Electrical, structural and rotordynamic analysis of ultra high speed motor with shrink fit rotor for air blower cooling fuel cells

This paper introduces a rotor with shrink fit and analyzes its structural analysis and rotordynamics by 3D FEA. An ultra speed motor prototype for air blower is manufactured cooling fuel cells at the rating of 15 kW, 120 krpm. Electrical analysis of motor is performed. The required performance of motor is a 15 kW, 120 krpm, 93 % efficiency ultra speed motor. Then the stability of the rotor structure with shrink fit is evaluated in non-loading and loading condition (120 krpm, 210°C). And then the 3D rotordynamic analysis and Campbell diagram considering shrink fit are examined for the critical speed of rotor. The analysis shows that the critical speed of the rotor is higher when the rotor is shrink fitted than when the rotor is not shrink fitted. The analysis also shows the increase of shaft stiffness when the rotor is shrink fitted. All the performances of the ultra speed motor prototype are verified successfully.