JPH05342968A - Circuit breaker - Google Patents

Abstract

PURPOSE:To reduce the size of a circuit breaker and reduce the cost thereof by performing a tripping operation through a voltage detecting circuit without providing a dedicated tripping device. CONSTITUTION:The excess current of a main circuit 5 is detected by an excess current detecting circuit 7 based on detected current from a current transformer 6a, 6b, or 6c. The excess current detecting circuit 7 sends a trip signal to a thyristor 10 so as to energize the trip coil 19 of a tripping device 9 in a forward direction. A voltage detecting circuit 11 gives a reverse direction energizing output to the trip coil 19 of the tripping circuit 9 when the voltage of a control power supply is an assigned voltage or more. The tripping device 9 performs a tripping operation so as to break the main circuit 5 when the voltage of the control power supply is insufficient, and when the excess current flows in the main circuit 5. As only one tripping device 9 is required, it is possible to save space and manufacture a circuit breaker at 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 in the main circuit is detected.

[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, and the output current of this current transformer is rectified by a rectifier circuit and then converted to an output voltage by a current-voltage converter circuit.Overcurrent flows in the main circuit and the output voltage exceeds the set value. When the output voltage becomes low, the trip coil of the trip device is energized to open the main circuit.

[0003]

By the way, in addition to the above-mentioned tripping operation for the overcurrent of the main circuit, when the main circuit is opened when the power supply voltage for control falls below a predetermined level, the conventional method is used. Another circuit breaker configured in the same manner as described above is provided in the main circuit so that the tripping operation is performed according to the voltage signal.

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

The present invention has been made in view of the above circumstances, and an object thereof is to reduce the cost and space of a structure for performing an trip operation due to an overcurrent and an undervoltage trip operation when a control voltage drops. It is to provide a circuit breaker that can be realized by.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to a tripping device which performs tripping operation by forward-direction energization of a tripping coil, and to detect tripping current of a main circuit to perform tripping operation to the tripping device. A circuit breaker having an overcurrent detection circuit for detecting the voltage of the control power supply and applying a reverse current output to the trip coil when the detected voltage is equal to or higher than a predetermined voltage. A detection circuit is provided, and the trip device operates the trip operation when forward conduction is performed from the overcurrent detection circuit in a state where the trip coil is provided with a reverse conduction output from the voltage detection circuit. The tripping operation is performed regardless of the presence or absence of forward energization from the overcurrent detection circuit when the reverse energization output from the voltage detection circuit to the trip coil is stopped. Having the features in place.

[0007]

According to the circuit breaker of the present invention, when the voltage of the control power supply is equal to or higher than the predetermined voltage, the voltage detection circuit gives a reverse energization output to the trip coil of the trip device. The trip device does not trip due to a lack of control power. However, when the trip device is energized in the forward direction by the overcurrent detection circuit detecting the overcurrent of the main circuit in this state, the trip device performs the trip operation to shut off the main circuit.

Further, when the voltage of the control power supply becomes lower than the constant voltage, the voltage detecting circuit stops the reverse energization to the trip device, so that the trip device performs the trip operation to open the main circuit. Cut off. That is, if an overcurrent flows in the main circuit or if the voltage of the control power supply is insufficient, the trip device operates in any case to shut off the main circuit.

[0009]

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, the power source side terminals 1a, 1b and 1c corresponding to the three phases are respectively connected to the main circuit contacts 2a, 2b and 2c and the main circuit conductors 3a and 3c.
It is connected to the load side terminals 4a, 4b and 4c via b and 3c, and these constitute the main circuit 5. Each of the main circuit conductors 3a, 3b, 3c is provided with a current transformer 6a, 6b, 6c using these as primary conductors.

The output terminals of the current transformers 6a, 6b, 6c are connected to the input terminals of the overcurrent detection circuit 7. The overcurrent detection circuit 7 outputs a trip signal from the control output terminal C by rectifying and converting the detection current input from the current transformers 6a, 6b, 6c and comparing the output voltage with a set voltage. It is a thing.

