Patent ID: 8592720

Claim:
A polarity switching control method in consumable electrode AC pulse arc welding under power supply from a welding power source, the method comprising: applying a peak current and a base current during an electrode-positive polarity period; applying an electrode-negative current during an electrode-negative polarity period; and conducting polarity switching between the electrode-positive polarity period and the electrode-negative polarity period in response to a temporary operation-stop signal for temporarily stopping the power supply from the welding power source, the temporary operation-stop signal being output following output of a pulse period signal that causes an average of variable welding voltage to be equal to a voltage setting; conducting the polarity switching from positive to negative after a predetermined delay period has lapsed in response to the temporary operation-stop signal that is also delayed from the pulse period signal by at least said predetermined delay period, when a single consumable electrode and a base metal come in short circuit with each other during the electrode-positive polarity period, said predetermined delay period being provided for the single consumable electrode; and conducting the polarity switching from positive to negative in response to the temporary power-stop signal that is not delayed from the pulse period signal, when the consumable electrode and the base metal do not come in short circuit with each other during the electrode-positive polarity period.