JP2001229802A - Circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit breaker of favorable switching performance with promotion of extinction of arc. SOLUTION: A downward notch 2b having an opening at distant position from a switching contact 10 to the direction of an arc extinguishing device is formed on an arc contact piece 2. Electromagnetic force excited by inverse current around the notch promotes diffusion of arc to permit an early extinction of arc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for improving the breaking performance of a circuit breaker.

[0002]

2. Description of the Related Art An example of a conventional circuit breaker is disclosed in JP-A-8-17.
No. 322. The circuit breaker shown in FIGS. 5 and 6 includes an input terminal 20, a fixed contact 2
1, movable contact 28, fixed contact 22, output terminal 2
In all three, current flows through a path formed by a component using a copper member. By operating an opening / closing mechanism (not shown), the movable contact 28 moves left and right within a predetermined range. When the movable contact 28 moves to the left from the state of FIG. 5, the movable contact 28 and the fixed contact 21 and When the electric current is interrupted by the separation of the electric contact 22 and the electric contact moves rightward, the movable contact 28 and the fixed contacts 21 and 22 come into contact with each other as shown in FIG. Since the input terminal 20 and the fixed contact 21 and the input terminal 23 and the fixed contact 22 are provided vertically symmetrically and perform the same operation, the input terminal 20 and the fixed contact 2
1 will be described.

A contact 24 is provided at one end of the fixed contact 21 as an opening / closing contact portion, and contacts a contact 29 of a movable contact 28 by the action of a contact pressure spring 25, and the fixed contact 21 extends upward. At the end, the input terminal 20 is acted upon by the action of the spring 26.
Is in contact with Further, an arc runner 27 is provided from immediately below the contact 24 to the upper side, and an arc extinguishing device 30 including a plurality of magnetic plates is provided near the upper portion of the arc runner 27.
Is fixedly provided.

The operation when the circuit breaker interrupts the current will be described. An opening command is issued from the state of FIG. 5 to operate the opening / closing mechanism, and the lower portion of the fixed contact 21 is moved leftward by the action of the contact pressure spring 25 following the movement of the movable contact 28 to the left. And the lower end 21a thereof comes into contact with the lower end 27a of the arc runner 27 to stop the movement of the fixed contact 21. As a result, only the movable contact 28 moves further leftward, the contact 29 and the contact 24 are opened, and an arc is generated between them.

In FIG. 6, the arc generated in this manner expands in an arc shape toward the arc extinguishing device 30 due to the blowing action of the electromagnetic force, and one of the arc ends is an arc runner 2.
7 and moves to the upper portion 27b immediately near the contact 24. Since the contacts 24 and the arc runner 27 have the same potential due to the contact of the lower ends of both the fixed contact 21 and the arc runner 27, the arc end extends over both the contact 24 and the arc runner 27. That is, as shown by the dashed line in the figure, the circuit current is from the upper part of the fixed contact 21 → the lower end 21a → the lower end 27a of the arc runner → the uppermost part 27b of the contact 24 of the arc runner 27 → the arc → the movable contact. The flow is divided into two paths: the upper end of the contact 28 → below the movable contact 28 and the upper part of the fixed contact 21 → the contact 24 → the arc → the upper end of the movable contact 28 → the lower part of the movable contact 28.

After a lapse of time, all of the arc ends shift to the arc runner 27, and the circuit current flows from the upper part to the lower end part 21a of the fixed contact 21 as shown by a two-dot chain line in the figure.
→ The lower end 27a of the arc runner → above the arc runner 27 → the arc → the upper end of the movable contact 28 → the arc flows further along the path below the movable contact 28, and the expansion of the arc further proceeds. Running upward, the arc is attracted to the arc extinguishing device 30 to be cooled and extinguished.

[0007]

As described above, immediately after the two contacts are opened in the current interruption operation, the current is applied to the contact 24.
And the arc runner 27. However, the contact upper portion 27b of the arc runner 27 and the contact portion
In addition to the fact that there is a gap between them and the fact that the current-carrying cross-sectional area of the arc runner 27 is relatively small,
In some cases, the transition from the to the arc runner 27 is not performed smoothly, so that there is a problem that it is not possible to realize a circuit breaker having a high breaking performance of breaking a larger current.

Accordingly, an object of the present invention is to provide a circuit breaker having better breaking performance by solving the above problems.

[0009]

In order to solve the above problems, a circuit breaker according to the present invention comprises an arc extinguishing device, a movable contact operated by an opening / closing mechanism, and a movable contact. An energization path is formed between one end provided on the surface and the other end extending in the direction of the arc-extinguishing device, and has a notch extending from the surface of the intermediate portion toward the one end. The portion up to the opening of the notch includes a fixed-side arc contact provided in a state exposed to the switching arc.

With such a configuration, when the movable contact and the fixed arc contact are separated, the arc end on the arc contact side is continuously connected to the open / close contact portion by the action of the electromagnetic force. Can be smoothly moved to the opening of the notch in the above, so that the arc can be easily expanded. In addition, a current in the opposite direction flows from the lower end of the opening to the opposing peripheral edge of the notch, and the electromagnetic force due to this current causes a further blowing action to expand the arc, lower the arc current, and to the arc extinguishing device. Hasten the invitation.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to an embodiment shown in FIGS. In addition, since the circuit breaker of the present embodiment is almost the same as the conventional circuit breaker, different parts are illustrated and described.

The fixed contact of this embodiment is different from the single movable contact in FIG. 4 in that three main contacts 1 provided on each of the left and right sides and two central arc contacts are provided in parallel. Consists of child 2. Hereinafter, the arc contact 2 which is a main part of the present application will be described. Incidentally, the circuit breaker of the present invention,
The main contact may be omitted.

