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Passive eddy-current damping as a means of vibration control in cryogenic turbomachineryLateral shaft vibrations produced by a rotating unbalance weight were damped by means of eddy currents generated in copper conductors that were precessing cyclicly in the gap formed by the pole faces of C-shaped, permanent magnets. The damper assembly, which was located at the lower bearing support of a vertically oriented rotor was completely immersed in liquid nitrogen during the test run. The test rotor was operated over a speed range from 800 to 10,000 rpm. Three magnet/conductor designs were evaluated. Experimental damping coefficients varied from 180 to 530 N sec/m. Reasonable agreement was noted for theoretical values of damping for these same assemblies. Values of damping coefficients varied from 150 to 780 N sec/m. The results demonstrate that passive eddy-current damping is a viable candidate for vibration control in cryogenic turbomachinery.
Document ID
19860015251
Acquisition Source
Legacy CDMS
Document Type
Technical Publication (TP)
Authors
Cunningham, R. E.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 5, 2013
Publication Date
February 1, 1986
Subject Category
Launch Vehicles And Space Vehicles
Report/Patent Number
E-2762
NASA-TP-2562
NAS 1.60:2562
Accession Number
86N24722
Funding Number(s)
PROJECT: RTOP 506-60-12
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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