| 摘要 |
PURPOSE:To compensate the output for the variation in the power source voltage and to increase the stability of the arc by detecting the peak voltage outputted from a welding transformer or the secondary side rectifier circuit and by controlling the invertor continuity time ratio according to the peak voltage so as to make the mean value of the welding output voltage the prescribed value. CONSTITUTION:A peak holding circuit 12 detects the peak value of the secondary voltage of a welding transformer 4 and adds it to a divider 13. The divider 13 then adds to error amplifier 15 as a feedback signal the signal smoothed by a capacitor C2 by performing an intermittence at the same continuity time ratio as that of inverter 3 of the signal transmitted from a pulse width control circuit 16. and the differential signal between this and the target value signal which is from the output voltage setter 14 is amplified by error amplifier 15, the switching element of the inverter 3 is driven by the pulse signal obtd. by comparing with the saw-toothed wave by the pulse width control circuit 16 and the continuity time ratio of the inverter 3 is varied in reverse proportion to the variation rate of the peak voltage detected by the peak holding circuit 12.
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