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Model Forum / General / Railroads / October 2004Building model maglev train
I am attempting to build a small scale model maglev train. Has this ever been done before? And if so are there any resources available where I could refer to? This is a picture of the cross section of a possible rail/car design, which I haven't tried yet. The rail is a 2x4 lined with permanent magnets on both sides and on the top. The car wraps around the 2x4 with permanent magnets attached to the car being repelled by the magnets on the 2x4. Does anyone know if this would actually make the car float without touching the 2x4? Or would the slightest touch to the car cause it to stick to one side of the 2x4? http://www.geocities.com/smpaladin/maglev.jpg Thanks for any feedback. > I am attempting to build a small scale model maglev train. Has this > ever been done before? And if so are there any resources available [quoted text clipped - 12 lines] > > Thanks for any feedback. You would only have to provide the right balance of magnetic strength to weight to achieve a floating balance. > > I am attempting to build a small scale model maglev train. Has this > > ever been done before? And if so are there any resources available [quoted text clipped - 16 lines] > weight to achieve a floating balance. > I think you would get a definite cogging effect, like turning a stepping motor. additionally you have no contact for conventional traction to propel the train. The prototype maglevs use coils (preferably superconducting but thats not needed for modeling) driven like a stepper motor for both lift and drive. Think of a linear stepper. Conceivably you could use permanent magnets in the train, and coils driven by a conventional stepper for the track and lift John H. > > > I am attempting to build a small scale model maglev train. Has this > > > ever been done before? And if so are there any resources available [quoted text clipped - 27 lines] > > John H. With the permanent magnets for lift, you must have one side of the track 'north' and the other side 'south' continuously. Using a direct linear stepper drive in that situation only allows you to go sideways two steps! Adding a longtitudinal linear stepper to the fixed magnet lift system will result in a bumpy ride because the drive magnetisim will affect the lift magnetisim. Back to the drawing board! How about magnetic lift and propeller drive(?) Regards, Greg.P. > > I am attempting to build a small scale model maglev train. Has this > > ever been done before? And if so are there any resources available [quoted text clipped - 15 lines] > You would only have to provide the right balance of magnetic strength to > weight to achieve a floating balance. Ummm... key word here being *only*. Magnetic force is extremely non-linear with distance and direction. 12-inch-to-the-foot mag-levs have fairly sophisticated closed-loop control circuitry governing electro-magnets to maintain correct levitation distance. Permanent magnets *might* work if you get the strengths, car weights, and C.G. just right. I think you'll have to run some experiments. How to you envision the propulsion system working? > > > I am attempting to build a small scale model maglev train. Has this > > > ever been done before? And if so are there any resources available [quoted text clipped - 24 lines] > > How to you envision the propulsion system working? This project is actually part of my senior project for high school. I have never really worked with magnets, electromagnets, or linear motors before, so I may be underestimating the difficulty of accomplishing this whole thing. This picture shows once again the cross section of the rail/car design, except now there is an electromagnet below the car, inbetween the two permanent magnets. The electromagnet switches polarity so that it is attracted and repelled by the permanent magnets on the track, moving it forward, and it keeps switching polarity at the right time to keep the car moving foward. I would need some kind of switch to detect when to change the polarity of the electromagnet. http://www.geocities.com/smpaladin/maglev2.jpg > This project is actually part of my senior project for high school. I > have never really worked with magnets, electromagnets, or linear [quoted text clipped - 10 lines] > I would need some kind of switch to detect when to change the polarity > of the electromagnet. Others have suggested "faking" it which is perfectly ok for modeling in general....but not for a HS project. As far as controling your mag coils.... The drive IC and its associated Hall Effect switches from an old floppy drive wiuld be a good starting point. You may be able to use coils from this source as well. Anyway its free starting point. You are going to have to study up on exactly how these drive chips function and how Hall Effect switches work to adapt them, but it should work. One problem I see is having the coils and control in the train rather than the track. There is no contact to provide control or power so wireless control and battery power would be required. If the permanent magnets are in the train and the coils in the track its simpler, but requires more coils and wiring. Remember that you must provide at least lift to every car, not just the "engine". For more help offgroup, e-mail me. John H. > Others have suggested "faking" it which is perfectly ok for modeling in > general....but not for a HS project. [quoted text clipped - 17 lines] > > John H. I