PROBLEM TO BE SOLVED: To provide a feeder circuit failure spotting device simple in configuration, low in manufacturing cost, and capable of high-accuracy failure spotting in case of any of grounding and short-circuiting failure.;SOLUTION: The device finds a short-circuit between the feeder and the trolley and determines the zone to be the failure zone upon detecting a reversal in the feeder current direction at the two posts at both ends of the failure zone. This enables failure point identification to be accomplished by checking the feeder current (one element) merely, and simplifies equipment and circuitry for the realization of a low-cost device. Using this device, complicated calculation such as vector analysis required in the prior art is dispensed with and less error attributable to grounding resistance occurs because the device isolates the failure zone by a digital judgement involving current direction (positive or negative). The result is an accurate failure spotting using a simplified configuration.;COPYRIGHT: (C)2003,JPO
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