US Patent 7466092 Polyphase motor

A multiphase motor includes a fixed part or stator energized by electric coils and a mobile part or rotor including N pairs of poles radially magnetized in alternate directions, N being not less than 4 while being other than a multiple of 3, and the stator including P×9 identical poles spaced apart by 40°/P, the stator poles being assembled consecutively by three so as to define a phase with a W-shaped circuit, assembling three consecutive stator poles, the central stator pole bearing the winding of the phase. At least one element for detecting the position of the rotor is arranged in a common stage with the stator poles, in a housing substantially equidistant between two consecutive stator poles not belonging to a common phase.