Abstract: A rotor composite type three-phase stepping motor having a stator consisting of two stator elements each having 6 n pieces of stator magnetic pole with Ns pieces of pole tooth formed on the tip end of each stator magnetic pole piece, and a permanent magnet held by the two stator elements therebetween, a rotor of magnetic material arranged so as to face to a periphery of the stator through an air gap, Nr pieces of pole tooth being formed on a periphery of the rotor, and exciting windings wound around each stator magnetic pole piece of the stator elements consisting of two sets of three-phase windings each wound around 3n pieces of stator magnetic pole among the 6 n pieces of stator magnetic pole.

Abstract: A two-phase permanent-magnet electric rotating machine in which vibration and noise are less is provided. The machine is constituted by: a stator having 2n main poles (n being an integer satisfying n≧2) each of which has at its end portion a predetermined number of magnetic teeth and has a winding provided thereon; and a rotor having permanent magnets formed so that N (north) and S (south) equal in number of the permanent magnets are alternately disposed in a direction of rotation of the rotor; wherein 2(n−1) alternate ones of the main poles are made to be in-phase and a half ones of the in-phase main oles have a polarity which is opposite to a polarity of the other ones. It is preferable to make the number of the magnetic pole pairs of N and S of the rotor be 4m±1 (m being an integer satisfying m≧1) when the value n is set to 2. It is preferable to form the windings so that the in-phase main poles of the stator are made to be alternately inverted in polarity.