| 摘要 |
PURPOSE:To continue the smooth welding with the little occurrence of spatters by impressing a next pulse current with a prescribed time lag even if a wire contact short-circuit takes place to select this lag time to a proper value. CONSTITUTION:A period of time T3 is the time when the contact short-circuit of a wire is firm and the short-circuit is not released by an oscillation of a molten part and the pinch force by a short-circuit current. In this case, since an arc short-circuit decision signal Vas is of a H level as it is to indicate a short-circuited state, an output signal VP of an AND element 17 is made to the H revel during tP3 which is a third time limit. As a result, an output signal VQ of an OR element 18 is made to the H revel during the period of time of tP3 and made to a reference clock signal VCK during a different period of time. Since said VQ signal is inputted to a clock input terminal of a first timer circuit 14, the first timer circuit 14 calculates the time long by the time of tP3 than a reference pulse period tP1 and commands the next pulse current impressing to an output control circuit 11. As a result, the wire contact short-circuit is released by a pulse current and weld defects due to the stabbing can be prevented.
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