| 摘要 |
PURPOSE:To elevate an excess responsibility and the reliability in the output short circuit detection at the cable extension time by arranging a pulse generating device and output short circuit detecting circuit to a short circuit conversion type DC arc welder. CONSTITUTION:A welding voltage detecting device 6, reference voltage generating device 7, comparator 8, etc. are arranged in the same conventional examples and the pulse generating device 10 to generate the weld detecting signal of 50ms-500ms with receiving a logical output from the comparator 8 and the output short circuit detecting circuit 11 to discriminate the generation of the output short circuit detecting signal by the existence of the weld detection signal transmitted from the pulse generating device 10 are provided. The comparator 8 compares the welding voltage and reference voltage and outputs a welding short circuit signal to the pulse generating device 10, which generates the pulse signal triggered by the rise signal of the weld short circuit signal and the continuous weld detecting signal if triggered again during the signal generation. In case of short circuit on the other hand the weld detecting signal becomes zero after being triggered and in that moment the output short circuit signal is transmitted and the output short circuit is detected.
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