JP2010140719A - Circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable electric current shutdown on an electric path of a circuit breaker not only when an excess current flows into the electric path, but also when the circuit breaker is in an overheated state even without the excess current flowing in the electric path. <P>SOLUTION: A tripping means of the circuit breaker unit is to structure a fixed side portion of an interior magnetic circuit member of a permanent magnet and a temperature-sensitive magnetic material whose magnetic permeability falls off by temperature rise, and to structure a movable side portion of the interior magnetic circuit member so as to be biased by elastic resilience force of a spring against magnetic attraction force between the movable side portion and the fixed side portion to make movement displacement by the elastic resilience of the spring forcing, as the magnetic attraction force becomes smaller than the elastic resilience of the spring within the magnetic circuit member, when excess current is detected and the magnetic circuit member is excited in a direction of reducing a magnetic field due to the permanent magnet by an excitation coil, or when temperature of the temperature-sensitive magnetic material exceeds a pre-established temperature. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a circuit breaker that cuts off an overcurrent of an electric circuit, and more particularly to a configuration of a tripping unit that operates an opening / closing mechanism.

  Prior arts related to the present invention and described in patent documents include, for example, Japanese Patent Application Laid-Open No. 04-75228 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2005-184924 (Patent Document 2). Technology has been developed. In Japanese Patent Laid-Open No. 04-75228, as a circuit breaker, when an output signal is input from an electronic overcurrent relay to a tripping coil of a tripping section, the direction of canceling the magnetic flux of the permanent magnet of the tripping section In Japanese Patent Application Laid-Open No. 2005-184924, there is described a temperature sensing switch in which the permeability decreases as the temperature increases. When the temperature-sensitive magnetic body does not exceed a predetermined temperature between the magnetic member provided on the fixed portion and the magnet member provided on the movable portion, the temperature-sensitive magnetic body is attached to the temperature-sensitive magnetic body. A configuration is described in which the magnet member is provided with a temperature-sensitive actuator that moves when the magnet member leaves the temperature-sensitive magnetic body when the temperature exceeds a predetermined temperature, and the movable portion is pushed by a spring member during the movement. The movable current-carrying terminal is connected to the spring. It is displaced against the elastic restoring force of the wood, and is configured to separate the contact portion from the contact portion of the current supply terminal of the fixed side.

Japanese Patent Laid-Open No. 04-75228 JP 2005-184924 A

  In the technique described in Japanese Patent Laid-Open No. 04-75228, when the output signal is not input from the electronic overcurrent relay to the tripping coil of the tripping section, the armature is not displaced. In the case where there is a deterioration of the contact or a failure in connection to the electric circuit, even if the current in the electric circuit is not excessive, the circuit breaker may be overheated due to the current and the circuit breaker may be burned out. Further, in the technique described in Japanese Patent Application Laid-Open No. 2005-184924, since the movable part of the temperature-sensitive actuator does not move unless the temperature of the temperature-sensitive magnetic body exceeds a predetermined temperature, for example, an electric circuit to which a temperature-sensitive switch is connected. If the temperature of the temperature-sensitive magnetic body does not exceed a predetermined temperature even when an overcurrent flows, the movable part of the temperature-sensitive actuator does not move and displace. For this reason, in this case, the overcurrent of the electric circuit remains energized without being interrupted, and burnout or the like occurs in the equipment connected to the electric circuit.

The problem of the present invention is that, in view of the state of the prior art, in the circuit breaker, even when an overcurrent flows in the electric circuit, the circuit breaker exceeds a preset temperature even if no overcurrent flows in the electric circuit. Even when an overheated state occurs, the current in the circuit can be cut off.
An object of the present invention is to provide a circuit breaker capable of solving such problems and further improving the reliability of the circuit breaker and ensuring safety widely.

  In order to solve the above-mentioned problems, in the present invention, the circuit breaker tripping means, the fixed side portion of the internal magnetic circuit member, the permanent magnet, and the temperature-sensitive magnetic material whose magnetic permeability decreases with increasing temperature, And the movable side portion of the magnetic circuit member is urged against the magnetic attractive force between the movable side portion and the fixed side portion by the elastic restoring force of the spring, and an overcurrent is generated. When the detected magnetic circuit member is excited by the exciting coil in a direction to reduce the magnetic field by the permanent magnet, or when the temperature of the temperature-sensitive magnetic material exceeds a preset temperature, the magnetic circuit member The magnetic attraction force is smaller than the elastic restoring force of the spring, and the movable side portion is moved and displaced by the elastic restoring force of the spring.

