Electrodynamic system comprising a variable reluctance machine

An electromagnetic system comprising, in combination, a variable-reluctance machine having a stator and a rotor both entirely comprised of highly permeable ferromagnetic material, the stator having salient poles defining a set of arcuate pole faces, stator field windings in two phase groups, the windings of each group being on alternate pairs of stator poles, the rotor having a set of arcuate pole faces, and switching means dependent on rotor position for sequentially connecting said stator field winding groups to an electric power source without reversal of stator pole magnetic polarities, each stator pole face sequentially closely confronting the arcuate pole faces of the rotor as the latter rotates, the stator, with alternate poles in two phase groups, having twice the number of poles compared with the number of rotor poles, each rotor pole having substantially twice the peripheral extent of each stator pole, the leading half, for a given rotational sense, of each rotor pole surface having therein deep trapezoidal slots, whereby the rectangular tooth-like portions between the slots can, because of saturation, sustain a gap flux-density of only one half that provided by the unslotted trailing half of each rotor pole surface, the trailing half of each rotor pole surface being uninterrupted and formed wholly of said ferromagnetic material, whereby the mechanical displacement of the rotor over which a uniform rate of flux increase occurs is extended to one stator pole pitch, thus providing torque continuity with a two-phase configuration.