摘要 |
A resistance welding power supply apparatus comprises a large-capacitance capacitor for storing resistance welding energy, a capacitor charging circuit, a switching element electrically connected between the capacitor and one electrode of a pair of welding electrodes, and a control unit for the switching element. If the welding current is less than a set current value at a point of time on the leading edge of a clock, then the control unit holds a control pulse for the switching element active or high from that point of time till the time when the welding current exceeds the set current value without being affected by the cycle of the clock. If the welding current exceeds the set current value at a point of time on the leading edge of the clock, then the control unit holds the control pulse inactive or low till a point of time on the leading edge of the next clock.
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