PURPOSE: To correct to decrease a current at the time of short circuit transfer and to correct to increase the current at the time of arc transfer by executing gate processing on both discriminating signals of the presence or absence of the current and voltage to form a differential signal for correcting the current and forming this differential signal into a signal added to a set signal of constant current control.
CONSTITUTION: The DC TIG arc welding machine is provided with a current detector 11 and a voltage detector 21 to detect the current and voltage of welding load 10, a current discrimination part (a current and voltage converter 12) to form the discriminating signal of the presence or absence of the current and a voltage discrimination part 22 to form the discriminating signal of the presence or absence of the voltage. In addition, a gate part 25 to execute gate processing on both discriminating signals, a differentiation circuit 26 to differentiate an output signal of this gate part 25 and an error amplifier 17 to form an error signal. between a signal added with the differential signal to the set signal of the constant current control and a current detection signal as a feed control signal of the constant current control are provided. The current at the time of starting an arc is corrected to a differential waveform where the short-circuit current is decreased and the arc transfer current is increased by the feed control signal. Consequently, the applicable current range is extended and the performance is improved.
IKEDA TETSURO
FUJIYOSHI TOSHIICHI
AOYAMA MASAHIRO
MORIGUCHI HARUO
KANO KUNIO
| JPS5395155A | 1978-08-19 |