JPH065189A - Circuit breaker - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize a tripping operation by an external voltage or an undervoltage without providing a dedicated tripping device, thereby achieving downsizing and cost reduction of the device. [Structure] The trip device 10 is an overcurrent trip coil 10a.
And an auxiliary trip coil 10b. The overcurrent determination circuit 9 determines the overcurrent of the main circuit 5 based on the detected currents of the current transformers 6a and 6b, turns on the thyristor 11, and energizes the trip coil 10a. The auxiliary trip coil 10b operates the trip device 10 according to the voltage applied from the external input terminals 13a and 13b. The overcurrent trip coil 10a of the trip device 10 is energized to perform a trip operation,
The tripping operation can be performed according to the input voltage from the external input terminals 13a, 13b, the main circuit 5 can be cut off by one tripping device 10, and the space can be saved at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker for operating a trip device to open the main circuit when an overcurrent flows in the main circuit.

[0002]

2. Description of the Related Art Conventionally, as a circuit breaker of this type, for example, a static circuit breaker is constructed as follows. That is,
A current transformer is interposed in the main circuit, the output current of this current transformer is rectified by a rectifier circuit, and then converted to an output voltage by a current-voltage conversion circuit, and an overcurrent flows in the main circuit and the output voltage exceeds the set value. When the output voltage becomes low, the trip voltage of the trip device is energized to open the main circuit.

[0003]

By the way, in addition to the case of performing the trip operation against the overcurrent of the main circuit described above, when the main circuit is opened by the voltage signal from the outside,
Usually, another circuit breaker configured as described above is provided in the main circuit so that the tripping operation is performed in accordance with the voltage signal.

However, in this case, since it is necessary to provide a dedicated device for performing the voltage trip operation, a special space is required in the circuit breaker, the size of the whole is increased, and the cost is high. There is a problem that becomes.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a structure for performing a tripping operation due to an overcurrent and a voltage tripping operation according to a voltage signal from the outside at low cost and with saving. It is to provide a circuit breaker that can be realized in a space.

[0006]

According to the present invention, an overcurrent detecting circuit for detecting an overcurrent in a main circuit, and a plunger is driven by energizing a trip coil from the overcurrent detecting circuit to open the main circuit. The present invention is directed to a circuit breaker equipped with a trip device, and is characterized in that the trip device is provided with an auxiliary trip coil capable of driving the plunger by energization from the outside. .

[0007]

According to the circuit breaker of the present invention, when the overcurrent of the main circuit is detected by the overcurrent detection circuit, the trip device operates as follows.
Since the trip coil is energized from the overcurrent detection circuit, the plunger is driven to perform the trip operation, thereby opening the main circuit. In addition, when the auxiliary trip coil is energized from the outside, the trip device drives the plunger to perform the trip operation, thereby opening the main circuit. As a result, one tripping device can perform an overcurrent tripping operation and a tripping operation according to a voltage signal from the outside, so that downsizing and cost reduction can be achieved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1 showing the electrical configuration, for example,
Power supply side terminals 1a, 1b corresponding to each phase of the single-phase AC power supply
Are respectively connected to the load side terminals 4a and 4b via the main circuit contacts 2a and 2b and the main circuit conductors 3a and 3b, which are open portions.
The main circuit 5 is configured by these components.
Each of the main circuit conductors 3a, 3b, 3c is provided with current transformers 6a, 6b using these as primary conductors.

The output terminals of the current transformers 6a and 6b are connected to the AC input terminals of the rectifier circuit 7, respectively. Rectifier circuit 7
A detection resistor 8 is connected between the DC output terminals of, and a voltage corresponding to the current flowing through the main circuit 5 is obtained at both terminals of the detection resistor 8. An overcurrent determination circuit 9 as an overcurrent detection circuit detects an overcurrent of the main circuit 5, and a detection resistor 8 is connected between its detection terminals A and B.

The trip device 10 opens the main circuit contacts 2a and 2b by a trip operation to shut off the main circuit 5. As described later, the overcurrent trip coil 10a and the auxiliary trip coil 10b are connected to each other. I have it. The overcurrent trip coil 10a is connected in series with the thyristor 11 and is connected between the detection terminals A and B of the overcurrent determination circuit 9. The gate of the thyristor 11 is the control output terminal C of the overcurrent determination circuit 9.
It is connected to the. Further, the series circuit of the auxiliary trip coil 10b and the current limiting resistor 12 has an external input terminal 13a,
It is connected between 13b.

