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Performance tests of a cryogenic hybrid magnetic bearing for turbopumpsExperiments were performed on a Hybrid Magnetic Bearing designed for cryogenic applications such as turbopumps. This bearing is considerably smaller and lighter than conventional magnetic bearings and is more efficient because it uses a permanent magnet to provide a bias flux. The tests were performed in a test rig that used liquid nitrogen to simulate cryogenic turbopump temperatures. The bearing was tested at room temperature and at liquid nitrogen temperature (-320 F). The maximum speed for the test rig was 14000 rpm. For a magnetic bearing stiffness of 20000 lb/in, the flexible rotor had two critical speeds. A static (nonrotating) bearing stiffness of 85000 lb/in was achieved. Magnetic bearing stiffness, permanent magnet stiffness, actuator gain, and actuator force interaction between two axes were evaluated, and controller/power amplifier characteristics were determined. The tests revealed that it is feasible to use this bearing in the cryogenic environment and to control the rotor dynamics of flexible rotors when passing through bending critical speeds. The tests also revealed that more effort should be placed on enhancing the controller to achieve higher bearing stiffness and on developing displacement sensors that reduce drift caused by temperature and reduce sensor electrical noise.
Document ID
19920011281
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Dirusso, Eliseo (NASA Lewis Research Center Cleveland, OH, United States)
Brown, Gerald V. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1992
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
E-6775
NAS 1.15:105627
NASA-TM-105627
Meeting Information
Meeting: International Symposium on Magnetic Bearings
Location: Alexandria, VA
Country: United States
Start Date: July 29, 1992
End Date: July 31, 1992
Accession Number
92N20523
Funding Number(s)
PROJECT: RTOP 590-21-31
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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