JPH0110840Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to speeding up the start of operation of the opening mechanism of a current-limiting circuit or circuit breaker equipped with an electromagnetic repulsion contactor.

Conventional current-limiting type circuit breakers have both movable and fixed contacts that are opened and closed via an opening/closing mechanism using a handle, and these movable contacts have a repulsion structure and are always closed in series with the main circuit. There is also a structure with an additional repulsive contact. When a large current such as a short circuit current flows, the repulsive contact instantly opens due to the electromagnetic repulsion force that acts between it and the fixed contact, thereby limiting the short circuit current. After a slight delay, the electromagnetic tripping device operates and completes the contact breakage via the opening/closing mechanism.

However, in the current electromagnetic tripping device, the attraction characteristics of the electromagnet become saturated as the current increases. Furthermore, in order to reduce the amount of force needed for the tripping operation, the tripping mechanism has a multi-stage pressure reduction structure, so it is not possible to increase the speed of the operation as the current increases. On the other hand, the speed of the electromagnetic repulsive contact increases as the current increases because the electromagnetic repulsive force increases in proportion to the square of the current.

As a result, the repulsive contact, which once opened when a large current passed, will
There are problems such as the beginning of reinstatement and re-contact, resulting in a decrease in shearing performance due to a decrease in the shearing distance, or strong contact welding.

This invention uses the movement of the repulsive contactor to act on the tripping device to speed up the operation of the opening mechanism, thereby eliminating the above-mentioned drawbacks of the conventional method.

An embodiment of this invention will be described with reference to FIG.

This figure is a sectional view showing an example of application to a structure in which a repulsive contactor is added in series to the main body. 1 is a well-known toggle link mechanism, 2 is a thermal electromagnetic trip device that performs tripping in response to overcurrent, 3 is an interlocking plate that constitutes the tripping mechanism and performs common tripping, and 4 and 5 are toggle link mechanisms. Main movable and fixed contact that opens and closes, 6 is a repulsive contact that opens and opens in response to large current,
7 is a fixed contact for this.

In the present invention, the interlocking plate 3 and the repulsive contact 6 are connected by a flexible metal wire 8 coated with insulation, and a groove 10 and a roller 9 are provided at the bent portion of the wire.

According to this structure, when a current large enough to open the repulsive contact 6 flows, the repulsive contact 6 instantly opens due to the electromagnetic repulsion force acting between it and the fixed contact 7, thereby limiting the short-circuit current. At the same time, the metal wire 8 transmits this movement to the interlocking plate 3 of the tripping mechanism. The interlocking plate 3 rotates clockwise around the fulcrum 3', and the latches 11, 12
The opening/closing mechanism performs a tripping operation via the terminal, causing the opening/closing mechanism to perform an opening operation, and completes the shearing and disconnection of the main contact. In a small overcurrent region where the repulsion contactor 6 does not operate, a conventional thermal or electromagnetic trip device is used to trip and disconnect.

The conditions that this transmission line must meet include good displacement response (less stretch), sufficient strength, and electrical insulation. It uses metal wire.

Normally, in a structure in which a separate current limiter is added to the circuit breaker or breaker body, the main unit itself is a single circuit breaker or breaker, so there is little space available, and a complicated tripping device is added. However, according to the present invention, it is only necessary to route a flexible wire into an empty space, and the above-mentioned tripping device can be easily added. Further, by adjusting only this line, the tripping operation time can be changed.

Figure 2 shows the characteristics of the opening time of the mechanism under instantaneous overload current when the present invention is applied to a 1000A frame circuit or disconnector. The characteristics indicated by the broken line are those due to conventional electromagnetic tripping. As is clear from the figure, the time required for the mechanism to open the electrode can be accelerated. This also eliminates the problem of welding.

In addition, conventionally, only a current limiter was used to perform the rupture, but with this invention, the opening time of the switching mechanism is faster, and the main contact opens at the same time as the repulsive contact. Therefore, arcs generated at two locations can be superimposed, further improving current limiting performance and increasing shear breaking capacity.

The above is an example of application to circuits and disconnectors with a structure in which a current limiter with an electromagnetic repulsion contactor is added to the main body.
The same applies to circuits and circuit breakers that do not have a current limiter and have a movable contactor of a repulsive structure.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a circuit breaker according to an embodiment of the invention, and FIG. 2 is a graph of opening start time versus current characteristics when the device of the invention is used. 2, 3, 11, 12: tripping mechanism, 6: movable contact, 8: flexible wire.

Claims (1)

[Scope of utility model registration request] a main movable contact that opens and closes an electric circuit; a repulsive contact that is connected in series with the main movable contact and is configured to repel and limit current when a large current occurs; and an overcurrent detector that responds to overcurrent; A circuit breaker comprising a tripping mechanism that trips the main movable contact by operation of the overcurrent detector, one end of which is connected to the repulsion contact and the other end of which is connected to the tripping mechanism. 1. A circuit breaker comprising a flexible wire, the flexible wire being stretched so as to transmit the movement of the repulsive contactor to the tripping mechanism.