Dry‑type transformers are widely used in local lighting, high‑rise buildings, airports, docks, CNC mechanical equipment and other occasions. Simply put, a dry‑type transformer is a transformer whose iron core and windings are not immersed in insulating oil.

Its cooling modes include natural air cooling (AN) and forced air cooling (AF). Under natural air cooling, the transformer can run continuously for a long time at rated capacity. With forced air cooling, the output capacity of the transformer can be increased by 50 %. It is applicable to intermittent overload operation or emergency accident overload operation. Since overload will cause significant increase of load loss and impedance voltage resulting in uneconomical operation, long‑term continuous overload operation is not allowed.