Arc welding power source

An arc welding power source that supplies a start current, a welding current and a crater current as an output current in accordance with an activating signal supplied from outside, the power source comprising:

• a start period setting unit that is configured to set a start period;
• a crater period setting unit that is configured to set a crater period;
• a current control unit that is configured to control the output current;
• a repeated welding period setting unit that is configured to set a repeated welding period;
• and
• a repetition number setting unit that is configured to set a repetition number of crater periods;
• wherein the current control unit is configured to cause the power source to supply the start current and the welding current consecutively while the activating signal is in an on-state, the start current being supplied for the start period, the welding current being supplied for a period following the start period, wherein the current control unit is configured to cause the power source to supply the crater current as a constant current after the activating signal is turned off, the crater current being supplied for a first crater period;
• wherein the current control unit is configured to cause the power source to supply a welding current for the repeated welding period following the first crater period, and to supply the crater current for a second crater period following the repeated welding period, the current control unit is configured to cause repetition of supplied current, and
• wherein the current control unit is configured to cause the power source to stop the supplying of the output current to terminate welding when a number of repeated crater periods, including the first crater period and the second crater period, reaches the repetition number of crater periods set by the repetition number setting unit.