Magnetic Levitation

If you are lifting an object other than the second magnet you throwing the equation into a curve proportional to to the weight of the lifted object.

Why?

why not beefy magnets alone?

These guys have never NOT had what I needed..

Here's a mid size with a hole

As in 2 permanent magnets opposing? Because I need to be able to lower it back down for other applications of the overhead projector and for transporting. This project will be used in a live light show.

It might help the collective effort if you explained what your ultimate goal is.

Also, how will a convex surface "project" the energy which will be radiating from the transducer in more than one direction?

Not sure magnetic suspension is the answer.

Seems like polyester fiber fill or even foam rubber would work as well...

Perhaps, but we're in the dark without some explanation of the set-up and the goal.

So far we're just producing vibrations that will make waves on the surface.

You got it! That is the goal!

The convex surface is just the container for the water and oil and coloring. The overhead projector takes care of that. Not concerned with that here, just magnetic suspension.

Excuse me. That would have been nice to know in the beginning.

I didn't think of it that way! I am learning a lot here and appreciate all the input! I am basically doing this just for fun to see if I can make it work but when it comes down to show time foam rubber may be the way to go. I was hoping the magnetic fields would perform the damping 'cause that would be sexy to the onlookers but at the end of the day, you go with what works best. I don't mind being wrong about my assumptions because I've learned more from my mistakes than from assuming I always have to be right. I want to thank you and everyone for taking the time to educate me!

Sooo? Are people supposed to be looking at the light show or the sexy foam rubber? .. I mean the sexy magnetic levitation?. .. or wait.. I mean the sexy electrically activated transportable overhead projector?

Something I leaned in light (and D) work. (you shouldn't notice the fixture so much as the effect of the lighting)

The old standby for folks that make holograms, which are very sensitive to vibration, is to have a heavy optical table supported by a semi-deflated inner tube. I don't know if you can do anything similar here.

Also check out Sorbothane.

The Sorbo feet will probably be what I wind up when all is said and done. Thanks for the direction!

If you end up using foam, use memory foam. I have used ear-plugs to good effect as "packing peanuts" for vibration damping. They are very good acoustic isolators and can be bought cheap in bulk.

Interesting video! Thanks! You got me thinking again

Like Andrew said, a magnet and copper will resist moving. So you can levitate your platform on one set of magnets then set other magnets on the side with a copper plate.

As the electromagnets power up the platform will slowly raise, the copper will resist the lift a bit but it will settle exactly where it would if the copper wasn't there. Then any movements from there would be resisted by the magnet. But unless you use a bunch of really strong magnets very close to the copper you may not see much dampening effect over very small vibrational movements.

Sounds like a fun project, post pictures if you get it to work...or if not! Remember not all research is successful but you learn from all research!!

Drew K

Thank you. I'll play with that Idea. And I agree, I learned more from failures than successes sometimes.Nothing ventured, noyhing gained, right?

You will have to see if the apparent stiffness of the magnetic field and the above mass have an own frequency low enough to avoid transmission of the table vibration to the magnetically supported mass.

If you could control the separation to be equal, the respective forces should be at least close to equal. However, like versus unlike poles present different situations of positive versus negative feedback, respectively.

(Edited to add) The repulsive effect may be somewhat less, because the "lines of force" will tend to diverge; wheres the attractive "lines of force" will tend to be concentrated.

Interesting. I always included a design factor so I don't have to run it full out to get the desired effect. Thank you!

Thank you, that helps in sizing the magnets.

Magnetic flux spring i designed for an encoder wheel on an inspection robot.

In general, no, the repulsive force would depend on the strength of the second magnet. Also magnetic force varies greatly with distance.

https://en.wikipedia.org/wiki/Force_between_magnets

You may find these videos informative. Everything from Sorbothane mats to spring/dashpot systems, to rope-springs, etc., for vibration dampening. Lots of different ways to tackle this problem. Also google vibration-dampening products.

Also consider that your vibration will not necessarily be in the vertical direction. Much of it will, conducted up through the floor, but not all of it. The vibrational axis could even vary with frequency depending the acoustics of the surroundings. This will be at loud concerts, yes?

Back In my DJ days I made my own clamshell flight cases for my Technique 1200 turntables. These are insanely well dampened already, but in music and sound there is always more shake and quake than desireable.

To combat the issue I lined the cases with convoluted foam. It added a couple inches to each dimension, but it worked like a charm.

..yea! Yea! Yea!.. it was the 80's

No. They are opposite.

