POWER SUPPLY (ALTERNATIVES) Russian patent published in 2003 - IPC

FIELD: ac power supplies for electric arc welding. SUBSTANCE: power supply designed for operation from supply mains to feed current to electrode-toworkpiece welding gap has high-power transformer that functions to transform mentioned supply voltage into ac output voltage and rectifier that converts ac output voltage into dc voltage applied between positive lead and common lead usually placed at zero potential and also between negative lead and common lead. Power supply has also positive selector switch that connects positive lead to common lead across gap when selector signal is fed to positive selector switch; negative selector switch used for connecting negative lead to common lead across gap when selector signal is supplied to negative selector switch; and pulse length modulator designed to produce pulses at frequency of at least about 18 kHz. Logic system has first circuit for feeding pulses to positive selector switch within first time interval, second circuit for feeding pulses to negative selector switch within second time interval, and collector for alternate engagement of first and second circuits to produce ac current for electric arc. EFFECT: simplified design. 24 cl, 22 dwg