JPS6376217A - Circuit breaker - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a circuit breaker for breaking an electric circuit, and particularly to an improvement in the structure for extinguishing an arc.

[Prior Art] Fig. 5 shows the structure of a conventional circuit breaker near the contacts and arc extinguishing plate.A fixed contact 4 and an arc runner 5 are fixed to a stator 3 by brazing. bolt 1
2 screws the stator 3 onto a base 6 made of an insulating material, and fixes the folded end portion 31 of the stator 3. The movable element 1 is provided with a movable contact 2, and in a closed circuit state, the movable contact 2 and the fixed contact 4 are in contact with each other.

In this closed circuit state, when an overcurrent flows through the f4 path, a tripping device (not shown) is activated to open the movable element l. At this time, there is an arc 9 between the movable contact 2 and the fixed contact 4.
occurs. This arc 9 is moved in the direction of arrow A above the arc runner 5 by electromagnetic force. The moved arc is stretched out and divided by the arc extinguishing plate 10,
The arc is extinguished.

[Problems to be Solved by the Invention] However, the conventional circuit breaker has the following problems.

If the arc does not move smoothly and moves to the side edge of the notch loa of the arc extinguishing plate 10 (arc 9a in FIG.
j! from arc extinguishing board 10). The arc sometimes stalled due to I electron emission. For this reason, there was a problem in that the arc did not travel quickly, the extinction of the arc was delayed, and the breaking performance deteriorated. Further, the arc once transferred to the arc runner 5 becomes unstable and re-ignites at the fixed contact 4, which may lead to a decrease in the breaking performance.

An object of the present invention is to solve the above problems and provide a circuit breaker with high breaking performance.

[Means for Solving the Problems] The circuit breaker according to the present invention includes a stator, a fixed contact provided on the stator, a movable element driven by a tripping device, and a movable element provided on the movable part. The arc guiding member has a movable contact which is moved into and out of contact with a fixed contact by a movable element, and a protruding part whose tip end is wider than the contact is provided in the center of the arc running surface of the arc guiding member.

[Function] The protrusion provided on the arc guide plate has the effect of concentrating the electric field on this part, and the wide tip side of the protrusion has the effect of stabilizing the arc.

[Embodiment] An embodiment of the present invention is shown in Fig. gJ1. The tip portion 31 of the stator 3 is formed by folding back, and a fixed contact 4 and an arc runner 5 which is an arc guiding member are fixed to the folded outer surface 3a by brazing. has been done.

The arc runner 5 is provided with a protrusion 5b, and in this embodiment, the upper surface 5C of the protrusion 5b is the contact surface 4a of the contact 4.
It is designed to be lower. This is fixed contact 4
This is to prevent the movable member 1 from coming into contact with the protruding portion 5b even if the movable member 1 disappears.

In the upper space of the arc runner 5, an arc extinguishing plate 10 made of a magnetic material is fixed to a side plate 11.

The details of the arc runner 5 used in this example are shown in Figure 2 (
Figure 2 (A) is a plan view, Figure 2 (A) is shown in (B).
B) is a side view. Arc running surface 5 of arc runner 5
A protrusion 5b is provided at the center of a. The protrusion 5b is narrow on the contact side 5x and wide on the tip side 5y.

The operation of the circuit breaker according to this embodiment will be explained with reference to FIGS. 1 and 2. Movable element 1 has movable contact 2
is provided, and the movable contact 2 and the fixed contact 4 are in contact with each other in the closed circuit state. In this closed circuit state, if an overcurrent flows through the circuit, a tripping device (not shown)
is activated to open the mover l. At this time, an arc 9 is generated between the movable contact 2 and the fixed contact 4. This arc 9 is moved in the direction of arrow A above the arc runner 5 by electromagnetic force. A protrusion 5b is provided on the arc running surface 5a of the arc runner 5, and an electric field is concentrated on this protrusion 5b. Therefore, the arc 9 moves quickly along the protrusion 5b. In other words, the arc 9 is on the arc running surface 5
Since the central part of the arc extinguishing plate 10 is moved, the notch 10a of the arc extinguishing plate 10
There is no risk of the arc coming into contact with the side end of the protruding part 5b, and the arc will not stick. Also, since the tip side 5y of the protruding part 5b is formed wide, the arc will have a nearly free shape, and the arc will not close to the tip msy. Stabilize. Therefore, fixed contact 4
There is little risk of the arc re-igniting.

