Outer Bearing Race Diagnosis by Means of Stray Flux Signals and Shannon Entropy

Bearings are a fundamental element that allows rotary movement in electric motors. It becomes essential for its operation under optimal conditions. However, it is one of the elements that tend to be most affected due to various inherent causes of its operating conditions. Although multiple methodologies have been proposed for diagnosing bearing faults, these are usually invasive, and the gradualness of the failure is not generally studied, nor is the behavior in various materials (ceramic, metallic, hybrid, etc.). This work proposes a non-invasive methodology based on analyzing magnetic stray flux signals using the Shannon entropy as an indicator to detect outer race failures under different degrees of wear damage and different construction materials. The obtained results demonstrate the effectiveness of the proposed method, which is validated on a kinematic chain (composed of a 0.746 KW induction motor, a belt and pulleys transmission system, and an alternator as a load).