Eccentricity detection procedure in electric motors by force transducer and search coils in a novel experimental test bench

There are several fault types that may arise in electric motors decreasing both reliability and comfort. Eccentricity is one of the main faults, and therefore, tools are needed to detect the motors that do not fulfil the quality requirements. This paper proposes a methodology based on a novel experimental test bench to assess both static and dynamic eccentricities, since it generates continuous and controlled values of both types of eccentricities. A permanent magnet synchronous motor is analysed in the test bench. The unbalanced magnetic pull is measured by a force transducer located below the stator and the electromagnetic field in the air gap is determined by search coils embedded around the teeth of the stator. The experimental results show the capability of these two variables to detect the presence of eccentricities, and determine its type (static or dynamic) and level.