A novel non-invasive method for detecting missing wedges in an induction machine

This paper presents a newly developed algorithm for evaluating the health of an induction machine. The proposed algorithm is based on spectrum analysis of an impedance calculated using measured stator current and voltage signals. The main idea is to calculate the frequency spectrum of the impedance for each power phase and compare specific differences between phases. Experimental investigations show that the method yields very accurate results and can form an important part of a machine monitoring system. In particular the presented method is shown to be successful in detecting missing wedges in electric motors.