| 摘要 |
PURPOSE:To detect simply and accurately besides the disconnection of a strand of an overhead electric wire, the degree of rusting by calculating the outputs of an eddy-current disconnection detector and an eddy-current rust detector by an arithmetic circuit, and indicating the result of calculation. CONSTITUTION:The output of the eddy-current disconnection detector 1 is inputted to the 1st comparator 2b through a full wave rectifier 2a. When it is lower than set voltage, a signal of low level is outputted and if higher, a signal of high level is outputted. On the other hand, the eddy-current rust detector 3 excites the surface of an electric wire by an exciting coil L1, and detects the voltage induced in a detecting coil L2 according to the conductivity of the surface and the output of a phase shifter 3b by a phase detector 3c and outputs the degree of rusting of the electric wire. This output is compared with the output of a voltage setting device 4a by the 2nd comparator 4b, and outputted as a signal of high level when the rust is nil and slight, and as a signal of low level when the rust is heavy. This output is inverted by an inverter 5a and logical product with the output of the comparator 2b is executed, and the presence of disconnection and the degree of rusting are indicated on an indicator 6.
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