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Electromagnets capability of repulsion.

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Abolyss

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Nov 6, 2007
5
I am wondering if anybody can inform me of how to use an electromagnet to repulse a small platform of Aluminium in the air to about 6 inches. NOTE: the platform is 65mm in radius and will have numerous amounts of neodymium magnets spread across the underside facing in same polarity to the electromagnet below. I'm still in confusion whether to place the electromagnet with poles facing vertically or horizontally (although the general theory is vertical). Any help in this matter would be greatly appreciated.
 
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You will need a fairly substantial electromagnet for a six inch suspension. Your flux lines will need to be opposing.

It appears from your comment that your EM is being applied at the point where the flux lines are following their return path.

If I were attempting to do this I would be starting with an EM of near 24 inches square for the field projection.

A bit more description of your device would be helpful.

Mike
 
Abolyss: In addition to MJR2's comments: Is the aluminum platform constrained so the neodymium magnets can't cause it to flip around and attract toward the electromagnet?

Merely applying a repulsive magnetic field is not enough to maintain stable repulsion. The platform/magnet assembly is not going to maintain repulsion on its own. It will try to flip around to attract towards the electromagnet.

What you are asking for is not easy.
 
I'm sorry for not offering so much detail to my explanation. I only wished to offer a general explanation first to break the ice. In answer to your questions the platform is stabalised by 4 plastic rods in a square formation as I understand the magnets will attempt to right themselves. I also have a limit of 9 volts for a power supply but I would think using 2 or maybe 3 such power supplies would be fine. I'm sure I could post a diagram to show my plans in better detail. The purpose of my experiment is to see if it is possible to raise a small platform to said height with quite a simple design. Diagram should be posted within a day or so. Thank you
 
While not impossible to get the 6 inch lift you want, it would take a very large, focused electro magnet. The amount of lift you could reasonably get is the gap between two opposed neo magnets (which also requires no power).
 
The wikipedia entry lists a high frequency AC levitation of AL directly, no magnets needed, maybe that might work better.
 
Dave,

The use of AC or eddy current force for levitation quicky heats the aluminum plate. The Wikipedia article mentions the levitation of a phone book with a aluminum plate inside. I wonder how long it took before the book started on fire.

Abolysis,

A nine volt bench type power supply or maybe two or three of them is not going to be enough to generate the field you need. The magnet I mentioned earlier as to where I would start is in excess of 1500 watts DC and 30000 ampturns.


Mike
 
Thanks for the advice, a diagram will be posted soon. Nearly finished. If 9 volts would not work I'm not sure how this could work. I may have acces to the power supply needed, but for the purpose of the experiment I can not surpass this voltage. Any other ideas as to how to levitate the platform are welcome as I'm stumped. Sreid posted earlier that 2 opposing neo magnets could give a substantial lift but as to how I would start and stop the levitation process is beyond me. Maybe a cover to go over the lower neo magnets. But I do not know any material that could block the magnetism of an N45 power neo magnet.
I hope to read the raplies thanks.
 
Your levitated thing is supposed to have aluminum and neodymium. Thick aluminum is repelled b ac field, nedymium permament magnets are effectively repelled by dc field of the proper polarity. You say you're using 9 volts but you don't say ac or dc. Which one?

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