Vibration Reduction in a Multimass Flexible Rotor Using a Midspan Magnetic Damper

The purpose of this study is to investigate the effects of a magnetic damper on a mul t imass rotor. A small three mass rotor which would simulate the dynamics of a centrally mounted steam turbine or compressor was built and a magnetic damper placed near the rotor midspan. The magnetic damper was constructed of four separate radially arranged silicon iron magnets with coil windings. A proportional aud derivative control circuit was employed to control the damper. The rotor was run at speeds frolll 0 to 10,000 rpm, through three natural rotor- bearing- support system resonances.