JP4684945B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker, and more particularly to a circuit breaker that protects an electric circuit from an overcurrent and improves a breaking performance.

The breaking operation in the circuit breaker is performed by restoring the insulation between the contacts by opening the contacts. At this time, it is known that an arc is generated between the contacts, and a voltage at both ends (hereinafter referred to as an arc voltage) increases as the contact opening distance increases. For this reason, by opening the contact at high speed, the arc is quickly stretched, the arc voltage is increased, and the insulation is restored, thereby improving the breaking performance. Many methods have been devised so far to open the contact at high speed, but it is known that a method using the repulsive force between currents is relatively effective. For example, a structure in which a stationary contact is folded as shown in Patent Document 1 corresponds to this.
JP-A-8-264095

  The circuit breaker according to the prior art employs a structure in which the stationary contact is folded in order to obtain the repulsive force between the currents, but there is a limit to making the distance between the currents closer. In addition, in the simple folding structure, the contact opening force is increased, but there is also a problem in that the speed is not sufficiently increased in the initial stage of contact opening due to the inertia of the movable contact.

  In order to solve the above two problems, the present invention arranges the current path of the stationary contact on the side of the movable contact so that the distance between the currents is close and the current parallel to the arc generated when the contact is opened. By providing a path, the arc itself generated even in the early stage of contact opening is pushed out and extended. Further, the shape of the fixed contact that realizes this structure becomes complicated and difficult to process, but the processing is facilitated by partially changing the width of the conductor.

  That is, the present invention includes a contact part including a movable contact and a fixed contact for opening and closing a main circuit, an arc extinguishing chamber that houses the contact part, an opening and closing mechanism that opens and closes the movable contact, In a circuit breaker having an overcurrent tripping portion that opens the movable contact when detecting an overcurrent of a circuit, the fixed contact faces the parallel contact with the movable contact and is movable. A hole or a notch portion larger than the width of the parallel portion of the movable contact is provided at a location where a current that is substantially parallel to and opposite to the current flowing in the contact flows. A circuit breaker having a structure in which a first current path portion located at a lower portion is configured to repel the stationary contact and the movable contact by a repulsive force between the currents when a main circuit current is interrupted to open a contact. It is.

  Further, according to the present invention, the stationary contact is provided with a second current path portion through which a current in a reverse direction flows substantially parallel to the arc generated when the contact is opened, and the repulsive force between the arc and the current A circuit breaker for deforming the arc.

  According to the present invention, the fixed contact has a fixed contact mounting portion, the first current path portion, and the first current path portion on the opposite side of the movable contact, and the first contact A third current path portion having a width smaller than that of the hole or notch portion is provided at a position facing the hole or notch portion provided in the current path portion, and the width of the conductor is partially changed. Circuit breaker.

  According to the present invention, this structure increases the contact opening force, and can open the contact at a higher speed than the conventional structure. In addition, the contact opening distance can be increased by extruding and extending the arc in the initial stage of contact opening. We can make up for the shortage. In addition, by making it possible to easily manufacture a part having this structure, the breaking performance of the circuit breaker can be improved at a low cost.

The best mode for carrying out the present invention will be described.
An embodiment of a circuit breaker according to the present invention will be described with reference to the drawings.

  Example 1 will be described. FIG. 1 is a diagram showing the structure of the circuit breaker of this embodiment. The circuit breaker according to the present embodiment includes a fixed contact 11 and a fixed contact 12 joined thereto, a movable contact 13 disposed at a position opposed to the fixed contact 11 and a movable contact 14 supporting the movable contact 13, and for opening and closing a current. An opening / closing mechanism 15 that drives the movable contact 14 and a tripping device 16 that drives the opening / closing mechanism 15 when an overcurrent flows to open the contacts are configured.

