POWER UNIT FOR DC ARC WELDING Russian patent published in 1994 - IPC

FIELD: welding. SUBSTANCE: power unit has circuit 1; filter made up of inductance coil 2 and capacitor 3; inverter consisting of controllable thyristors 7, 8, 9, 10, switching capacitors 4, 5, protective inductance coil 6 and switching-matching transformer 11; low-voltage amplifier with gates 12, 13 and load in the form of ripple filter 15 and welding circuit 15. Power unit includes also control system consisting of voltage sensor 16, comparators 18 and 19, two Schmitt triggers 20 and 21, single-shot multivibrators 23 and 24, master oscillator 22, AND circuits 25 and 27, OR circuits 29, 30, and 31, 32, pulse shaper-distributor 33. Use of controllable reverse gates in resonance inverter makes employment of high-voltage amplifier at power unit input unnecessary. EFFECT: reduced losses of true power and improved efficiency of power unit. 3 dwg