Inductrack

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Inductrack is a completely passive, fail-safe magnetic levitation system, using only unpowered loops of wire in the track and permanent magnets (arranged into Halbach arrays) on the vehicle to achieve magnetic levitation. The track can be in one of two configurations, a "ladder track" and a "laminated track". The ladder track is made of unpowered Litz-wire cables, and the laminated track is made out of stacked copper or aluminum sheets.

There are two designs: the Inductrack I, which is optimized for high speed operation, and the Inductrack II, which is more efficient at lower speeds.

1 Description
2 Stationary Cars
3 See also
4 References
5 External links

[edit] Description

Inductrack was invented by a team of scientists at Lawrence Livermore National Laboratory, headed by physicist Richard F. Post, for use in maglev trains.<ref>A New Approach for Magnetically Levitating Trains — and Rockets</ref> The only power required is to push the train forward against air and electromagnetic drag, with increasing levitation force generated as the velocity of the train increases over the loops of wire.

Its name comes from the word inductance or inductor; an electrical device made from loops of wire. As the magnet array (with alternating magnetic field orientations) passes over the loops of wire, it induces a current in them. The current creates its own magnetic field which repels the permanent magnets.

When neodymium–iron–boron permanent magnets are used, levitation is achieved at low speeds, allowing it to lift 50 times the magnet weight. The test model levitated at speeds above 22 mph, but Richard Post believes that on real tracks, levitation could be achieved at "as little as 1 to 2 mph". Below the transition speed, the magnetic drag increases as the vehicle's speed increases and approaches the transition speed, but above this transition speed, the magnetic drag decreases as the vehicle's speed increases. <ref>Track To The Future: Maglev Trains On Permanent Magnets — Scott R. Gourley — Popular Mechanics</ref>

The Inductrack II variation uses two Halbach arrays, one above and one below the track to double the levitating magnetic field without substantially increasing the weight or footprint area of the Halbach arrays, while having lower drag forces at low speeds.<ref>Toward More Efficient Transport: The Inductrack Maglev System — Presented by Richard F. Post, 10 October 2005</ref>

Several maglev railroad proposals are based upon Inductrack technology. The U.S. National Aeronautics and Space Administration (NASA) is also considering Inductrack technology for launching rockets.

[edit] Stationary Cars

For use at embarkation/debarkation areas, an implementation using a moving track would continue levitating the car while stationary. With a loop construction similar to a flat escalator supported by stationary track there would be no moving parts friction. Also, the elimination of the need for wheels during starting/stopping of the cars simplify car construction and maintenance.