| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a power supply for an electric railcar, which detects a short circuit failure of a backflow preventing element for preventing current from flowing backward from a filter capacitor to an overhead contact line. Ž<P>SOLUTION: When power is turned on, an initial charging circuit 19 turns off a short circuit switch 7 and charges the filter capacitor 9 via a charging resistor 6. When the charging of the filter capacitor 9 is completed, the initial charging circuit 19 turns on the short circuit switch 7 and suppresses a rush current to the filter capacitor 9 when the power is turned on. When operation stops, a discharging circuit 20 discharges the filter capacitor 9 via the initial charging circuit 19. When operation stops, a current detecting sensor 5 disposed between the initial charging circuit 19 and the discharging circuit 20 detects a discharging current from the filter capacitor 9 via the initial charging circuit 19. If the discharging current detected by the current detecting sensor 5 exceeds a predetermined value when the operation stops, a failure detecting section 18 determines that the backflow preventing element 8 of the initial charging circuit 19 is short-circuited. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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