| 摘要 |
PROBLEM TO BE SOLVED: To provide an insulation detection apparatus for an ungrounded power supply for improving reliability in the detection of an insulated state. SOLUTION: The insulation detection apparatus is provided with first switching means S1, S2; second switching means S1, S4; third switching means S2, S3; fourth switching means S3, S4 for connecting a detection means 11 for detecting a voltage across both the terminals of a capacitor 9 after breaking respective first, second, and third switching means; and a arithmetic means 11 for computing insulating resistors Rp, Rn to the grounding potential section 7 in the power supply 3. The arithmetic means 11 estimates the supply voltage of the power supply 3, based on a detection voltage by the detection means 11 after breaking the first switching means, calculates the fluctuation ratio of the supply voltage during the time for detecting a voltage across both the terminals of a capacitor 9 for calculating each estimated supply voltage, correcting each detection voltage by the detection means 11 after breaking the second and third switching means in the previous insulation detection cycle, based on the fluctuation ratio of the calculated supply voltage, and computes the insulating resistors Rp, Rn to the grounding potential section 7 of the power supply 3 from each corrected detection voltage and the supply voltage being estimated in the previous insulation detection cycle. COPYRIGHT: (C)2004,JPO
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