A series circuit of a reverse current blocking diode 8, a trip device 9 and a thyristor 10 is connected between the output terminals A and B of the overcurrent detection circuit 7. The gate of the thyristor 10 is connected to the control output terminal C of the overcurrent detection circuit 7.

The input terminals A and B of the voltage detection circuit 11 are connected to the control power source input terminals 12a and 12b, respectively, and between the output terminals C and D are connected to the reverse current blocking diode 13 and the series circuit of the trip device 9. Has been done. The trip device 9 is configured such that the energization direction from the overcurrent detection circuit 7 and the energization direction from the voltage detection circuit 11 are opposite to each other.

Next, the construction of the trip device 9 will be described with reference to FIG. In FIG. 2, a tubular guide 15 is fixed to the center of a container-shaped magnetic material frame 14, and a fixed iron core 16 is fixed to the bottom surface of the right end thereof. A permanent magnet 17 and a trip coil 19 wound around a bobbin 18 are arranged between the guide 15 inside the frame 14 and a cap 20 is attached to the left opening of the frame 14.

The movable iron core 21 is the guide 1 of the frame 14.
5 is slidably inserted, and a coil-shaped release spring 22 is inserted in a portion protruding to the outside. The release spring 22 is located between the projection 21a provided on the tip of the movable iron core 21 and the cap 20 of the frame 14,
The movable iron core 21 is biased in the direction of the arrow P in the drawing, which is the trip direction. Next, the operation of this embodiment will be described.

In the trip device 9, the movable iron core 21 is moved to the movable core 21 in the state where no current or force is applied from the outside.
Two forces are working. That is, the movable iron core 21
Is the force F0 in the direction of arrow P due to the urging force of the release spring 22.
While receiving, the anti-arrow P due to the attractive force of the permanent magnet 17
It receives force F1 in the direction.

In this case, the lines of magnetic force from the permanent magnet 17 are
A magnetic circuit R formed by a path passing through the movable iron core 21, the fixed iron core 16 and the frame 14 passes in the direction of the arrow S to apply a suction force F1 to the movable iron core 21.

When the trip coil 19 is not energized, the force F0 by the release spring 22 on the movable iron core 21 in the direction of arrow P becomes larger than the force F1 by the permanent magnet 17 in the direction of counter arrow P. Is set to (F0> F1). Therefore, in this state, the movable iron core 21 is in the position of the state in which the movable iron core 21 is projected and tripped by the action of the force F0 by the release spring 22.

When the voltage of the control power source supplied from the control power source input terminals 12a and 12b is above a predetermined level and normal, the voltage detecting circuit 11 outputs the output terminal C,
An energization output is given from D. As a result, the trip coil 19 of the trip device 9 is energized in the reverse direction via the diode 13.

When the trip coil 19 is energized in the opposite direction, as shown in FIG. 2, magnetic lines of force pass through the magnetic circuit R in the direction of arrow S, so that the trip coil 19 moves in the direction of arrow P opposite to the movable iron core 21. Produces a suction force F2.

As a result, the attraction force F2 acts on the movable iron core 21 in addition to the force F1 of the permanent magnet 17 in the direction of arrow P. This combined force (F1 + F2)
Becomes larger than the force F0 by the release spring 22 in the direction of arrow P (F1 + F2> F0), and the movable iron core 21 is pulled in the direction opposite to the arrow P, that is, in the direction close to the fixed iron core 16. Therefore, the control power input terminal 12 is
When the normal control power supply voltage is applied from a and 12b, the tripping operation by the tripping device 9 is not performed.

