| 摘要 |
PURPOSE:To perform the AC are welding with a high SR ratio without deflecting the magnetization of a welding transformer by combining the DC output control with the AC output control or combining the DC output controls with different output polarity. CONSTITUTION:When first thyristor groups 3 and 4 in a two phase full-wave rectifier circuit are ignited alternately for every half-cycle of power source frequency, the DC output smoothened by a reactor 7 is obtained. Furthermore, when one thyristor 3 of the first thyristor group and a second thyristor 5 are ignited alternately, currents with reversed polarity half-waves and straight polarity half-waves are allowed to flow through the thyristors 3 and 5 by a commutating action of the reactor 7 respectively and the AC output with current frequency is obtained and the AC to DC conversion of the output can be carried out without using a changeover switch of a main circuit. Furthermore, the AC output with frequency different from the power source frequency is obtained and the SR ratio (ratio of the currents with straight polarity half-waves and reversed polarity half-waves) can be highly changed by repeating the DC output control and the AC output control alternately.
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