Finite Element Analysis for Fault Diagnosis in Broken Rotor Bar of a Polyphase Induction Motor

The polyphase induction motor (PIM) is widely used for domestic/industrial purposes, well known for its robust construction and performance. Due to continuous operation, wear, and tear these machines suffer from different faults. Early fault detection of these machines is important to avoid a breakdown that can increase the production of the entire sector. Nearly 10% of faults are related to broken rotor bars (BRB) of PIM. This paper proposes the flux distribution of healthy, one, and two BRB. The Finite Element Method (FEM) is used to design the stator (24 slots) and rotor bars (20), which are meshed in ALTAIR Flux software to predict the unbalanced forces due to the BRB. The machine is designed by building the geometry which is meshed with 54,177 nodes, 6032-line elements, and 27,054 surface elements. From the analysis, the torque and current of one and two BRB are progressively decreased with the increase in resistance. The inter bar current of BRB flows in the adjacent rotor bars increasing the current in healthy bars. These currents flow in the healthy bar for a long duration can deteriorate the healthy bar. The FEM provides an efficient method for the detection of flux orientation. The simulation results with high currents related to one and two BRB might enhance the fault isolation of adjacent rotor bars. A test machine is considered and MCSA is executed on PIM. The experimental results identify the BRB.