An on-board device for condition based maintenance on inverted fed induction machines

The target of this work is to design and test an on-board diagnostic device able to detect a rotor fault in a small cage rotor inverter-fed induction machine. In particular, the system computes the values of two indexes introduced by the authors in previous work. The capability of the aforementioned indexes to detect rotor asymmetries in open loop asynchronous AC drive systems has been previously evaluated. In this paper the author will demonstrate that the proposed indexes are effective even when a closed-loop speed control strategy is employed. The developed diagnostic device has been integrated in a V/f inverter drive system featuring encoder-feedback. A proper experimental setup allowed to simulate rotor faults and to evaluate the performance of the diagnostic system. In the last part of the work the experimental results will be presented and discussed.