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Post by OziRiS on Feb 24, 2015 12:07:22 GMT
And yes seriously I do keep a bunch of magnets on my desk, as I am playing around with a levitation track.... I am determined to build one. My main problem is balancing the "car" on the track so it stays there and doesnt fall off the sides. So finding a balance point "Inside" a magnetic field is of great interest to me... Not really a technologically advanced solution, but... Guard rails...? |
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Post by silverdragon on Feb 25, 2015 10:16:39 GMT
Heh heh heh.. I was ahead of you on that, but there is an idea that fits with what I was thinking..
I have utilised a toy boat hull, and a "V" formation track.
The magnets push up and slightly sideways towards each other at the same time...
It looks to be working, sort of, but you idea of guard rails is good...
If I put a fence at each side, and maybe a small wheel that in normal balance is not quite in contact with that fence, it can be used to "steer" this "ship" on corners where they ships momentum is greater than magnets can repulse.
You have an idea I can use.
I can now go forward quite well if I think on the lines of a Dry "Canal" using magnetic force rather than Water to float this boat....
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Post by the light works on Feb 25, 2015 21:43:43 GMT
I have two magnets on my desk right now. Can I just check.. What you are trying to do is "balance" an object in a magnetic field so it stays where it is between the two on the fine point where it has equal attraction to both magnets. Is this the same as trying to balance a sharpened pencil on its point.... Can be done, but the slightest movement in either direction is a fail.... And yes, this is why I come here as well. This is twirgling my knurd. And yes seriously I do keep a bunch of magnets on my desk, as I am playing around with a levitation track.... I am determined to build one. My main problem is balancing the "car" on the track so it stays there and doesnt fall off the sides. So finding a balance point "Inside" a magnetic field is of great interest to me... But that is sideways to the point under discussion, and yes, this is interesting me in a weird way?... I believe typically the way is to make the magnetic field so it creates an interlocking structure. the most simple would be to make the field so it has a channel down the middle, by setting additional magnets to form a guardrail system. |
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Post by GTCGreg on Feb 25, 2015 21:57:06 GMT
Heh heh heh.. I was ahead of you on that, but there is an idea that fits with what I was thinking.. I have utilised a toy boat hull, and a "V" formation track. The magnets push up and slightly sideways towards each other at the same time... It looks to be working, sort of, but you idea of guard rails is good... If I put a fence at each side, and maybe a small wheel that in normal balance is not quite in contact with that fence, it can be used to "steer" this "ship" on corners where they ships momentum is greater than magnets can repulse. You have an idea I can use. I can now go forward quite well if I think on the lines of a Dry "Canal" using magnetic force rather than Water to float this boat.... Just a thought. Make your side guard rails out of wood, plastic or some other non-ferrous material. Then glue bismouth foil to the guard rails. Mount two magnets on the front and back sides of your carts. The bismouth will repel the magnets regardless of their polarity and should keep your cart in the center of the track. In fact, if you make the roadbed out of bismouth, all you need is magnets on the cart bottoms and no magnets on the track at all. The carts should just float above the track. Bismouth Foil |
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Post by the light works on Feb 25, 2015 22:11:24 GMT
Heh heh heh.. I was ahead of you on that, but there is an idea that fits with what I was thinking.. I have utilised a toy boat hull, and a "V" formation track. The magnets push up and slightly sideways towards each other at the same time... It looks to be working, sort of, but you idea of guard rails is good... If I put a fence at each side, and maybe a small wheel that in normal balance is not quite in contact with that fence, it can be used to "steer" this "ship" on corners where they ships momentum is greater than magnets can repulse. You have an idea I can use. I can now go forward quite well if I think on the lines of a Dry "Canal" using magnetic force rather than Water to float this boat.... Just a thought. Make your side guard rails out of wood, plastic or some other non-ferrous material. Then glue bismouth foil to the guard rails. Mount two magnets on the front and back sides of your carts. The bismouth will repel the magnets regardless of their polarity and should keep your cart in the center of the track. In fact, if you make the roadbed out of bismouth, all you need is magnets on the cart bottoms and no magnets on the track at all. The carts should just float above the track. Bismouth Foilin the US, a person can acquire bismuth shot for reloading shotshells, which would theoretically produce a more robust maglev cushion. - not sure if it is available in the UK. edit: this based on a wrecking yard worker who posed on the Disco boards that the image of a wrecking yard elecromagnet picking up a car by the roof was false because the sheet metal of the roof was too thin for the magnet to "grip" effectively. |
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Post by GTCGreg on Feb 26, 2015 1:21:00 GMT
edit: this based on a wrecking yard worker who posed on the Disco boards that the image of a wrecking yard elecromagnet picking up a car by the roof was false because the sheet metal of the roof was too thin for the magnet to "grip" effectively. I've personally seen cars picked up by their roofs using a junk yard magnet. What I don't know is if the engine/drivetrain had already been removed. Bismuth is a very brittle metal. I don't know how formable bismuth foil is, but I do know they sell it. |
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Post by the light works on Feb 26, 2015 1:37:21 GMT
edit: this based on a wrecking yard worker who posed on the Disco boards that the image of a wrecking yard elecromagnet picking up a car by the roof was false because the sheet metal of the roof was too thin for the magnet to "grip" effectively. I've personally seen cars picked up by their roofs using a junk yard magnet. What I don't know is if the engine/drivetrain had already been removed. Bismuth is a very brittle metal. I don't know how formable bismuth foil is, but I do know they sell it. the way the guy talkes, I suspect the ones you saw may have had the engine and drivetrain removed. the salvage yard I take my metal to only uses the magnets for small scrap - they use grapples for anything big. that would be another argument in favor of using bismuth shot to make the roadbed. - no formability challenges. |
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Post by silverdragon on Feb 26, 2015 7:09:09 GMT
You lot are getting to advanced too quick....
