Power source apparatus for alternating-current arc welding, capable of supplying an alternating-current welding current having any waveform

摘要

There is disclosed a power source apparatus for an alternating-current arc welding. In the power source apparatus, a reference signal generator periodically generates a reference signal having a predetermined waveform, and a direct-current power source outputs a current periodically changing in response to the reference signal, the outputted current having a waveform corresponding to that of the reference signal. Thereafter, a switching circuit supplies an alternating-current welding current to a welding load so as to sequentially change the polarity of the welding current from a straight polarity to a reverse polarity and from the reverse polarity to the straight polarity in synchronization with the reference signal by switching the current outputted from the power source in response to the reference signal.