would greatly prefer having coils in the track to provide the propulsion of the car, rather than having the coils, power, sensors mounted on the car, since that would make it much heavier. But as you point out, having electromags in the track would require large amounts of coils and wiring. As of now, since I am only trying to demonstrate the principles of a linear electric track combined with levitation, I am planning to create a "test" track, maybe a couple of feet in length. The questions are will I be able to buy or create electromagnets strong enough to pull the car? From what I plan, if I use Hall Effect sensors (which I am not at all familar with) to detect when the car is over a specific coil, and then to switch that coil's polarity to attract or repel the car, I would need a Hall Effect sensor to accompany each row of coils for the entire length of the track. So right now I see two distinct parts of the maglev, 1. The levitation part, which involves permanent magnets lined along the track and under the car to levitate it, and 2. The propulsion part, having coils either on the car or on the track, for which I'm leaning towards having the coils on the track. > I would greatly prefer having coils in the track to provide the > propulsion of the car, rather than having the coils, power, sensors [quoted text clipped - 4 lines] > am planning to create a "test" track, maybe a couple of feet in > length. you would only need about ten coils per foot of track > The questions are will I be able to buy or create electromagnets > strong enough to pull the car? Yes, the coils from floppy drives should be good for a few ounces of car, and are free. So are all the Hall switches you need as they are on the same little board as the coils. Hall switches are (simplified) semiconductors, like transistors, which are magnetic sensitive. You will probably need a single power transister current booster on each phase to run as many coils as you will need. From what I plan, if I use Hall Effect > sensors (which I am not at all familar with) to detect when the car is > over a specific coil, and then to switch that coil's polarity to > attract or repel the car, I would need a Hall Effect sensor to > accompany each row of coils for the entire length of the track. True, but you would switch a group of one third of all coils together, so only three sets of coils. > So right now I see two distinct parts of the maglev, 1. The levitation > part, which involves permanent magnets lined along the track and under > the car to levitate it I think you will find that permanent magnets in the track won't work for lift because of the cogging effet, and interfering action with the coils magnetics. 2. The propulsion part, having coils > either on the car or on the track, for which I'm leaning towards > having the coils on the track. With no switching (ie coils energized but steady state) you would get your lift. Think of a helicopter in hover, then as coils shift to the helicopter moving off. John H. > > I would greatly prefer having coils in the track to provide the > > propulsion of the car, rather than having the coils, power, sensors [quoted text clipped - 36 lines] > > John H. Here is a possible design that I've come up with for the propulsion, disregarding the levitation. http://www.geocities.com/smpaladin/maglev6.gif Since I'm relatively new to electronics, the above design may not even work in principle. When the track is turned on, all of the coils on the track would be turned on and have N polarity. The only time a coil would have S polarity is when the hall sensor behind it is turned on by a magnetic field. That magnetic field is caused by the permanent magnet with polarity N that's attached beneath the "car". Once the "car" moves past that hall sensor, it turns off, which makes the coil in front of it go back to N polarity. This cycle repeats over and over. The key component here is the yellow switch that reverses the polarity of the coil as long as a smaller current is applied to it. Is there even a type of switch that would do that? If so, what is it called and where could I get more information about it? Also, does anyone know where I could buy cheap permanent magnets in large numbers? > Here is a possible design that I've come up with for the propulsion, > disregarding the levitation. [quoted text clipped - 17 lines] > Also, does anyone know where I could buy cheap permanent magnets in > large numbers? Both coils and permanent magnets have both N and S ends on each ( I don't know of anyone who has made Monopoles yet) Coils and magnets would be positioned at right angles to the track (vertical). As far as switches for the coils are concerned, at low current, simple binary buffers (4, 6 or 8 per IC). at higher current a two transister pair would work. Permanent magnets are in every stepper motor in every dead floppy disc ever made, usually in a disc form. that can be cut or broken (scribe and snap like glass) to get smaller magnets. Otherwise your design looks OK. John H smpaladin@yahoo.com (smpaladin) wrote in message > Also, does anyone know where I could buy cheap permanent magnets in > large numbers? Try All Electronics or American Science and Surplus http://allelectronics.com/ http://www.sciplus.com/ to name a couple. Google-up the electronic surplus places. And just for grins, a link to diamagnetic levitation: http://www.scitoys.com/scitoys/scitoys/magnets/suspension.html -dave Search for the terms: halbach magnet array levitation . > > > I am attempting to build a small scale model maglev train. Has this > > > ever been done before? And if so are there any resources available [quoted text clipped - 17 lines] > > Ummm... key word here being *only*. You noticed that too huhh - isn't language fun :-) > Magnetic force is extremely > non-linear with distance and direction. 