JP4036317B2 - Tracking breaker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tracking compatible circuit breaker that shuts off a main circuit when a tracking current is detected .
[0002]
[Prior art]
Generally, the short-circuit current due to tracking short-circuit caused by dust or the like adhering between electrodes such as power plugs of electrical equipment is a discontinuous current of about several A to 200 A. I can't. Therefore, as shown in FIG. 4, in the tracking breaker, the current transformer 32 passed through the main circuit (not shown) detects the current of the main circuit, and the output current of the current transformer 32 is converted into an A / D conversion circuit. 33 is converted into a digital signal and input to the MPU 34, and the MPU 34 compares it with waveform information such as the peak value and duration of the tracking current stored in the memory 35. When the peak value and duration conditions are satisfied, the detected current is detected. Is a tracking current, a trigger signal is output from the trigger circuit 36, the trigger element 37 is turned on, and the trip coil 38 is driven by turning on the trigger element 37 to open the switching contact 39 of the main circuit. It has become.
[0003]
The crest value and the duration are set to about 100 A and the duration is set to about 100 ms so that unnecessary operation is not caused by an inrush current of a home appliance or the like.
[0004]
[Problems to be solved by the invention]
However, it is not easy to generate a discontinuous short-circuit current having a peak value of about 100 A and a duration of about 100 ms, and the conventional tracking breaker has no test circuit.
[0005]
Accordingly, in view of the above problems, an object of the present invention is to provide a tracking compatible circuit breaker that can check whether the circuit breaker detects a tracking current and normally performs a circuit breaking operation .
[0006]
[Means for Solving the Problems]
In order to achieve the above object , according to the present invention, a current transformer passing through a main circuit detects a current, and the detected current is compared with a tracking current waveform information stored in a memory by the MPU for tracking. A tracking circuit breaker that opens and shuts off the open / close contact of the main circuit when it is judged to be a current, and has a test circuit that artificially generates a tracking current, and the test circuit is a test button for turning the circuit on and off A pulse circuit for generating a test circuit condition pulse stored in the memory under the control of the MPU, a first contact point connected in series and a current-limiting resistor through the current transformer, and a current transformer a detection resistor and the second contact, characterized by being configured with a sustain circuit for maintaining the output characteristic of the current transformer connected in series with a high output across the output terminals.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, when the current transformer that has passed through the main circuit detects the current, and the detected current is compared with the tracking current waveform information stored in the memory by the MPU, the main circuit determines A tracking circuit breaker that opens and shuts off the switching contact of the circuit includes a test circuit that generates a tracking current in a pseudo manner, and the test circuit stores a test button for turning the circuit on and off and a memory controlled by the MPU. A pulse circuit for generating a pulse of a stored test circuit condition; a first contact connected in series; a momentary switching circuit formed by passing a current limiting resistor through the current transformer; and a second contact between the output terminals of the current transformer And a maintenance circuit to connect the detection resistor in series and maintain the output characteristics of the current transformer at high output, the circuit breaker detects the tracking current and operates normally. It is possible to confirm whether or not the.
[0008]
【Example】
An embodiment of a tracking breaker according to the present invention will be described with reference to the accompanying drawings of FIGS.
[0009]
In the tracking breaker 1, the current transformer 2 detects the current of the main circuit (not shown), the output current of the current transformer 2 is digitally converted by the A / D conversion circuit 3, and is input to the MPU 4. Is compared with the waveform information such as the peak value and duration of the tracking current stored in the memory 5, and when the conditions of the peak value and duration are satisfied, it is determined that the detected current is the tracking current, and the trigger circuit 6 A trigger signal is output from the trigger element 7 to turn on the trigger element 7, and the trigger coil 7 is turned on to drive the trip coil 8 to open the switching contact 9 of the main circuit.
[0010]
The crest value and the duration are set to about 100 A and the duration is set to about 100 ms so that unnecessary operation is not caused by an inrush current of a home appliance or the like.
[0011]
The test circuit includes a test button 10 for turning on / off the test circuit, a pulse circuit 11 for generating a pulse of the test circuit condition stored in the memory 5 under the control of the MPU 4, and a first contact C1 connected in series. The instantaneous switching circuit 12 formed by passing the current resistor R1 through the current transformer 2, and the second contact C2 and the detection resistor R2 are connected in series between the output terminals of the current transformer 2, and the output characteristics of the current transformer 2 are It is comprised with the maintenance circuit 13 for maintaining at high output.
[0012]
