摘要 |
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. A mechanical angle formed between the adjacent magnetic pole pieces in the 3n pieces of magnetic pole with each set of three-phase windings is 60° m/n and a mechanical degree angle formed between the 3n pieces of magnetic pole with each set of three-phase windings is (60° m/n-thetas), where Nr is a number of rotor pole teeth, each of n, m and Ns is an integer not less than 1, and thetas is a step angle of (30°-Nr) k where k is an integer number not less than 1.
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