Magnetic bearings have relatively low power consumption compared to fluid film and rolling element bearings. They are now candidates for supporting gas turbines and aeropropulsion engines. This paper describes the design and construction of permanent magnet biased, actively controlled magnetic bearings for a flexible rotor. The rotor was originally supported in fluid film bearings consuming as much as 3000 watts of power. For the magnetic bearing, both permanent magnets and electromagnets are used in a configuration which effectively provides the necessary fluxes in the appropriate air gaps to support the rotor. The theoretical development related to the bearing design is presented along with some experimental performance results. The results include measurements of power consumption, load capacity, bearing linearized coefficients, and the dynamic response of the rotor. The measured total power consumption, excluding shaft losses, was 210 watts in the permanent magnet biased bearing.

1.
Allaire, P. E., Soitore, C. K., Maslen, E. H., and Humphris, R. R., 1991, “Low Power Design of Magnetic Bearings Using Permanent Magnet Biasing,” Proceedings of the NASA International Symposium on Magnetic Suspension, Aug., pp. 317–330.
2.
Boden, K., and Fremerey, J. K., 1992, “Industrial Realization of the ‘SYSTEM KFA-JU¨LICH’ Permanent Magnet Bearing Lines,” Proceeding of MAG’92, Magnetic Bearings, Magnetic Drives, and Dry Gas Seals Conference and Exhibition, Alexandria, VA, July, pp. 43–60.
3.
Humphris
R. R.
,
Kelm
R. D.
,
Lewis
D. W.
, and
Allaire
P. E.
,
1986
, “
Effect of Control Algorithms on Magnetic Journal Bearing Properties
,”
ASME Journal of Engineering for Gas Turbines and Power
, Vol.
108
, pp.
624
632
.
4.
Keith, F. J., Maslen, E. H., Humphris, R. R., and Williams, R. D., 1990, “Switching Amplifier Design for Magnetic Bearings,” Magnetic Bearings, Proceedings of the Second International Symposium, Tokyo, July, pp. 212–218.
5.
Maslen, E. H., Allaire, P. E., and Scott, M. A., 1988, “Magnetic Bearing Design for a High Speed Rotor,” Magnetic Bearings, Proceedings of the First International Symposium, Springer-Verlag, New York, pp. 137–146.
6.
Maslen, E. H., and Bielk, J. R., 1992, “A Stability Model for Flexible Rotors with Magnetic Bearings,” ASME JOURNAL OF DYNAMIC SYSTEMS, MEASUREMENT, AND CONTROL, March, pp. 172–175.
7.
Meeks, C, 1989, “Trends in Magnetic Bearing Design,” Paper presented at Naval Sea Systems Command Magnetic Bearing Forum, Washington, D.C., July.
8.
Ohkami, Y., Okamato, O., Kida, T., Murakami, C., Nakajima, A., Hagihara, S., and Yabuuchi, K., 1981, “A Comparison Study of Various Types of Magnetic Bearings Utilizing Permanent Magnets,” Proceedings of the Fifth International Workshop on Rare Earth-Cobalt Permanent Magnets and Their Applications, Roanoke, VA, June, pp. 165–178.
9.
Sortore, C. K., Allaire, P. E., Maslen, E. H., and Humphris, R. R., 1990a, “Design of Permanent Magnet Biased Magnetic Bearings for a Flexible Rotor,” Mechanical Failures Prevention Meeting, Virginia Beach, VA, Apr., pp. 89–95.
10.
Sortore, C., Allaire, P., Maslen, E., Humphris, R., and Studer, P., 1990b, “Permanent Magnet Biased Magnetic Bearings: Design, Construction, and Testing,” Magnetic Bearings, Proceedings of the Second International Symposium, Tokyo, July, pp. 175–182.
11.
Studer, P. A., 1975, NASA, Magnetic Bearing, Patent 3865442, Patent Application 100637, Feb.
12.
Studer, P. A., 1980, NASA, Linear Magnetic Bearing, Patent 4387935, Patent Application 214361, December.
13.
Tsuchiya, K., Inoue, M., Nakajima, A., Ohkami, Y., and Murakami, C, 1989, “On Stability of Magnetically Suspended Rotor at High Rotational Speed,” Presented at the Aerospace Sciences Meeting, Reno, Nevada, Jan.
14.
Wilson, M., and Studer, P. A., 1981, “Linear Magnetic Bearings,” Proceedings of the Fifth International Workshop on Rare Earth-Cobalt Magnets and Their Applications, Roanoke, VA, June, pp. 217–236.
This content is only available via PDF.
You do not currently have access to this content.