  According to the present invention, in the circuit breaker, even when an overcurrent flows through the electric circuit, or when the circuit breaker enters an overheated state without an overcurrent flowing through the electric circuit, the electric current in the circuit is interrupted. Thus, the reliability of the circuit breaker can be further improved, and a wide range of safety can be ensured.

Embodiments of the present invention will be described below with reference to the drawings.
1-3 is explanatory drawing of the circuit breaker as an Example of this invention. FIG. 1 is a diagram showing the structure of a circuit breaker as an embodiment of the present invention, FIG. 2 is a diagram showing a state when the tripping means in the circuit breaker of FIG. 1 is not energized, and FIG. It is a figure which shows the state at the time of energization or overheating of the trip means in the circuit breaker.

  In FIG. 1, 1 is a circuit breaker as an embodiment of the present invention, 10a and 10b are external electric circuits to which the circuit breaker 1 is connected, and 11a is an electric circuit of the circuit breaker 1 connected to the external electric circuit 10a. The connection terminal 11b is a circuit connection terminal of the circuit breaker 1 connected to the external circuit 10b, 12 is a fixed contact, 13 is a movable contact, 13a is a pivot point of the movable contact 13, and 14 is a movable contact. 13 is an opening / closing mechanism section for moving the movable contact 13 from the non-contact state to the contact state with respect to the fixed contact 12, and 15 is an open / close mechanism section for moving the open / close mechanism section 14 to the movable contact position. Tripping means for actuating the contact 13 with respect to the fixed contact 12 from a contact state to a non-contact state, 16 is a current transformer as a current detection means for detecting the current of the electric circuit, 17 is a handle, 18 is The movable contact 13 An arc extinguishing section that suppresses an arc generated between the fixed contact 12 and the fixed contact 12 when the fixed contact 12 is brought into a non-contact state, 19 is a case, and 21 is a mechanical output from the tripping means 15. A trip lever 22 in the rotating opening / closing mechanism 14, 22 is a trip metal fitting in the opening / closing mechanism 14, and 23 is a hook in the opening / closing mechanism 14. An electric circuit inside the circuit breaker 1 (hereinafter referred to as an internal electric circuit) is formed between the terminals 11a and 11b via a fixed contact 12 and a movable contact 13. The external electric circuits 10a and 10b and the internal electric circuit are collectively referred to simply as an electric circuit. The fixed contact 12 and the movable contact 13 constitute a contact portion, and the contact portion is connected to an electric circuit, and the electric circuit is closed or opened by contact or non-contact between the movable contact 13 and the fixed contact 12. . The opening / closing mechanism section 14 is configured to have a four-bar linkage mechanism, and the tripping means 15 rotates the movable contact 13 around the pivot fulcrum 13 a so that the movable contact 13 is moved with respect to the fixed contact 12. The connected state can be changed from the connected state to the disconnected state, and the movable contact 13 is rotationally displaced about the rotational fulcrum 13a by the operation of the handle 17 so that the movable contact 13 is not connected to the fixed contact 12. The connection state can be changed from the connection state, and the connection state can be changed from the connection state to the disconnection state.

  The trip means 15 includes a magnetic circuit member and an exciting coil, and the magnetic circuit member includes a fixed side portion including a permanent magnet, a movable side portion having a magnetic material, and the movable side portion as a fixed side portion. And a spring that is urged by an elastic restoring force against the magnetic attractive force between them, and when the current transformer 16 as a current detecting means detects an overcurrent of the electric circuit (internal electric circuit), A current is applied to the coil, and the magnetic circuit member is excited in a direction to reduce the magnetic field generated by the permanent magnet. As a result, the magnetic attractive force between the movable side portion and the fixed side portion is restored to the elasticity of the spring. The movable side portion is moved and displaced with respect to the fixed side portion by the elastic restoring force of the spring, and the opening / closing mechanism portion 14 is moved to the movable contact 13 by the displacement. On the other hand, it becomes a contactless state To operate as. As a result, the electric circuit is turned off in the circuit breaker 1, and the overcurrent is interrupted.

