| 摘要 |
PURPOSE:To obtain a titled device for improving a quality of a start point of a base metal and executing a stable welding thereafter, by feeding a pulse current to an AVC motor by a changeover switch at the time of starting to an AVC circuit, and bringing an electrode to slow descent, contact, inversion, and quick ascent by its counting number. CONSTITUTION:When a torch switch 14 is turned on, a touch arc start controlling circuit 10 switches a changeovers switch to a point B, and an electrode 1 is made to descent slowly by rotating an AVC motor 8 by a negative voltage pulse by a pulse oscillator 15 and a touch speed setting device 12. On the other hand, a revolving speed of the AVC motor 8 is counted 17 by a pulse generator 16, and as soon as the electrode 1 contacts to a base metal 2, the electrode 1 is inverted instantaneously and ascends quickly to a designated counting number 17 by a revolving speed of a positive voltage ascending speed setting device 13 of the AVC motor 8. Thereafter, a switch 11 is switched to a point A, and the electrode 1 executes a stable welding of a prescribed arc length by an AVC circuit 9. The electrode 1 contacts slowly to the base metal, the shock is softened, a quality of a contact of the base metal 1 is improved by an instantaneous quick ascent to a prescribed height, and also a stable arc welding is executed thereafter. |
