| 摘要 |
PURPOSE:To execute various improvements with respect to an elevation of a quality of a welding joint, by making a welding current conduct simultaneously to plural welding heads, detecting separately generation of a nugget, and cutting off simultaneously the electric conduction when the nugget generation of all heads is completed. CONSTITUTION:A welding current is made to flow simultaneously to welding heads 5, 6 and 7 through welding transformers 2, 3 and 4 by one AC electronic switch 1. Subsequently, generated welding nuggets are detected by detectors 8, 9 and 10, are converted to quantity of electricity by transducers 11, 12 and 13, and are compared with a set value of a setting device 17 by comparators 14, 15 and 16. Subsequently, when they coincide with the set value, the cmparators 14, 15 and 16 transmit a nugget completion signal. As a result, a counting circuit 18 cuts off the welding current of each welding head through an electric conduction controller 22, an ignition signal generator 21 and the AC electronic switch 1. On the other hand, an indicator 20 displays the time required for the nugget completion, by which easiness of generation of the nugget and its rate of lack of uniformity, etc. can be known. |
