FIELD: electrical engineering; winding manufacture. SUBSTANCE: semiconducting protective coating that covers conductor at its exit from slot is built of two sections. First section closest to slot area is maximum 40 mm long and length of second one is minimum 200 mm. Protective coating enamel is filled with microscopic carborundum powder of 20-28 mcm dispersion, its content being 75-800 parts by weight, and doped with microscopic aluminum powder of 40-60 mcm dispersion that functions as regulating additive, its amount being in first section 5-12% of carborundum mass and in second section, 2-4% of carborundum mass. First section is electrically connected to electrical machine magnetic circuit and second one, to first section and abuts against the latter. Winding insulation is subjected to high-voltage tests by applying maximum admissible breakdown voltages and measures are taken to suppress ionizing effects in protective coating. EFFECT: enhanced mechanical endurance and reliability of winding insulation and stability of protective coating. 2 dwg
