JPH0582007A - Leak alarm - Google Patents

Abstract

PURPOSE:To find a wiring breaker, which generated the leak alarm, at a glance among wiring breakers located in a wiring board with other control equipment or the like-by adding a flash circuit to a display lamp of a leak alarm. CONSTITUTION:When the leak current is generated in a main electric circuit 3, the current in proportion to the leak current is flowed in the secondary side of an inserted zero-phase current transformer 9. The voltage at a product of this current and a resistance 17 is input to input terminals (a), (b) of a control circuit 8, and when this voltage exceeds a preset threshold value, the control circuit 8 outputs the signal current from an output terminal (c) to a thyrister 5 to turn it on. The voltage is thereby applied between both terminals of an output relay 4 and to a timer circuit 26, and the tamer circuit 26 outputs the signal at a flicker mode from an output terminal (d) thereof to repeat ON and OFF of a transistor 21. Since a display lamp 7 repeats the flash, a breaker corresponding to the alarm is found at a glance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth leakage alarm device which detects an earth leakage in a main electric circuit and outputs an alarm.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram showing an example of a conventional earth leakage alarm device. Transformer 1 connected to a control power supply (not shown)
A surge absorber 3 connected to the secondary side of the transformer 1, a rectifier circuit 2 having its input terminal connected to the secondary side of the transformer 1, and a series connection between the output terminals of the rectifier circuit 2. An output relay 4 and a thyristor 5 connected to each other, a smoothing capacitor 12 connected between the output terminals of the rectifier circuit 2 via a current limiting resistor 15, and an input terminal connected to both terminals of the smoothing capacitor 12. a and b are connected between both terminals of a resistor 17 connected in parallel to the secondary coil of the zero-phase current transformer 9 through which the three-phase main electric circuit 31 penetrates, and the output terminal C thereof is connected to the series resistor 16 and the parallel resistor. A control circuit 8 connected to the gate of the thyristor 5 via a capacitor 10, a current limiting resistor 14 and a reset switch 6 connected in series between the output terminals of the rectifying circuit 2, the current limiting resistor 14 and the reset. Sui A capacitor 13 connected between the connection point of the switch 6 and the anode of the thyristor 5, current limiting is connected in series between both terminals of the output relay fourth resistor 18
And an indicator light 7.

When a leakage current is generated in the main electric circuit 31,
An unbalanced current is generated in the main electric circuit 31, and a secondary current proportional to the leakage current flows through the resistor 17 on the secondary side of the zero-phase current transformer 9. A voltage which is a product of the secondary current and the resistor 17, that is, a voltage which is proportional to the leakage current is input to the input terminals a and b of the control circuit 8. When the leakage current exceeds a preset threshold value, a signal current is output from the output terminal C of the control circuit 8 to the gate of the thyristor 5, and the thyristor 5 is turned on. When the thyristor 5 is turned on, the capacitor 13 is charged through the current limiting resistor 14, the output relay 4 is operated, and the indicator lamp 7 is turned on to warn of the electric leakage. When the thyristor 5 is turned on once, the turning on is continued. Therefore, even if the earth leakage occurs once, even if the earth leakage is recovered, the earth leakage warning is continued. Press the reset switch 6 to release the earth leakage warning. When the reset switch 6 is pressed, the electric charge of the previously charged capacitor 13 is applied to the thyristor 5 in the opposite polarity, the thyristor 5 is turned off, and the leakage alarm is released.

This type of leakage alarm is often used by incorporating it into a circuit breaker for wiring. FIG. 3 is a front view of a wiring breaker in which an earth leakage alarm device is incorporated. A front panel 31 of the wiring breaker is provided with an indicator lamp 7 of the earth leakage alarm device and a reset switch 6, and a signal line of the output relay 4. 4A is pulled out to the outside. Reference numeral 34 is an operation handle of the wiring breaker, and 32 and 33 are main terminals. In addition, this main terminal 3
When 2, 3 are connected to the power source side and the load side of the main electric circuit 31 shown in FIG. 2, the main electric circuit 31 is configured to pass through the through holes of the zero-phase current transformer 9.

[0005]

When the above-mentioned earth leakage alarm device is incorporated in a circuit breaker for wiring and used, the circuit breaker for wiring is usually arranged in the same switchboard as other control devices,
The output relay of the built-in leakage alarm device is often connected to the central monitoring panel by a signal line, and the central monitoring panel often monitors the leakage. In the power distribution circuit, particularly important circuits do not shut off immediately even if a leak occurs.If a leak alarm is issued, a worker goes to the switchboard to check the status of the leak accident and take necessary measures, and then apply the appropriate wiring. The circuit breaker is shut off.

