JPH01189833A - Arc extinguishing device for circuit breaker - Google Patents

Abstract

PURPOSE:To simplify an arc extinguishing device and decrease its occupation space by providing an exhaust hole exhausting the arc gas on the upper section of the vertical piece of an arc runner. CONSTITUTION:An arc extinguishing device is formed with an arc runner 4 made of a magnetic material, this runner 4 has nearly an L-shape, the tip of a horizontal piece 4a is formed in nearly a U-shape, it is fitted to cover the fixed contact 2 of a power source terminal plate 1, a vertical piece 4b is erected along a rising piece 1c. When an excessive current flows in a circuit breaker, this current flows through the fixed contact 2 and a movable contact 16, the movable contact 16 is driven to be separated from the fixed contact 2. An arc is generated across the contacts 2 and 16 at this time, this arc is run by the arc runner 4 as shown by the arrow (a), the arc resistance is increased by the cathode voltage drop and the cooling effect of the arc, and the arc disappears. The arc gas is smoothly exhausted through an exhaust hole 7 on the upper section of the runner 4 by the pressure of the arc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an arc extinguishing device that extinguishes arcs generated when a circuit breaker is opened and closed.

[Prior Art 1] Conventionally, as shown in FIG. 4, a circuit breaker of this type includes a switching device 11 equipped with a trip mechanism and an electromagnetic side 12 housed in a housing 10, and input/output terminals 13. 1
When an excessive load current flows between 4 and 4, the electromagnetic side 12 operates, and the electromagnetic side 12 is activated. The opening/closing device 11 is located at the tip of the movable iron piece 15 at the position 12.
Trip! There is one that trips the structure and disconnects the movable contact 16 inserted into the load circuit from the fixed contact 2. The handle 17 is used to open and close the contacts 2 and 16 of the opening/closing device W111 and to release the trip state. By the way, in a circuit breaker in which such an excessive current flows between the fixed contact 2 and the movable contact 16, an arc is generated when the movable contact 16 is opened from the fixed contact 2.
There was a problem that the contacts 2 and 16 were worn out. Therefore,
Some devices are equipped with an arc extinguishing device to extinguish this arc. However, conventional arc extinguishing devices often consist of a grid block in which flat grid plates are stacked at predetermined intervals, and an arc runner (which guides the arc to the grid block), so the arc extinguishing device occupies a large space. Therefore, there was a problem that it was difficult to use it for small circuit breakers.

There was also the problem that arc gas generated by the arc could not be smoothly exhausted.

[Problem to be Solved by the Invention 1] The present invention has been made in view of the above-mentioned points, and its object is to provide a circuit breaker that can occupy a small space and can smoothly exhaust arc gas. The purpose of the present invention is to provide an arc extinguishing device.

[Means for Solving Problem 7a] In order to achieve the above object, the present invention provides a power supply terminal board having a fixed contact that comes into contact with a movable contact that is driven by a switching mechanism when an excessive current flows. , an L-shaped arc runner made of magnetic material whose horizontal pieces are erected with horizontal pieces joined to cover the fixed contacts of the power terminal board, and an L-shaped arc runner made of magnetic material that covers almost the entire surface of the power terminal board side of this arc runner and is arranged along the arc runner. The arc runner has an insulating plate provided therein, and an exhaust hole for exhausting arc gas is formed in the upper part of the vertical piece of the arc runner.

(Function) As described above, the present invention comprises an L-shaped arc runner made of a magnetic material in which the horizontal pieces are joined and erected so as to cover the fixed contacts of the power terminal board, and the arc runner on the power terminal board side of the arc runner. By configuring the arc extinguishing device with insulating plates that cover almost the entire surface and are arranged in parallel along the 7-kufunna, the arc extinguishing device has a simple structure, and an exhaust hole for exhausting arc gas is provided at the top of the vertical piece of the arc runner. By forming an exhaust hole in the traveling direction of the arc traveling by the arc runner, the arc bus can be smoothly exhausted.

(Example 1) An embodiment of the present invention is shown in Fig. WS1 and Fig. 2.

The arc extinguishing device of this embodiment is attached to a power terminal board 1 having a fixed contact 2 at one end and the other end serving as a terminal portion 1a for connecting a power line. The power supply terminal board 1 has its center bent upward to form a rising piece 1c, and its upper part horizontally bent to form a terminal portion 1a. This terminal 51m is provided with a screw hole 3 into which a terminal screw is screwed. The arc extinguishing device of this embodiment is formed of an arc runner 4 made of a magnetic material. This arc runner 4 has an abbreviated shape, and the tip of the horizontal piece 4a is formed into a substantially U-shape, and is attached so as to cover the fixed contact 2 of the power terminal board 1.
The vertical piece 4b is erected along the rising piece 1c. Projections 6 to be inserted into the fixing holes 5 of the power terminal board 1 are provided on the lower surfaces of both sides of the fixed contacts 2 of the power terminal board 1 of the horizontal piece 4a.