The operation of the test circuit will be described. First, when the test button 10 is turned on, a signal is input to the MPU 4. The MPU 4 activates the test circuit condition stored in the memory 5 by this input signal, and the pulse circuit 11 starts the instantaneous switching circuit. 12 and the sustain circuit 13 are output with pulse signals. The frequency of the pulse is controlled to be different from the frequency of the power supply waveform of the current flowing through the main circuit, and the duration is controlled to about 100 ms, which is the same as the criterion for determining the tracking current.
[0013]
The instantaneous opening / closing circuit 12 opens and closes the first contact C <b> 1 by the pulse signal of the pulse circuit 11. As a result, the power supply waveform is finely divided by pulse control, and a pseudo tracking current is generated.
[0014]
The maintenance circuit 13 opens and closes the second contact C2 simultaneously with the first contact C1 of the instantaneous switching circuit 12 by the pulse signal of the pulse circuit 11. For this reason, even if a very small current of 100 mA is passed through the current transformer 2, it can be made the same potential as the detection voltage of 100A by the detection resistor R2 of the maintenance circuit 13, and the power load of the current limiting resistor R1 of the instantaneous switching circuit 12 can be reduced. Can be small. Even if the duration of the pseudo tracking current exceeds 100 ms, the power burden of the current limiting resistor R1 does not exceed the standard value.
[0015]
Since the current waveform of the pseudo tracking current generated in this way is similar to the tracking current waveform information stored in the memory, when the current transformer 2 detects the pseudo tracking current, the MPU 4 determines that it is abnormal and drives the trip coil 8. And the operation check of the circuit breaker 1 can be performed by interrupting the main circuit.
[0016]
In order to store these components in the circuit breaker case 14, connection terminals 15a and 15b are provided at both longitudinal ends of the circuit breaker case 14, and a printed circuit board 16 on which a test circuit is mounted below one connection terminal 15a. The trip coil 8 is disposed below the other connection terminal 15b, the current transformer 2 is disposed between the printed circuit board 16 and the trip coil 8, and the connection terminal 15a and the other connection terminal 15b are disposed. A toggle link mechanism portion 18 that is interlocked with the handle 17 protruding from the upper surface of the circuit breaker case 14 is disposed between the connection terminal 15b, and the switching contact 9 is provided between the toggle link mechanism portion 18 and one connection terminal 15a. The bimetal 19 is disposed between the toggle link mechanism 18 and the other connection terminal 15b.
[0017]
Further, the test button 10 is arranged so as to protrude from the handle operating surface of the circuit breaker case 14.
[0018]
【The invention's effect】
As described above , according to the present invention, the current transformer detects the current by passing through the main circuit, and the detected current is compared with the tracking current waveform information stored in the memory by the MPU. In the tracking breaker that opens and shuts off the switching contact of the main circuit when judged to be present, the test circuit includes a test circuit that artificially generates a tracking current, and the test circuit includes a test button for turning the circuit on and off, A pulse circuit for generating a test circuit condition pulse stored in the memory under the control of the MPU, a first contact point connected in series and a current-limiting resistor through the current transformer, and an output of the current transformer The circuit breaker detects the tracking current by connecting the second contact and the detection resistor in series between the ends and maintaining the output characteristics of the current transformer at a high output. Te there is an effect that it is possible to determine whether to block operates normally.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a tracking breaker according to the present invention.
FIG. 2 is a longitudinal sectional view of a tracking breaker according to the present invention.
FIG. 3 is a plan view of a tracking breaker according to the present invention.
FIG. 4 is an explanatory diagram of a conventional tracking breaker.
[Explanation of symbols]
1 Circuit breaker for tracking 2 Current transformer 3 A / D conversion circuit 4 MPU
DESCRIPTION OF SYMBOLS 5 Memory 6 Trigger circuit 7 Trigger element 8 Trip coil 9 Switching contact 10 Test button 11 Pulse circuit 12 Instantaneous switching circuit 13 Maintenance circuit 14 Circuit breaker case 15 Connection terminal 16 Printed circuit board 17 Handle 18 Toggle link mechanism part 19 Bimetal

Claims (1)

When the current transformer detects the current through the main circuit and compares the detected current with the tracking current waveform information stored in the memory by the MPU, it determines that the current is a tracking current. A tracking circuit breaker that opens and shuts off includes a test circuit that generates a tracking current in a pseudo manner, and the test circuit stores a test button for turning on and off the circuit and the memory under the control of the MPU. A pulse circuit for generating a pulse of the test circuit condition, a first contact point connected in series and a current switching circuit penetrating the current transformer, and a second circuit between the output terminals of the current transformer. A tracking breaker comprising: a contact circuit and a detection resistor connected in series to maintain a high output power characteristic of the current transformer.

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