Dry-type transformers are widely used in applications such as local lighting, high-rise buildings, airports, docks, and CNC machinery. Simply put, a dry-type transformer is one in which the iron core and windings are not immersed in insulating oil.
Cooling methods include natural air cooling (AN) and forced air cooling (AF). With natural air cooling, the transformer can operate continuously at its rated capacity. With forced air cooling, the output capacity can be increased by 50%. This method is suitable for intermittent overload operation or emergency overload conditions; however, because load losses and impedance voltage increase significantly during overload-resulting in inefficient operation-prolonged continuous overload operation should be avoided.