I just want a quick proof of concept that magnets will be enough to float the thing, I have yet to work out propulsion.
So far its a sort of gravity feed... by tilting the track...
Its a project I dont mind playing with a while yet.
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Post by GTCGreg on Feb 26, 2015 14:51:23 GMT
You lot are getting to advanced too quick.... They're just brain farts. Feel free to explore or ignore at your discretion. |
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Post by silverdragon on Feb 27, 2015 7:15:05 GMT
I will be taking them all on board for future use, I just havnt got that far yet.
Did you all solve the original question yet by the way?...
I was thinking I may have gone off on a tangent myself.
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Post by c64 on Sept 2, 2015 13:36:30 GMT
With regard to iron, I think the basic rules on attraction are based upon flux-line density and NOT divergence/convergence. In other words, where ever the flux lines are more closely packed together (even if parallel), you get a stronger magnetic attraction? So, if that's true, and it really has nothing to do with the fact that the flux lines are converging or diverging (it is, instead, based solely upon density of line population) then, in a parallel plate arrangement of two poles of a magnetic system, the attraction of iron to whatever side the iron is closest, is based on the lines of flux being packed together close enough to make the strength necessary to attract the iron, and not because the lines need to be converging or diverging (as stated, they could even be parallel). So, I think my question can best be stated as, "do parallel lines of magnetic flux, tightly packed together, create magnetic attraction, OR do the lines of magnetic flux need to be converging/diverging to create attraction of iron?" Also, if close parallel lines cause attraction, would lines packed together even closer (near by) make the iron ball move toward the more densely packed lines? Thanks for the video! Cool stuff! This is correct. The magnetic "lines" actually fight each other trying to gain the most possible distance between each other. The reason is that they distract each other since they have the same direction. N-N and S-S will distract each other, a basic rule of magnetism. The key word you are looking for is "homogeneous", not uniform. You can't make homogeneous magnetic fields using permanent magnets at all. There is a way to create a limited homogeneous field for experiment purposes. You need two electro magnets, two coils called a "Helmholz pair" or "Helmholz coil". The idea is that inside a long coil, the field lines are in parallel in the middle of the coil:  The reason is simple, the field lines must all run through the coil and the dimension of the coil traps them so they can't diverge. But such a long coil is inconvenient since you can't reach inside to make your experiments. If you cut out the middle of the coil, you can reach in and if the remaining ends of the coil are not too far apart, you have an almost homogeneous field. A Helmholz pair (or -coil) is made of two identical coils facing each other with the distance between them is exactly half the diameter of the coils:  If you imagine a box between the coils which is 1/3 by 1/3 by 1/3 of the gap width, the field inside this imaginary box is as perfectly homogeneous as possible in a real world. There is an easy way to DIY one. Go to a recycling yard and find two identical CRT TVs or monitors. At least two of the same brand and size. Just behind the front of the TV there is a black hoselike think snaking around the large side of the picture tube. This is the degauss coil which is usually plugged into the main board near where the power cable enters the TV. unplug it and take it out. Now you have two neat coils you can plug directly into the mains. Wrap them in several layers of electricians tape while shaping them to a round ring. Attach a power plug with switch or use a switched power bar to each coil and you are almost done. You can use a wooden board which is as wide as the diameter of the coils to pull them over and fix them to the board with the correct distance. Then whatever you put onto the middle of the board is inside the homogenous part of the field so you can play with your metal bits. Of course the field is AC but this doesn't matter much for basic experiments to attract iron. It is pretty strong, you might want to regulate it with an adjustable transformer. You can also try to get a HVDC PSU on eBay. |
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