Condition monitoring of induction motors fed by Voltage Source Inverters. Statistical analysis of spectral data

This paper presents the results of an ongoing investigation focused on the development of an expert system for condition monitoring of induction motors fed by Voltage Source Inverters (VSIs), extrapolating a previously successfully proven method suited for utility supply. However, when trying to obtain a generic method valid for any type of converter and at any operating frequencies further considerations have to be made. A controlled laboratory experiment has been performed in which a great deal of tests was carried out progressively drilling a hole in one of the rotor bars of an induction motor. A statistical analysis of the results is presented in detail and some conclusions useful for condition monitoring are drawn.