Abstract

Several studies have focused on modeling and analyzing the impact of rotor faults in conventional low-pole-count machines, while related research on low-speed high-torque (LSHT) machines with a high pole count remains limited. In these machines, the combination of low speed, high inertia, and high torque levels presents a critical application for advanced diagnosis techniques. The present paper aims to describe and quantify the impact of rotor faults on the performance of LSHT machine types during the design stage. Specifically, 10-pole and 16-pole synchronous reluctance machines (SynRMs), permanent magnet synchronous machines (PMSMs), and squirrel-cage induction machines (SCIMs) are assessed by means of detailed 2D simulations. The effects of eccentricity, broken rotor bars, and partial demagnetization are studied, with a focus on performance variations. The results show that LSHT PMSMs are not significantly affected by the partial demagnetization of a few magnets, and the same holds true for common faults in SynRMs and SCIMs. Nonetheless, a significant increase in torque ripple was observed for all evaluated faults, with different origins and diverse effects on the torque waveform, which could be hard or invasive to analyze. Furthermore, it was concluded that specialized diagnosis techniques are effectively required for detecting the usual faults in LSHT machines, as their effect on major performance indicators is mostly minimal.