Transformer windings are designed to meet three fundamental requirements such as mechanical, thermal and electrical. they are cylindrical in shape and are assembled concentrically.
The low tension windings are of the helical type, single or multiplayer, using flat copper strips, depending upon the size and current rating of the transformer.
The high tension winding consist of paper covered round conductors. For higher voltage continuous disc winding are used.
The windings are rigidly supported by pressboard washer and spacers.
Interlayer cooling ducts are provided to ensure that the temperature gradient between windings and oil and hence the hot spot temperature is minimized and a high life expectancy is achieved. Insulation between layers and turns is based upon the impulse test level of the voltage class of the windings specified in ISS 2062.completed core coil assembles are dried prior to impregnation with transformer oil.