The control power supply input terminals 12a and 12b
When the input voltage from the power source drops below a predetermined level, the voltage detection circuit 11 stops the reverse energization output to the trip device 9. As a result, in the trip device 9, the attraction force F2 of the trip coil 19 against the movable iron core 21 in the direction opposite to the arrow P disappears, and the force F0 of the release spring 22 in the direction of arrow P becomes large, so that the movable iron core 21 moves. Is arrow P
The main circuit contact 2a is moved so as to project in the direction
The tripping operation of the inner ring 2c is performed and the main circuit 5 is cut off.

Further, as described above, when the voltage of the control power supply is normal, the trip device 9 operates as follows depending on the detection state of the overcurrent detection circuit 7. That is, the energizing current of the main circuit 5 corresponds to each phase, and the current transformers 6a, 6b,
6c, and when the energization current becomes larger than a predetermined current value, the overcurrent detection circuit 7 detects this and outputs a trip signal from the control output terminal C to turn on the thyristor 10. .. As a result, an energization path is formed from the output terminal A of the overcurrent detection circuit 7 to the output terminal B via the diode 8, the trip device 9 and the thyristor 10, so that the trip coil 19 of the trip device 9 is energized. become.

When the trip coil 19 of the trip device 9 is energized by the overcurrent detection circuit 7, it produces a magnetic flux in the magnetic circuit. It occurs in the opposite arrow S direction. As a result, the force F3 in the direction opposite to the arrow P is newly applied to the movable iron core 21.
Four forces F0, F1, F2 and F3 act on 1. In this case, with respect to the movable iron core 21, F0 and F
3 acts in the direction of arrow P, F1 and F2 act in the direction opposite to arrow P, and the combined force at this time is set so that (F0 + F3)> (F1 + F2) (1). Therefore, the movable iron core 21 is moved in the direction of the arrow P, the tripping operation is performed, and the main circuit 5 is opened.

According to the present embodiment as described above, the voltage detection circuit 11 causes the trip device 9 to operate normally when the control power supply voltage input from the control power supply input terminals 12a and 12b is higher than a predetermined level. In this state, a reverse energization output is applied to hold so that the trip operation is not performed, and when an overcurrent of the main circuit 5 is detected by the overcurrent detection circuit 11, a trip signal is applied in the forward direction to pull it. Since the tripping operation is performed, one tripping device 9 can perform the overcurrent tripping operation and the undervoltage tripping operation. Therefore, the device can be downsized and can be manufactured at low cost.

[0026]

According to the circuit breaker of the present invention, with respect to the trip coil of the trip device, the voltage detection circuit detects a voltage shortage of the control power supply to stop the energization output in the reverse direction. Since the overcurrent detection circuit detects the overcurrent of the main circuit and gives the energization output in the forward direction, the tripping operation is performed by one tripping device in any of the above cases. Therefore, there is an excellent effect that the size of the entire device can be reduced and the device can be manufactured at low cost.

[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, 2b, 2c are main circuit contacts, 5 is a main circuit, 6a, 6
b and 6c are current transformers, 7 is an overcurrent detection circuit, 9 is a trip device, 10 is a thyristor, 11 is a voltage detection circuit, 12a,
12b is an external power input terminal, 16 is a fixed iron core, 17 is a permanent magnet, 19 is a trip coil, 21 is a movable iron core, and 22 is a release spring.

Claims (1)

[Claims] 1. A trip device for performing a trip operation by forward conduction of a trip coil, and an overcurrent detection circuit for detecting an overcurrent of a main circuit to cause the trip device to perform the trip operation. The circuit breaker comprises a voltage detection circuit that detects the voltage of the control power supply and provides a reverse current-carrying output to the trip coil when the detected voltage is equal to or higher than a predetermined voltage. In the state where the reverse coil energization output is given to the trip coil, the trip operation is performed when the forward current is energized from the overcurrent detection circuit, and the trip coil has the voltage detection circuit. The circuit breaker is configured to perform the trip operation regardless of the presence or absence of forward energization from the overcurrent detection circuit when the reverse energization output is stopped.