| 摘要 |
PURPOSE:To start the arc without contact and to prevent the generation of spatters in the starting of the arc by supplying a starting gas of the spark discharge initiation voltage lower than that in the welding stage as a shielding gas. CONSTITUTION:When a welding start signal is emitted from a control circuit, an electric motor 6 runs at a low speed and feeds a consumable electrode 5 at a low speed toward the work 10. An electric power source 1 and a high frequency power source 2 generates output, and the voltage superposed with a high frequency voltage is applied between the electrode 5 and the work 10. At the same time, a solenoid valve 11 opens and a shielding gas for starting is released from a gas source 13 through a nozzle 9 to weld zones. When the spacing between the electrode 5 and the work 10 goes closer than the spark discharge initiation gap, the welding arc is generated. On detection of the generation of the arc, a solenoid valve 14 is opened and a solenoid valve 13 is closed. The feed speed of the electrode 5 is charged to the speed in the welding stage and the supply of high frequencies is stopped. |
