Patent ID: 6028290
Filing Date: 2000-02-22
Classification: B23K

Abstract:
An arc welding apparatus which enables manual welding and one of CO2 welding, MIG welding and TIG welding, the apparatus comprising:at least three thyristors for controlling an output current of a welding transformer, said at least three thyristors connected to a secondary winding of a welding transformer,a control circuit for executing current control of the at least three thyristors,a gate signal switchover circuit for executing selective switchover between gate signals transmitted from said control circuit to a selected plurality of said at least three thyristors, anda reactor for smoothing the output current,wherein the arc welding apparatus controls a voltage drop in said welding transformer by means of said at least three thyristors according to a signal of the control circuit and supplies the voltage to an output of the arc welding apparatus via said reactor,wherein said gate signal switchover circuit executes selective connection so as to operate a thyristor of the at least three thyristors connected to a low voltage tap of the secondary winding of said welding transformer when performing CO2 welding, MIG welding and TIG welding, and said gate signal switch over circuit executes selective connection so as to operate another thyristor of the at least three thyristors connected to a high voltage tap of the secondary winding of said welding transformer when performing manual welding.