Effects of rotor misalignment in airgap on dynamic response of an eccentric rotor in BLDC motor

Vibration of a BLDC motor is a coupled phenomenon between mechanical characteristics and magnetic origins which takes place through the motor airgap. When relative misalignment of a rotor in the airgap is introduced during assembly, the dynamic characteristics of the motor system are affected. The rotor-motor system used in a washing machine is modeled using FETM and magnetic forces in a BLDC motor with radial rotor eccentricity are determined analytically. The transient whirl responses of a rotor system supported on two roller bearings with relative misalignment in. the motor airgap are investigated by considering mechanical and magnetic coupling effects, Results show that rotor misalignment in the airgap considerably affects the vibration of the rotor-motor system.