Radial Loading of Hydrodynamic Bearings Due to Magnetic Variation
Anomalies during integration of a small-scale hydrodynamic pump motor prompted an investigation into all sources of radial loading on the bearings, and revealed that overall loads were insufficiently characterized. Experimental measurements demonstrated that magnetic forces in the pump motor contributed to significant amounts of radial loading on the bearings, potentially causing wear over long periods of operation and premature failures. The magnitude of these magnetic forces was determined for the rotor and stator separately, as well as for the rotor-stator assembly by designing various experimental setups able to recreate the pump motor without hydrodynamic bearings. Characterization of these magnetic forces led to changes in manufacturing processes and enabled selective choices of components, improving the pump motor hardware in order to meet NASA’s Europa Clipper project requirements.