Diagnosis of stator inter-turn fault and supply voltage unbalance using phase-angle and magnitude of the line currents spectra

This paper describes a new diagnosis approach to discriminate between the supply voltage unbalance and the stator inter-turn fault in induction motor. This approach is based on a simple monitoring of the combined information related to both magnitude and phase-angle obtained from the fundamental by the three line currents frequency analysis. In addition, to simplify the interpretation of the data; a new graphical tool based on a triangular representation is suggested. This representation, depending on its size and orientation, enables to visualize in a simple manner, the existence of the stator inter-turn fault and its discrimination with respect to a supply voltage unbalance. The experimental results obtained show the efficiency and the reliability of this new approach.