Single-phase switched reluctance motor design

The evolution of a novel form of single-phase switched reluctance motor, suitable for example for high-speed fans is described. The motor has four stator and four rotor poles, but only two coils. The new motor is derived by simple analysis from the basic 2-pole machine using sweeping assumptions. It is predicted to have only half the core length, less copper loss, but significantly more iron loss than the 2-pole form. These conclusions are tested using computer-based analysis, and test results from a prototype motor are presented which confirm the attractiveness of the design. Attention then turns to the starting problem of all such machines, and a method using permanent magnets is shown to be particularly appropriate for the new motor. The operation of this method is analysed, and simulated starting responses are compared with experimental results