Fault detection and diagnosis of aero-starter-generator based on spectrum analyses

Faults in aero-starter-generator could be detected and diagnosed by analyzing the spectrum of motor armature current could be effectively detected and diagnosed. Because rotation speed is fluctuating during the operation of the motor and the ripple of current is proportional to the speed fluctuation, if the sampling period of current is constant, the spectrum of current would spread over a wide range. The fuzziness of spectrum characteristics made fault detection and isolation difficult. While using sampling which is synchronized with the rotation speed this problem could be solved based on analysis of the resulted order ratio spectrum. Experiment on fault detection and isolation is conducted. Four faults (broken coil, broken connection between coil and commutator, short circuit between two neighboring conductors and eccentricity of rotor) can be detected and isolated by the proposed method.