JPS63264843A - Circuit breaker - Google Patents

Abstract

PURPOSE:To prevent the arc short circuit at the rear end sections of arc extinguishing plates and improve the break performance by covering the rear end sections behind notches of the arc extinguishing plates with an insulating film. CONSTITUTION:A stator 3, a fixed contact point 4 provided on the stator 3, a mover 1 driven by a disconnecting device, a movable contact point 2 provided on the mover 1 and disconnected from the fixed contact point 4 by the mover 1, an arc introducing member 5 fixed to the stator 4 at one end, and arc extinguishing plates 30 are provided, and an insulating film 32 is formed on the rear end sections behind notches of the arc extinguishing plates 30 made of a magnetic material. An arc 9 is moved to the rear end sections 30c of the arc extinguishing plates, but the rear end sections 30c of the arc extinguishing plates 30 are covered with the insulating film, thus the arc short circuit does not occur. Since the insulating film 32 is provided behind the notches, the time when the arc is touching the metal section is long, and the arc is cooled efficiently. A circuit breaker with the high break performance is obtained accordingly.

Description

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

[Prior Art] Fig. 4 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 electric circuit, a tripping device (not shown) is activated to separate the movable element 1.

At this time, an arc 9 is generated between the movable contact 2 and the fixed contact 4. This arc 9 is moved by the arc runner 5 due to electromagnetic force.
can be moved in the direction of arrow A. FIG. 5 shows this state as a plan view. The arc-extinguishing plate 10 made of a magnetic material is provided with a notch IQa for introducing an arc. Therefore, the arc 9 is moved in the direction of arrow A due to the deflection of the magnetic lines of force. The moved arc is
The arc-extinguishing plate 10 stretches, divides, and extinguishes the arc.

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

In the event of a large current short circuit accident or high voltage interruption, an arc may come out from the rear end of the arc extinguishing plate 10, causing an arc short circuit 40. When the arc short circuit 40 occurs, there is a problem in that the arc voltage decreases and the breaking performance deteriorates.

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 element. It is equipped with a movable contact that comes into contact with and separates from a fixed contact by a movable element, an arc induction member whose one end is fixed to the stator, and an arc extinguishing plate, and an insulating coating on the rear end behind the notch of the arc extinguishing plate made of magnetic material. is formed.

[Function] The insulating film provided at the rear end of the arc-extinguishing plate prevents arc short circuits at the rear end of the arc-extinguishing plate.

[Embodiment 1] An embodiment of the present invention is shown in FIG. rtS1. The tip portion 31 of the stator 3 is formed by being folded back, and a fixed contact 4 and an arc runner 5 are fixed to the folded outer surface 3a by brazing. A protrusion 50 is provided on the side of the arc extinguishing plate 300, protrudes from a hole provided in the arc extinguishing side plate 11, and is fixed by caulking. The arc-extinguishing plate 30 is made of a magnetic material, and a part thereof has an insulating film 32.
is provided.

As this insulating film 32, an arc-resistant paint such as Citruc epoxy electrostatic powder made of water-soluble alumina or liquid ceramic is preferable. 11 is soaked and formed. The insulation degree 1th32 is provided so as to cover the arc rear end portion 30c, and is provided behind the notch. Note that if the insulating film 32 is provided to cover the caulked protrusion 50, there is no risk of the caulked part rusting, and when the circuit breaker vibrates, powder will be generated from the end surface of the arc-extinguishing side plate 11 and mixed between the contacts. This may cause defects.

The insulating film 32 can suppress the generation of this powder.

The operation of the circuit breaker according to this embodiment will be explained with reference to FIG. 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 electric circuit, a tripping device (not shown) is activated to separate the movable element 1. 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. After I&, the arc 9 is moved to the rear end portion 30C of the arc extinguishing plate 30. At this time, since the rear end 30c of the arc-extinguishing plate 30 is covered with an insulating film, no arc short circuit occurs.Also, since the insulating film 32 is provided behind the notch, the arc will not reach the metal part. The longer the arc is in contact with the arc, the more efficiently the arc is cooled.

In addition, as another embodiment, after the arc extinguishing plate 30 is dipped in the paint to a predetermined position, only the arc extinguishing side plate 11 may be dipped in the paint so that its entire surface is immersed. Powder generated when the circuit breaker vibrates can be suppressed more completely.

[Effects of the Invention] In the circuit breaker according to the present invention, the rear end portion of the arc-extinguishing plate behind the notch is covered with an insulating film. Therefore, it is possible to prevent arc end shorting at the rear end of the arc-extinguishing plate, and to efficiently cool the arc, thereby improving the breaking performance. That is, a highly reliable circuit breaker 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, FIG. 2 is a diagram showing details of the arc-extinguishing plate used in the circuit breaker of FIG. 1, and FIG. FIG. 4 is a side view showing main parts of a conventional circuit breaker, and FIG. 4 is a diagram showing details of an arc-extinguishing plate used in the circuit breaker of FIG. 3. ■ is a mover, 2 is a movable contact, 3 is a stator, l! 5 is a fixed contact, 5 is an arc runner, and 30 is an arc extinguishing plate. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (3)

[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. an arc induction member fixed to the arc induction member, and a plurality of magnetic materials provided in the upper space of the arc induction member to form a surface substantially perpendicular to the arc, and with an insulating film formed on the rear end behind the notch. A circuit breaker comprising: two arc-extinguishing plates. (2) The arc-extinguishing plate is fixed by caulking after inserting a protrusion provided on the side of the arc-extinguishing plate into the arc-extinguishing side plate. circuit breaker. (3) The circuit breaker according to claim 2, wherein the insulating film is formed by dipping the arc-extinguishing plate and the arc-extinguishing side plate in an arc-resistant insulating paint.