Image Number 3 for United States Patent #4373148.
A rotor rotating electric machine having a toroidal winding assembly wound n a toroidal helix configuration. The toroidal winding includes four coils, each of which is wound in the form of a toroidal helix around a thin cylindrical ring. A rotor, coaxially rotatable within the toroidal winding, includes a magnetic assembly which has alternately a plurality of north pole permanent magnets and a plurality of south pole permanent magnets. Excitation of the toroidal winding assembly will, in turn, cause the rotor to rotate in a predetermined direction.