Power Transformer- Cooling Methods-Natural Oil Cooling

Natural Oil Cooling

The oil in the ducts, and at the surface of the coils and cores, takes tip heat by conduction,
and raises cool oil from the bottom of the tank rising to take its place. A continuous circulation of oil is completed by the heated oil flowing to the tank sides where cooling to the ambient air occurs and falling again to the bottom of the tank. Oil has a large coefficient of volume expansion with increase of temperature, and a substantial circulation is readily obtained so long as the cooling ducts in the cores and coils are not unduly