JP2000188031A - Contact device of circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide excellent short circuit current breaking performance by installing a pair of coils and a connecting conductor, and positioning the connecting conductor in the vicinity of a moving contact and a fixed contact so that a magnetic flux in the opening locus direction of the moving contact generates when short circuit current flows. SOLUTION: A connecting conductor 12 is arranged in the position corresponding to almost the middle part of a moving locus of a moving contact 3 when a fixed contact 2 is opened, and a plurality of arc-extinguishing grids are installed in a part enveloped with a U-shaped fixed contact. When short circuit current flows, the moving contact 3 is separated from the fixed contact 2 by electromagnetic repulsion, and an arc column A is generated. Short circuit current flows from a power source side terminal 1 through a route of a coil 10, the connecting conductor 12, a coil 11, the fixed contact 2, the arc column A, the moving contact 3, and a moving contact 4. A magnetic flux H1 generating becomes twice the case of only one coil, blowing action is made strong, and an arc can more quickly be extinguished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact device for a circuit breaker, and more particularly to a technique for improving short-circuit current breaking performance thereof.

[0002]

2. Description of the Related Art An example of a conventional circuit breaker is shown in FIG. This circuit breaker has a fixed contact 24 bent in a U-shape having a power supply terminal 1 at one end and a fixed contact 2 at the other end, and a load terminal (not shown) having a movable contact 3 at one end and a movable contact 3 at one end. And a contact holder 6 rotatably supporting the movable contact 4 by a contact shaft 5.
A contact pressure spring (not shown) for urging the movable contact 4 in a counterclockwise direction, an opening / closing mechanism 7 for rotating the contact holder 6 (not described in detail), and arms on both sides of the movement locus of the movable contact 3 It has an arc-extinguishing grid 25 formed of a plurality of magnetic plates each having a shape cut out in a “V” shape so as to be formed and held between a pair of insulating plates.

In this circuit breaker, a contact holder 6 is rotated clockwise by operating an opening / closing operation handle 8 by operating an opening / closing operation handle 8, and the movable contact 3 is separated from the fixed contact 2 so as to open the circuit. The current can be interrupted. Instead of operating the opening / closing operation handle 8, a tripping device (not shown) may detect an overcurrent and operate the opening / closing mechanism 7, thereby interrupting the current. Furthermore, when a large current such as a short-circuit current flows through the circuit breaker, an electromagnetic repulsion generated between the movable contact 3 and the fixed contact 2 and the opposed fixed contact 24 and the movable contact 4, the movable contact 4 rotates clockwise as indicated by a dashed line and the movable contact 3 is fixed to the fixed contact 2 without waiting for the operation of the tripping device.
Separated from At this time, an arc current flows between the movable contact 3 and the fixed contact 2, and a high-temperature arc column A is generated. The arc column A is attracted in the direction of the arc-extinguishing grid 25 by magnetic action. The arc column A extends and is cooled by the arc-extinguishing grid 25 to increase the arc resistance. As a result, the arc is extinguished and the current is interrupted. .

[0004]

The arc-extinguishing grid 25 of the conventional circuit breaker has an effect of cutting off a large current. However, the arc-extinguishing grid 25 alone could not cut off the short-circuit current more excellently, that is, the larger short-circuit current, only by the inducing and cooling action of the arc. Therefore, an object of the present invention is to realize a contact device of a circuit breaker having a better short-circuit current breaking performance with a simple configuration.

[0005]

In order to solve the above-mentioned problems, a contact device of a circuit breaker according to the present invention comprises a fixed contact having a terminal at one end and a fixed contact at the other end; A movable contact that has a movable contact that contacts and separates from the fixed contact, a contact holder that rotatably holds the movable contact, an opening and closing mechanism that rotates the contact holder, a movable contact and a fixed contact, A contact pressure spring for urging the movable contact in a direction in which the movable contact and the fixed contact are separated from each other, and an arc extinguishing grid for extinguishing an arc generated when the movable contact and the fixed contact are separated from each other. The contact has a pair of coils disposed opposite to both sides of the movable contact and the fixed contact so as to generate a magnetic flux crossing the separation locus of the movable contact when a short-circuit current flows, and a magnetic flux generated in the pair of coils is generated. In the same direction And a connection conductor for connecting a pair of coils in series with each other, the connection conductor being located near the movable contact and the fixed contact so as to generate a magnetic flux in the direction of the separation locus of the movable contact when a short-circuit current flows. I have to do that.

