Advance Topic
Basic of SR Motor

Normally, motor is made from lamination sheets which are punched into desired dimension and shape. Each lamination sheet allows the magnetic flux to flow on its 2D plane and this effectively creates a 2D flux path. There is another type of soft magnetic material available in the form of coated powder iron. This material is known as dielectromagnetics or soft magnetic composite (SMC). When SMC material is used to make an electric motor, the material is pressed at high pressure in a die which resemble the shape of the motor. The motor produced using SMC material have isotropic characteristic which enable the distribution of magnetic flux in 3D.

The concept of 3D flux path SR motor is shown in Figure 12. By using SMC material, the flux path is no longer restricted to the plane since SMC exhibits isotropic characteristic. The new 3D flux path is shown by the dotted line in Figure 12. The 3D flux path is effectively shorter than the flux path in a lamination sheet. This has several advantages and in term of the magnetic circuit of the motor, less MMF is required to energise the motor due to the shorter flux path.

Switched Reluctance Motor with 3-Dimensional Flux Path
Next: Sensorless Control of Switched Reluctance Motor - An Overview
Figure 12