| 摘要 |
PURPOSE:To prevent sudden burn-through of a wire and an unstable arc due to a magnetic arc blow, by constituting so that a welding wire is conducted in a state that a welding wire is contacted with a molten pool. CONSTITUTION:In a state that a welding wire 6 does not contact with a base material 2, output voltage of an power source 8 is applied to a relay 10 through a resistor 11, the relay 10 is energized, and a normally closing contact 12 is in an open state. When welding is started, an arc is generated and the wire 6 contacts with a molten pool of the base material 2, both ends of an energizing of the relay 10 are short-circuited by the welding wire 6, energizing of the relay 10 is released, the normally closed contact point 12 in opening state is closed, and to the wire 6, a preheating current is supplied from the power source 8. |
