What is a Switched Reluctance Motor?
Switched reluctance (SR) motor is a brushless AC motor. It has simple mechanical construction and does not require permanent magnet for its operation. The stator and rotor in a SR motor have salient poles. The number of poles presence on the stator depends on the number of phases the motor is designed to operate in. Normally, two stator poles at opposite ends are configured to form one phase. In this configuration, a 3-phase SR motor has 6 stator poles. The number of rotor poles are chosen to be different to the number of stator poles. A 3-phase SR motor with 6 stator poles and 4 rotor poles is also known as a 6/4 3-Phase SR motor.
SR motor has the phase winding on its stator only. Concentrated windings are used. The windings are inserted onto the stator poles and connected in series to form one phase of the motor. In a 3-Phase SR motor, there are 3 pairs of concentrated windings and each pair of the winding is connected in series to form each phase respectively. The mechanical structure of a 6/4 3-Phase SR motor is shown in Figure 1. Other configurations of SR motor such as 4/2 2-Phase SR motor (with irregular rotor) and 8/6 4-Phase SR motor are shown in Figure 2 and Figure 3.