PURPOSE: To improve the stability of an arc by discriminating the contact state between a wire and a material to be welded and an arc generating state of the time of starting an arc, and shifting a lower speed than a wire feed speed to a set speed.
CONSTITUTION: When a welding start switch 7 is turned on, a timer circuit 14 is operated, and by a control signal of the timer circuit 14, a wire feed speed switching circuit 10 inputs a set value of a low speed wire feed setting part 11 to a wire feed motor driving circuit 5 for another prescribed time (the time which has been set by a timer). After the prescribed time has elapsed, a set value of a welding condition wire feed setting part 12 is inputted automatically to the wire feed motor driving circuit 5 by the wire feed speed switching circuit 10. The prescribed time in this case is determined by the required for the time when a wire 2 contacts to a material to be welded 8, and an arc is generated, and the time required for the time when the wire 2 is fed for a short time through an interval extending from the tip of a welding chip to the material to be welded 8 by an inching operation in a welding work.
IMANAGA AKIYOSHI
SHINADA TSUNEO
HITACHI SEIKO KK
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