Online diagnosis and analysis on failure of loose weld coils to permanent-magnetic DC motors

The inherent relationship between the mean value of static armature current, pulsant frequency of static armature current or its pulsation amplitude and the failure state of loose weld coils was recognized by analyzing the changing mechanism of armature current on the state of loose weld coils. And then the failure diagnosing model to loose weld coils was established. According to the model, failure experiments on several motors with loose weld coils were studied. The consistency between experimental results and the failure mechanism analysis shows that the model presented in this paper to diagnose the permanent magnetic DC motor online with loose weld coils is feasible. And it provides a research approach to establish a universal diagnosing model for permanent-magnetic DC motor.