1 to 3, each arc contact 2 is rotatably supported by a common shaft 3. Further, the arc-shaped outer periphery of the arc contact 2 and the terminal 4 are electrically connected by a connector 7 rotatably supported by a shaft 5 and urged by a spring 6. Further, the arc contact 2 is urged by a contact pressure spring 8 at its lower portion so as to rotate clockwise. The arc contact 2 thus supported has its lower end 2a in contact with the lower end 9a of the fixedly provided arc horn 9 to prevent clockwise rotation. Further, the arc contact 2 is provided with a contact 10 on a surface near the lower end thereof, and has an opening at an upper middle portion of the surface on which the contact 10 is provided, and has a groove-shaped notch directed toward the lower right end. 2b is formed.

The main contact 1 which is not the main part of the present application
Although not shown in detail, like the arc contact 2, it is held on the shaft 3 and is not formed with a groove-shaped notch, but a spring 6, a connector 7, and a contact pressure spring 8 are provided respectively. Can be In the opening operation, the movable contact 11
The lower end of the main contact 1 is formed so that the rotation stops before the rotation of the arc contact 2 when the arm moves leftward, and the contact 14 and the contact 13 of the movable contact are separated. At this time, the contacts 10 and 13 of the arc contact 2 are in a contact state. For this reason, all or most of the circuit current is transferred to the arc contact 2, and almost no arc is generated at the contact 14, and the damage is small. For this reason, even if the closing operation is performed again, stable energization is performed.

As shown in FIG. 4, in the arc horn 9 of this embodiment, the main contact 1 covers the upper part from the vicinity of the contact 14 and the arc contact 2 covers the upper part from the opening of the notch 2b. Is formed.

The operation of interrupting the current when a large overcurrent flows through the circuit breaker of this embodiment having the above-described configuration will be described below. The overcurrent tripping device (not shown) operates, and the arc contact 2 and the main contact 1 move counterclockwise from the state shown in FIG. 1 as the movable contact 11 moves leftward. Rotate. First, the rotation of the main contact 1 is stopped by the arc horn 9 and the contact 10 is
4, the current flowing through the main contact 1 is transferred to the arc contact 2 with almost no arc.

Next, the rotation of the arc contact 2 is stopped by the arc horn 9, the contact 10 is separated from the contact 13, and an arc is generated. As shown in FIG. 2, at this time, the arc expands due to the blowing action of the electromagnetic force of the current, one end of the arc moves from the contact 13 to the upper end of the movable contact 11, and the other end moves the surface of the contact 10 upward. It moves to the lower end of the running notch 2b. During or after the movement of the arc end, the current flows from the terminal 4 to the connector 7 to the opposite edge of the notch 2b of the arc contact 2 as shown by the dashed line.
It flows along the path of the opening of the notch 2b → the arc → the upper end of the movable contact 11 → the lower part of the movable contact 11. When a current flows through such a path, the electromagnetic force of the currents flowing in opposite directions at the opposing peripheral edges of the notch 2b further applies a blowing action to expand the arc and increase the arc resistance.

Further, as time passes, the movable contact 11 moves to the left as shown in FIG. 3, the arc end on the arc contact side moves to the arc horn 9, the arc continues to expand, and the arc extinguishing device continues. The circuit current is greatly attenuated by being attracted to 12. At this time, the circuit current is: terminal 4 → connector 7 → lower end 2 a of arc contact 2 → lower end 9 a of arc horn 9 → upper part of arc horn → arc → upper end of movable contact 11 → movable contact 11 Flows in the lower part of the path. The current is interrupted before the movable contact 11 stops.

The embodiment of the present invention has been described above. However, the embodiment of the present invention disclosed above has the following features.
This is merely an example, and the scope of the present invention is not limited to the above embodiment of the present invention. The scope of the present invention is defined by the appended claims, and is intended to include all modifications within the scope and meaning equivalent to the appended claims.

[0020]

The present invention is embodied in the above-described embodiment. In order to promote the expansion of the arc immediately after the movable-side contact and the fixed-side arc contact are separated, the opening / closing contact portion of the arc contact is promoted. A notch having an opening at a position away from the notch is provided so as to generate an electromagnetic force of a current flowing around the periphery of the notch, so that an effect of improving the breaking performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of a circuit breaker according to an embodiment of the present invention, showing a main part of a closed state.

FIG. 2 is a diagram corresponding to FIG. 1 showing a state at the moment when a contact is opened.

FIG. 3 is a diagram corresponding to FIG. 1, showing a state immediately before completion of a shut-off operation.

FIG. 4 is a front view showing a fixed contact and an arc runner of the present invention.

FIG. 5 is a side view of a conventional circuit breaker in a closed state.

FIG. 6 is a partial view of a conventional circuit breaker immediately after a contact is opened.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main contact 2 Arc contact (2a lower end, 2b notch) 8 Contact pressure spring 9 Arc horn (9a lower end) 10, 13, 14 Contact 11 Movable contact 12 Arc extinguishing device

Claims (2)

[Claims] An arc extinguishing device, a movable contact operated by an opening / closing mechanism, one end provided on a surface with an opening / closing contact portion that comes into contact with / separates from the movable contact, and extends in the direction of the arc extinguishing device. An energization path is formed between the opening and the end, and a notch extending from the surface of the intermediate portion toward the one end is provided, and a portion from the opening / closing contact portion to the opening of the notch is exposed to the opening / closing arc. A fixed-side arc contact provided in a state,
A circuit breaker comprising: 2. The circuit breaker according to claim 1, further comprising an arc runner covering said arc contact in a direction from said opening to said arc extinguishing device.