Patent ID: 9162307
Filing Date: 2015-10-20
Classification: B23K

Abstract:
1. A method for performing AC arc welding in which a negative-polarity period and a positive-polarity period for performing welding are alternated between a first period and a second period corresponding to a first AC frequency based on a positive control signal and a negative control signal, the method comprising: alternating the positive control signal between a high level for the first period and a low level for the second period, the high level of the positive control signal producing the positive-polarity period; alternating the negative control signal between the low level for the first period and the high level for the second period, the high level of the negative control signal producing the negative-polarity period, wherein the positive control signal and the negative control signal are separate from each other and are complementary to each other, and wherein the high level is greater than the low level; a detection step for detecting an arc interruption during welding; and a control step for, upon detection of the arc interruption in the detection step, reigniting an arc by outputting the high level of the positive control signal and the high level of the negative control signal for a period shorter than the first period and the second period corresponding to the first AC frequency, wherein in the control step, welding is performed at a second AC frequency higher than the first AC frequency, and wherein upon detection of the arc while welding is performed at the second AC frequency, the AC frequency is returned to the first AC frequency.