Evaluation Of AMB Turbomachinery Auxiliary Bearings
Kirk, R.G., Raju, K.V.S., Swanson, E.E., 1996
Proc Fifth Colloquium on Turbomachinery, Turbo and Power Machinery Research Center, Seoul National University, Seoul, Korea, May 6-11.
The use of active magnetic bearings (AMB) for turbomachinery has experienced substantial growth during the past two decades. The advantages for many applications make AMBs a very attractive solution for potentially low loss and efficient support for both radial and thrust loads. New machinery must be shop tested prior to shipment to the field for installation on-line. For AMB turbomachinery, one additional test is the operation of the auxiliary drop or overload bearings. A major concern is the ability of the selected auxiliary bearing to withstand the contact forces following an at-speed rotor drop. The proper design of AMB machinery requires the calculation of the anticipated loading for the auxiliary bearings. Analytical techniques to predict the rotor transient response are reviewed. Results of transient response evaluation of a full-size compressor rotor are presented to illustrate some of the important parameters in the design for rotor drop. In addition, selected results for two test rotors used for research and development at the Virginia Tech Rotor Dynamics Laboratory are discussed.