Three phase oil-immersed distribution transformers 50 Hz, from 50 to 2500 kVA with highest voltage for equipment not excceeding 36 kV - Part 6: Requirements and tests concerning pressurised corrugated tanks; German version HD 428.6 S1:2002— 6 стр.
Transformers with copper windings; oil immersed natural cooling (S), three-phases, 50 Hz up to 630 kVA and insulation class 20 N (EEC standard series)— 2 стр.