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

Abstract

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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P-H</sub> 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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P-H</sub> spectrum, even those related to other faults.