Resistance welding power supply apparatus

A resistance welding power supply apparatus allowing a welding current to flow through a pair of welding electrodes that come into pressure contact with workpieces to be welded together to effect a resistance welding of said workpieces, said resistance welding power supply apparatus comprising:

• a capacitor having first and second electrodes electrically connected to said pair of welding electrodes, respectively, said capacitor storing electric energy for resistance welding in the form of electric charges between said first and second electrodes;
• first switching means electrically connected between said capacitor and said welding electrode;
• first control means which provide a switching control of said first switching means, for supply of resistance welding current;
• a rectifying circuit which rectifies an AC power supply voltage of a commercial frequency into a DC voltage for output;
• an inductance coil having one end electrically connected to one output terminal of said rectifying circuit and having the other end electrically connected both to the other output terminal of said rectifying circuit and to said first electrode of said capacitor;
• second switching means electrically connected between output terminal of said rectifying circuit and said inductance coil;
• second control means which provide a switching control of said second switching means, for charging said capacitor;
• and
• a rectifying element having one terminal electrically connected to said one end of said inductance coil and having the other terminal electrically connected to said second electrode of said capacitor, said electrical connections being made in such a direction as to allow a freewheeling current to flow from said inductance coil.