JPH01255116A - Arc-suppressing chamber for circuit breaker - Google Patents

Abstract

PURPOSE:To improve arc-suppressing ability with a simple structure and with the leak of the pressure in an arc-suppression chamber limited, and improve the breaking performance in particulary an intermediate and low current region by narrowing the width of the notched opening part of an arc-suppressing plate than the inside. CONSTITUTION:The width of the opening part 16a of the notch 16 of an arc- suppressing plate 15 in the arc-suppressing chamber 14, in which arc-suppressing plates 15 in which the moving part of a movable contact 6 is notched in a U- or V-shaped state are multiply laminated in the inside of a U-shaped bulkhead at regular intervals, is composed with the width narrowed than the inside. Here, a projected piece 15a is provided to the plate 15, a leak is limited by receiving pressure with the inside edge surface (plate pressure surface), and the pressure within the chamber 14 is retained. This makes the arc-suppression chamber, having a high arc-suppression ability, of a circuit breaker to be obtained.

Description

[Detailed description of the invention] [Fields of use in industry]

The present invention relates to an arc extinguishing chamber of a circuit breaker such as a wiring breaker or an earth leakage breaker.

[Conventional technology]

Figures 4 and 5 show an example of a circuit breaker.
The figure is an electrical sectional view, and FIG. 5 is a partially cutaway plan view. In FIGS. 4 and 5, inside a molded resin case consisting of a main body 1 and a cover 2, there are a fixed contact 4 which also serves as a terminal plate having a fixed contact 3, a movable contact 6 having a movable contact 5, and an extinguisher. The arc chamber 7 and the like are accommodated. Note that 6a indicates the open position of the movable contact 6. The arc-extinguishing chamber 7 is constructed by stacking a large number of arc-extinguishing plates 0 at intervals inside a partition wall 8 formed by bending arc-resistant insulating plates into a U-shape. The arc-extinguishing plate 9 is made of an iron plate, and the part where the movable contactor 6 moves is cut out in an LJ-shape or a V-shape, and the protrusions at both ends of the plate are fitted into both sleeves of the partition wall 8 to be held. There is. lO is the arc horn. As shown in FIG. 4, such an arc extinguishing chamber 7 is arranged opposite to the movable contact 6 so as to surround the movement trajectory of the movable contact 6 from the closed position shown by the solid line to the open position shown by the broken line 6a. It is located. In such a circuit breaker, when a short circuit occurs in the circuit, the trip device 11 operates and the trip mechanism 1 is activated.
2, the movable contact 6 opens and separates to a position 6a shown in chain lines in FIG. At this time, an arc is generated between the fixed contact 3 and the movable contact 5. This arc is drawn into the arc extinguishing plate 9 and moves toward the back of the °ζ notch. This arc is cooled by the arc-extinguishing plates 9 and is divided into short arcs between each arc-extinguishing plate 9, increasing the arc voltage. Then, the insulating material forming the partition wall 8 is exposed to high temperature and arc-extinguishing gas is generated due to thermal decomposition.
The pressure inside the arc extinguishing chamber 7 rises by 2. This gas is blown onto the arc together with the air inside the mold case to extinguish the arc.

[Problem to be solved by the invention]

FIG. 6 is an enlarged plan view of the arc extinguishing chamber 7. As shown in FIG. 6, in the conventional arc extinguishing chamber 7, the notch 9 of the arc extinguishing plate 9
The width of a is uniform from the entrance to the back. For this reason, the gap dimension A at the notch opening is large, and the leakage of gas pressure from this part toward the opening/closing mechanism 13 (Fig. 4) becomes large, and the pressure inside the arc extinguishing chamber 7 increases when the medium and small current region is interrupted. It did not rise and could not rapidly extinguish the arc. An object of the present invention is to provide an arc extinguishing chamber of a circuit breaker that reduces gas leakage from the arc extinguishing chamber and improves arc extinguishing ability.

[Means for Solving the Problems] This invention provides an arc-extinguishing plate having a cutout in a tJ-shape or a 7-shape in which the movable contact moves. In the arc extinguishing chamber of a large number of stacked circuit breakers, the width of the opening of the cutout of the arc extinguishing plate is narrower than that of the inside. [Function] By configuring the opening of the notch in the arc-extinguishing plate to be narrower than the inside, leakage of arc gas pressure generated inside the notch in the arc-extinguishing plate is reduced.

【Example】

Hereinafter, the present invention will be explained in detail based on FIGS. 1 to 3. Note that the same parts as those in the conventional example are denoted by the same reference numerals, and the explanation thereof will be omitted. FIG. 1 is a perspective view of the arc extinguishing chamber 14 of the present invention, cut approximately in the middle. In FIG. 1, arc extinguishing plate 15
is provided with a protruding piece 15a extending toward the movable contact 6 at the opening 16a of the notch 16.
The width of 6a is narrowed. FIG. 2 is a cross-sectional view of the arc extinguishing chamber 14 with the movable contact 6 separated, and FIG. 3 is a plan view thereof. When the circuit breaker performs a breaking operation and the movable contact 6 opens, an arc 17 is generated between the fixed contact 3 and the movable contact 5 as shown in FIG. As a result, as mentioned above, the pressure within the arc extinguishing chamber 14 increases, and this pressure spreads exponentially as shown by the arrow in FIG. In particular, the opening/closing machine side 13 without bulkhead 8
Leakage occurs to the sides. Therefore, in the illustrated embodiment, a protruding piece 15 is provided on the arc extinguishing plate 15.
A is provided, and the inner end surface (plate pressure surface) receives the pressure, thereby reducing leakage and maintaining the pressure inside the arc extinguishing chamber 14.

【Effect of the invention】

According to this invention, with a simple configuration in which the width of the notch opening of the arc extinguishing plate is made narrower than the inside, leakage of pressure in the arc extinguishing chamber is reduced and arc extinguishing ability is increased, and the arc extinguishing ability is improved, especially in the medium and small current range. Performance can be improved.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is a perspective view of the arc extinguishing chamber broken approximately at the center, FIG. 2 is a longitudinal sectional view of the arc extinguishing chamber illustrating the generation of arc, FIG. 3 is a plan view of FIG. 2. Figure 4 is a sectional view showing the general configuration of a circuit breaker.
FIG. 5 is a partially cutaway plan view, and FIG. 6 is an enlarged plan view of the conventional arc extinguishing chamber. 6: Movable contact, 8: Partition wall, 14: Arc extinguishing chamber, 15: Arc extinguishing plate, 15a: Projecting piece, 16: Notch, 16a: Notch opening. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1) In the arc extinguishing chamber of a circuit breaker, in which a large number of arc extinguishing plates, each having a U-shaped or V-shaped notch in which the movable contact moves, are stacked at intervals inside a U-shaped partition wall. , an arc extinguishing chamber of a circuit breaker, characterized in that the width of the opening of the notch of the arc extinguishing plate is narrower than that of the inside.