The base of the fixed part of this arc runner 4 is formed one step higher,
A horizontal piece 8a of an insulating plate 8, which will be described later, is inserted therein. In the upper part of this vertical piece 4b, exhaust holes 7 consisting of three horizontally elongated holes are bored in the vertical direction. This arc runner 4 is fixed to the power terminal board 1, and the vertical piece 4b is erected along the rising piece 1c of the power terminal board 1. A gap is provided between the base of the piece 1c and the horizontal piece 4a of the arc runner 4 and the base of the piece 1b forming the fixed terminal 2 of the power terminal board 1,
An L-shaped insulating plate 8 is interposed in this gap.

Note that the insulating plate 8 has flexibility.

When excessive current flows through the circuit breaker, fixed contact 2
This current flows through the movable contact 16 and the movable contact 1
6 is driven away from the fixed contact 2. At this time, a 7-k occurs between the contacts 2 and 16. This arc travels as shown by arrow A in FIG. 2 by the arc runner 4, and the arc resistance increases due to the cathode voltage drop and the arc cooling effect, and the arc is extinguished. By the way, at this time, since the exhaust hole 7 is formed in the upper part of the arc runner 4, which is the direction in which the arc travels, the air is exhausted from the exhaust hole 7 by the pressure of the arc. At this time, since the insulating plate 8 has flexibility, it bends in the direction away from the arc runner 4 (to the left in FIG. 2), and the arc gas is exhausted. By forming the exhaust hole 7 in the arc runner 4 in this way, the arc gas can be smoothly exhausted. Further, as described above, since it can be constructed from only the arc runner 4 and the insulating plate 8, the construction is simple and the space occupied can be reduced. Note that this insulating plate 8 normally closes the exhaust hole 7 of the arc runner 4 to prevent dust and dirt from outside from entering the circuit breaker.

Furthermore, since the arc runner 4 is made of a magnetic material,
It is possible to provide magnetic shielding between the power supply terminal plate 1 and the movable contact, which has the effect of preventing reverse arc drive.

(Example 2) FIG. 3 shows another example of the present invention. In the above-mentioned embodiment, the exhaust hole 7 was formed by three horizontally elongated holes arranged in parallel in the vertical direction of the arc runner 4, but in this embodiment, as shown in FIG. The exhaust hole 7 is formed by arranging long elongated holes in parallel in the horizontal direction. In this case, exhaust hole 7
Since the space between the two becomes the path for the arc to travel, the arc bus can be evacuated smoothly due to the pressure inside the circuit breaker due to the arc, further reducing the possibility of restriking due to molten metal ions, etc. can do.

[Effect of the Invention 1] As described above, the present invention is capable of opening/closing W when an excessive current flows.
It is attached to a power terminal board that has a fixed contact that comes into contact with a movable contact that is driven by one structure, and is made of magnetic material and has an L-shaped horizontal piece that is erected and joined to cover the fixed contact of the power terminal board. The arc runner is equipped with an insulating plate that covers almost the entire surface of the power terminal board side of the arc runner and is arranged in parallel along the arc runner, and an exhaust hole for exhausting gas is provided in the upper part of the vertical piece of the arc runner. It consists of an L-shaped arc runner made of a magnetic material with horizontal pieces joined to cover the fixed contacts of the power terminal board, and an L-shaped arc runner made of magnetic material that covers almost the entire surface of the power terminal board side of the arc runner. By configuring the arc extinguishing device with the insulating plates arranged in parallel along the arc runner, there is an advantage that the arc extinguishing device can be simplified and the space occupied can be reduced.

Further, since the exhaust hole for exhausting the arc gas is formed in the upper part of the vertical piece of the arc runner, by providing the exhaust hole in the running direction of the arc traveling by the arc runner, there is an effect that the arc gas can be smoothly exhausted.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of essential parts of an embodiment of the present invention, FIG. 2 is a partially cutaway side view of a circuit breaker using the same, and FIG. 3 is a diagram of another embodiment of the present invention. FIG. 4 is an exploded perspective view of the main parts and a sectional view of the conventional example. 1 is a power terminal board, 2 is a fixed contact, 4 is an arc runner, 7
is an exhaust hole, and 8 is an insulating plate. Agent Patent Attorney Ishi 1) Chief 7 Figure 3 Figure 4

Claims (1)

[Claims] (1) It is attached to a power terminal board that has a fixed contact that comes into contact with a movable contact that is driven by the opening/closing mechanism when an excessive current flows, and a horizontal piece is joined and stands up so as to cover the fixed contact of the power terminal board. The arc runner is equipped with an L-shaped arc runner made of a magnetic material, and an insulating plate arranged in parallel along the arc runner to cover almost the entire surface of the power terminal board side of the arc runner. An arc extinguishing device for a circuit breaker, characterized in that the arc extinguishing device is formed by forming an exhaust hole for exhausting.