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.

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[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.[1] [2] 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 inversely with the vehicle's speed [3], reaching for example, a lift to drag ratio of 200:1 at 500 km/h, which is far higher than any aircraft.[4]

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.[5]

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.

American Maglev Technology is developing commercial Inductrack systems.

[edit] See also

[edit] References

  1. ^ A New Approach for Magnetically Levitating Trains — and Rockets
  2. ^ Richard F. Post, "MagLev: A New Approach", Scientific American January, 2000.
  3. ^ Track To The Future: Maglev Trains On Permanent Magnets — Scott R. Gourley — Popular Mechanics
  4. ^ In "MagLev: A New Approach", above, section on "The Issue of Efficiency"
  5. ^ Toward More Efficient Transport: The Inductrack Maglev System — Presented by Richard F. Post, 10 October 2005

[edit] External links

Patents