Next, the structure of the trip device 10 will be described with reference to FIG. In FIG. 2, a cylindrical guide 15 is provided at the center of a container-shaped magnetic material frame 14.
Is fixed, and a fixed iron core 16 is fixed to the bottom surface thereof. A permanent magnet 17, an overcurrent trip coil 10a, and an auxiliary trip coil 10b are arranged between the inside of the frame 14 and the guide 15.

The movable iron core 18 is the guide 1 of the frame 14.
5 is slidably inserted, and a coil-shaped release spring 19 is inserted in a portion protruding to the outside. The release spring 19 is located between the movable iron core 18 and the permanent magnet 17, and is in a state of urging the movable iron core 18 in the direction of the arrow P, which is the trip direction. Next, the operation of the present embodiment will be described. First, the case where the auxiliary trip coil 10b is used as a voltage trip coil will be described.

That is, the trip device 10 is in a state in which two forces are acting on the movable iron core 18 in a state in which no current is applied or no force is applied from the outside. That is, the movable iron core 18 receives a force F0 in the arrow P direction due to the biasing force of the release spring 19 and a force F1 in the opposite arrow P direction due to the attraction force of the permanent magnet 17.

In this case, the magnetic lines of force of the permanent magnet 17 pass through a magnetic circuit formed by a path passing through the movable iron core 18, the fixed iron core 16 and the frame 14 to exert an attractive force F1 on the movable iron core 18. is there.

When the overcurrent trip coil 10a is not energized, the force F1 by the permanent magnet 17 in the direction opposite to the arrow P is applied to the movable core 18 by the release spring 19 in the direction P. The force is set to be larger than F1 (F0 <F1). Therefore, in this state, the movable iron core 18 is pulled into the inside of the frame 14 by the action of the force F1 by the permanent magnet 17, as shown in the figure.

When an overcurrent flows in the main circuit 5 in such a state, the voltage appearing between the terminals of the detection resistor 8 via the current transformers 6a and 6b and the rectifying circuit 7 becomes larger than a predetermined voltage. . As a result, the overcurrent determination circuit 9 outputs a trigger signal from the control output terminal C to the gate of the thyristor 11 to turn on the thyristor 11.

When the thyristor 11 is turned on, a current flows through the overcurrent trip coil 10a and a magnetic force acts on the movable iron core 18. At this time, the overcurrent trip coil 10
The magnetic force F2 due to a acts so as to cancel the magnetic force F1 due to the permanent magnet 17, and its magnitude acts so that the following equation is established. That is, since the relationship such as F0> F1-F2 (1) is established, the movable iron core 18
Is moved in the direction of the arrow P by the release spring 19 so that the tripping operation is performed. Therefore, the main circuit contacts 2a and 2b of the main circuit 5 are cut off by the flow of the overcurrent.

Next, in the above-mentioned state, the external input terminal 13
When an external voltage is input from a and 13b to perform the trip operation, the auxiliary trip coil 10b is energized via the current limiting resistor 12. As a result, the auxiliary tripping coil 10b generates magnetic lines of force in the magnetic circuit of the tripping device 10 to exert a magnetic force on the movable iron core 18.

At this time, the magnetic force F3 generated by the auxiliary trip coil 10b acts so as to cancel the magnetic force F1 generated by the permanent magnet 17, and its magnitude acts so that the following equation is satisfied. That is, since the relationship such as F0> F1-F3 (2) is established, the movable iron core 18
Is released in the direction of arrow P by the release spring 19 to perform the tripping operation. Therefore, the main circuit contacts 2a and 2b of the main circuit 5 are cut off by the application of the external voltage.

Next, the case where the auxiliary trip coil 10b is used as an undervoltage trip coil will be described. That is, in this case, in a normal case, a predetermined voltage is applied through the external input terminals 13a and 13b, and therefore the auxiliary trip coil 10b is in a state of being energized.

As described above, in the trip device 10, the movable spring 18 is released by the release spring 19 so that the arrow P
The force F0 in the direction acts, and the permanent magnet 17 causes the opposite arrow P
A force F1 in the direction acts. And these forces F
In addition to 0 and F1, the movable iron core 18 is acted on by the magnetic force of the auxiliary trip coil 10b in a direction F opposite to the arrow P.

