Commutator motor

摘要

A motor comprises a yoke (25) as casing, a shaft (23) extending along a center of the yoke, an annular stator (27) fixed to the yoke and an armature (24) fixed to the shaft (23) to rotate with the shaft inside the stator. The armature comprises a plurality of teeth (37) on the outer circumferential surface. A wire is wound on any of the teeth to form a normal coil (39a). Another wire is wound on another of the teeth to form a brake coil (39b) that is a short circuit. When the motor rotates much faster, the brake coil (39b) produces magnetic flux which acts as load against the rotation of the motor to allow the motor to rotate slower.