Reluctance Motor-An Overview

A reluctance motor works on the principle of reduced reluctance.  Reluctance motors have high power density.  However, their downsides are low efficiency, low torque and low pullout torque.  However, they are ideal for small power applications such as hard disk drive motor, Analog electric meters, etc.

The reluctance motor works on the principle that a piece of iron placed in a magnetic field will rearrange itself such that the reluctance of the magnetic path is minimal. 

The Reluctance motor consists of a wound stator.  The rotor is made of laminated material in which poles are cut so that a salient pole rotor is produced.  The number of rotor poles is made less than the number of stator poles. 

When a three phase supply is connected to the stator, a rotating magnetic field is set up. The rotor tries to align itself in a minimum reluctance path with reference to the magnetic field of the stator.  As the stator magnetic field keeps rotating, the rotor moves along with it. 

Reluctance Motors are classified into

Switched Reluctance Motors and

Synchronous Reluctance Motors