Improvement of rotational torque and suspension force by winding arrangement in a bearingless motor drive for a solid-liquid separator

This paper presents an improved mechanism for a solid-liquid separator (SLS) which separates solid and liquid from its mixture by using the centrifugal force and specific gravity difference. A bearingless motor (BELM) is applied for the SLS to reduce its mechanical loss, vibration and acoustic noise. In the proposed BELM an increase in suspension force is realized by modifying the winding arrangement under a constant motor volume. The proposed winding arrangement is explained in detail and the principle of the suspension force generation is also introduced. The rotational torque and the suspension force are computed by finite element (FE) analysis software using the improved machine model. The computed results clearly satisfy the target capacity of SLS. In addition, the torque ripple is successfully reduced by skewing the rotor. The proposed BELM with the modified winding arrangement is found to be suitable for application in industrial SLS particularly, for mining industries.