Finite Element Analysis of a Split-Phase Induction Machine with Open-Circuit Fault and its Mitigation

The multiphase winding structure makes an induction machine fault tolerant, even with one or more of its stator phases open-circuited or isolated. The easiest way to realize a split-phase induction motor (SPIM) is by splitting the phases of a three-phase induction motor. In this paper, Finite Element Analysis (FEA) of a SPIM operating with a single phase open-circuit fault, with and without compensation for mitigating low frequency torque pulsations, that are inherent in machines operated with faults, is presented for the first time. FEA of a split phase induction motor with a single winding open circuit is studied and presented in this paper. During fault, there is an unbalance generated within the motor, which modifies magnetic fields with in the airgap of the motor. This unbalance can be avoided by modifying the currents in the healthy coils to generate the same rotating magneto-motive force, similar to the healthy motor. A compensated current profile was given to run the motor, within the limits of machine. Based on the FEA, it can be predicted how much the motor can be up-rated under faulty conditions to achieve the same performance. Earlier studies were done on analytical and modeling aspects.In this work, FEA simulations provides more insight into the system especially on how the flux waveform in air gap varies during healthy, one coil failure and under compensation are presented. This work proves that through FEA simulations and compensation of currents, the flux shape is restored in the machine.