Analysis of vibration for permanent magnet motors considering mechanical and magnetic coupling effects

Vibration of a rotor-bearing system driven by an electric motor is a coupled phenomena between mechanical characteristics and magnetic origins through the airgap. With the advent of new high energy magnetic material together with high precision motor applications, magnetic sources of vibration are becoming more serious. This paper investigates the transient whirl responses of a rotor system with purely mechanical origins and compares it with that of magnetically coupled origins. The results show that magnetically coupled sources significantly affect the vibration of the rotor-motor system.