Hyperloop Transportation says it will use a ‘cheaper, safer’ form of magnetic levitation The Hyperloop arms race is real: VIDEO
Hyperloop Transportation says it will use a ‘cheaper, safer’ form of magnetic levitation The Hyperloop arms race is real
Hyperloop Transportation Technologies, one of two LA-based startups working to build Elon Musk’s futuristic transportation system, announced today that it has licensed a technology called "passive magnetic levitation" to power its prototype. The system is "a cheaper, safer alternative" to regular magnetic levitation, or maglev, which is currently in operation powering high-speed trains in China and Europe.
Passive magnetic levitation, which was developed by the late physicist Richard Post in 2000, uses unpowered loops of wire in the track and permanent magnets in the train pod to create levitation. By contrast, maglev requires complex and expensive infrastructure upgrades, such as power sources placed at intervals along the track. Post, who worked for the Lawrence Livermore National Laboratory in Livermore, California, until his death in 2015, called his new system "the Inductrack."
According to a Scientific American article by Post from January 2000
Called the Inductrack, the new system is passive in that it uses no superconducting magnets or powered electromagnets. Instead it uses permanent room-temperature magnets, similar to the familiar bar magnet, only more powerful. On the underside of each train car is a flat, rectangular array of magnetic bars called a Halbach array. (It is named after its inventor, Klaus Halbach, a retired Lawrence Berkeley National Laboratory physicist.) The bars are arranged in a special pattern, so that the magnetic orientation of each bar is at right angles to the orientations of the adjacent bars [see top illustration on this page]. When the bars are placed in this configuration, the magnetic-field lines combine to produce a very strong field below the array. Above the array, the field lines cancel one another out.
The second critical element is the track, which is embedded with closely packed coils of insulated wire. Each coil is a closed circuit, resembling a rectangular window frame. The Inductrack, as its name suggests, produces levitating force by inducing electric currents in the track. Moving a permanent magnet near a loop of wire will cause a current to flow in the wire, as English physicist Michael Faraday discovered in 1831. When the Inductrack's train cars move forward, the magnets in the Halbach arrays induce currents in the track's coils, which in turn generate an electromagnetic field that repels the arrays. As long as the train is moving above a low critical speed of a few kilometers per hour-a bit faster than walking speed-the Halbach arrays will be levitated a few centimeters above the track's surface.
By Andrew J . Hawkins on May 9, 2016
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