“…To improve the AWSC fault diagnosis accuracy and reliability by effectively using the fault-related features extracted from various sensors, a variety of fault diagnosis methods based on the physical characteristics have been developed on the different types of motors, mainly including induction motors [12,13,14,15,16], synchronous generators [17,18,19,20], brushless dc motors [21,22,23,24] and permanent magnet motors [25,26,27,28]. All of them are primarily based on the harmonic currents of the stator or rotor [12,18,21,25], the sequence component of the current [14,22], the magnetic characteristics [13,19,23,27], the vibration characteristics [20,24,28] and some novel feature quantities [16,26]. However, due to the little impact of a small-turn short-circuit on the electromagnetic field, the above methods perform poorly in VFRMs.…”