In such a normal state, in order to prevent the tripping operation by the tripping device 10, the above-mentioned forces F0, F1 and F4 are set to have the following relationship. That is, the relationship is F0> F1 (3) F0 <F1 + F4 (4).

That is, for the movable iron core 18, the equation (3)
As shown in, the force F in the direction of arrow P by the release spring 19
0 is set to be larger than the force F1 by the permanent magnet 17 in the direction opposite to the arrow P. Then, in such a state, when the force F4 in the direction opposite to the arrow P due to the energization of the auxiliary trip coil 10b acts, as shown in the equation (4), the opposite arrow P
It is set so that the combined force in the direction becomes large and the tripping action is not performed.

When an overcurrent flows in the main circuit 5 in such a set state, the voltage appearing between the terminals of the detection resistor 8 via the current transformers 6a and 6b and the rectifying circuit 7 becomes larger than a predetermined voltage. Become. As a result, the overcurrent determination circuit 9
Outputs a trigger signal from the control output terminal C to the gate of the thyristor 11 to turn on the thyristor 11.

When the thyristor 11 is turned on, a current flows through the overcurrent trip coil 10a, and a magnetic force acts on the movable iron core 18. At this time, the overcurrent trip coil 10
The force F2 in the direction of arrow P by a acts to cancel the magnetic force F1 by the permanent magnet 17, and its magnitude is
It works so that the following equation holds. That is, since the relationship such as F0> F1 + F4-F2 (5) is established, the movable iron core 18
Is moved in the direction of arrow P by the release spring 19 to perform a tripping operation. Therefore, the main circuit contacts 2a and 2b of the main circuit 5 are cut off by the flow of the overcurrent.

Next, in the above-mentioned state, the external input terminal 13
When the voltage applied from a and 13b decreases,
The energizing current to the auxiliary trip coil 10b also decreases, and the force F4 on the movable iron core 18 in the direction opposite to the arrow P decreases. Then, when the input voltage from the external input terminals 13a and 13b becomes less than the predetermined voltage, F4 in the direction opposite to the arrow P becomes small and the above equation (4) is not satisfied. That is, the force due to the insufficient voltage is F4a
If (<F4), then F0> F1 + F4a (6). Therefore, the movable iron core 18 is released in the direction of arrow P, and is tripped. The main circuit contacts 2a and 2b of the main circuit 5 are cut off by the application of an external voltage. .

According to this embodiment, the trip device 10 is constructed by providing the auxiliary trip coil 10b in addition to the overcurrent trip coil 10a, and the external input terminals 13a, 13 are provided.
Since the auxiliary trip coil 10b is energized according to the input from b, the trip operation of the main circuit 5 can be performed by an external voltage or an undervoltage in addition to the overcurrent trip operation. As a space-saving, the overall size can be reduced and the cost can be reduced.

In the above embodiment, the case where the present invention is applied to the main circuit 5 of the single-phase AC power supply has been described, but the present invention is not limited to this, and may be applied to the main circuit of the three-phase AC power supply. Of course.

[0030]

According to the circuit breaker of the present invention, the trip device is provided with the auxiliary trip coil so that the trip operation of the main circuit can be performed according to the voltage signal from the outside. In addition to the tripping operation of the main circuit due to overcurrent, the tripping operation due to an external voltage or undervoltage can be performed with the same tripping device, so that the entire device can be downsized to save space and at low cost. It has an excellent effect that it can be realized.

[Brief description of drawings]

FIG. 1 is an electrical configuration diagram showing an embodiment of the present invention.

FIG. 2 is a vertical sectional side view of the trip device.

[Explanation of symbols]

2a and 2b are main circuit contacts, 5 is a main circuit, 6a and 6b are current transformers, 7 is a rectifier circuit, 8 is a detection resistor, 9 is an overcurrent determination circuit (overcurrent detection circuit), 10 is a trip device, 10a is an overcurrent trip coil, 10b is an auxiliary trip coil, 11 is a thyristor, 12 is a current limiting resistor, 13a and 13b are external input terminals, 16 is a fixed iron core, 17 is a permanent magnet, and 18 is a movable iron core (plunger). , 19 are release springs.

Claims (1)

[Claims] 1. An overcurrent detection circuit for detecting an overcurrent of a main circuit, and a trip device for driving a plunger by energizing a trip coil from the overcurrent detection circuit to open the main circuit. In the circuit breaker, the trip device includes an auxiliary trip coil capable of driving the plunger by energization from the outside.