The invention relates to a three-phase unequal-turns fractional slot concentrated winding, wherein each phase of winding is formed by serially connecting 12 coils with
pitch of 1; each coil of four coils in the 12 coils has the turns of n, wherein n is a natural number, and each coil of the rest 8 coils has the turns of 2n; the turns ratio of two kinds of unequal-turns coils is 2:1; three phases of windings are in difference of 1200 electric angles and are of three-phase symmetrical windings; the slot fullness of each slot is balanced; a
stator iron core is inclined to 1 / 7 slot
pitch; and thethree phases of windings can be in r connection or Y connection. The unequal-turns fractional slot concentrated winding not only preserves the advantages, such as coil
pitch of 1, capability of beingdirectly wound on one tooth and short winding end part of a concentrated winding with slot number q=1 / 2 of each phase and each pole, but also overcomes the serious defects that the q=1 / 2 equal-turns concentrated winding has the potential
harmonic content up to 27.3 percent in the
induction phase and poor performance, and a multipole permanent
magnet servo motor cannot be used in a
servo system with strict requirements on position precision. The three-phase unequal-turns fractional slot concentrated windings has the potential
harmonic content less than 2 percent in the
induction phase, reachesan ideal sinusoidal wave state, ensures that the permanent
magnet servo motor reaches high performance, can be used for the fields, such as
numerical control laths having strict requirement on position precision, and the like and has the advantages of traditional process, easiness in implementation and excellent performance, thereby having an actual popularization meaning.