[0006] With this configuration, since the magnetic flux generated when the movable contact and the fixed contact are separated from each other and traverses the arc column is generated from the two coils in the same direction, a larger arc blows in the direction of the arc-extinguishing grid. Acts to expedite arc extinction in the arc extinction grid. Further, the connection conductor connecting the two coils arranged on both sides of the movable contact and the fixed contact is arranged in a direction orthogonal to the separation locus of the movable contact. Since the magnetic flux generated in this connection conductor is in the direction of the above-mentioned moving trajectory of the movable contact, the magnetic flux rotates the root of the arc column so as to lick the peripheral edges of the surfaces of the movable contact and the fixed contact, thereby causing the arc column to move. In addition to lowering the temperature at the root, the rotating directions of the roots of the arc column at the movable contact and the fixed contact are opposite to each other, so that the arc column is twisted, the arc resistance increases, and the arc disappears faster.

[0007] A repulsive opening / closing contact is provided between the terminal of the fixed contact and the fixed contact, which is repelled by electromagnetic force due to a short-circuit current and is opened, and one of the repelling open / close contacts is rotatably held. It can also be configured to be attached to one end of the contact. According to this configuration, when a short-circuit current flows, the repelling movable contact is opened together with the movable contact and the fixed contact, so that the arc disappears more quickly.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the embodiments shown in FIGS. Note that the same reference numerals are given to the same components as those in the conventional technology, and the description thereof will be omitted. A contact device for a circuit breaker according to a first embodiment is shown in FIGS. This first
The fixed contact 9 in the embodiment has the power supply side terminal 1 at one end and the fixed contact 2 at the other end similarly to the fixed contact 24 of the conventional device shown in FIG. 5, as shown in FIG. To
The coil 10 and the coil 11 facing each other and the connecting conductor 12 connecting them are formed in a plane “U” shape,
The fixed contact 2 is attached to the coil 11 so as to be surrounded by them. The coil 10 rises upward from the power supply side terminal 1 in FIG. 1, passes through the vicinity of the movable contact 3 in the separated state shown by the dashed line, and then passes through the vicinity of the fixed contact 2 and the movable contact 3 in the contact state. Formed and arranged in an inverted "C" shape. On the other hand, the coil 11 has one end 1
1a is bent at a right angle, and the fixed contact 2 is attached thereto. The fixed contact 2 is formed and arranged in a “C” shape in FIG. 1 so as to pass near the fixed contact 2 and the movable contact 3 in the contact state.
The other end is connected to the coil 10 via the connection conductor 12. One end 11a of the coil 11 faces the movable contact 4, and when a short-circuit current flows, an electromagnetic repulsion acts between the two.

The connecting conductor 12 is disposed at a position corresponding to a substantially middle portion of the moving trajectory of the movable contact 3 when it is separated from the fixed contact 2, and is surrounded by a "U" -shaped fixed contact 9. The part is provided with a plurality of arc extinguishing grids 13.

The operation of interrupting the short-circuit current of the embodiment thus formed will be described. When a short-circuit current flows through the circuit breaker, the movable contact 3 is separated from the fixed contact 2 by an electromagnetic repulsion, and an arc column A is generated. At this time, the short-circuit current flows from the power supply terminal 1 through the path of the coil 10, the connection conductor 12, the coil 11, the fixed contact 2, the arc column A, the movable contact 3, and the movable contact 4. The connection conductor 12 flows from the front surface to the rear surface in FIG. When the current flows through the coils 10 and 11 in this manner, a magnetic flux H1 is generated so as to cross the arc column A from the front surface of the paper of FIG. In this case, a blowing action is provided. This blowing action is caused by current flowing in the same direction (clockwise) in the coil 10 and the coil 11.
Since the generated magnetic flux H1 is twice as large as that of only one of the coils, the action is stronger and the arc is extinguished more quickly.

Further, when a current flows in the connecting conductor 12 in a direction from the front surface to the rear surface of the paper of FIG. 1, a clockwise magnetic flux H2 is generated around the connecting conductor 12, and the magnetic flux H2 is separated near the arc column A. Movable contact 3 in state (upper)
From the contact point 2 (downward). This magnetic flux H
Due to 2, the root of the arc column A on the surface of the fixed contact 2 and the movable contact 3 rotates so as to lick the periphery of these surfaces. As described above, the root of the arc column A is cooled by the movement, and the rotation direction of the root of the arc column A at the periphery of the fixed contact 2 and the movable contact 3 is opposite to each other. Thus, the arc resistance is increased, and the arc is extinguished more quickly.

A contact device for a circuit breaker according to a second embodiment is shown in FIGS. Also in the second embodiment, the same components as those in the prior art and the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The fixed contact 14 in the second embodiment is different from the power supply terminal 1 in FIG.
Conductor 1 that rises upward from above and passes through the vicinity of the movable contact 3 at the separated position indicated by the dashed line and is bent downward.
5, a resilient movable contact 17 rotatably held by a shaft 16 below the conductor 15, a resilient movable contact 18 attached to the tip of the resilient movable contact 17, and A conductor 19 having bent portions 19a and 19b formed by bending the lower portions of its arms inwardly at right angles, and a contact and separation with a repulsive movable contact 18 provided on the lower surface of the bent portion 19a. The fixed contact 2 is formed on the upper surface of the bent portion 19b. The repulsive movable contact 17 is urged clockwise around the shaft 16 by a spring (not shown), and is urged by a spring 21 so as to always contact the conductor 15.

