| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a device and method for measuring the leakage current Igr value flowing through a ground insulation resistor of electric equipment and its circuit that are driven by a switching power supply such as an inverter. <P>SOLUTION: A signal processing section 14 for signal-processes the ground voltages VU, VV and VW of the switching power supply 2 sequentially input by a change-over switch 10 and the leakage current 10 detected from a power supply cable 4 by a zero-phase current transformer 8, and measures the phase difference between one of the ground voltages VU, VV and VW and the leakage current 10, and signal-processes it. The leakage current Igr flowing via a ground leakage resistor 7 is calculated based on the effective value of the leakage current 10 obtained in the signal processing section 14, the effective values of the ground voltages VU, VV and VW, and the phase difference between one of the ground voltages VU, VV and VW and the leakage current 10. The leakage current Igr calculated by the arithmetic section 15 is displayed on a display section 16. <P>COPYRIGHT: (C)2009,JPO&INPIT |
