Unipolar Motor

A unipolar motor is a type of small DC electric motor commonly found in small, portable cassette players. It is also used in stepper motors.

Its name is derived from its construction, which employs a magnetic strip wrapped around the inner wall of the housing such that one of its poles faces the inside, while the other faces outward. Although a true unipolar magnet (magnet with only one pole) exists only in theory, the name is appropriate for its function. The motor behaves as if the magnet were unipolar, since only one of its poles is influencing the armature.