With detection resistance and insulating resistance and the detection resistance which are jointed

摘要

The insulating resistance detection system (50), the coupling condenser (52) with detection resistance (54) with the pulse oscillating circuit (56) with the point of measurement of common mode electric potential (30) connecting in series, the part and the coupling condenser of the insulating resistance sensing station which is formed (52) with detection resistance (54) with the filter which processes the interchange signal v _{X of the} connection (58), the amplifier (60), the crest value detector (62), the control section (70) it includes with the part of the insulating resistance judgment section which it possesses. The control section (70), insulating resistance decrease is detected the crest value detector (62) according to output, fluctuation of common mode electric potential is required HVCPU (40) vis-a-vis in order to decide the breakdown of the insulating resistance sensing station, the crest value detector of front and back of common mode electric potential fluctuation (62) the function which decides the breakdown of the insulating resistance judgment section from output change possesses.