Patent ID: 8400044

Claim:
A machine comprising a rotor and a stator, the machine is a polyphase induction electromotive machine, the stator comprises: (i) a first group of primary, concentrated windings, arranged on a first side of the rotor; and (ii) a second group of primary, concentrated windings, arranged on a second, opposite, side of the rotor; wherein the primary windings of each group comprise a plurality of coils which, in use each carry current(s) and produce a magnetic field, the coils of the second group being in a displaced position relative to the coils of the first group, so that corresponding coils of each group are not aligned and an n-pole travelling harmonic of the magnetic field is substantially cancelled, where n is a positive, even integer, and (a) the substantially cancelled n-pole travelling harmonic has a wavelength and the coils of the second group are displaced relative to the coils of the first group by half of that wavelength or by an odd, non-zero, integer multiple of half of that wavelength or (b) the substantially cancelled n-pole travelling harmonic has a wavelength and the current(s) through the coils of the second group are reversed relative to the currents(s) through the coils of the first group and the coils of the second group are displaced relative to the coils of the first group by that wavelength or a non-zero, integer multiple of that wavelength.