摘要 |
A controller for a welding machine in which workpieces are pinched between a pair of electrodes through which welding current is supplied to weld the workpieces, the controller includes a circuit for detecting an amount of resistance between the electrodes, a circuit for monitoring occurrence of a phenomenon that interelectrode resistance detected by the detecting circuit shifts from an upward tendency to a downward tendency, and a circuit for cutting off welding current after occurrence of the phenomenon monitored by the monitoring circuit, and when an absolute value of a time derivative of the interelectrode resistances detected by the detecting circuit becomes less than the predetermined value.
|