Inverter type DC resistance welding machine

摘要

Disclosed is an inverter type DC welding machine incorporating constant-power control to assure a high and reliable quality of weld. The pulse width of the high-frequency output of the inverter circuit is controlled at the inverter switching rate by the constant-power control on a feedback loop basis in which the value of a weld power actually supplied to the portion to be welded between electrodes is computed and the computed value is compared with the value of a reference weld power to produce an error signal for controlling the operation of the inverter circuit, so that the actual weld power is maintained constant regardless of variations in the resistance of the portion to be welded during a welding operation.