Electronic Levitron...How the heck does this thing work?

[allcanadian]

@TK

I hate to burst your bubble, AC... but your system, if I am reading it right, is exactly the "Mendocino Motor" levitation system, also used by Steorn in the vertical plinth Orbos and also used by me in the video of the ES powered motor above.  I don't think you'll be able to patent it...

I figured someone might have patented something similar because it seemed like a good idea, I did a patent search but couldn't find anything. Although in a vertical orientation there is no actual shear force while on the horizontal axis there is. The shear force and the fact that any force could be balanced within itself is what inspired me. In any case it is known now so if someone can find some value in it then it's all good, it felt really good giving away my work even if it was patented by someone else. God I hope this isn't habitual or I'm really screwed, lol.

Edit... No my magnets are not arranged like that in the picture you posted, they are not one inside the other ie radial they are facing each other on each end on the axis of rotation. I made a pretty crappy picture below to show the layout, the load force is the shear force between the magnet faces acting downward. The magnet faces want to align with one another despite the fact the load is forcing it to move downward out of alignment. Think of a shear pin only the pin is a magnetic field.

BTW congrats on reading Moore's book. Not too many people know about his work. I guess you've seen my Dirod and some of the demos I've done with it.

I thought his book was awesome, it is one thing to understand something and quite another to explain it in terms anyone can understand. I have also built a small dirod, my variation of a charge doubler and a 24" Van de Graaff I need to brush some dust off of this week for my daughters science project. I just so happen to see the charge doubler up on a shelf collecting dust and will include a picture.
I imagine you have had your fair share of fun with leakage then?, it's kind of like herding cats.


AC

[Pirate88179]

With a lot of power you can levitate non-magnetic metals like copper or aluminum or brass with an AC electromagnet running at 50/60 Hz. The changing polarity of the field induces eddy currents in the metal piece and those eddys produce a magnetic field that opposes the field from the magnet (like polarities, switching very rapidly) so the metal plate rises up above the electromagnet pole pieces. John Hutchison did some of his fake videos like this.
It does take a bit of power though, and generates heat in both the electromagnet and the levitated metal. But no sensors or switching are needed, just the AC in the electromagnet. I used to demonstrate it with a "magnetic floor sweeper" we had at the lab, using a big variac for control and a chunk of aluminum plate for the levitated object. I don't have anything with the right pole pieces now, though.

TK:

OK, now this is interesting to me.  I understand the use of diamagnetic materials for the levitating disk, but, what if a real perm. mag were used?  I feel like you would need to be able to adjust inputs to get it to hover but, in theory anyway, the AC is doing the work of a pole reversal circuit no?  That is why I was thinking about being able to adjust the freq. to find the sweet spot balance point vs the weight of the hovering disk.  This approach, of course, would not "adjust" to different weights of the hovering disk but, I am still thinking that, along with the perm. mags to keep the disk contained, it might still hover?  Am I wrong in thinking this?

PS  I have always wanted a variac, we used to have a very nice one in my machine shop.  I can get a smaller one online for about $65.00.  It is on my list of wanted stuff.

A.C.

Good to see you here again, I believe it has been a while.

Bill

[TinselKoala]

TK:

OK, now this is interesting to me.  I understand the use of diamagnetic materials for the levitating disk, but, what if a real perm. mag were used?  I feel like you would need to be able to adjust inputs to get it to hover but, in theory anyway, the AC is doing the work of a pole reversal circuit no?  That is why I was thinking about being able to adjust the freq. to find the sweet spot balance point vs the weight of the hovering disk.  This approach, of course, would not "adjust" to different weights of the hovering disk but, I am still thinking that, along with the perm. mags to keep the disk contained, it might still hover?  Am I wrong in thinking this?

PS  I have always wanted a variac, we used to have a very nice one in my machine shop.  I can get a smaller one online for about $65.00.  It is on my list of wanted stuff.

A.C.

Good to see you here again, I believe it has been a while.

Bill

No, I guess I didn't explain it very well. It isn't a case of diamagnetism, it's a case of induced currents producing a field that opposes the AC EM's field. It's an AC version of the classic demonstration of dropping a magnet down a copper pipe. The AC EM field is alternating; this changing field induces the eddy currents that circulate in the plate sitting on top of the pole pieces of the EM. These eddies are changing direction just as the EM field is changing polarity. The eddies have their own associated fields which oppose, that is, they act in repulsion, to the changing field from the AC EM. This produces a net force that tends to force the plate away from the pole pieces of the electromagnet. The levitation height is dependent only on the amount of power you can put into your AC electromagnet, so you can control the height with the Variac feeding the EM. No sensors, no frequency changing, just current, the more the merrier.  It's still an unstable situation though, like balancing on a basketball; the levitated object will tend to move out of the sweet spot sideways if you let it.
Here, I found a video. Some people are calling this "diamagnetic" levitation, but it isn't an effect of a magnetic field being excluded, like the diamagnetic bismuth plate hovering over a permanent magnet. It is an eddycurrent effect, the induced eddys have their own magnetic field which acts in repulsion to the EM's field.
http://www.youtube.com/watch?v=1kUPibd9620

[TinselKoala]

@AC: I like your little ES machine. And I'd love to see your big VDG in operation, I've built a few of them myself and I'm getting ready to make another small one. The only ES machine I have here is my big Bonetti machine, packed away in its crate,  and yes... leakage is a problem, since the relative humidity here is almost always quite high. It's like 90 percent right now, no way I could get a static machine to work without drying the air. Damp air causes water to condense onto surfaces and that bleeds away the ES charge quickly and even prevents some machines from working at all, as you know.  The rest of my static machines and demo devices are stuck up in Ontario-- where they work great, especially in winter!