FIG. 3(A) shows details of the arc runner 5 according to another embodiment.
Figure 3 (A) is a plan view, Figure 3 (B) is shown in (B).
is a fi11 side view. The stator 3 is formed by folding a tip 31, and a fixed contact 4 is fixed to the folded outer surface 3a by brazing. The inner dimension of the fold is larger than the thickness of the arc runner 5, which is an arc guiding member, and the arc runner 5 is fixed to the inner fold 3b by a bolt 14, which is a screwing means. The arc runner 5 is provided with a notch 5f to avoid interference with the tip 31 of the stator 3. In this embodiment, since the notch 5f is provided, there is no risk that the mover 1 will come into contact with the arc runner 5 even if the fixed contact 4 wears out.Therefore, in this embodiment, the upper surface 5C of the protrusion 5b is to lower the arc resistance by forming it higher than the contact surface 4a of
The arc is made to easily move from the fixed contact 4 to the arc runner 5.

Further details of an arc runner 5 according to another embodiment are shown in FIG.
Figure (B) is a side view. In this embodiment, a boule 5p is provided on the tip side of the protrusion 5b. The area of this boule 5p is made smaller than the area of the arc spot formed to keep the current density corresponding to the rated breaking current constant. Also, the area of the boule 5p is the fixed contact 4
is smaller than the area of In this example, Boolean 5
Since the arc is provided at the boule 5p, the arc is stabilized at the boule 5p, and there is little risk of re-ignition at the fixed contact 4.

[Effects of the Invention] The circuit breaker according to the present invention has a structure in which a protrusion is provided in the center of the arc running surface of the arc guiding member, the protrusion being wider on the tip side than on the contact side.

Therefore, the electric field concentrates on the protrusion, causing the arc to travel quickly, and since the arc travels through the center of the arc guiding member and does not come into contact with the side edges of the notch in the arc extinguishing plate, the arc is extinguished.・Quick cooling. Furthermore, the arc is stabilized on the tip side of the protrusion, and there is no re-ignition at the fixed contact.

That is, a circuit breaker with high breaking performance can be provided.

[Brief explanation of the drawing]

Fig. 1 is a side view showing the main parts of a circuit breaker as an embodiment of the present invention, and Fig. 2 (A) is! 1! A plan view showing the details of the arc runner used in the circuit breaker shown in Fig. 1, Fig. 2 (B) is a side view of Fig. 2 (A), and Fig. 3 (A) is a plan view showing details of the arc runner used in the circuit breaker of Fig. 1. 3(B) is a side view of FIG. 3(A), and FIG. 4(A) is a plan view showing details of the arc runner in another embodiment. B) is a side view of Fig. 4(A), Fig. 5 is a side view showing the main parts of a conventional circuit breaker, and Fig. 6 is a side view of the arc extinguishing plate used in the circuit breaker of Fig. 5. It is a figure showing details. 1 is a mover, 2 is a movable contact, 3 is a stator, 4 is a fixed contact, 5 is an arc runner, 5b is a protrusion, and IO is an arc extinguishing plate. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (5)

[Claims] (1) A stator, a fixed contact provided on the stator, a movable element driven by a tripping device, a movable contact provided on the movable element and connected to and separated from the fixed contact by the movable element, one end of which is connected to the stator. 1. A circuit breaker comprising: an arc guiding member fixed to the arc guide member, the arc guiding member having a protrusion formed in the center of the arc running surface and having a tip side wider than a contact side. (2) A pool with an area smaller than the area of the arc spot formed so as to keep the current density corresponding to the rated breaking current constant is provided on the tip side of the protrusion of the arc induction member. A circuit breaker according to claim 1. (3) The circuit breaker according to claim 2, characterized in that the area of the pool is smaller than the area of the contact. (4) The arc induction member is brazed to the folded outer surface of the stator, and the upper surface of the protrusion of the arc induction member is formed lower than the contact surface of the fixed contact. A circuit breaker according to any one of claims 1 to 3. (5) The stator is folded back so that the outer surface is folded almost perpendicular to the direction of arc firing, and the inner folded dimension is wider than the thickness of the arc guiding member. shall be fixed to the folded inner surface of the stator by bolts screwed from the folded outer surface of the stator, and the upper surface of the protruding part of the arc induction member shall be formed higher than the contact surface of the fixed contact. A circuit breaker according to any one of claims 1 to 3, characterized in that: