Abstract: A single phase stepper motor is formed of a rotor having a shaft carrying a driving pinion and a permanent magnet and a stator having a body of diamagnetic or paramagnetic material, a field winding producing an excitation field transverse to the axis of the rotor shaft and a pair of diametrically opposed auxiliary poles spaced from the excitation field. The permanent magnet is constructed of a lanthanide ferromagnetic alloy, such as a lanthanide cobalt alloy and preferably a samarium cobalt alloy; and the permanent magnet has a moment of inertia substantially the same as or less than the moment of inertia of the combination of the rotor shaft and the driving pinion. The stator body has a plurality of pairs of holes therein for supporting a U-shaped, rod-like member having ends forming the auxiliary poles in a plurality of positions to permit adjustment of the direction of rotation and torque of the rotor.