A single stack variable reluctance stepper motor has a salient pole stator. The stator has a concentrated windings which are placed over the stator poles. The number of phases of the stator depends upon the connection of the stator coils. There are three or four windings. The rotor is made up of ferromagnetic materials and carries no windings.
The stator and rotor are made of high-quality magnetic materials having very high permeability. Thus, a very small exciting current is required. When a DC source is applied to the stator phase with the help of a semiconductor switch, a magnetic field is produced. The axis of the rotor aligns with the axis of the stator