Pulse arc welding apparatus

摘要

A pulse arc welding apparatus feeds a consumable electrode with a constant rate, and arc-welds by applying a welding current constituted of a pulse current of a constant voltage characteristic and a base current of a constant current characteristic between the consumable electrode and a work piece. A pulse frequency correction circuit outputs a frequency correction value fe to a pulse frequency control circuit, such that when the pulse current upper limit value or lower limit value is selected continuously in a predetermined number of times at a pulse current comparison and adjustment circuit, pulse frequency is increased/decreased by a predetermined value DELTA -f by DELTA -f in accordance with the selected number of times. According to the pulse frequency control, the pulse arc welding apparatus is capable of substantially increasing a response of an arc length control, and enabling to follow a change of a welding condition and a fluctuation of the distance between a contact tip and a work piece promptly.