| 摘要 |
PROBLEM TO BE SOLVED: To prevent the end of a wire from welding to a welding object by generating an unnecessary arc the instant at which the welding wire contacts to the welding object. SOLUTION: In this arc start control method, when the welding wire is advanced and fed, and it is judged that the welding wire contacts to the welding object, an initial current is turned on and the welding wire is backed off the welding object. When the welding wire is away from the welding object by this backing off and an initial arc is generated, the welding wire is advanced and fed again and a steady output current is turned on and the initial arc is shifted to a steady arc. In this case, in order to judge contact of the welding wire to the welding object, application of an output voltage Vw from a welding power source device has been allowed to stop, a contact judge voltage Vt is applied between the welding wire and the welding object from a contact judge voltage application circuit VT which is built in the welding power source device, and the contact is judged by turning on a small current value of a contact judge current It up to a point that the arc is not generated by contacting both of them. The welding at the time of contact can be prevented by this contact judge operation.
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