Analytical approach of the stator current frequency harmonics computation for detection of induction machine rotor faults

The aim of this paper is to analyze theoretically and experimentally the stator current of a three-phase squirrel cage induction machine in order to show how it is influenced by rotor faults. The approach used for this study analyzes the modification introduced by n broken rotor bars in the rotor cage magnetomotive force (MMF) and then, estimates the resulting frequency spectrum in the stator current. This approach is validated in a 3 kW-230 V/400 V-50 Hz-2850 rpm-2 poles three-phase induction machine, showing the sensible frequency components to this fault condition.