DC arc welding apparatus using high-frequency pulse current

A DC arc welding apparatus using a high-frequency pulse current comprising:

• a rectifier bridge for commutating AC voltage and for applying DC voltage having a substantially smooth waveform to a circuit comprising an electrode and a workpiece for welding,
• a first switch connected between one side of an arc load formed between the electrode and the workpiece and a positive output side of the rectifier bridge,
• a second switch connected between the other side of the arc load and a negative output side of the rectifier bridge,
• a capacitor one end of which is connected to a contact of the rectifier bridge and the first switch and the other end of which is connected to a contact of the rectifier bridge and the second switch,
• first and second rectifiers connected so as to charge energy accumulated in the inductance of the circuit comprising the electrode and the workpiece during the OFF state of the first and second switches to the capacitor, and
• control means for detecting two predetermined instantaneous values of the welding current passed through the arc load and for providing ON and OFF commands to one of the switches to reciprocate the welding current for plural times in a range between the two instantaneous values during the ON state of the other switch.