| 摘要 |
A capacitor type welding power unit incorporates a constant-current charging control circuit which serves to control a charging current being supplied to a capacitor so as to be substantially constant during the charging. By such a control circuit, which typically performs a thyristor firing control, the charging voltage of the capacitor is made to follow a reference signal, which is preferably set to change linearly with time, and it reaches a preset target value in a predetermined time regardless of fluctuations in the supply voltage. Furthermore, such a control circuit enables the capacitor to be directly connected to the output terminals of a rectifier circuit with no charging resistor being provided so as to reduce resistance heating and so as to lower power consumption in charging the capacitor.
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