POWER SUPPLY APPARATUS FOR WELDER

摘要

A welder power supply apparatus ( 10 ) includes an inverter ( 20 ), which is driven intermittently when an electrode ( 34 ) and a workpiece ( 36 ) are separated from each other and no arc is being generated between them, whereby power loss generated in the inverter ( 20 ) when the inverter ( 20 ) is driven in the non-load state of the power supply apparatus and power loss caused by exciting current flowing through an transformer ( 24 ) disposed in the output of the inverter ( 20 ) can be reduced. The inverter ( 20 ) is driven continuously when output current (Io) becomes higher than a threshold value (Ib) after the electrode ( 34 ) and the workpiece ( 36 ) are brought into contact with each other for starting arcing between them. In this manner, the arcing can be initiated without fail