The Totally Enclosed Fan Cooled Motor is the most widely used type of motor. It consists of frame which totally encloses the motor. Thus there is no airflow between the inside of the motor and the outside. However, the frame is not airtight.
The term "Totally Enclosed" means that the motor is dust proof. It is however not submersible.
Cooling occurs by means of a fan which blows air over the frame. The air which passes over the frame removes the heat created by the motor. The enclosure has fins to maximize the surface area to enhance cooling.