| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device wherein the number of the winding taps can be reduced in a transformer and further finely adjust output voltage and to facilitate this adjustment. SOLUTION: The connecting positions of taps T provided on the primary windings Pu, Pv, Pw of a welding transformer WT are changed by a selector switch SW2. As a result, the transformation factor of the transformer WT is changed and the voltage value of output voltage for arc processing is adjusted stepwise. In addition, the ignition angles of the thyristors SCR1 to SCR3 of a secondary rectifying circuit DR2 are controlled by an ignition angle control circuit 12. As a result, direct-current output voltage generated from alternating-current voltage obtained as the result of transformation at the transformer at the rectifying circuit DR2, that is, the voltage value of output voltage for arc processing is continuously adjusted. Thus, output voltage for arc processing can be continuously adjusted (finely adjusted) by control of the ignition angles of the thyristors SCR1 to SCR3 at the rectifying circuit DR2 even though the number of taps on the primary windings Pu, Pv, Pw is reduced. COPYRIGHT: (C)2009,JPO&INPIT
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