JPH05128960A - Circuit breaker - Google Patents

Abstract

PURPOSE:To determine the cause of an accident instantly at the time of trip operation by installing an accident displaying means which is driven while corresponding to only one signal between triger signals based on short-circuit current or over current. CONSTITUTION:When triger signals Tp or Te are produced by the abnormality of supplied electric current I, a trip coil 10 is excited through a trip circuit 9 and a closing switch is released to shut an electric power source. At that time if the cause of the accident is over current, a releasing coil 17 is not excited and thus a short circuit displaying button 16 does not work. Meanwhile when the cause of the accident is short circuit, corresponding to the signal Tp, a releasing coil exciting circuit 18 is turned on simultaneously with the trip of the switch 3 so that the coil 17 is excited and the button 16 works. As a result, simultaneously with the trip operation, the button 16 is projected from the surface of a case and shows that the accident is due to the short circuit current and consequently a worker can distinguish the cause of the accident immediately and start the trouble solving work. The electricity supplying system is thus recovered quickly.

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 tripping an electronic tripping mechanism to cut off a power source when a short circuit current or an overcurrent is detected, and more particularly to a circuit breaker capable of instantaneously determining the cause of trip. It concerns circuit breakers.

[0002]

2. Description of the Related Art Generally, a circuit breaker including a trip mechanism is inserted in a power supply system for a load (motor, etc.),
When the supply current value indicates the short-circuit current level (about 10 times the rated value) or when the overcurrent level (about 2 times to several times the rated value) is continued for a predetermined time, the trip mechanism is immediately tripped and the power is shut off. It is designed to protect the load.

FIG. 6 is a block diagram showing a conventional circuit breaker when a power supply system of a three-phase AC power supply is used. In the figure, 1 is an input terminal connected to the power supply side, 2 is an output terminal connected to the load side, 3 is an opening / closing switch inserted between the input terminal 1 and the output terminal 2, and 4 is a power supply to a load. Is a rectifier circuit for full-wave rectifying the detected supply current I of each phase.

Reference numeral 6 is an abnormality detecting means or IC for generating the trigger signals Tp and Te when the rectified supply current I has an abnormal value, which is composed of the following 61 to 65 elements. 61 is a peak conversion circuit that converts the peak Ip of the rectified supply current I into an effective value, 62 is an instantaneous circuit that generates a trigger signal Tp when the peak Ip exceeds the short-circuit current level, and 63 is a rectified supply current An effective value conversion circuit for obtaining an effective value Ie of I, and a long time circuit 64 for generating a trigger signal Te when the effective value Ie exceeds the overcurrent level and continues for a long time. Reference numeral 65 is a test signal circuit for checking the soundness of the IC 6, and inputs the test signal It to the peak conversion circuit 61 and the effective value conversion circuit 63 at the time of checking.

Reference numeral 7 is a test terminal for inputting a test signal from the outside to the test signal circuit 65. 8 is the effective value Ie
Is an LED that is driven when indicates an overcurrent level,
The long-time circuit 64 continues to be driven until it outputs the trigger signal Te. Reference numeral 9 is a trip circuit which is turned on by a trigger signal Tp or Te from the IC 6, and includes two parallel thyristors which are fed from the rectifier circuit 5 and turned on individually by trip signals Tp and Te. Reference numeral 10 is a trip coil that is excited by energization of the trip circuit 7 to open the open / close switch 3.

The trip circuit 9 and the trip coil 10 are
It constitutes trip means for disconnecting the load from the power supply in response to the trigger signals Tp and Te. The trip means 9 and 10 together with the open / close switch 3 and the IC 6 constitute an electronic trip mechanism.