When the second embodiment is compared with the first embodiment, one of the conductor 15, the resilient movable contact 17, the resilient movable contact 18, the resilient fixed contact 20, and the conductor 19 including the bent portion 19a is formed. The coil 10 of the first embodiment
Is formed. A coil corresponding to the coil 11 of the first embodiment is formed by the other arm of the conductor 19 and its bent portion 19b. Further, the fixed contact 2 in the second embodiment is the same as the conductor 1 in FIG.
9 is located above the center of the U-shape,
8 and the repulsion fixed contact 20 are arranged so as to be located on the lower side. Therefore, the arc-extinguishing grid 22 provided corresponding to the fixed contact 2 and the movable contact 3 of the second embodiment is formed in an “L” shape so as to surround the fixed contact 2 from the left side and the lower side in FIG. ing. Also, the repulsive movable contact 18
Also, an arc-extinguishing grid 23 corresponding to the repelling fixed contact 20 is provided.

The operation of the second embodiment thus constructed is such that when a short-circuit current flows, the movable contact 3 is separated from the fixed contact 2 by the electromagnetic repulsive force and the repulsive movable contact 18
Are separated from the repelling fixed contact 20. As a result, the arc generated between the fixed contact 2 and the movable
The same operation as in the embodiment occurs, and the repulsive movable contact 1
An arc generated between the fixed contact 8 and the repelling fixed contact 20 is also attracted toward the arc-extinguishing grid 23 to be extinguished, so that the arc can be extinguished earlier than in the first embodiment.

[0015]

The present invention is embodied in the above-described embodiment. When a short-circuit current flows, a pair of coils that generate a magnetic flux that crosses the moving trajectory of the movable contact is provided on both sides of the switching contact. The effect is greater and the connecting member connecting both coils is provided near the contact part of the switching contact, so the magnetic flux generated by the current flowing through the connecting member moves the root of the arc column, cools the arc column, and reduces the arc length. In addition to the effect of increasing the length of the arc, the arc can be extinguished faster and the short-circuit breaking performance can be improved, and such an effect can be realized with a simple configuration. Further, by providing a contact that repels by electromagnetic force due to current on one side of the coil, an effect of further improving the short-circuit current interruption performance can be achieved.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing a circuit breaker incorporating a contact device according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a fixed contact used in the contact device of FIG. 1;

FIG. 3 is a partially cutaway side view showing a circuit breaker incorporating a contact device according to a second embodiment of the present invention.

FIG. 4 is a plan view showing a fixed contact used in the contact device of FIG. 3;

FIG. 5 is a partially cutaway side view showing a conventional circuit breaker.

[Explanation of symbols]

1 power supply side terminal, 2 fixed contact, 3 movable contact,
4 movable contacts, 5 contact axes, 6 contact holders,
7 opening / closing mechanism, 8 opening / closing operation handle 9, 14 fixed contact, 10, 11 coil, 12 connection conductor,
13, 22, 23 Arc-extinguishing grid, 15, 19 conductors, 16 axes, 17 repulsive movable contacts, 18 repulsive movable contacts, 20 repulsive fixed contacts, 21 spring

Claims (2)

[Claims] 1. A fixed contact having a terminal at one end and a fixed contact at the other end, a movable contact having a movable contact at one end contacting and separating from the fixed contact, and rotating the movable contact. A contact holder for freely holding, an opening / closing mechanism for rotating the contact holder, a contact pressure spring for urging the movable contact in a direction in which the movable contact and the fixed contact come into contact, and the movable contact And an arc-extinguishing grid for extinguishing an arc generated when the fixed contact is separated from the fixed contact, wherein the fixed contact is separated from the movable contact when a short-circuit current flows. And a pair of coils disposed on both sides of the movable contact and the fixed contact so as to generate a magnetic flux crossing the pair of coils, so that a magnetic flux generated in the pair of coils is in the same direction. Connection conductors connected to a row, wherein the connection conductor is located near the movable contact and the fixed contact so as to generate a magnetic flux in the direction of the separation locus of the movable contact when a short-circuit current flows. A contact device for a circuit breaker. 2. A resilient switching contact is provided between the terminal of the fixed contact and the fixed contact, which is repelled by electromagnetic force due to a short-circuit current and is opened, and one of the repelling switching contacts is rotatably held. 2. The contact device for a circuit breaker according to claim 1, wherein the contact device is attached to one end of the repulsive movable contact.