Non-invasive fault diagnosis for switched-reluctance machines with incorrect winding turns, inter-turn winding faults and eccentric rotors

This paper describes a study into the forces that occur in a switched reluctance motor with faults. These forces can be used for non-invasive diagnosis of inter-turn faults and rotor eccentricity in switched-reluctance machines by monitoring of the vibrations on the machine casing. The technique uses a transient finite element analysis and produces characteristics for the forces on the teeth and net force on the rotor in terms of the current, winding and rotor positioning. The forces can be detected on the actual machine using accelerometers. The faults that produce an unbalanced radial force on the rotor are very noticeable if it has vibrating components and these are very apparent when using accelerometers attached to the stator casing. They also cause secondary problems such are worn bearings. The shorted-turns current is studied and it is illustrated that this current is high, which leads to burn-out.