Next, the operation of the conventional circuit breaker shown in FIG. 6 will be described. First, the current I supplied from the power supply to the load is detected by the current transformer 4 for each phase, full-wave rectified by the rectifier circuit 5, and input to the peak conversion circuit 61 and the effective value conversion circuit 63 in the IC 6. .. The peak conversion circuit 61 and the effective value conversion circuit 63 select the maximum phase of the detected supply current I and operate in response to the maximum current value. Peak conversion circuit
The reference numeral 61 converts the peak Ip of the supply current I into an effective value and inputs it to the instantaneous circuit 62 in order to remove the noise component peak superimposed on the supply current I. The effective value Ie is obtained and input to the long-time circuit 64.

When the peak Ip shows a short circuit current level (for example, 10 times or more of the rated value), the instantaneous circuit 62 immediately generates a trigger signal Tp to flow through the thyristor in the trip circuit 9 to energize the trip coil 10. Get excited. This allows
The open / close switch 3 is opened, the load is disconnected from the power supply, and the operation of the IC 6 and the excitation of the trip coil 10 are completed.

On the other hand, when the effective value Ie indicates an overcurrent level (for example, several times the rated value or more), the long time delay circuit 64 uses the LED
8 to indicate that the supply current I is at the overcurrent level, generate a trigger signal Te when the overcurrent level continues for a predetermined time or longer, and pass the thyristor in the trip circuit 9 to pass the trip coil. Energize and energize 10. As a result, the open / close switch 3 is opened and the load and the IC 6
The power supply to the LED 8 is cut off, and the operation of the LED 8 also ends.

As described above, the trip circuit 9 is triggered by the trigger signal Tp when the short-circuit current is detected and by the trigger signal Te when the overcurrent is detected.
The trip coil 10 can be excited via the, and the open / close switch 3 can be cut off to disconnect the accident circuit. Also, IC6
The test terminal 7 is regularly checked to check the soundness of
Then, the test signal It is input to determine whether the electronic trip mechanism normally operates.

However, after the power is cut off by the trip, no means for indicating whether the trip operation is caused by the short-circuit current or the overcurrent is provided. Need to investigate.

[0012]

As described above, the conventional circuit breaker has a problem that it takes time to investigate the cause because it cannot be externally determined whether the trip operation is due to an overcurrent or a short circuit current. It was

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a circuit breaker capable of immediately identifying the cause of an accident during a trip operation.

[0014]

A circuit breaker according to the present invention is provided with a failure display means driven in response to only one of a trigger signal based on a short circuit current or an overcurrent.

[0015]

According to the present invention, at the same time as the trip operation due to the occurrence of the accident, the failure display means is activated to immediately indicate whether the accident is due to the short-circuit current or the overcurrent.

[0016]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, and 1 to 10 are the same as those described above. 16 is a short-circuit display button that is projected in response to the trigger signal Tp based on the short-circuit current, and 17 is a short-circuit display button that is responsive to the trigger signal Tp 16
Is a release coil for driving the in the protruding direction. Reference numeral 18 is a release coil exciting circuit for exciting the release coil 17 in response to the trigger signal Tp, and includes a thyristor which is turned on by the trigger signal Tp. The release coil excitation circuit 18 and the release coil 17 are connected in parallel to the trip circuit 9 and the trip coil 10.

FIG. 2 is a perspective view showing the appearance of the circuit breaker shown in FIG. 1, and the short-circuit display button 16 projects from the end face of the case and can be manually operated. 3 is a perspective view showing the drive mechanism of the short-circuit display button 16, and FIG. 4 is an exploded perspective view showing the drive mechanism of FIG. 3 in detail.

3 and 4, 21 is a plunger coaxial with the short-circuit display button 16, 21a is a flange portion of the plunger 21,
Reference numeral 22 denotes a release spring that abuts on the collar portion 21a and urges the plunger 21 in the protruding direction, and 23 denotes a short-circuit display button 16 via the collar portion 21a.
Stopper 24 for restricting the protrusion amount of the stator, 24 is a stator forming a magnetic circuit for releasing the plunger 21 in the protrusion direction, 25
Is a mounting frame for shielding the magnetic circuit including the stator 24 from an external magnetic field, 26 is a screw for fixing the stator 24 and the mounting frame 25, and 27 is a screw for fixing the stopper 23 and the mounting frame 25.

