A Novel Methodology for the Reliable Detection of Static and Dynamic Eccentricity in Induction Motors via Frequency Isolation in the Stray Flux

Amongst the several induction motor fault types, rotor eccentricity is very frequently present either inherently or due to stresses, inducing fault incidents and fault-inducing actions during machine disassembly/reassembly. Although several diagnostic solutions have been proposed for the dynamic eccentricity fault, the reliable detection of static eccentricity during machine operation still poses a challenge. This is due to the inherent nature of the fault and the masking of fault-related signatures from dominant harmonics by elements such as the machine geometry or design-related harmonics. This work presents a novel methodology for the reliable detection of static and dynamic eccentricity in 3-phase induction motors using harmonic isolation in stray flux signals, during the steady-state operation of the machine. The results are demonstrated on a 4kW induction motor by extensive FEA simulations.