JPS6113524A - Circuit breaker - Google Patents

Abstract

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

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electric circuit breaker, and more particularly to an electric circuit breaker equipped with an arc runner for guiding an arc generated when an electric circuit is interrupted. .

[Conventional technology]

Conventionally, there has been a device of this type as shown in FIG. In the figure, an arc-extinguishing grid is provided in front of the movable contact l with contact /a, and the fixed contact part 3 is connected to the contact 3.
with metal to the conductor 3b provided with a.

It was equipped with a plate-shaped arc runner.
In the power circuit, when the movable contact 1 is closed, current flows from the contact /a to the contact 3a, and flows through the conductor 3b. GRIDCO, ARCLAN, and NADA handle arcs that occur when electrical circuits are opened.

With the above configuration, a current detection relay (not shown) is activated by a short circuit, a fault, or a fault current generated during overload operation in the electrical circuit, and mechanically detects The movable contact l is opened. At this time, contact /a and contact 3a
An arc 5 occurs between.

This arc j is induced by electromagnetic force in the arc runner l, and the arc is further induced in the direction of the arrow, and the arc S is split by the grid controller. Due to the cathode voltage drop and the arc cooling effect, the arc resistance increases and the arc j is extinguished. to complete the shutdown.

During the above operation, the arc runner Hiroshi is exposed to the arc SK, as shown in Figure 3, the arc runner tei melts, and the portion lIa shown by the dashed line in Figure 3 melts away, losing its function as an arc runner. If you don't lose it, it will interfere with the next cutoff. Further, the generation of metal gas at this time deteriorates the condition of the arc extinguishing space, and the longer the shutoff time is, the more unfavorable it is in terms of shutoff performance.

Conventional circuit breakers were constructed as described above, so
This had the disadvantage that the arc runner was exposed to the arc over its entire circumference, increasing the amount of metal gas and deteriorating the interrupting performance. Another drawback was that the arc runner lost its function after the arc runner was fused.

[Summary of the invention]

The present invention was made in order to eliminate the above-mentioned drawbacks of the conventional circuit breaker, and provides a circuit breaker which is provided with an arc guard that protects the side and bottom surfaces of an arc runner from arcs.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 5 to g. FIG. 3 shows a fixed contact portion according to the present invention, and the fixed contact portion 3 has a female thread 3c formed at the end of a conductor 3b with a biased contact point 3a, and an arc runner bow is attached thereto. The arc guard 6 made of an insulator is attached to the fixed contact part 3, and has l pairs of mutually parallel retainers tlfga in contact with or close to both side surfaces of the arc runner bow.

As with the conventional one, the electrical circuit is from the contact point of the flexible Ur contactor (not shown in the figure) to the contact point 3a, and further via the conductor 3IJ to the 1st part (not shown) screwed with the female screw 3c. energized.

Next, the operation will be explained. As in the conventional example, when a fault current is detected and the movable contact is opened, an arc is generated and this arc is guided from the contact to the arc runner bow.

In FIG. 6, the arc S is guided from the contact point 3a to the arc runner trough. The arc at this time! FIG. 7 shows the state in which the arc guard 6 is close to both sides of the arc runner t, so the arc S is restricted from the side and bottom surfaces of the arc runner t. 5, only one direction is exposed, so less metal gas is generated and the condition of the arc extinguishing space is not deteriorated. Further, even after the shutoff is completed, the arc runner bow is only worn out on one side as shown in Figure 1, so it is possible to prevent the arc runner bow from melting away.

Furthermore, in this embodiment, the arc guard 6 is enlarged so that the box-shaped portion 6b also protects the area around the contact 3a, which further suppresses the generation of metal gas and limits the passing current at the time of interruption to extinguish it. It improves the condition of the arc space and the breaking performance is economically improved.

In the above embodiment, a circuit breaker is used (4I), but a disconnector or other switching device may be used, and the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, since the exposure of the arc runner to the arc generated during shutoff is limited, the condition of the arc extinguishing space during shutoff is improved, and the shutoff performance is improved. Further, it is possible to prevent melting and loss of the arc runner.

[Brief explanation of the drawing]

Figures 1 to WC44 show a conventional device, where Figure 1 is a side sectional view of the main part, Figure 2 is a side sectional view of the main part for explaining the operation, and Figure 3 is the first @ for explaining the operation. A cross-sectional view taken along the line I[-11I, and FIG. 9 is a partial side cross-sectional view for explaining the operation. Fig. 5 to Fig. J show one embodiment of the present invention, Fig. 5 is an exploded perspective view of the main part, Fig. 1 is a side sectional view of the main part for one MQ Ming, and Fig. 7 is an explanation of the operation. FIG. 6 is a cross-sectional view taken along the line ■--■, and the second figure is a cross-sectional view of the same portion as the second figure showing the final state. L...Movable contact, Co...Grid, 3...Fixed contact portion, 3a...Contact, 3b...Conductor, D...Arc runner, 6...Arc guard, 6a...Protection wall, 6b... Box-shaped part. In each figure, the same reference numerals indicate the same or corresponding parts. Figure 1 (ri) Figure 3) 7f, t, figure] Figure 5 Figure 6

Claims (2)

[Claims] (1) A current detection relay that detects fault current flowing during short circuits or overload operation, a movable contact that is mechanically coupled to this current detection relay and opens and closes the electrical circuit, and a A contact, a conductor constituting the electric path, a plate-shaped arc runner for guiding the arc generated when the current is cut off, and a side surface of the arc runner for guiding the arc generated when the current is interrupted. A circuit breaker, characterized in that the fixed contact portion is made of an arc guard made of an insulating material for protection. (2) The circuit breaker according to claim 1, comprising an arc guard in which a box-shaped part is formed to protect the contacts of the fixed contact part.