Electromagnetic suspension and levitation

Abstract

The phenomenon of levitation has attracted attention from philosophers and scientists in the past. The recent advances, notably in power electronics and magnetic materials, have focused this attention within the last decade on the application of electromagnetic suspension and levitation techniques to advanced ground transportation. Regardless of the fact that there is, in effect, a separate technology involved for each electromagnetic method, the whole subject is given a blanket title of 'maglev'. There is also a very wide range of industrial applications to which magnetic suspension techniques could be profitably applied, particularly in the area of high-speed bearings to reduce noise and to eliminate friction, and yet only high-speed ground transportation has caught the imagination of the media. This review deals with the physics and engineering aspects of the four principal contenders for advanced ground transportation systems and describes the most up-to-date developments in Germany, Japan, USA and the UK in this field. This article also describes some of the very recent challenging developments in the application of electromagnetic suspension and levitation techniques to contactless bearings. A fairly comprehensive bibliography is given to enable the more interested reader to pursue the topic further in any one of the technologies dealt with in this review.

Feasibility of a magnetic suspension for second generation gravitational wave interferometers

“…6 3 and with a gap of 5 cm: as a cross-check, this value corresponds to the one found in Fig. 5 with the same configuration.…”

Feasibility of a magnetic suspension for second generation gravitational wave interferometers

“…For our computation, we use Nd-Fe-B magnets which have currently the higher residual magnetization (B r = 1.3 T); the density of this material is ρ = 7.4 g/cm 3 . For each magnet, the dimensions to be optimized are the length, that is the size of the rectangular parallelepiped in the direction the optical axis of the suspended mirror, the width, defined as the size along the transfer dimension and the vertical thickness.…”

“…As it is well known, a stable levitation in a constant magnetic field can be obtained only with superconducting and diamagnetic materials [1][2][3][4]. Using superconducting materials requires low temperature operation; thus, their integration in the seismic suspension of GW detectors looks complex and expensive.…”

“…Magnetic levitation systems find several applications [1][2][3][4] in physics and engineering, ranging from small force measurements to transportation systems. In this paper, we analyze the possibility of using magnetic levitation as a future upgrade of the sophisticated suspensions used in long baseline interferometric Gravitational Wave (GW) detectors like, for example, Virgo [5].…”

“…In Section 2, the general principle of stable levitation [3] is shortly recalled. Then, the numerical procedures used to compute the forces between the different magnets are described.…”