However, since there are many indicator lights such as other control devices in the switchboard, it is often time consuming for an operator to find the corresponding breaker for wiring although it is urgent.

An object of the present invention is to provide an earth leakage alarm when the circuit breaker for wiring in which the earth leakage alarm is incorporated is arranged in the same switchboard as other control equipment, for example. An object of the present invention is to provide an earth leakage alarm device capable of finding out a breaker for wiring at a glance.

[0008]

In order to achieve the above-mentioned object, the present invention provides a zero-phase current transformer inserted in a main electric circuit and a main electric circuit connected to a secondary side of the zero-phase current transformer. In a leakage alarm device equipped with a control circuit that outputs a signal when the leakage current of the circuit exceeds a set value, and an output relay and an indicator lamp that operate according to the output signal of this control circuit, a blinking circuit that causes the indicator lamp to blink. Set up.

[0009]

Since the earth leakage alarm of the present invention has a blinking circuit for making the indicator light blink, even if a circuit breaker incorporating this earth leakage alarm is arranged in the same switchboard as other control equipment, for example. The indicator lights of other control devices are normally continuously lit, and a leak alarm device incorporating the leak alarm device of the present invention that blinks and lights at the time of a leak alarm can be found at a glance.

[0010]

FIG. 1 is a circuit diagram showing an embodiment of the earth leakage alarm device of the present invention. Where the earth leakage alarm device of the present invention shown in FIG. 1 differs from the conventional earth leakage alarm device shown in FIG. The flashing circuit 29 is connected in series with the lamp 7. This blinking circuit 29 is connected between both terminals of the output relay 4 and has a flicker mode (a mode in which ON and OFF operations are continuously repeated according to a predetermined order and time after the power supply voltage is applied from the output terminal d). ), A timer circuit 26 formed of, for example, an integrated circuit device, and a transistor 21 whose output is input to its base via a series resistor 24 and a parallel resistor 25.
The collector and emitter of this transistor 21 are the indicator lamp 7
And are connected in series. In addition, the resistor 2 connected in series
2, 23 and the capacitor 27 are for setting the time width of ON / OFF operation of the timer circuit by the time constant.

When a leakage current is generated in the main electric circuit 31 and the thyristor 5 is turned on, a voltage is applied between both terminals of the output relay 4. This voltage is simultaneously applied to the timer circuit 26, the timer circuit 26 outputs a flicker mode signal from its output terminal d, and the transistor 21 is repeatedly turned on and off by this signal. Turning on the transistor 21,
The indicator light blinks repeatedly when it is turned off repeatedly.

Other operations are similar to those of the conventional earth leakage alarm device shown in FIG.

[0013]

In the earth leakage alarm device in which the blinking circuit is added to the indicator lamp of the present invention, for example, even if the circuit breaker in which the earth leakage alarm device is incorporated is arranged in the same switchboard as other control devices. Since the indicator lights of other control devices are normally continuously lit, and the leakage alarm device incorporating the leakage alarm device of the present invention that blinks and lights at the time of the leakage alarm can be found at a glance, it is a particularly important power distribution circuit. Workers can quickly check the status of leakage accidents and take necessary measures in an emergency when a leakage alarm is issued.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a leakage alarm device of the present invention.

FIG. 2 is a circuit diagram showing an example of a conventional earth leakage alarm device.

FIG. 3 is a front view of a distribution breaker in which the conventional earth leakage alarm device shown in FIG. 2 is incorporated.

[Explanation of symbols]

 4 Output relay 7 Indicator 8 Control circuit 9 Zero-phase current transformer 29 Flashing circuit 31 Main electric circuit

Claims (2)

[Claims] 1. A zero-phase current transformer inserted in the main electric circuit and a control connected to the secondary side of the zero-phase current transformer, which outputs a signal when the leakage current of the main electric circuit exceeds a set value. A leakage alarm device comprising a circuit, an output relay that operates according to an output signal of the control circuit, and a display lamp, the leakage alarm device including a blinking circuit that causes the indicator lamp to blink. 2. The earth leakage alarm device according to claim 1, wherein the earth leakage alarm device is incorporated in a distribution breaker for use.