insulating material for the insulator 10, the arc 5 is rapidly cooled by the pyrolysis gas because the heat conductivity of the pyrolysis gas of hydrogen gas generated when heated by the arc 5 is high. By cooling the arc 5, the cross section of the arc is reduced and the current density is increased, thereby increasing the attraction force to the back plate 8 and increasing the arc voltage due to the cooling effect. Further, the arc extinguishing part 11 bypasses the magnetic flux Φ _{1 '} flowing outside the drive coil 6 shown in FIG. Since it is not linked to the magnetic flux, the movable contact 4 is not driven in a direction approaching the fixed contact 2, and the extension of the arc 4 is not inhibited. Preferred examples of the insulator 9 are shown in the table below.

[Table] 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. This is shown for the purpose of comparison. In this table, polymethylpentene resin is Structural formula characterized by (R is an alkyl group and C _o
H _2o+1 , n = 1, 2, 3...), and polybutylene resin refers to the resin where n = 1 in the above structural formula.
i.e. Polymethyl methacrylate resin refers to a resin with a structural formula characterized by Polybutylene terephthalate resin refers to a resin with a structural formula characterized by Polycarbonate resin refers to a resin with a structural formula characterized by It refers to a resin with a structural formula characterized by . Here, △Hcpd is the sum of the energies of all the bonds that make up the compound, △Hc is the sum of the energies of the bonds that produce carbon in the thermal decomposition reaction of the compound, and △Hvol produces volatiles (pyrolysis gas). The sum of the energies of the bonds, ΔH _CH , is the sum of the energies of the C-H bonds that produce hydrogen as a pyrolysis gas. Further, △Hvol/△Hcpd indicates the ease of generating volatile substances, and △H _CH /△Hcpd indicates the ease of generating hydrogen gas. 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. In addition, the value of binding energy (unit: Kcal/
mol) is C-C:83, C=C:147, C-H:
99, C-N: 70, C≡N: 213, C-O: 84, C
=O: 171, C-F: 105, C-Cl: 78, C-Si:
69, N-H: 93, O-H: 110,

〔Effect of the invention〕

According to the arc extinguishing device of the present invention, since the magnetic body bypasses the magnetic flux flowing outside the drive coil, it is not linked to the separated movable contactor and the arc. Also, since the arc is attracted by the U-shaped magnetic plate, the attraction force is large. Moreover, the arc is pressed against the insulator and cooled by thermal conduction, and the arc is cooled by pyrolysis gas generated by the arc being heated by the insulator, so the arc voltage can be increased to extinguish the arc. This not only promotes high-speed opening of the movable contact and extension of the arc, but also provides a strong arc suction force.The structure of the arc extinguishing device is simple and compact, and it also maintains high current-limiting performance. effective.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a side view thereof, FIG. 3 is a sectional view showing the state immediately after opening, FIG. 4 is a sectional view showing the opening state, and FIG. 6 is a perspective view showing the operating principle of the drive coil, FIG. 6 is an arc voltage characteristic diagram of various insulators, and FIG. 7 is a sectional view showing a circuit breaker to which an embodiment of the present invention is applied.
FIG. 8 is a perspective view of a proposed example. 1... Fixed contact, 2... Fixed contact, 3... Movable contact, 4... Movable contact, 5... Arc, 6...
...Drive coil, 7... Side plate, 8... Back plate, 9...
Magnetic material, 10...Insulator, 11... Arc extinguishing part.

Claims (1)

[Claims] 1. A fixed contact having a fixed contact, a movable contact facing the fixed contact and having a movable contact that contacts and separates from the fixed contact, and a movable contact that is connected in series to the fixed contact and has a fixed contact and a movable contact. the movable contactor being arranged on both sides of the contact state of the contact;
The movable contact is linked to the excessive current flowing through the movable contact and the fixed contact to drive the movable contact in a direction away from the fixed contact, and the arc between the movable contact and the fixed contact is caused to move toward the opposite side of the movable contact and the fixed contact. A pair of drive coils that generate a magnetic flux that is driven to extend in a direction perpendicular to the direction, a pair of side plates located on the side where the movable contacts of these drive coils are separated, and the movable contacts and fixation of the pair of side plates. An insulator that generates pyrolysis gas due to the heat of the arc is coated on the inside of the magnetic body formed in a U shape by connecting the side remote from the contact and a back plate parallel to the opening/closing direction of the movable contact. An arc extinguishing device comprising an arc extinguishing section.