Universal approach to diagnose the failures of permanent-magnetic DC motors

An universal diagnosing model to the representative failures of permanent-magnetic DC motors is established based on its armature current feature extracting. The inherent relationship between the changing mechanisms of armature current and the parameters or rotating speed of permanent-magnetic DC motor is disclosed by analyzing its dynamic and static mathematical model. The failure diagnosing model is proposed. According to the model, the failure experiments on several motors with the representative failures such as open circuit of components or brush wear and short circuit between coils are studied. And the failure mechanism is analyzed. The consistency between experimental results and the failure mechanism analysis shows that the model presented in this paper to diagnose the failures of permanent magnetic DC motor is feasible and universal.