Gear tooth surface damage fault profile identification using stator current space vector instantaneous frequency

A non-invasive technique for the diagnosis of the gear tooth surface damage fault based on the induction machine stator current space vector instantaneous frequency analysis is presented. The profile produced by the gear tooth surface damage fault in the mechanical torque experimented by the driven electrical machine is primarily investigated. Then, it is shown that the periodic behavior of this particular shape produces fault-related frequencies in the stator current and hence harmonics namely integer multiple of rotation frequency in the instantaneous frequency of the stator current space vector. The results show possible non-invasive gear tooth surface damage fault detection with fault sensitivity comparable to most of the invasive methods. A dedicated experimental set-up, based on a 250W squirrel-cage three-phase induction machine shaft-connected to a single-stage gear, has been used for this purpose.