Resistance-welding power supply apparatus

摘要

Disclosed is a resistance-welding power supply apparatus comprising a large-capacitance capacitor 20 for storing a welding energy in the form of electric charge, a charging unit 18 for charging the capacitor 20 up to a predetermined voltage, a transistor group 22 electrically connected between the capacitor 20 and a welding electrode 24 on one hand, and a control unit 30 for causing a switching action of the transistor group 22 at a predetermined frequency during the weld time to provide a control of a welding current I. The charging unit 18 includes a charging transformer 14 and a rectifying circuit 16. The control unit 30 includes a main control unit 32 for providing a control of the witching action of the transistor group 22 by way of a drive circuit 44. The control unit 30 further includes various sensors, measuring circuits and an arithmetic circuit, for providing a feedback control of the welding current, an interelectrode voltage or a welding power. <IMAGE>