Gear Tooth Surface Damage Fault Detection Using Induction Machine Stator Current Space Vector Analysis

A noninvasive technique for the diagnosis of gear tooth surface damage faults based upon the stator current space vector analysis is presented. The torque oscillation profile produced by the gear tooth surface damage fault in the mechanical torque experimented by the driven electrical machine is primarily investigated. This profile consists of a mechanical impact generated by the fault followed by a damped oscillation that can be identified through the mechanical system torsional natural frequency and damping factor. Through theoretical developments, it is shown that the periodic behavior of this particular shape produces fault-related frequencies in the stator current and harmonics integer multiple of the rotation frequency in the stator current space vector instantaneous frequency. The fault signature related to the gear tooth surface damage fault is predicted through the numerical simulation. The simulation results are validated through experimental tests, illustrating a possible noninvasive gear tooth surface damage fault detection with a fault sensitivity comparable to invasive methods. A dedicated experimental setup, which is based on a 250-W squirrel-cage three-phase induction machine that is shaft connected to a single-stage gear, has been used for this purpose.