And what interference is this magnetic field going to have on your projector? These projector instruction are clear that a strong magnetic field interferes with the unit.

Even keeping the unit away from electrical cables that carry large amounts of current.

http://www.mitsubishielectric.com/bu/projectors/downloads/pdf/xl6u/manual_xl6u.pdf

Have you considered this?

http://www.diffen.com/difference/Electric_Field_vs_Magnetic_Field

When done right, maglev produces negligible external fields; maglev trains, for instance, which use very powerful magnetic fields to lift the train off the guideway. The field has to be kept out of the passenger compartment especially, given the problems it could pose for pacemakers, credit cards, and so forth.

Another example (though not maglev, specifically) are the voice-coil actuators inside hard disk drives. Here you've got powerful neodymium magnets just millimetres away from spinning disk surfaces highly sensitive to magnetic fields. So yeah, it can be done.

Thanks for the link to the article on electromagnetic fields, good read. But the projector is not a video projector but an overhead. Pretty much no electronics to screw up with said fields.

https://www.youtube.com/watch?v=azsqhKg8hX8

This may assist in the stabilisation of said projector if you build a maglev unit.

http://www.crealev.com/product/clm-2/

The manufacturer claims up to 10kg supported but doubtfull the units are cheap from the Netherlands.

This all helps my understanding of how magnetics works. Thank you.

The answer is no.

Is that a definitive No or a maybe No? Yes?

OK, so you want statistics: The statistical answer is: 964789717413148681431431786174411711871416178414640447 to 1, the answer is no. This classes as highly unlikely, rather than unlikely or probably unlikely.

The answer actually is "No, due to remanence."

The attraction between two magnets at a given distance is greater than their repulsion at that same distance. This due to the fact that, when the facing poles are aligned N-S, the alignment of the atomic dipoles within both magnets improves somewhat, strengthening their fields slightly. When the facing poles are either S-S or N-N, the atomic dipole alignments diverge slightly, weakening the field in both magnets and therefore the repulsive force between them but, as both magnets have very high remanence, the difference is rather slight.

Now if we substitute, say, an iron pellet having the same dimensions as one of the magnets, the attractive force is measurably less than it is between two N-S facing magnets. This due to iron's lower remanence, or tendency to retain an imposed magnetic field. Hence the attractive force between a magnet and the pellet drops-off more quickly with increasing distance than it would between two N-S facing magnets with increasing distance, and faster than the repulsive force would drop off between two N-N or S-S facing magnets, because of their higher remanence. As the field weakens, thermal effects increasingly scramble the iron's atomic-dipole alignments and so the iron contributes less and less to the net field strength.

If the magnetic field is very strong, another effect can happen: saturation. Once the atomic dipoles within the iron all fully aligned with the field, further increasing the field strength, say, by moving the magnet closer, contributes negligible additional effect, i.e., the force-distance curve flattens out.

So, to answer the OP's question: "No."

I thought it had something to do with the electrons in the materials? As the magnetic field moves them away in the repulsion system the superposition of the electrons from the center of the magnetic field is farther than when they are in attraction because the attraction moves the electrons closer to the other magnetic field.

Drew K

The conduction-band electrons don't play a major role in making a metallic permanent magnet a magnet. They would certainly play a role were a net current flowing through the material, but there is not in the absence of a changing field.

What does play a major role is the alignment of the atoms' magnetic moments, each atom behaving as a tiny dipole magnet. The atoms are not mobile, but can and do rotate in-place under the influence of a magnetic field. In certain materials like those used to make permanent magnets, their orientations are relatively fixed as well. Not entirely rigidly - the orientation can rotate somewhat - but it is much more fixed than in, say, soft iron, where they can freely rotate and why iron has a low remanence.

Now when a changing external field is applied, the conduction-band electrons (think of the material as permeated with a highly-mobile electron 'gas') will flow in a net direction (producing an opposing magnetic field) but, once the field stops changing, the current will cease and the electrons will once again randomly diffuse through the material. This does not, however, explain the strength difference between attractive and repulsive forces, as this effect is still observed when the field is completely static.

Ceramic/ferrite magnets are much less conductive than metallic magnets, almost insulators, and so what few conduction-band electrons there are do not freely permeate the material as they would were the magnet a metal. Yet in these materials the same differences between attractive and repulsive forces are also observed and so clearly the effect cannot be due to conduction-band electrons. It is due to the alignment of atomic dipoles.

Dude, are you a teacher? If not you should be cause I just got school'd! I am fascinated by magnets and love learning more about them, thanks :-)

Drew K