JP4776638B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker provided with a movable movable contact such as a circuit breaker for a wiring or an earth leakage breaker, and in particular, is disposed in the vicinity of a pair of a movable contact and a fixed contact and extinguishes when interrupted. The present invention relates to a circuit breaker including an insulator that discharges gas and enhances current limiting performance.

  In the conventional circuit breaker, the rotary movable contactor has a configuration in which an insulating member for generating arc-extinguishing gas at the time of breaking is disposed in the vicinity of the contact point (see, for example, Patent Document 1).

Japanese Patent No. 3392441 (page 3, right column, line 48 to page 4, left column, line 20, FIG. 6)

  In the conventional circuit breaker, the insulation for the purpose of discharging arc-extinguishing gas at the time of breaking and improving the current-limiting performance in the vicinity of the two movable contacts provided at both ends of the movable contact and the stationary contact that contacts and energizes each. However, because the insulator and the shape of the insulator provided in the vicinity of the two contact pairs are the same, the initial interruption performance cannot be obtained or the internal pressure of the insulator is excessive. In order to increase, there has been a problem that a high-strength casing material has to be used, resulting in an increase in cost.

This invention was made in order to solve the above-described problems, and by making the structure (shape, material) of one insulator and the other insulator provided in the vicinity of two contact pairs different,
An object of the present invention is to provide a circuit breaker capable of optimally controlling the internal pressure in the vicinity of the contact and enhancing the current limiting performance at the time of breaking, and reducing the cost by reducing the cost of the housing material.

  The circuit breaker according to the present invention is provided with a rotating movable contact having movable contacts at both ends, and a fixed contact that cooperates with the movable contact of the movable contact. A power supply side terminal and a load side terminal that cause an electric current to flow to the movable contact and generate an electromagnetic repulsive force to the open position in the movable contact, a rotary drive rod that transmits a rotational force to the movable contact, In a circuit breaker that is fixed and has a tension spring that applies a contact pressure of a movable contact that presses the movable contact against the fixed contact at a closing position of the circuit breaker, the power supply side terminal and the load side terminal are each paired An insulator that discharges arc-extinguishing gas that enhances the current-limiting performance by an arc between each contact pair is arranged near the movable contact and the fixed contact, and one (power-side terminal) insulator is generated. Arc extinguishing gas amount and the other (negative Extinguishing gas amount insulator occurs side terminal) is obtained by disposing the insulating material differently.

  According to the circuit breaker of the present invention, one of the insulators provided in the vicinity of the two contact pairs is different in shape (arrangement position) and material from the other insulators, so that the arc-extinguishing gas can be obtained. Since the generated amount is different, the internal pressure in the vicinity of the contact can be optimally controlled, and the current limiting performance at the time of interruption can be enhanced. Further, the housing material can be made inexpensive and the cost can be reduced.

  The above-described and other objects, features, and effects of the present invention will become more apparent from the detailed description and the drawings in the following embodiments.

Embodiment 1 FIG.
A circuit breaker according to Embodiment 1 of the present invention will be described below with reference to FIGS. 1 is a cross-sectional view showing an off state of a movable contact of a circuit breaker according to Embodiment 1 of the present invention, FIG. 2 is a cross-sectional view showing a state where a circuit breaker is on, and FIG. FIG. 4 is a cross-sectional view showing the periphery of the fixed contact cut along BB in FIG. 1.
In addition, in each figure, the same code | symbol shall show the same or an equivalent part.
In FIG. 1 to FIG. 4, the movable contact 1, the power supply side terminal 2, and the load side terminal 3 are provided in the arc extinguishing chamber 7 provided with the exhaust ports 7 a and 7 b. A rotational force from a not-shown) is transmitted through the rotational drive rod 6 so as to rotate. When the circuit breaker is turned on, as shown in FIG. 2, the movable contact 1 a comes into contact with the fixed contact 2 a installed at one end of the power supply side terminal 2, and the other movable contact 1 b is installed at one end of the load side terminal 3. It contacts with the fixed contact 3a made.

The screw hole 2b for connecting to the electric wire is provided at one end opposite to the fixed contact 2a of the power supply side terminal 2, and the fixed contact 3a of the load side terminal 3 is provided. A screw hole 3b connected to the overcurrent tripping element is provided at one end opposite to the above.
In addition, the tension springs 4 and 5 are arranged in the rotation drive rod 6 to generate contact contact pressure that presses the movable contacts 1a and 1b of the movable contact 1 against the fixed contacts 2a and 3a when the circuit breaker is on. ing.

