Finite Element Modeling of Demagnetization Fault in Permanent Magnet Direct Current Motors

This paper presents the results of a demagnetization effect on the Permanent Magnet Direct Current (PMDC) Motors. A Finite Element Model (FEM) of a PMDC motor has been developed and analyzed for healthy and faulty conditions. The model of a faulty machine can be developed by changing one or more parameters of the machine to incorporate a fault. Since this paper focuses on the demagnetization fault, therefore this fault is incorporated by changing the magnetic coercivity (HC) parameter of a permanent magnet in the rotor of the machine. The change in coercivity parameter is used as the demagnetization factor which changes the machine parameters such as flux linkage and current in the coil. The Finite Element (FE) analysis on the developed models of healthy and faulty machines is done to obtain the profile of flux linkage, magnetic flux density, torque and current plots. The deviation brought in the current and flux linkage of the machine identifies the demagnetization fault in PMDC. The equivalent change in HC causes change in magnetic flux density (BM) that validates the direct relation of HC with BM. This work builds on the existing research on modeling demagnetization faults in Permanent Magnet Synchronous (PMSM) Motors. Future work will be on FE modeling of demagnetization fault in PMSM and conducting lab experiments to validate the findings.