  The tripping means 15 is also used when the temperature in the circuit breaker 1 rises and exceeds a preset temperature even when the energization current does not reach the overcurrent level during energization of the electric circuit. Operates the open / close mechanism 14 so that the movable contact 13 changes from the connected state to the non-contact state with respect to the fixed contact 12 in a state where no current is supplied to the exciting coil. In other words, the tripping means 15 has a temperature-sensitive magnetic material whose permeability decreases with an increase in temperature in the fixed side portion of the magnetic circuit member, and the temperature in the circuit breaker 1 increases and the temperature-sensitive magnetism is increased. When the temperature of the material exceeds a preset temperature, the magnetic permeability of the temperature-sensitive magnetic material decreases, increasing the magnetic resistance of the magnetic circuit and decreasing the amount of magnetic flux in the magnetic circuit. As a result, the magnetic attractive force between the movable side portion and the fixed side portion becomes smaller than the elastic restoring force of the spring, and the movable side portion moves relative to the fixed side portion by the elastic restoring force of the spring. Due to the displacement, the opening / closing mechanism unit 14 is operated so that the movable contact 13 changes from the connected state to the non-contact state with respect to the fixed contact 12. Thereby, the electric circuit is turned off in the circuit breaker 1, and the energized current is interrupted.

When the movable side portion of the magnetic circuit member of the tripping means 15 is moved and displaced by the elastic restoring force of the spring, the trip lever 21 is rotated in the opening / closing mechanism portion 14 based on the moved displacement, thereby the trip lever. 21 and the trip fitting 22 are disengaged, the trip fitting 22 rotates, the trip fitting 22 and the hook 23 are disengaged, and the hook 23 rotates to rotate the movable contact 13 around the fulcrum 13a. The movable contact 13 and the fixed contact 12 are disconnected from each other and moved away from the fixed contact 12.
Hereinafter, the same reference numerals as those in FIG. 1 are attached to the components of the circuit breaker 1 in FIG. 1 used in the description.

FIG. 2 is a diagram showing a state when the tripping means 15 in the circuit breaker of FIG. 1 is not energized.
In FIG. 2, 151 is a permanent magnet, 152 is a temperature-sensitive magnetic material whose magnetic permeability decreases with increasing temperature, 153 is a block-shaped fixed yoke, 154 is a cylindrical fixed yoke, 155 is a plate-shaped fixed yoke, 156 Is a movable yoke made into a rod-like body, 157 is an exciting coil, 158 is a bobbin, 159 is a compression coil spring as a “spring” that applies an elastic restoring force to the movable yoke 156 in the X-axis direction, and 160 is a movable A spring engaging member 200 fixed to the yoke 155 and engaged with the compression coil spring 159 is a magnetic flux generated by the permanent magnet 151. The permanent magnet 151, the temperature sensitive magnetic material 152, the fixed yokes 153, 154, 155 and the movable yoke 156 constitute a magnetic circuit member, and among these, the permanent magnet 151, the temperature sensitive magnetic material 152, the fixed yokes 153, 154, 155. Constitutes the fixed side portion of the magnetic circuit member, and the movable yoke 156 constitutes the movable side portion of the magnetic circuit member. The magnetic circuit is formed by these magnetic circuit members. In the configuration of FIG. 2, the magnetic flux 200 emitted from the permanent magnet 151 passes through the magnetic circuit member through the fixed yokes 154 and 155, the movable yoke 156, the fixed yoke 153, It passes through the order of the warm magnetic material 152 and returns to the permanent magnet 151. When the movable yoke 156 is in contact with the fixed yoke 153 at the position a and no current is supplied to the exciting coil 157, the movable yoke 156 has a magnetic attraction force generated by the magnetic flux 200 of the permanent magnet 151 and a compression coil spring 159 on the fixed yoke 153 side. It is sucked in the -X-axis direction against the elastic restoring force. As the temperature-sensitive magnetic material 152, a material having a characteristic that when the temperature exceeds 150 ° C., the magnetic permeability is reduced to, for example, 60% or less of the magnetic permeability at normal temperature. When the magnetic permeability of the temperature-sensitive magnetic material 152 becomes 60% or less of the magnetic permeability at normal temperature, the magnetic attractive force acting on the movable yoke 156 in the state of FIG. 2 is the elasticity of the compression coil spring 159 in the X-axis direction. It is designed to be smaller than the restoring force. On the contrary, the compression coil spring 159 is designed so that the elastic restoring force in the X-axis direction is larger than the magnetic attractive force when the magnetic permeability is lowered. The movable yoke 156 is inserted into the exciting coil 157, and the compression coil spring 159 is concentrically fitted to a part of the movable yoke 156. The temperature of the temperature-sensitive magnetic material 152 and the temperature of the entire circuit breaker 1 are substantially equal. When the temperature of the temperature-sensitive magnetic material 152 exceeds 150 ° C., the temperature of the circuit breaker 1 also exceeds 150 ° C. According to the experiment by the inventors, the temperature 150 ° C. at which the movable yoke 156 is moved and displaced in the X-axis direction in the tripping means 15 is a limit temperature at which the circuit breaker 1 does not burn or break. If the temperature is higher than this, the circuit breaker 1 may be burned or broken, and if the temperature is lower than this, the decrease in the magnetic permeability of the temperature-sensitive magnetic material 152 is small.
Hereinafter, the same reference numerals as those in FIG. 2 are used for the components of the configuration in FIG. 2 used in the description.