  When an overcurrent flows through the circuit breaker of this embodiment and the tripping device 16 operates, the movable contact 14 is rapidly moved by the opening / closing mechanism 15, and the movable contact 13 is separated from the fixed contact 12. The current path by the fixed contact 11 is generated from the side lower part of the movable contact 14 at a portion (first current path) 1a substantially parallel to the movable contact 14 and between the contacts when the current is interrupted. A portion (second current path portion) 1b that is substantially parallel to the arc to be generated.

  FIG. 2 is a diagram for explaining the principle of the circuit breaker according to the present embodiment, and shows a state during the breaking operation. The fixed contact 21 shown in FIG. 2 has a first current path portion 2a in which a current substantially parallel to and opposite to the lateral lower portion of the movable contact 22 flows, and when a fault current is interrupted. Are provided with a second current path portion 2c through which a current substantially parallel to and opposite to the arc 2b generated between the contact points flows. When a fault current flows through the circuit breaker, first, the current 2d flowing to the movable contact 22 from the current flowing through the first current path portion 2a of the fixed contact 21 receives a repulsive force, so that the movable contact 22 opens at high speed. Then, the arc 2b is stretched by separating the distance between the contacts. Next, the arc 2b generated between the contacts flows in the second current path portion 2c of the stationary contact 21 in a direction in which the arc 2b is pushed in response to the repulsive force from the current 2c which is substantially parallel to and opposite to the arc 2b. It is deformed (illustrated by a dotted line), the arc 2b is stretched beyond the distance between the contacts, and the arc 2b disappears.

  FIG. 3 is a view showing the shape of the stationary contact of this embodiment. The fixed contact includes a contact mounting portion 3a, a divided first current path portion 3b, a third current path portion 3c having a narrow width, and a terminal portion 3d. The third current path portion 3c having a narrow width is divided so that a tool necessary for forming the divided first current path portion 3b or a part thereof can be inserted from below. The width is equal to or smaller than the hole provided in the path 3b. Note that the first current path portion 3b can be provided with only one by providing a notched portion instead of providing two holes divided in a fixed contact made of a plate-like body.

1 is a structural diagram of a circuit breaker according to Embodiment 1. FIG. The principle explanatory drawing of the circuit breaker of Example 1. FIG. FIG. 3 is a structural diagram of a stationary contact in the circuit breaker according to the first embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Fixed contact 12 Fixed contact 13 Movable contact 14 Movable contact 15 Opening / closing mechanism part 16 Tripping device 1a Current path parallel to the movable contact 1b Current path parallel to the arc 21 Fixed contact 22 Movable contact 2a First Current path part 2b Arc between contacts 2c Current parallel to arc 2d Current of movable contact 3a Contact mounting part 3b First current path part 3c Third current path part 3d Terminal part

Claims (2)

A contact portion having a movable contact and a fixed contact for opening and closing the main circuit, an arc extinguishing chamber for storing the contact portion, an opening and closing mechanism for opening and closing the movable contact, and when an overcurrent is detected in the main circuit In a circuit breaker comprising an overcurrent tripping section for opening the movable contact,
The fixed contact faces the parallel contact of the movable contact in parallel and substantially parallel to the current flowing through the movable contact, and the width of the parallel portion of the movable contact at a location where a reverse current flows. By providing a larger hole or notch portion as a first current path portion located at the lower side of the parallel portion of the movable contact, the stationary contact is caused by the repulsive force of the current when the main circuit current is interrupted said to repel the movable contact, we have a structure for opening the contacts and,
The fixed contact is provided on the opposite side of the movable contact with respect to the fixed contact mounting portion, the first current path portion, and the first current path portion and in the first current path portion. And a third current path portion having a width smaller than that of the hole or notch portion at a position facing the hole or notch portion, and the width of the conductor is partially changed. Circuit breaker. The circuit breaker according to claim 1,
The fixed contact is provided with a second current path portion through which a current in a reverse direction flows substantially parallel to the arc generated when the contact is opened, and deforms the arc by a repulsive force between the arc and the current. Circuit breaker characterized by.

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