FIELD: electrical engineering; plasma processes, arc welding, gaseous discharge devices and light sources. SUBSTANCE: ac voltage source of device has three groups of thermal of which terminals of first group are common ones. Device has at least one regulating transformer. First terminal of transformer primary winding is connected with one of terminals of minimum voltage source, and second terminal of primary winding is connected with one of terminals of winding operating voltage. First terminal of secondary winding is connected through second and each following terminals with common point of capacitors, and second terminal of secondary winding is connected with second terminal of primary winding of each regulating transformer. EFFECT: enlarged operating capabilities ties, enhanced reliability and safety. 5 cl, 4 dwg