12-inch-to-the-foot mag-levs > have fairly sophisticated closed-loop control circuitry governing > electro-magnets to maintain correct levitation distance. Permanent > magnets *might* work if you get the strengths, car weights, and C.G. > just right. I think you'll have to run some experiments. I'm sure it could be done using 'suck it and see' methods - a model doesn't have to carry varying loads. > How to you envision the propulsion system working? See my other post. >>>>I am attempting to build a small scale model maglev train. Has this >>>>ever been done before? And if so are there any resources available >>>>where I could refer to? >>Magnetic force is extremely >>non-linear with distance and direction. 12-inch-to-the-foot mag-levs >>have fairly sophisticated closed-loop control circuitry governing >>electro-magnets to maintain correct levitation distance. Permanent >>magnets *might* work if you get the strengths, car weights, and C.G. >>just right. I think you'll have to run some experiments. I predict, that using permanent magnets ALONE, you will not be able to get the "train" to freely levitate without flipping or twisting over. No matter how many permanent magnets you use, and no matter how they are mounted to the train and supporting tracks, somehow, the train will always be unstable and not float at all. If this were to be possible to do (using only permanent magnets), we would have countless magnetic floating toys and gadgets already. I hope my prediction is proven false. Arnie Morscher > >>>>I am attempting to build a small scale model maglev train. Has this > >>>>ever been done before? And if so are there any resources available [quoted text clipped - 18 lines] > I hope my prediction is proven false. > Arnie Morscher I think it's possible if the vehicle wraps around a "T" shape track. Certainly there would need to be side magnets on the vehicle to keep it centered but with careful balance of lifting magnets and weight only a non-magnetic safety tang/strip under the "T" head would be sufficient. >>I predict, that using permanent magnets ALONE, you will not be able to >>get the "train" to freely levitate without flipping or twisting over. No [quoted text clipped - 12 lines] > centered but with careful balance of lifting magnets and weight only a > non-magnetic safety tang/strip under the "T" head would be sufficient. I maintain my prediction, the intial condition remains, "using permanent magnets ALONE", thus, no "non-magnetic safety tang/strip" thingy is allowed. Please, Please, someone prove me wrong. We could make some money. Arnie Morscher > I maintain my prediction, the intial condition remains, "using permanent > magnets ALONE", thus, no "non-magnetic safety tang/strip" thingy is > allowed. > > Please, Please, someone prove me wrong. We could make some money. Look up Earnshaw's theorem, and then some of the ways people have found to work around it. > > I maintain my prediction, the intial condition remains, "using permanent > >> magnets ALONE", thus, no "non-magnetic safety tang/strip" thingy is >> allowed. >> >> Please, Please, someone prove me wrong. We could make some money. > Search for the terms: halbach magnet array levitation ..... I did. Very interesting. I like it. But: "When the train car is at rest (in a station), no levitation occurs, and the car is supported by auxiliary wheels." So, my prediction still holds, but seems to be threatened by very smart scientists and engineers. > Look up Earnshaw's theorem, and then some of the ways people have found > to work around it. Ah excellent. So, Earnshaw says that my prediction is correct, but then easily defeated by simple things like spinning. I love this spinning toy: http://www.levitron.com/ Very interesting stuff. I think I will by myself a levitron for christmas. Thanks for all the cool links, Arnie Morscher >>> I predict, that using permanent magnets ALONE, you will not be able to >>> get the "train" to freely levitate without flipping or twisting over. No [quoted text clipped - 20 lines] > > Arnie Morscher Your statement, as presented, is likely true. However, no mag-lev system, model or prototype that I've ever heard of does NOT use some form of "non-magnetic safety tang/strip thingy" (read "guideway"), if for nothing else than to hold the magnets (permanent or electromagnetic). Usually these are either a "T" shape as mentioned, or a "U" shaped channel. The train either sets in the "U" or straddles the "T". Mag-levs usually configure their magnet arrays in "repulsive" mode, as it is inherently stable. The car will self-levitate at a height where gravity and magnetism balance. A few mag-levs have been built using "attractive" mode, but these are inherently unstable, and require elaborate feedback to control the strength of the magnets, adding much complexity. It CAN be done, but why bother? Dan Mitchell ============ >I am attempting to build a small scale model maglev train. Has this >ever been done before? And if so are there any resources available [quoted text clipped - 12 lines] > >Thanks for any feedback. Hi The principles on which this could be done were posted in an article in the British model railway magazine Model Railways in