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Showing posts with label MAGLEV WIND TURBINES. Show all posts
Showing posts with label MAGLEV WIND TURBINES. Show all posts

Saturday, August 29, 2009

Maglev wind turbine.

A Maglev wind turbine or Maglev windmill would use magnetic levitation to replace conventional bearings in the design of a wind turbine. A recent design of Maglev wind turbine was developed in China by Guangzhou Energy Research Institute. This design of Maglev wind turbine claims to utilize winds with starting speeds as low as 1.5 meters per second (m/s), and cut-in speeds of 3 m/s. Such Maglev wind turbine should be able to add 1,000 hours of operation annually to wind power plants in areas with an average wind speed of 3 m/s.[1] However, since the energy available in wind varies so the power produced by Maglev wind turbine at such velocities would be lower than conventional wind turbines under higher speed winds.
The rotating turbine shaft in Maglev wind turbine is supported by magnetic levitation instead of ball bearings. Magnetic bearings have been used for smaller turbines and pumps, but they generally can't handle impacts disturbing the shaft, and generally require actively controlled electromagnets. Making magnetic bearings strong enough to handle the loads of a Maglev wind turbine would use prohibitive amounts of power just keeping the electromagnets running. The Chinese design of Maglev wind turbine is said to use permanent magnets to support the rotor shaft.
Little detailed technical information supporting these claims about Maglev wind turbine is available in English.
Chinese company Zhongke Hengyuan Energy Technology invested CN¥400 million in building the base for the maglev wind turbine generators, in which construction began in November 2007. Maglev Wind Turbine Technologies Inc. announced the launch of a wind turbine power generating device based on magnetic levitation called the Maglev Wind Turbine on July 26, 2007.

Mysterious Maglev wind turbine


Maglev wind turbine has been a big splash on Worldwatch's blog, Treehugger and inhabitat. The original article about Maglev wind turbine
was in Chinese Xinhua News paper, and as per this article about Maglev wind turbine some of the claims from the English and web media are misleading.

First of all Maglev wind turbine won't be levitating off the ground, and won't be frictionless as well, but these may be significantly more efficient than existing windmills. The magnetic levitation that Maglev wind turbine would use is between the rotating shaft and the fixed base of the machine, basically taking the place of ball bearings. Such magnetic bearings have been used for decades in smaller turbines and pumps by Ebara, Leybold, Seiko-Seiki, and others. However, they generally can't handle being bumped around much because the magnetic force isn't that strong enough. Making magnetic bearings strong enough to handle the loads put on them by Maglev wind turbine would be hard, and would use prohibitive amounts of power just keeping the electromagnets running strongly enough. However, the Worldwatch article says the new Chinese device uses "full-permanent" magnets, meaning there are no electromagnets, only cleverly placed permanent ones, so it should use no power. It sounds like they will be used on small turbines (perfect for home use), which would be similar in scale to the pumps and industrial turbines currently using magnetic bearings. But who knows, in a few years it might be possible to scale them up for Maglev wind turbine.
Unfortunately there's not a shred of additional technical information in the article about Maglev wind turbine’s structure. so we can only speculate what their solution was for the mysterious Maglev wind turbine. Some are speculating that they're probably using Halbach arrays in a system like the Inductrack invented at Lawrence Livermore Labs several years ago. Any permanent magnet system would doubtless need lots of Neodymium ("rare earth") magnets, which may have questionable sustainability when mined in large amounts, but as it happens China is rich in that element--in fact, energy.buzz points out that China owns 90% of the world's market of rare earth magnets. Since July 2006 Maglev wind turbine remains a mystery with very little details and even lesser news.