PURPOSE: To maintain a constant welding current by outputting the major part of a welding current from a movable iron core type power source device and by controlling the variation in the welding current outputting from said power source device by an SCR type power source device.
CONSTITUTION: The total current of the welding current to be outputted from a movable iron core type power source device 10 and the welding current for variation controlling to be outputted from an SCR type power source device 11 is detected by a current detector 12. The detected current signal outputted by this current detector 12 and the set current being set in advance with setting to the welding conditions to a setter 13 are compared by a comparator 14. The welding current to be outputted by the SCR type power source device 11 is made variable with inputting the deviation signal to be outputted from this comparator 14 into a commander 15 and with controlling the ignition phase of the thyristor of the SCR type power source device 11 by the commander 15 so as to make the deviation signal in zero.
SATO YUKIHIKO
SATO YOSHIKAZU
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