Derivation of Pole Configuration in Switched Reluctance Machines

A Switched Reluctance Machine (SRM) is identified by the number of stator poles and number of rotor poles. An SRM has salient poles both on the stator and the rotor. When an electrical phase is energized with constant current, the electromagnetic torque is dependent on the relative position between the stator and rotor poles. Depending on the number of stator and rotor poles, each stator pole has a certain electrical position. The center of axis for each of the stator and rotor poles stands at a certain mechanical angle. A switched reluctance machine will have a locked rotor condition when all phases are at either an unaligned position or aligned position. In some certain cases, even though the SRM configuration is symmetric and balanced, different phases might have the same electrical angle. These phases are connected to different electrical circuits, but they can be excited with the same current.