Unbalance Response Analysis on the High Speed Flywheel Motor Supported by Active Magnetic Bearings

The rotor dynamics model of a composite flywheel storing energy of 25MJ driven by permanent magnetic motor with power of 400kW supported by active magnetic bearings running at the speed of 12000-24000rpm was built to carry out the unbalance response from Dyrobes. The flywheel shaft was lumped to 21 elements, and there are several major assumptions involved in the basic modeling of the rotor bearing system. There are three critical speeds of 1350rpm, 2650rpm and 13450rpm below 24000rpm. The forward whirl mode shapes are translational, conical and bending. The maximum amplitudes of the rotor under different unbalance conditions were obtained. The maximum vibration amplitude is at the speed of 13450rpm near the motor rotor magnetic bearing. These data are necessary to guide the design of AMB and protective bearings.