Dictionary of Electrical Engineering

Commonly used terms in the Electrical industry.

switched reluctance machine
a doubly salient, singly excited electrical machine that contains a different number of poles on the stator and rotor. Since there are a different number of poles on the rotor and stator, only one stator phase can be aligned at a time with the rotor.

When operated as a motor, the stator phases are sequentially switched on and off to pull the rotor into alignment with them. This requires knowledge of the rotor position to properly excite the stator phases. The switched reluctance machine can also operate as a generator. In this case the stator windings are charged with a current as the rotor comes into alignment. When the current reaches a determined level, the windings are reconnected to send current out of the machine.
As the rotor is driven, the inductance drops, causing an increase in current.

This type of machine requires an external capacitor bank, switches and diodes in each phase, and a sophisticated control system to operate.