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A squirrel-cage three-phase induction motor with eccentric rotor and parallel connections in the stator can be represented by five equivalent sequence-circuits of virtually centered-rotor machines, as mathematically proved in a companion paper. The five circuits allow the calculation of stator and rotor fault-related currents, in form of 2(p±1)-pole space vectors for 2p-pole machines. The formal calculation of fault-related currents is very useful for defining fault indicators and tools for diagnosis, and in case of parallel-connected stators (like in many traction motors) the split-phase current signature analysis becomes possible. This paper validates the sequence-circuit modeling by comparing the theoretical results with simulations of a 1130kW traction induction motor with static, dynamic, and mixed faults in both no-load and full-load conditions. The simulations are carried out by using a full mesh-model of the motor, implemented by winding functions. A good match is obtained between theoretical calculations and simulations. Moreover, the role of the cage damping on the eccentricity-related current signatures is evidenced. It is shown that the cage damps not only the signature of static fault but also that of dynamic fault, and that the damping itself is load-dependent in the latter case. [ABSTRACT FROM PUBLISHER]

A 1130kW squirrel-cage induction motor used for railway traction is analyzed in this paper in case of eccentric rotor. Since the motor has parallel-connected windings, the air-gap unbalance makes rise unbalanced currents in the stator branches, and the split-phase current signature analysis can be attempted for fault detection. The split-phase currents are better analyzed when transposed in the complex domain, by using symmetrical components. Moreover, the rotor cage currents must be carefully taken in account in the model, since they develop a powerful damping effect on the signature of static eccentricity. This paper shows that the faulted machine can be represented by the superimposition of five equivalent circuits corresponding to five centered-rotor virtual machines, useful for fault-related split-phase current calculation. The mathematical modeling shown in this paper is useful to carry out a diagnostic method, as shown in a companion paper. The latter also reports confirmatory simulations of the faulted 1130kW motor, based on winding function approach. [ABSTRACT FROM PUBLISHER]