New 39 series three phased oil-immersed transformer uses new structures of insulation and anti-shortcut etc. Its features are advanced internationally. Comparing to s7 series, the empty loading loss decreases 10.25% in average, empty loading current decreases 37.9%, loading loss decreases 22.4% in average, it is the upgraded version for energy saving. Main functions and characters • low loss, energy saving visible; • core is in round form, multi-stage, and entire tilted three stages seaming and lapping structure; • high and low voltage coils are wrapped with oxygen free copper coil. All high voltage coils are made with several layered bucket structure. • reasonable structure • new parts and new fixing parts Packed in wooden case