FLASH BUTT WELDING DEVICE

PURPOSE:To economize energy by providing a voltage type inverter contg. a smoothing capacitor as a welding power source and conducting intermittently the welding current for charging and discharging of the smoothing capacitor in accordance with the pressure to be exerted to both ends of materials to be welded. CONSTITUTION:A converter part 7, a smoothing reactor 8 and the smoothing capacitor 9 are contained into the circuit of the inverter 6. Pressure is exerted to an upset cylinder 4 intermittently for a specified period. On the other hand, single phase AC current to electrodes 2, 3 is conducted by the signals of respectively corresponding transistors 11, 12, 10, 13 of control units 15, 16 and a pair of control units 14, 17 during the time when the pressure is exerted to the materials 1 to be welded. The capacitor 9 repeats the charge and discharge in accordance with the interrupted conduction of the current. The unbalance in the 3-phase power source is eliminated and the smaller input is required by the above-mentioned method. Economization of energy is thus made possible.