Comparison of Bearingless Slice Motor Topologies for Pump Applications

This paper compares two bearingless slice motor topologies, namely the temple and slotless designs, with respect to the achievable motor efficiency for pump applications. Stator losses, passive stiffness properties and the achievable torque are determined by means of 3D FEM simulations. Some basic pump design guidelines are introduced and the expected motor performance is evaluated for typical operating conditions encountered in medical applications. It is shown that the temple design outperforms the slotless design in all but low pressure applications. Two prototypes, one radial and one axial pump, are manufactured by means of stereolitograpy 3D printing. The hydraulic characteristics of the designs are measured using the temple and slotless motor for the radial and the axial pump, respectively. The radial pump exhibits significantly higher pressure-numbers, while the axial design yields higher flow-numbers.