FIG. 3 shows that when a current is applied to the exciting coil 157 of the tripping means 15 in the circuit breaker 1 of FIG. 1 or when the circuit breaker 1 becomes overheated due to the current flowing in the circuit. It is a figure which shows the state of the trip means 15 when the temperature of a warm magnetic material exceeds 150 degreeC.
In FIG. 3, 153 a is a surface of the fixed yoke 153 facing the movable yoke 156, and 156 a is a surface of the movable yoke 156 facing the fixed yoke 153. FIG. 3 shows that the magnetic attractive force on the movable yoke 156 by the magnetic flux of the permanent magnet 151 is lower than that in the state of FIG. 2 and becomes smaller than the elastic restoring force in the X-axis direction of the compression coil spring 159. This is a case where the displacement is moved and displaced in the X-axis direction by the elastic restoring force of the compression coil spring 159.

  When an overcurrent in the electric circuit (internal electric circuit) is detected by the current transformer 16 as the current detecting means, a current is supplied to the exciting coil 157 of the tripping means 15, and the magnetic circuit member becomes a permanent magnet by the current supply. It is excited in the direction in which the magnetic field due to 151 decreases. As a result, the magnetic attractive force between the movable yoke 156 and the fixed yoke 153 decreases and becomes smaller than the elastic restoring force in the X-axis direction of the compression coil spring 159, and the movable yoke 156 Due to the elastic restoring force, it is moved and displaced in the X-axis direction. Due to the displacement of the movable yoke 156, the trip lever 21, the trip fitting 22 and the hook 23 of the opening / closing mechanism 14 are operated, and the movable contact 13 is rotated by the operation, and the fixed contact 12 is changed from the connected state to the non-contact state. To do. As a result, the electric circuit is turned off in the circuit breaker 1, and the overcurrent is interrupted.

  Further, even when the energizing current does not reach the overcurrent level during energization of the electric circuit, the temperature in the circuit breaker 1 rises and becomes overheated, and the portion of the tripping means 15 on the fixed side of the magnetic circuit member When the temperature of the temperature-sensitive magnetic material 152 exceeds 150 ° C., which is a preset temperature, the magnetic permeability of the temperature-sensitive magnetic material decreases to 60% or less at room temperature, and the magnetic resistance of the magnetic circuit is reduced. Increase the amount to reduce the amount of magnetic flux in the magnetic circuit. As a result, the magnetic attractive force between the movable yoke 156 and the fixed yoke 153 decreases and becomes smaller than the elastic restoring force in the X-axis direction of the compression coil spring 159, and the movable yoke 156 Due to the elastic restoring force, it is moved and displaced in the X-axis direction. The displacement of the movable yoke 156 activates the trip lever 21, the trip fitting 22, and the hook 23 of the opening / closing mechanism section 14, and the movable contact 13 is rotated by the operation and changes to a non-contact state with respect to the fixed contact 12. Thereby, the electric circuit is turned off in the circuit breaker 1, and the energized current is interrupted.

