Title page for ETD etd-04072009-040837
|Type of Document
||Transient response technique applied to active magnetic bearing machinery during rotor drop
||Master of Science
|Kirk, R. Gordon
|Mitchiner, Reginald G.
|Wicks, Alfred L.
|Date of Defense
The active magnetic bearing (AMB) is a relatively new technology which has
many advantages compared with conventional bearing design. In an AMB system,
the rolling-element back-up bearings are indispensable to protect the magnetic
bearing rotor and stator, and other stationary seals along the rotor shaft. In this
paper, a theoretical formulation is proposed and solved numerically to examine the
transient response of the flexible rotor, from the time just previous to the AMB
shuts down and including the rotor drop onto the back-up bearing. The backward
whirl of the rotor, which may lead to the destructive damage of the machinery, has
been analytically predicted at very light support damping and very high support
damping. Also, the vibration due to the non-linearity of the contact point geometry
has been included in the analysis. The influence of the support damping on the
displacement of the disk and also the contact force between the journal and the
inner-race of the back-up bearing have been computed for various rotor system
parameters. By comparing these results with the optimum support damping for
the simple flexible rotor model, it is shown that this support damping optimization
can be applicable for specifying the required optimum range of support damping
for the back-up bearings of AMB systems.
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