the 1970's by no lesser person that Porfessor Laithwaite. Esentially the method was as previously posted of a long linear motor providing both lift and propulsion. The frequency the switching of the coils setting the speed. I have a copy of the article some where but it may take a while to find. Regards Tony Cane > I am attempting to build a small scale model maglev train. Has this > ever been done before? And if so are there any resources available [quoted text clipped - 12 lines] > > Thanks for any feedback. If you're thinking of plain flat magnets, such as are used for closet latches, it won't work. These are magnetised crosswise, so that there's an N and one end (or side) of the magnet and an S on the other. Move the train slightly, and you'll have N poles on the train opposite S poles on the track, and click! A locked in place train. The only way to make it work is to arrange the magnets such that only S, say, on the train and the track face each other, the N poles facing the other way. Then the train will float. In fact it will be impossible to make the train and the track latch onto each other. You could set flat magnets on edge in grooves in the top surface of the track and along its sides, with their S poles facing up and out, with a corresponding arrangement on the train. Flat magnets with S on one surface and N on the other would be simpler (just glue them in place), but AFAIK there aren't any available, leastways not cheap ones. The reason real maglev uses supercooled electromagnets is to produce sufficient field strength to lift the train, and to make it possible to switch fields on train and track slightly out of phase to move the train along the track. You'd have to find some other way to move your train - maybe air blown through holes underneath then train? HTH&GL Do like the rest of us do when we build simulations of the real world,,,,, FAKE IT!!! Seriously, get like a hot wheels car set and use those wheels under the "MAGLEV" train. Now for a powered unit...hmmmmm I got it.... Go to a toy store and buy a "MINI RACER" these are very little R/C racers about 2 inches long maybe...only about $20 US. put it together have fun... send us a photo Good luck from the U&I rr in Central NY > I am attempting to build a small scale model maglev train. Has this > ever been done before? And if so are there any resources available [quoted text clipped - 12 lines] > > Thanks for any feedback. > Do like the rest of us do when we build simulations of the real world,,,,, > FAKE IT!!! > Seriously, get like a hot wheels car set and use those wheels under the > "MAGLEV" train. Now for a powered unit...hmmmmm That doesn't really cut it for senior high school projects. My apologies to you, Mark. I read the post in here thinking you were building , well a model like the rest of us. It's what the newsgroup is about, You didn't mentioned it was a science project, which is cool, but it's a tiny fact left out. anyway, enjoy the newgroup and good luck. > My apologies to you, Mark. > I read the post in here thinking you were building , well a model like the > rest of us. It's what the newsgroup is about, You didn't mentioned it was > a science project, which is cool, but it's a tiny fact left out. anyway, > enjoy the newgroup and good luck. Hey Mr Leftie: 1) This whole question about modeling a maglev train was raised by smpaladin@yahoo.com, not by me. http://tinyurl.com/3zm8y 2) smpaladin@yahoo.com, who originally questioned about building a maglev model train, said that this was a science project: http://tinyurl.com/69v5y You have two incorrect facts in your message: 1) it wasn't me building the maglev model (I'm working on a section tool house and a yard office right now), and 2) The "tiny fact" that it was a science project was not left out of the discussion before you replied. If you're going to come back with a smart-a.s answer, at least try to get your facts straight. I've finally bought or ordered and recieved all the parts that I need to begin the track and train: Hall sensors, power transistors, sheets of styrofoam, two small wood beams, ceramic wire, magnet strips. I'll keep this thread posted on my progress. >I've finally bought or ordered and recieved all the parts that I need >to begin the track and train: Hall sensors, power transistors, sheets >of styrofoam, two small wood beams, ceramic wire, magnet strips. > >I'll keep this thread posted on my progress. It can be done. The only questions are how easily, with what hardware, and how affordable? Good luck and I wish you success. I look forward to reading your progress. Jay All the world's a stage - and everybody's a critic. All messages from domain hotmail.com have been blocked. Good Day, I saw your post after it was almost of this list. Revell made a model of the German Maglev,in HO. I have one on my layout but it only runs about 5 feet.It is part of my central rail,bus,maglev,subway and monorail terminal. I had to scratch built about 3 feet of rail. I used a system of magnets,3 strip type.One on top of the rail and one on each side.They are set so they repel and make the maglev float. I use a fine fish line to pull the maglev back and forth,the line goes down under the layout to a motor which moves the line back and forth.Two photo switches start and reverse the motor. The maglev leaves the terminal the hides behind a group of buildings.A timer then kicks in and the maglev reappears. UNCLE YESTERDAY WAS TODAY IS TOMORROW WILL BE |
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