Mag Lev

[Motorhead]

I need a source for magnet mfgr. who can produce ring magnets of a large diameter.

About 9ft. dia. with opposing poles.

E-mail me if you have any info at www.fibertool@cox.net

[windstuffnow]

  9ft in diameter?  Can you imagine how difficult it would be to handle these magnets?  I envision rolling this baby into the shop for the beginning process of assembling... suddenly I notice all the tools on the wall pointed directly at me as the holders seem to be giving away... then in a second my entire shop implodes.

  Ok back to reality... wouldn't it be more cost effective to use sections to make the ring you want.  I may be able to help... but you'll not find anyone to make a 9ft ring...

Have Fun

Ed

[Motorhead]

Ed,

 If the magnets produce the same force in section that's fine. I'll achieve the same result.After my last bout with Neos I can respect their inherent ability to cuase a catastrophy with out much warning. My thumb is just now healing,the picture I got was nearly the same as yours.If not worse

Back to the goal. I want to produce a ring of opposing permanent magnets to levitate a given load as it rotates from zero to possibly 100 rpm at that 9ft dia.

I also want to cast them so side load is negated by the shape of each opposing ring.

Meaning angled faces of mags to keep load centered.

Phil

[windstuffnow]

  From 0 to 100 rpm?  You really only need bearings.  You can reduce the friction by removing the grease in the bearings and using light oil.  At 100 rpm they'll last forever.  A magnetic bearing set up in the size and strength your talking about may be a massive expence for a job that 2 $10.00 bearings will handle.

  How much load or weight do you plan to float?

Ed

[Motorhead]

Ed,

Without tipping my hand,this is an experiment,to find what happens without any of the structural support required by the conventional bearings to tie all the forces to one point.This is a way to negate turbulance from supporting structural members.

i.e. simplicity. i'm not looking for any arguments regarding this,just a method.

Phil

[windstuffnow]

  If this is 9 ft in diameter ( say od) what would the id be of the magnetic ring?  Just to get an idea of the size of magnet(s) you would need to float this "object".  Also, what strength of magnet... how thick should the magnet be.  I know that 1 magnet in the 9ft range would be out of the question for many reasons but segments could be made and assembled on site.  Let me know

Have Fun

Ed

[troy]

Keep in mind that stability in a magnetically levitated rotating object turns out to be a very elusive target.  For some interesting reading on the subject, do a google search for "levitron".  This is a magnetically levitated toy top using  two ring magnets similar to what you describe except on a much smaller scale. There are lots of sites that describe the physics behind it.

For decades, this phenomenon was considered impossible due to insufficient stabilizing force available from the gyroscopic effect vs the inherently unstable repulsive forces of the opposing magnets.  Then some guy who didn't know any better just went and did it.  Don't you just love the underdog?!

The story of the top itself is also interesting in it's own right.  Invented by a brilliant recluse and stolen and marketed by a second, who made millions.

In industrial magnetic bearings, they use conventional bearings to get the object rotating up so speed and then withdraw the conventional bearings and allow the magnetic bearing to take over.

Good luck and have fun!

troy

[Motorhead]

Ed,

The rings would be 4" in width and 2" high each. I load (weight of object being supported is 300lbs)The lower ring should have an angled face 45 deg that runs half the thicknes using 2/3rd the surface,i.e. looking at a cut away view starting from I.D. at the top small flat then angle the twards bottom of profile another small flat.I can send a drawing to you if you like,that would be easier to comprehend.

Having way too much fun

Phil

[windstuffnow]

  You can send a diagram for clarity of exactly what your looking for.

Ed

[Andrew]

I saw many extremely large magnetic float bearings before. Some supporting over 500 tons! Now how in the hell do they do that. One in particular was the magnetic float bearing inside one of the solar telescopes at the New Mexico Solar observatory on sacremento peak. This had a huge platform stabilized in the center to do research and other things without being effected by gravity, or whatever. It was enormous, maybe 25 stories tall, and maybe 15 stories underground! Made almost completly of steel. It was so cool though that you could turn the thing with your finger. I felt real strong! Back to the point, mag lev can be done, but it is evtremely hard to work with, and takes exact precision to set it up right. If all possible I would reccomend to avoid it. Mercury float, and other float type bearings work well.

-Andrew