Fully pitched-winding switched-reluctance and stepping-motor arrangements

The author introduces the concept of using a fully pitched winding in a switched-reluctance or stepping motor. It is demonstrated that such a winding configuration results in more efficient use of the electric circuit, with each phase contributing to torque for more than half of the cycle of rotation. As a result, for many machine configurations significantly greater torques are predicted for a given frame size. In contrast to the short-pitched windings conventionally employed in such machines, the new configuration is shown to derive virtually all its torque from the rate of change of mutual inductance between phases. A number of different idealised current-excitation patterns are investigated, using both unipolar and bipolar excitation, and the mean output torques produced by the various configurations are compared