Diagnosis of induction machines using external magnetic field and correlation coefficient

The statistical analysis of faulty induction machine has proved to be a useful tool for prediction of main effects due to faults. So this paper proposes a mathematical model for diagnosis of the inter-turn short circuit in the stator winding of electrical machines. This model uses the Pearson correlation coefficient and a pair of sensors, placed at 180° from each other around the machine to measure the external magnetic field in the machine vicinity. The data obtained from each sensor are analyzed and compared with each other when the load varies. It will be shown that one can obtain high probability to detect the fault using this method and experimental results show that the new method has high reliability level for fault detection. On the other hand, the presented method does not require any knowledge of a presumed machine healthy former state.