Eccentricity fault indices in synchronous reluctance machines with different rotor geometries

Synchronous reluctance motors (SynRMs) have gained significant attention in modern drive applications owing to their magnet-free rotor structure, high efficiency, and robust performance under various operating conditions. Nevertheless, SynRMs remain prone to electrical and mechanical faults that can deteriorate their reliability. Among these, eccentricity faults are critical, as even minor misalignments between the rotor and stator can lead to unbalanced magnetic forces, increased vibration, and electromagnetic stress. This study investigates static (SE), dynamic (DE), and mixed (ME) eccentricity faults in SynRMs featuring three and four-flux barrier rotor geometries through 2D transient finite element analysis. The results reveal that ME causes the most severe electromagnetic distortion, while the three-flux barrier rotor exhibits higher torque ripple and reduced torque capability due to diminished saliency. Torque ripple is identified as the most sensitive fault indicator, increasing by up to 33% under ME. These findings provide valuable insights into the relationship between rotor geometry, fault severity, and machine performance, guiding future SynRM design and monitoring strategies.