A new method to detect inter-turn short-circuit in induction motors

It is well known that stator winding faults such the inter-turn short circuit are the most frequent source of breakdowns in induction motors. Early detection of any small inter-turn short circuit during motor operation would eliminate some subsequent damage to adjacent coils and stator core, reducing then the repair cost. To achieve this purpose, the present paper proposes a new method, called Park-Hilbert (P-H), to detect stator faults in induction motors using a combination between the Hilbert transform and the Extended Park´s Vector Approach. The P-H approach is based on the spectral analysis, via the FFT, of the PSVM_P-H that represents the Park´s Square Vector Modulus computed starting from the amplitudes of the three-phase current´s analytical signals obtained by Hilbert Transform. The theoretical bases of the P-H method are presented, and the experimental tests which are carried out on a special 3kW three-phase induction motor confirm the efficiency of the proposed method and corroborate that this fault doesn´t have new specific spectral signatures, but it causes important increases on the amplitudes of all harmonics that were present in the PSVM_P-H spectrum, even those related to other faults.