Self-centering Magnetic Suspension?

[Stocker]

Is it possible to make a magnetic suspension that is self-centering? mrjam's amazing CDP has me wondering if the vertical centering component could be eliminated by a DIYer.

Using three, four or more as required magnets, arranged as if in a bowl shape, with poles appropriately opposed; to suspend a similarly anti-bowl shaped suspended object

clear-as-mud ascii rendering
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And the big question: would it still transmit vibrations? Would many small magnets be better than a few strong ones? Could the setup be arranged slightly less than perfectly and still work?

Maybe with some platic bump-stops to prevent large shocks from damaging things.

[Steve Eddy]

Originally posted by Stocker
Is it possible to make a magnetic suspension that is self-centering? mrjam's amazing CDP has me wondering if the vertical centering component could be eliminated by a DIYer.

Using three, four or more as required magnets, arranged as if in a bowl shape, with poles appropriately opposed; to suspend a similarly anti-bowl shaped suspended object

clear-as-mud ascii rendering
--\__/--
-\___/-

And the big question: would it still transmit vibrations? Would many small magnets be better than a few strong ones? Could the setup be arranged slightly less than perfectly and still work?

Well, to date Earnshaw's Theorem still holds and no static array of magnets will be stable.

If it were stable, it would still transmit vibrations at and below its resonant frequency and isolate from vibration above its resonant frequency.

That's really all this stuff is anyway, simple mechanical resonant systems, i.e. spring/mass combinations. Ideally what you want is a resonant frequency that is well below the lowest frequency you want it to isolate and you want the resonance to be very high Q (i.e. very little loss).

se

[I_Forgot]

Even if you could make it work, you'd get no end of grief from the golden ears who would complain about audio pollution due to the stray magnetic fields all over the place.

The magnets are really just acting as springs and WILL transfer vibration across the air space between them, as a spring would.

If you must use magnets, you could suspend the object from a single wire (balancing will be a problem) and restrict its motion using magnets located under, over, or around it...

Another thing to consider is that the whole system is undamped whether you use springs or magnets. I think you would want to damp any vibrations that are transferred so they don't keep things ringing.

I_F

[Circlotron]

Click on "Maglev"

[jcx]

diamagnetic interaction can apparently enable stable "passive" magnetic suspension:

http://www.mae.ncsu.edu/courses/Mae5...Levitation.htm

(from American Scientist online, search: diamagnetic levitation

http://www.americanscientist.org/tem.../assetid/35120

in case they pull the classroom link to the article)

[Stocker]

interesting. thanks guys.