| 摘要 |
PURPOSE:To stabilize the arc actuation with enabling to start an arc by low frequency by installing a frequency shifting device to the arc welder of inverter type using a switching element or of series chopper method. CONSTITUTION:The shunt 11 to detect a welding current in nearly the same arrangement as before of an inverter unit 1, transformer 2 for welding, etc., the current detecting circuit 12 to detect the DC signal voltage of from the shunt 11, the frequency switching circuit 13 having the frequency switching property with receiving the signal from the current detecting circuit 12 and the driving circuit 14 to drive the switching element of the inverter unit with receiving the signal from the frequency switching circuit 13 are provided. With the device like this a big current can be obtd. with lowering the switching frequency at the arc starting time and after the arc actuation with increasing the switching frequency the current waveform with less current ripples can be obtd. and the welding work can be performed stably.
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