Spot welding apparatus and its power supplying method

A spot welder apparatus, comprising:

• a single welding power source (5);
• a plurality of spot welders (1A, 1B, 1C) activated by welding current supplied by said single welding power source (5);
• a welding current distributor (7) connected between said single welding power source (5) and said spot welders (1A, 1B, 1C) for distributing the welding current for said spot welders (1A, 1B, 1C) selectively, said welding current distributor (7) including;
• a branch unit (11);
• control means for controlling an operation of said branch unit (11);
• a plurality of automatic switches (13A, 13B, 13C) connected between said branch unit (11) and said spot welders (1A, 1B, 1C), respectively, for activating and deactivating said spot welders;
• and
• wherein said control means executes the steps of:
• cyclically checking whether start signals have been generated by a plurality of said spot welders (1A, 1B, 1C);
• activating said branch unit (11) so as to supply welding current to a first one of said plurality of spot welders which first generates a start signal while keeping the remaining ones of said plurality of spot welders under electrically pressurized conditions;
• activating said branch unit (11) so as to supply welding current to a next one of said plurality of spot welders which next generated a start signal, after said first one of said plurality of spot welders has been deactivated;
• and
• repeating the above steps so that each one of said plurality of spot welders are activated in sequence of the start signals generated.