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Do you think the Inductrack technology devoloped for maglev trains and firing misiles can be used to power a vehicle? I mean something like this:

[IMG:760:542]http://img100.imageshack.us/img100/3633 ... opyru8.jpg[/img]

[IMG:760:542]http://img211.imageshack.us/img211/9428 ... opyjw5.jpg[/img]

You´ll need a small external power sorce to get it spinning and then apply power to the coil and off you go You´ll also need small wheels to keep the magnets from touching the coil when it´s sitting still...

Would it offer advantages (ex. zero friction, less weight) over traditional electro motors? Would it work? I´m sorry If it´s been talked about before

Well, I agree: it can be used. And, yes, if you're sorry because it has been posted before, then you should be sorry (I don't see why, but suit yourself). Here is what was posted:

Halbach array Nice link, it explains how to build a monopole "for engineers", a thing that is "forbidden" in physics: I built my own and is on the fridge door. Notice all the magnetic flux is confined to one side of the circle only. The magnet I have on the fridge only sticks to the door by one side, the other side exerts no magnetic force at all (or is too feeble to allow it to stick to the door). Most of my friends that have studied physics are amazed by it. I use it frequently to explain the differences between physics and engineering...

I haven't tried to make a circular one, but without empiric experience I dare to guess you don't need the "little wheels" you mention, because the flux is symmetrical:


Inductrack As you say, it's easy to imagine the track being bent in a circular shape and use it as a wheel. Notice it self centers so, again, I would say no need for little wheels:


Slightly OOT, SKF magnetic bearings (mostly used on satellites gyroscopes) As you can imagine, you can substitute this kind of magnetic bearing for the array shown in the first picture. I wonder why nobody has done it:


BTW, that was a cool thread, I still get mail from people that stumble upon it: Spherical wheels The couple of links I repeat above are in page 2. This was the first thread in which I made a mistake... (maybe the only one ). In it there is also a link and a photo that I repost about the Jhon Hopkins wheel, with a complicated paper about how to spin a wheel through the use of electric fields:

Jhon Hopkins sphere

I said that I´m sorry because some people around here obviously get uppset If you ask something without searching for it previously

Thanks for the links, I´ll check them out.
So it´ll work but what do you think is there any advantage over the cuurent brushless motors? I definitly think it´ll have less friction

I´ll run simulation on my friend´s Comsol Multiphysics in Januari (he´s not around now) and see what happens

I just can't help wondering what sort of interactions would happen between cars in bumper-to-bumper traffic.

Also, those maglev rails are accurate to +/- 2mm per kilometer. Car wheels has to deform more than that.

Would it be so hard to shield the magnets from the "outside world"? I don´t think so, dont know how much would it weight though

"Also, those maglev rails are accurate to +/- 2mm per kilometer. Car wheels has to deform more than that."-I dont really understand what you mean here (my english maybe)

And Ciro, about the small wheels... the thing levitates only with current in the coil and with enough speed, when you sit still there is no current and no speed so you have no levitation

That's true, tomislav. However, couldn't you use an "opposite" Halbach array, as a hub, on the center of the first image of my previous post? I thought that was evident...

In that case, as I "see" it, you don't need energy to levitate the rim. Besides, it does not matter how much the tire deforms, the hub and rim don't deform in an appreciable way. Finally, the interference won't matter, I think.

So, you don't need a rail: you "wrap up the rail" around the Halbach, as I commented on the second photo: you create a "circular track" inside the wheel, that is, a magnetic bearing. It's like the difference between rolling something on logs (like Egyptians allegedly did), which roughly correspond to the second photo, and rolling something using a bearing, which corresponds to the first photo. That's what I "get" from your post, at least.

Maybe I'll try to build a bearing like that during these vacations. I haven't seen one before. Have any of you? I imagine that the problem will be the simmetry in the direction of the axle... Maybe (double maybe!) it will behave like a lubricated bearing: the more the hub comes closer to the rim, the more repulsion you get among them.

