Active Part Assembly

 
 

Coils and cores (built without top yoke) form major inputs to the Active Part Assembly process. Adequate insulation packing is given between LV coils and the core, while lowering. The end insulation is properly adjusted and coordinated to minimize the effects of any surge voltages. The top wooden compression rings are placed in position. This prevents collapse of the coils due to radial forces developed during short circuit. This is followed by top yoke lacing. The top yoke is handled only once, thus contributing to reduction of Iron loss.

Cores are clamped using wooden beams, which also hold the coils firmly, thus eliminating chances of axial movements of the coils. The wooden beam construction also makes the transformer compact and facilitates mounting of tap switch. It provides an added benefit of better insulation in the transformer. Connections to off- circuit switch or on-load tap changer are carried out. The on-load tap changer is either an integral part of the core-coil assembly or it is installed on the outside of the tank, depending upon the type of tap-changer.

Upon completion of all the necessary connections and conducting the quality checks, the active part assemblies are kept ready for further processing.