Patent ID: 6087629
Filing Date: 2000-07-11
Classification: B23K,H02M

Abstract:
A method for controlling a DC current arc welding system having a converter, the method comprising:tapping a transformer, having a transformation ratio, the transformer operably connected to an AC main, to, in turn, allow the transformer to supply the converter with a preliminary voltage and a preliminary current;triggering pulses at a predetermined firing angle to at least one thyristor;selecting a desired one of a steady DC current welding mode and a pulsed DC current welding mode;wherein if the desired selected mode comprises one of a steady DC current welding mode, the method further includes the step of:varying the firing angle of the at least one thyristor of the converter, to, in turn, fine tune the preliminary voltage and current;wherein if the desired selected mode comprises one of a pulsed DC current welding mode, the method further includes the step of:setting a base current through the transformation ratio of the transformer; andrapidly changing the firing angle symmetrically of the at least one thyristor of the converter time dependently to form a pulsed current, which in turn, superimposes the pulsed current onto the base current.