Bearing Fault Numerical Model for the Closed-slot Rotor Submersible Motor

A numerical model of the bearing fault of a motor with a closed-slot rotor using the finite element method (FEM) is proposed. The rotor's radial motion can be regarded as static eccentric at the defect time points and healthy at other time points. The frequency of the harmonic component is analyzed corresponding to bearing fault in stator current according to the radial movement of the motor shaft. Moreover, the relative permeability variation region is established to achieve the radial motion of the rotor with bearing fault. Firstly, the relative permeability variation region is established in the health and static eccentric models. Then, the defect time points are estimated and the static eccentricity model by transient field is analyzed. Finally, the relative permeability of the variable region in the static eccentric model is imported into the variable region of the health model at the defect time points. The simulation results show that the air gap flux density of the bearing fault model is different from that of the health model and static eccentric models. In addition, the stator current contains harmonic components of the bearing fault. The analysis results prove the applicability of the proposed model.