An industrial case study of on-line current monitoring and finite element analysis to diagnose airgap eccentricity problems in large high voltage 3-phase induction motors

The on-site case history of pump motors at an oil storage loading facility confirms that on-line current monitoring can diagnose abnormal levels of airgap eccentricity in large induction motors. The time stepping FE predictions have confirmed previously observed experimental phenomena. The FE analysis has to be done off-line due to the computing power required but the predictor curves can be subsequently included into an on-line current monitoring system such that the degree of severity of airgap eccentricity can now be estimated and load conditions can be simulated