ARC IGNITION FOR ARC WELDING APPARATUS

摘要

A welding electrode (102) and a workpiece connected with a welding power source (106) are simultaneously connected to at least two additional high voltage power sources (110, 112). A short aperiodic high voltage pulse is transmistted from the firt high voltage power source (110) to a gap between the electrode and the workpiece, creating an electric discharge and current conducting duct in the air between the electrode (102) and the workpiece. This short pulse is superimposed by another long, high voltage pulse from the second high voltage power source (112). A stretched pulse appears, and the duration of the current discharge increases. The current conducting duct is heated, its resistance decreases and an arc is ignited. When the voltage in the current conducting duct decreases to a value less than that of the open circuit of the welding power source (106), welding current starts flowing from the latter through the welding electrode (102) and arc to the workpiece.