I still think your mag-bearing design is going to turn out to be a variation of the ones I mentioned, I don't quite get the image you drew. It would seem to me that the shaft would snap to one side or the other and stick there, and I don't quite see how it doesn't droop down from gravity and rest on the "pins" sticking out axially from the shaft. I'd like to see some good photos of the apparatus if you have them, or even better a video showing the parts and their orientations. Certainly I could describe the operation of the Mendocino Motor system in the same words you used in the first description. If not... maybe you've found a counterexample to Earnshaw's Theorem, and that would be a big deal indeed!

ETA: Oh, I think I may be starting to "get it". Those pins are fixed to the frame magnets and are pressing gently on the ends of the shaft, right? So this keeps the shaft from snapping to one side. And it's the fringing fields from the "backside" of the magnets rather than the facing sides that keep the thing from drooping down. More like my "nikolayev trailer hitch" with the big ring magnet and the smaller cylinder magnet, locking into place. Maybe?

[allcanadian]

@TK

@AC: I like your little ES machine. And I'd love to see your big VDG in operation, I've built a few of them myself and I'm getting ready to make another small one. The only ES machine I have here is my big Bonetti machine, packed away in its crate,  and yes... leakage is a problem, since the relative humidity here is almost always quite high. It's like 90 percent right now, no way I could get a static machine to work without drying the air. Damp air causes water to condense onto surfaces and that bleeds away the ES charge quickly and even prevents some machines from working at all, as you know.  The rest of my static machines and demo devices are stuck up in Ontario-- where they work great, especially in winter!

Oh the grief I have had with leakage, lol, one trick is to bake all PVC parts in the oven at low heat then coat them with a non-conductive clear coat. I also use a hair dryer on high heat to drive off residual moisture before start up. Leakage is like trying to carry water with a vegetable strainer but as you say in winter or before a thunder storm things really fire up.

ETA: Oh, I think I may be starting to "get it". Those pins are fixed to the frame magnets and are pressing gently on the ends of the shaft, right? So this keeps the shaft from snapping to one side. And it's the fringing fields from the "backside" of the magnets rather than the facing sides that keep the thing from drooping down. More like my "nikolayev trailer hitch" with the big ring magnet and the smaller cylinder magnet, locking into place. Maybe?

Your almost there just reverse it, the stabilizing pin is on the rotating shaft end and runs through the hole in the ring magnets which is why ring magnets must be used in this design. The whole premise is based on a pretty simple effect. Stick a magnet to a bench then place another magnet over the first in attraction. The faces of the magnets in attraction will want to "align" perfectly with one another. Now try and "slide" the top magnet off, we can see there is a magnetic shear force which is preventing the top magnet from sliding away and this is the same force which carries the load overcoming the force of Gravity only I use a 1mm gap to reduce the sliding friction. I simply use a magnet pair on each end of the shaft to balance the forces and the force causing the magnet faces to align is the force which counteracts Gravity. I made a better picture below which should explain things, two floating pins can be used however I use one because it's easier. The pins are simply to hold a position of equilibrium between the two magnetic fields and any contrivance could be used to replace the pins.

I still think your mag-bearing design is going to turn out to be a variation of the ones I mentioned, I don't quite get the image you drew. It would seem to me that the shaft would snap to one side or the other and stick there, and I don't quite see how it doesn't droop down from gravity and rest on the "pins" sticking out axially from the shaft. I'd like to see some good photos of the apparatus if you have them, or even better a video showing the parts and their orientations. Certainly I could describe the operation of the Mendocino Motor system in the same words you used in the first description. If not... maybe you've found a counterexample to Earnshaw's Theorem, and that would be a big deal indeed!

Earnshaw's theorem holds so far as I know, believe me I have tested it in every way possible, lol. However it is an observation of a phenomena without any specific details as to how it may be applied practically. My magnetic bearing capitalizes on the effects of Earnshaw's theorem as follows. Earnshaw basically said a system of magnets will always be unstable because there is no point of balance in the system and the magnets will always move towards one another. However what he did not say was that "the closer the magnets are to a point of equilibrium the smaller the force to hold them in equilibrium" which is my premise. Thus any load be it 1 Kg, 100 Kg or 1000 Kg may be applied to the shaft however the force to hold the load in equilibrium between the magnet pairs will not change because it is perpendicular to the load. I should note that I have since found a way to hold the equilibrium position without any pins or mechanical devices... a work in progress.

I should also note the load shaft is "floating" and one would think it would move about however with strong magnets and small gaps it is rock solid. I mean I can literally grab the shaft and hold the machine up in the air and shake it and it feels like a solid shaft making the connection to the frame.

AC