  As shown in FIGS. 1 and 3, the both sides of the movable contact 1a and the fixed contact 2a are extended in the opening direction of the movable contact 1a to discharge arc-extinguishing gas at the time of short-circuit interruption to improve the current limiting performance. Insulator 8 is installed. Further, as shown in FIGS. 1 and 4, the both sides of the movable contact 1b and the fixed contact 3a are extended in the opening direction of the movable contact 1b, and the arc extinguishing gas is discharged when the short circuit is interrupted, thereby providing current limiting performance. An insulator 9 for increasing the height is provided, and the insulator 9 is provided with a flat plate portion 9a so as to cover the periphery of the fixed contact 3a. The distance L between both side surfaces of the insulator 8 is such that the distance L> the distance M 1 with respect to the distance M between both side surfaces of the insulator 9.

In the arc-extinguishing chamber of the circuit breaker according to the first embodiment configured as described above, when the short circuit is interrupted, the arc is generated from the insulator 8 by the thermal energy of the arc generated between the contact pair of the movable contact 1a and the fixed contact 2a. Compared to the arc-extinguishing gas, the arc-extinguishing gas generated from the insulator 9 due to the thermal energy of the arc generated between the contact pair of the movable contact 1b and the fixed contact 3a is more preferable to the insulator 9 than the generated arc. Since it receives more heat energy soon, the amount of emissions increases.
Therefore, the current limiting performance can be further improved as compared with the case where the insulator 8 having the same shape is disposed on both sides of the movable contact 1a and the fixed contact 2a, and the movable contact 1b and the fixed contact 3a.

  On the other hand, when the insulator 9 having the same shape is disposed on both sides of the movable contact 1a and the fixed contact 2a, and the movable contact 1b and the fixed contact 3a, an excessive internal pressure is generated, and the material of the arc extinguishing chamber 7 is expensive. There is a concern that it will be necessary to change to a high-strength material, but by disposing differently shaped insulators 8 and 9 at both contact pairs, the generated internal pressure can be reduced, and the arc extinguishing chamber material cost can also be reduced. .

In the case of repeatedly interrupting a current several times the rated current, if the insulator is too close to the contact point, a phenomenon occurs that the insulation resistance on the surface of the insulator is lowered and the current is not easily cut off.
Also in the first embodiment, since the insulator 9 is disposed on both sides of the movable contact 1b and the fixed contact 3a near the contact, the current region several times the rated current is repeatedly cut off. However, the insulator 8 provided on both side surfaces of the other contact pair 1a and 2a, which is arranged in series in the circuit, is provided with an insulator away from the contact. Even when a current several times larger than the current is repeatedly interrupted, there is no problem with the interrupting performance.

  In the above description, the distance from the insulator to the arc (the shape of the insulator) has been described. For example, when an insulator having the same shape is provided at both contact pairs, the material of the insulator is changed. Needless to say, the same effect can be expected by using one having a large amount of generated gas and the other having a small amount of generated gas.

It is sectional drawing which shows the OFF state of the circuit breaker in Embodiment 1 of this invention. It is sectional drawing which shows the ON state of the circuit breaker in Embodiment 1 of this invention. It is sectional drawing which shows the surroundings of the stationary contact cut | disconnected by AA of FIG. 1 which shows Embodiment 1 of this invention. It is sectional drawing which shows the fixed contact periphery cut | disconnected by BB of FIG. 1 which shows Embodiment 1 of this invention.

Explanation of symbols

1 movable contact, 1a, 1b movable contact,
2 Power supply side terminal, 2a Fixed contact, 2b Screw hole,
3 Load side terminal, 3a Fixed contact, 3b Screw hole,
4, 5 tension spring, 6 rotation drive rod,
7 Arc extinguishing chamber, 7a, 7b Exhaust port,
8 Insulator, 9 Insulator, 9a Flat part.

Claims (3)

  A rotary contact having a movable contact at both ends, and a fixed contact that cooperates with the movable contact of the movable contact, and a current flows to the movable contact when a short-circuit current is generated. A power source side terminal and a load side terminal for generating an electromagnetic repulsive force to the open position in the child, a rotary drive rod for transmitting the rotational force to the movable contact, fixed to the rotary drive rod, and at a closing position of the circuit breaker In a circuit breaker including a tension spring that applies contact pressure of a movable contact that presses the movable contact against the fixed contact, in the vicinity of the movable contact and the fixed contact forming a pair of the power supply side terminal and the load side terminal, An insulator that discharges arc-extinguishing gas that enhances the current-limiting performance by the arc between each contact pair at the time of circuit interruption is disposed, and the amount of arc-extinguishing gas generated by one (power supply side terminal) insulator and the other (load Side terminal) is generated. Circuit breaker, characterized in that the amount of arc gas is arranged the insulator differently.   2. The circuit breaker according to claim 1, wherein the amount of arc extinguishing gas generated by making the one insulator and the other insulator different in shape is different.   2. The circuit breaker according to claim 1, wherein the amount of arc extinguishing gas generated by changing the material of the one insulator and the other insulator is different.

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