Single-phase stepping motor with permanent magnet rotor - has even number of pole arms extending from opposite halves of stator into space around rotor

摘要

A motor with a predetermined direction of rotation comprises a permanent-magnet rotor (4) with an even number of poles and circumferential magnetisation, and a two-part stator (1) surrounding the coil (9). Small rectangular pole arms extend into the space between the rotor (4) and the coil (9), in pairs which have alternate polarity. The pairs of pole arms can be six in number and their spacing around the rotor is such that diametrically opposed pole arms (e.g. 7,8) are of opposite polarity and pertain to the respective parts (2,3) of the stator (1). ADVANTAGE - Simple implementation of motor affords high efficiency even in region of low torque. Resultant radial force on rotor is reduced, even with small number of poles.