| 摘要 |
PROBLEM TO BE SOLVED: To detect the damage part of a conductor such as an insulated electric wire for an overhead power distribution, an overhead transmission line or the like. SOLUTION: The sensor coil L arranged in the periphery of an electric wire 1 to be measured is equipped with a flaw detection coil L10, an exciting coil L20 and a resonating coil L30. The coils L10, L20 and L30 are respectively constituted of upper and lower saddle-shaped flaw detection coils L10a and L10b, upper and lower saddle-shaped exciting coils L20a and L20b, and upper and lower saddle shaped resonating coils L30a and L30b and arranged on the outer surface of the electric wire 1 to be measured in opposed relationship so as to surround the electric wire 1 to be measured. These flaw detection coil L10, exciting coil L20 and resonating coil L30 are constituted as one set comprising three coils. A resonance circuit having a condenser, an amplifier, a variable resistor or the like is connected to the resonating coil L30 and the variable resistor in the resonance circuit is preliminarily adjusted so that the resonance circuit is operated when a current exceeding a threshold value flows through the resonating coil L30 or a voltage exceeding a threshold value is generated in the resonating coil L30. COPYRIGHT: (C)2005,JPO&NCIPI
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