FIG. 5 is a sectional view showing the structure of the magnetic circuit in FIG. 4 taken along the line AA. Reference numeral 28 is a permanent magnet magnetized in the illustrated direction, for example, the N pole is joined to the stator 24. Reference numeral 29 is a stator joined to the S pole of the permanent magnet 28, and forms a closed loop of magnetic flux with the plunger 21 and the stator 24. The release coil 17 is interposed between the stators 24 and 29 to cancel the magnetic flux generated by the permanent magnet 28.

The operation of the embodiment of the present invention shown in FIG. 1 will now be described with reference to FIGS. First, in the initial state, the short circuit display button 16 is manually pressed to contact the stator 29, and is magnetically coupled to the permanent magnet 28 via the stator 29. Therefore, the plunger 21 opposes the restoring force of the release spring 22 and opposes the permanent magnet 28.
It is held by suction on the side.

Here, similarly to the above, when the trigger signal Tp or Te is generated due to the abnormality of the supply current I, the trip coil 10 is excited through the trip circuit 9, the open / close switch 3 is opened, and the power is shut off. Is done. At this time,
If the cause of the failure is an overcurrent, the release coil 17 is not excited and the short-circuit display button 16 does not operate.

However, if the cause of the failure is a short circuit, the release coil exciting circuit 18 is turned on at the same time as the opening / closing switch 3 trips in response to the trigger signal Tp.
Is excited to activate the short-circuit display button 16. That is, since the excitation of the release coil 17 is in the direction of canceling the magnetic poles of the permanent magnet 28, the suction holding force of the plunger 21 by the permanent magnet 28 is reduced, and the plunger 21 works together with the short circuit display button 16 and the restoring force of the release spring 22. Is released in the protruding direction. At this time, since the mounting frame 25 shields the large current magnetic field inside the circuit breaker, the plunger 21 does not malfunction.

Therefore, at the same time as the trip operation, the short-circuit display button 16 protrudes from the case surface as shown in FIG. 2 to indicate that the short-circuit current causes a failure. As a result, the worker can immediately move to work to eliminate the cause of the failure, and the power supply system is quickly restored.

Example 2. In the above embodiment, the fault display means is a short-circuit display button responsive to the trigger signal Tp.
Although 16 is used, an overcurrent display button (not shown) that responds to the trigger signal Te may be used. Also, short-circuit display button 16
However, it is needless to say that the same operational effect can be obtained even if other display means is used.

[0025]

As described above, according to the present invention, the failure display means driven in response to only one of the trigger signals based on the short-circuit current or the overcurrent is provided, and the failure display means is operated simultaneously with the trip operation. Since it is made to operate, there is an effect that a circuit breaker that can immediately identify the cause when an accident occurs can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view showing the external appearance of an embodiment of the present invention.

FIG. 3 is a perspective view showing a drive mechanism of failure display means according to an embodiment of the present invention.

FIG. 4 is an exploded perspective view showing the drive mechanism of FIG. 3 in detail.

5 is a cross-sectional view showing the structure of the magnetic circuit in FIG.

FIG. 6 is a block diagram showing a conventional circuit breaker.

[Explanation of symbols]

 3 Open / close switch 4 Current transformer (current detection means) 6 IC (abnormality detection means) 9 Trip circuit 10 Trip coil 16 Short circuit display button 17 Release coil 18 Release coil excitation circuit I Supply current Tp, Te Trigger signal

Claims (1)

[Claims] 1. A current detecting means for detecting a supply current from a power source to a load, a first trigger signal when the supply current indicates a short-circuit current level, and the supply current having an overcurrent level set to a predetermined level. A circuit breaker including an abnormality detection unit that generates a second trigger signal when the time continues for a time or more, and a trip unit that disconnects the load from the power source in response to the first or second trigger signal. The circuit breaker according to claim 1, further comprising a failure display unit driven in response to only one of the first and second trigger signals.