Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: labview1958 on 03/01/2006 23:31:34
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I am trying to understand the electromagnetic lift and drag forces in a maglev electrodynamic system at the atomic level. Can someone help?
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quote:
Originally posted by labview1958
I am trying to understand the electromagnetic lift and drag forces in a maglev electrodynamic system at the atomic level. Can someone help?
I'm usually confused, but after reading this, I'm more confused than usual.
Maglev is a technical application of magnetism. Are you asking for an atomic description how electromagnetism works? All maglev is is an abbreviation of magnetic levitation.
As for lift and drag, these are attributes of aerodynamics (or fluid dynamics if you want to fly in something other than air). Clearly, drag has a relevance to any vehicle, even a motor car, and it has the same relevance to a maglev vehicle that it would have to any other terrestrial vehicle.
Two wikipedia pages that would be relevant are:
http://en.wikipedia.org/wiki/Magnetic_levitation explains the general principles of magnetic levitation.
http://en.wikipedia.org/wiki/Maglev_train discusses the particular application of maglev to trains.
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I am interested in the electromagnetic drag force and not the aerodynamic drag. Why does the electromagnetic drag occurs? What roles does the electrons, atoms etc play ?
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A generator works by changing a magnetic field through a loop of wire, if the loop is closed a current will flow. A current flowing through a coil is an electromagnet which will interact with the original magnet to oppose the movement. If you think about it this means that energy is conserved - you have to do extra work changing the magnetic field (turning the handle) if you draw extra current from your coil.
Now in the case of the maglev train, you are moving some very strong magnets about and you can think of a lump of conductor as lots of shorted out loops. So if you move the train near a lump of conductor currents will flow that produce a magnetic field that acts to oppose the motion hence a braking force.