Spin dryers use high-speed motion to force water out of wet fabric. As the dryer drum turns, centrifugal force drives moisture away from the center of the drum and into drain holes. Electric spin dryers combine this force of motion with heat whereas manual, or non-heating, dryers rely on the fast movement of the drum to dry clothes.
Electric spin dryers force air through a heating element and a motor to blow air into the drum during the spinning process. According to experts at How Stuff Works, "The fan is a centrifugal type of device -- as it spins, it flings the air to the outside, sucking air from the center and forcing it out the duct at the back of the dryer." Heated air blows from the top of the dryer, forcing debris into the lint trap as it escapes through the lint screen and into the ventilation system.
Electric spin dryers use an engine and a belt pulley system to force the drum to move at high speeds. Smaller belts propel the engine to turn the drum while a larger belt keeps the unit in place within the machine. The dryer fan is also controlled by a pulley system that hooks to the main motor.