| 摘要 |
PURPOSE: A leakage current measurement device is provided to perform the measurement without stopping the operation of an electric device, and judges the insulation state of the electric device by measuring a leakage current component by an equivalent earth insulation resistor. CONSTITUTION: A current trans sensor(2) is clamped to an electric line(1) or a ground line of a device to be measured, and detects a leakage current flowing through the electric line or the ground line. A current voltage conversion circuit(3) converts an output signal of the current trans sensor into a voltage signal. A voltage amplification circuit(4) amplifies an output signal of the current voltage conversion circuit. A voltage division amplification circuit(6) is connected to a voltage line of the device, and divides a circuit voltage of the voltage line and also amplifies it. A multiplier circuit(5) multiplies the output of the voltage amplification circuit and an output of the voltage division amplification circuit. A low pass filter(7) removes a high frequency component from an output signal of the multiplier circuit. A leakage current display circuit(8) displays a leakage current signal of the low pass filter. A leakage current comparison judgement circuit(9) judges whether the leakage current signal exceeds or is below a reference value. And a judgement result display circuit(10) displays the judgement result of the leakage current comparison judgement circuit.
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