Fault Analysis in Inverter-Fed and Line-Fed Induction Motors: Investigating Increased Bearing Friction and Rotor Eccentricity Using Finite Element Method

In this paper, it is proposed that diagnosing faults in induction motors is a necessary process in the industry to improve the reliability of these machines. The analysis of bearing faults can be categorized by their effects and the signs that the machine manifests, such as increased friction, which can lead to negative torque, and rotor eccentricity, which can cause fluctuations in the air gap and potentially result in serious issues for the machine. This study investigates the electromagnetic field of an induction motor under two types of faults: increased friction and rotor eccentricity. The motor is supplied by both a three-phase voltage source from the main line and a three-phase voltage source from a PWM inverter in open loop configuration, using the finite element method (FEM). Key electromagnetic field parameters, including flux line distribution, flux density distribution, and radial air gap flux density, are analyzed. The analysis of the electromagnetic characteristics of the open-loop voltage source inverter-fed induction motor is conducted for both healthy and static eccentricity fault conditions, utilizing finite element analysis. The importance of electromagnetic field analysis lies in its ability to provide data regarding the positions of the stator and rotor, as well as the mechanical parameters of the induction motor. Consequently, monitoring the magnetic fields in the air gap and the current is often employed for diagnosing faults in induction motors.