| 摘要 |
PURPOSE:To provide a detection circuit for disconnection which detects abnormality for each core wire by providing detection coils, and filter, peak holding and comparison circuits in accordance with the number of core wires and providing a changeover switch to the comparators. CONSTITUTION:Detection circuits 8 consisting of magnetic sensors of the number corresponding to the number of core wires of a cable for welding of a spot welding device are provided to detect the change in welding current. The output of each coil 8 is fed through an amplifier circuit 12 to a filter circuit 13, by which a smooth DC voltage is obtd. and is stored in a peak holding circuit 14. The voltage is compared with a reference voltage in a comparator 15, and when said voltage is higher than a reference voltage, an output voltage is generated at an output terminal 16. The result of the discrimination is displayed on an indicating lamp 22. The output side of each set of the comparator 15 is changed over by a changeover switch 23 and the reference value is set at an optional value. The disconnection of the core wire is quickly and surely detected by such circuit. |
