Inductrack
From Free net encyclopedia
Inductrack is a completely passive magnetic levitation train system, using only unpowered loops of wire in the track and permanent magnets (in Halbach arrays) on the train to achieve magnetic levitation. Inductrack was invented by Lawrence Livermore National Laboratory physicist Richard E. Post. 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.
An Inductrack variation uses two Halbach arrays 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.
Several maglev railroad proposals are based upon Inductrack technology.
See also
- SkyTran — a Personal rapid transit proposal that uses inductrack technology.