Anyway, I'll keep you informed.

EDIT: After thinking for a while, that idea is irrealizable. Any moving magnetic field will create a force. Perhaps as a torque coupling... but definitely, not for bearings, unless you use it as a an electric motor, as checkered mentions.

Quite a while

ago I did some cursory calculations (on paper) on coil- and railguns, just for the heck of it. Not an altogether uninteresting field of research. Anyway, if you don’t want to be entirely dependent on your friend’s Comsol Multiphysics, there are also electromagnetics programs available under the GNU open licence. The tradeoff being that you need to invest time in getting your head around programs that have been created with limited (temporal) resources, of course. You might want to look if these amount to something that might help you along, or a hindrance (be extra careful to examine what other programs you might need to run these):

FEMM by David Meeker – link
Radia by ESRF – link
GetDP/gmsh combo by Patrick Dular, Christophe Geuzaine and Jean-François Remacle – link

I’m sure there are others as well. I don’t know if it’s surprising or not, but RC applications are very advanced in electric motors these days ... they did the brushless thing, and some other stuff as well. I did find at least one example of a home built Halbach array thingy online, by this Swiss guy Wolfgang (pictures linked from his site also):

Halbach innenläufer - link




But I do think that companies big and small (Siemens VDO, L2ES, TM4, Mitsubishi, PML Flightlink among many others) are all working on integrated wheel motors, be they Halbach array or not. Look into those as well, albeit as usual when it comes to corporate stuff, information can be scarce.

Halbach Array Calculations Paper:
http://www-sldnt.slac.stanford.edu/nlc/ ... -067_2.pdf

The more I

look into this, the more obvious it becomes that practically all major car manufacturers have done at least one hub motor prototype thus far (to the extent I didn't deem it necessary to link everything I found here). They started to appear about ten years ago and noe it looks as if time is ripe for large scale commercialisation. If I'm not wrong, you'll have no trouble in securing such a unit in a couple of years, unless you don't want to build one yourself. You might also want to investigate Solomon Technologies, Wavecrest Labs BluWāv and UQM Technologies while you're at it. This is what Mitsubishi's MIEV unit looks like:



Images linked from speedsportlife.

Then on to some theory: Three-Dimensional Field Solutions for Multi-Pole, Cylindrical Halbach Arrays in an Axial Orientation, NASA/TM—2006-214359 - link, PDF, some basic theory and equations. Ironless wheel motor for a direct drive vehicle application (Greaves, Simpson, Guymer, Walker & Finn), SERG, University of Queensland - link, PDF, many design aspects considered, i.e. efficiency, basic requirements, sizing equations all of which can prove to be useful. The Rocky Mountains Institute Hypercar project is worth a look, it has evolved into some kind of an idea to produce carbon fiber elements. The Queensland Uni UltraCommuter didn't seem very active, but can be interesting as well. Design of an electrical machine with integrated flywheel (Colotti, von Burg), Aspes AG - link, PDF, a Halbach array envisioned in a kinetic energy storage unit, or in a F1 context, the KERS unit.

And a couple of commercial programs (software packages, rather) which look interesting as well: Magsoft and Ansoft Maxwell 3D.

Edit: Further interesting papers in

Development and Testing of an Axial Halbach Magnetic Bearing, NASA/TM—2006-214357 - link, PDF
Ambient-Temperature Passive Magnetic Bearings: Theory and Design Equations, LLNL, 1997 - link, PDF
Ironless High-Power-Density Permanent Magnet Electric Motors Designed for Emissionless Aircraft Propulsion, Glen Glenn AEFT, NASA - link
The Gemini electric motor (link) apparently shows some promise in increasing efficiency (even twofold) but I didn't look into it yet in such depth as to perceive to what degree this has been validated.

Edit 2: Here's one company more: e-traction (link), they provide quite specific data on their motors and have some working examples (mainly in heavy vehicles, but lighter ones are in the works).

Thanks for the links guys, great reading
I´ll post results from the simulation after I run it, for everyone interested...