  According to the circuit breaker 1 of the embodiment of the present invention, even when an overcurrent flows through the electric circuit, or when the circuit breaker 1 becomes overheated without overcurrent flowing through the electric circuit, The current of the electric circuit can be interrupted, the reliability of the circuit breaker can be further improved, and a wide range of safety can be ensured.

  In the case of the above embodiment, the temperature-sensitive magnetic material 152 has a characteristic that the magnetic permeability decreases to 60% or less at room temperature when the temperature exceeds 150 ° C. The elastic restoring force of the compression coil spring 159 in the state of FIG. 2 is increased, and the magnetic attractive force acting on the movable yoke when the temperature-sensitive magnetic material exceeds 150 ° C. is greater than the elastic restoring force. If the temperature is reduced, the temperature-sensitive magnetic material may have a magnetic permeability that exceeds 60% at room temperature when the temperature exceeds 150 ° C.

It is a figure which shows the structure of the circuit breaker as an Example of this invention. It is a figure which shows the state at the time of the deenergization of the trip means in the circuit breaker of FIG. It is a figure which shows the state at the time of energization or overheating of the trip means in the circuit breaker of FIG.

Explanation of symbols

1 ... Circuit breaker,
10a, 10b ... external circuit,
11a, 11b ... Electric circuit connection terminals,
12: Fixed contact,
13 ... movable contact,
14 ... Opening / closing mechanism,
15: Tripping means,
151: Permanent magnet,
152 ... temperature-sensitive magnetic material,
153, 154, 155 ... fixed yoke,
156 ... movable yoke,
157 ... Excitation coil,
158 ... bobbins,
159 ... compression coil spring,
160... Spring engaging member,
16 ... current transformer,
17 ... handle,
18 ... arc extinguishing part,
19 ... Case,
21 ... Trip lever,
22 ... Trip fitting,
23 ... Hook,
200: Magnetic flux.

Claims (3)

A circuit breaker connected to an electric circuit for detecting an electric current of the electric circuit and interrupting an overcurrent;
A contact portion that is connected to the electric circuit and that closes and opens the electric circuit by contact and non-contact between the movable contact and the fixed contact;
Current detection means for detecting the current in the circuit;
An opening / closing mechanism that rotationally displaces the movable contact around a fulcrum and places the movable contact in a contact state or a non-contact state with respect to the fixed contact;
A magnetic circuit member and an exciting coil, and when the current detecting means detects an overcurrent, the energization of the exciting coil causes the movable side portion of the magnetic circuit member to move and displace relative to the fixed side portion; Tripping means for operating the open / close mechanism by displacement so that the movable contact is not in contact with the fixed contact;
Comprising
The tripping means is
The fixed side portion of the magnetic circuit member is configured to have a permanent magnet and a temperature-sensitive magnetic material whose magnetic permeability is reduced by a temperature rise, and
A spring for biasing the movable side portion of the magnetic circuit member by an elastic restoring force against a magnetic attractive force between the fixed side portion;
When the current detecting means detects an overcurrent and the energizing coil is energized and the magnetic circuit member is excited in a direction to reduce the magnetic field by the permanent magnet, or the temperature of the temperature-sensitive magnetic material is preset. When the measured temperature is exceeded, the magnetic attractive force between the movable side portion and the fixed side portion becomes smaller than the elastic restoring force of the spring, and the movable side portion is moved and displaced by the elastic restoring force of the spring. It is a configuration to
A circuit breaker characterized by that.   When the temperature of the temperature-sensitive magnetic material of the fixed side portion of the magnetic circuit member exceeds 150 ° C., the trip means has a magnetic attractive force between the movable side portion and the fixed side portion of the spring. The circuit breaker according to claim 1, wherein the circuit breaker is configured to be smaller than an elastic restoring force. The tripping means is
The movable side portion of the magnetic circuit member is a rod-like body inserted into the excitation coil, and the spring is a compression coil spring fitted concentrically to the movable side portion. Circuit breaker as described.

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