Fault diagnosis of turn-to-turn short circuit in field winding of aircraft brushless exciter

As the core component of an aircraft generator, the health of brushless exciter is critical to high-quality generation and flight safety. Its stator field winding is prone to insulation deterioration under various stresses, leading to turn-to-turn short-circuit (TTSC) fault. Diagnosing this type of fault, especially in the early stage, can greatly enhance the safety and reliability of aircraft generators. In this paper, on the basis of analysing the effect of field winding TTSC on field current, a fault diagnosis method based on the mean and fractional harmonics of field current was proposed, which is verified on the exciter model. The correlation analysis between different degrees of TTSC and fault features was discussed, which leads to the selection of the optimal fault characteristics for fault diagnosis. The results show that the selection of mean and 150 Hz harmonics as fault features can effectively reduce the support vector machine fault diagnosis time while ensuring diagnostic accuracy. This non-intrusive fault diagnosis method has good application value in engineering.