The Medium Voltage windings are manufactured using industry-leading constant tension automatic winding process，with aluminium or copper conductors, insulated with a film of polyester in class F and H and C in case of special projects. The resin used to encapsulate the windings is an epoxy-resin with added alumina, silicon and other additives. This is prepared in temperature controlled conditions in a special mixing machine. The cycle of polymerisation is controlled by a software in order to guarantee the two temperature values, correct jellification and therefore the polymerisation. The partial discharges measured on Medium Voltage windings are less than 5 pC at 1,3 Un. The regulation of the primary voltage is obtained directly moving the nearby diagram.
double layer winding where the primary insulation either consists of a high heat resistant polyesterimide coating with a temperature index of 200°C or Nomex thread winding of the temperature class C (220°C). As the operating temperature of Varelen Cast Resin Transformers rarely reaches the limit of the temperature class F (155°C), the primary insulation has sizeable temperature reserves.
cast resin dry type transformers is that the conductors of the high voltage winding are completely encapsulated in a cast resin body with a smooth surface. This can only be carried out in moulded formers under vacuum. Varelen production technology and materials used can also be distinguished through important unique features which set them apart technically from other cast resin transformers and make them a very dependable and very reliable solution.
• Reversed equipped
Cast Resin Transformers’ low voltage winding is almost always used as a full length foil winding. The advantages of this form of winding are evident:
• Reduction of additional losses
• Even temperature distribution in the coil
• High short circuit consistency
Varelen Electric Co., Ltd