Analysis of radial forces based on rotor eccentricity of bearingless switched reluctance motors

Eccentricity always changes rotor position in air gap, which greatly influences the distribution of magnetic flux in air gap and causes a great disturbance force. Therefore eccentricity is always restricted by an application of capture bearing in industry. Factors of unbalance forces based on eccentricities decide on successful design of bearing controller. In this paper, a mathematical model to calculate the forces based on eccentricity is created. Considering eccentricity, air gap of motor should be so chosen for an applied capture bearing, that eccentric force cannot exceed maximal winding levitation forces. All of the calculation and analysis are made for a novel switched reluctance bearingless motor (SRBM) with a single layer winding.