| 摘要 |
PURPOSE:To facilitate the detection of troubled wires with a reduced number of cables to be examined as brought into contact with a detector section by cutting the magnetic field as produced by the detection current fed to the core of a specified cable 0-50% of the max. level as reference with a limiter. CONSTITUTION:There are the calibration mode for memorizing a necessary value for the operation of a limiter and the detection mode for detection of a specified mode. A switch 30 is turned ON to enter the calibration and as a core 31 and a search coil 22 is approach a cable, the search coil 22 generates a voltage proportional to the magnetic field. This voltage is converted into a digital signal with an A/D converter 24 via an amplifier 23 and read out with a CPU25. A voltage value for the operation of a limiter, so designed that a strong magnetic field alone near a specific cable is sensed by cutting all weak magnetic field below 0-50%, is memorized into a memory 26. With such an arrangement, the detection signal is produced only when a search coil 12 and a core 11 gets in contact with the specific cable and can be indicated on a display 28. |
