The Inductrack Approach to Magnetic Levitation
Abstract
Concepts developed during research on passive magnetic bearing systems at the Lawrence Livermore National Laboratory gave rise to a new approach to magnetic levitation, the Inductrack. A passive induced-current system employing permanent magnets on the moving vehicle, the Inductrack maximizes levitation forces by a combination of two elements. First, the permanent magnets on the vehicle are arranged in a ''Halbach array,'' a magnet configuration that optimally produces a periodic magnetic field below the array, while canceling the field above the array. Second, the track is made up of close-packed shorted electrical circuits. These circuits couple optimally to the magnetic field of the Halbach array. As a result, levitating forces of order 40 metric tonnes per square meter of Halbach array can be generated, using NdFeB magnets whose weight is a few percent of the levitated weight. Being an induced-current system, the levitation requires motion of the vehicle above a low transition speed. For maglev applications this speed is a few kilometers per hour, walking speed. At rest or in the station auxiliary wheels are needed. The Inductrack is thus fail-safe, that is, drive system failure would only result in the vehicle slowing down and finally settling on its auxiliary wheels.more »
- Authors:
- Publication Date:
- Research Org.:
- Lawrence Livermore National Lab., CA (US)
- Sponsoring Org.:
- USDOE Office of Defense Programs (DP) (US)
- OSTI Identifier:
- 791522
- Report Number(s):
- UCRL-JC-138593
TRN: US200302%%739
- DOE Contract Number:
- W-7405-Eng-48
- Resource Type:
- Conference
- Resource Relation:
- Conference: 16th International Conference on Magnetically Levitated Systems and Linear Drives, Rio de Janeiro (BR), 06/06/2000--06/11/2000; Other Information: PBD: 19 Apr 2000
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 33 ADVANCED PROPULSION SYSTEMS; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; ACCELERATION; CONFIGURATION; CONSTRUCTION; DESIGN; LEVITATION; MAGNETIC BEARINGS; MAGNETIC FIELDS; MAGNETS; METRICS; NASA; PERMANENT MAGNETS; ROCKETS; SLOWING-DOWN
Citation Formats
Post, R F, and Ryutov, D D. The Inductrack Approach to Magnetic Levitation. United States: N. p., 2000.
Web.
Post, R F, & Ryutov, D D. The Inductrack Approach to Magnetic Levitation. United States.
Post, R F, and Ryutov, D D. Wed .
"The Inductrack Approach to Magnetic Levitation". United States. https://www.osti.gov/servlets/purl/791522.
@article{osti_791522,
title = {The Inductrack Approach to Magnetic Levitation},
author = {Post, R F and Ryutov, D D},
abstractNote = {Concepts developed during research on passive magnetic bearing systems at the Lawrence Livermore National Laboratory gave rise to a new approach to magnetic levitation, the Inductrack. A passive induced-current system employing permanent magnets on the moving vehicle, the Inductrack maximizes levitation forces by a combination of two elements. First, the permanent magnets on the vehicle are arranged in a ''Halbach array,'' a magnet configuration that optimally produces a periodic magnetic field below the array, while canceling the field above the array. Second, the track is made up of close-packed shorted electrical circuits. These circuits couple optimally to the magnetic field of the Halbach array. As a result, levitating forces of order 40 metric tonnes per square meter of Halbach array can be generated, using NdFeB magnets whose weight is a few percent of the levitated weight. Being an induced-current system, the levitation requires motion of the vehicle above a low transition speed. For maglev applications this speed is a few kilometers per hour, walking speed. At rest or in the station auxiliary wheels are needed. The Inductrack is thus fail-safe, that is, drive system failure would only result in the vehicle slowing down and finally settling on its auxiliary wheels. On the basis of theoretical analyses a small model vehicle and a 20-meter-long track was built and tested at speeds of order 12 meters per second. A second model, designed to achieve 10-g acceleration levels and much higher speeds, is under construction under NASA sponsorship, en route to the design of maglev-based launchers for rockets. Some of the presently perceived practical problems of implementing full-scale maglev systems based on the Inductrack concept will be discussed.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {4}
}