| 摘要 |
<p>An pulse arc welding apparatus feeds a consumable electrode (8) with a constant rate, and arc-welds by applying a welding current constituted of a pulse current of a constant voltage characteristic and a base current of a constant current characteristic between the consumable electrode (8) and a workpiece (9). A pulse current control circuit (17) outputs a pulse current command value, based on a difference signal between a pulse voltage detector (15) and a pulse voltage setting device (16). A pulse frequency control circuit (14) outputs a pulse frequency command value, based on a difference signal between a pulse current detector (12) and a pulse current setting device (13). Setting devices (22,23) which output a pulse current upper limit value or lower limit value are provided. A pulse current comparison and adjustment circuit (24) inputs a pulse current command value and a pulse current upper limit value or a pulse current lower limit value, and outputs the pulse current upper limit value, when the pulse current command value is larger than an upper limit value of a pulse current, and/or outputs the pulse current lower value when the pulse current command value is less than a lower limit value of the pulse current, and outputs the pulse current command value in a case except the above. The pulse frequency correction circuit (26) outputs a frequency correction value fe to the pulse frequency control circuit, such that when the pulse current upper limit value or lower limit value is selected continuously in a predetermined number of times at the pulse current comparison and adjustment circuit (24), the pulse frequency is increased/decreased by a predetermined value DELTA f by DELTA f in accordance with the selected number of times. <IMAGE></p> |
