Four-phase stepper motor with superimposed rotor windings - wound in opposite directions on each soft-iron axis carrying one pole magnetically aligned at alternate steps

摘要

The four rotor poles (20-23) are supported by axles (5-8) orthogonal to one another which serve also as cores for the rotor windings (1-4). Each pair of collinear axles (e.g. 5,7) carries two windings (1A-1B,3A-3B) superimposed in opposite directions to minimise inductance, and extending past the rotor shaft (10). The stator yoke (17) has six permanent magnets (11-16) spaced at 60 deg. around its internal surface with alternate polarity, giving a complete rotation in 12 equal steps of 30 deg. ADVANTAGE - Better use of space available for windings. Complexity of external circuits for digital control reduced.