Full seal power transformer cancels the oil conservator and uses the fin-plate of the corrugated oil tank as the heat radiator,at the same time it expands or shrinks along with the increase or decrease of transformer oil,and it makes the transformer interior be isolated from atmosphere to prevent the oil degradation,as well as insulation damp and ageing,and then enhances the reliability of operation.Adopt the high quality cold-rolled silicon steel sheet as the iron core,so that it can effectively improve the distribution of magnetic flux density inside the iron core,reduce the noises and loss.The coils adopt the high strength enameled wire (or paper covered wire),it has the cylindrical structure(or pancake structure),the ampere-turn is distributed evenly,the insulation structure is reasonable,and it has the strong anti-short circuit ability.All the fasteners inside the oil tank use the retaining nuts to ensure that they cannt become loose during operation after long distance transport.The surface of oil tank shall be coated with the conformal coating(damp-proof,mildew-proof,salt fog-proof)after phosphate treatment,so they can be widely used in the bad service environments like metallurgical industry,mining industry,petrochemical industry,etc.