Large scale electromagnetic hover sculpture HELP [really quite ]

[s2mega]

large scale electromagnetic hover sculpture... HELP! [really quite urgent...]

Hi all!

i'm a design student, trying to find out about the feasibility of a project I'm working on...

http://i.1asphost.com/s2mega/magnet.jpg

the concept goes like this: a "bowl" structure, lined with electromagnets, all with the same polarity facing towards the centre of the bowl, levitates a large chrome-finished ball (built as light as possible from perhaps fibre-glass or any other light-weight material, to lessen the load on the mechanism), within which is magnet/electromagent constructs which give the object an opposite polarity, which brings me to my first question:

1. is it possible to have entirely a single polarity on an magnetically charged object? either negatively or positively... if it is impossible then...

a second concept involves a cable running from the base of the ball to the base of the bowl, holding it while its negative pole is on the underside of the ball, repelled by the positive pole facing up at the bottom of the bowl, but held in place by the cable. theoretically i think is is quite sound... i hope.

2. is this feasible? and,

3. if so, what kind of power drain would be needed to power such a construction? would it be feasible as a sculpure?

4. is there a magnetic-field retardant material that could force the field to not radiate off the side of the sculpture, possibly ripping zips and gold teeths off unsuspecting viewers?

5. how big would the magnetic field be if one of this magnitude was constructed? with shielding? without shielding?


a professor in physics informed me about the concept of an induction coil, where a coil is twisted in such a way that the topmost last turn is REVERSED, and that, he says, creates a zone of zero force (or something similar) in the centre of the coil, where a metallic object (non-magnetic) may be levitated.

6. is an induction coil feasible on such a large scale? and its implications? power drain?


thank you so much for enduring throught this rather long problem, any any any assistance that you may offer would be rewarded with my eternal gratitude! it is rather urgent, too...

thank you again, and in advance!

 

[pervect]

the answer to at least part of your question is easy. Nobody has discovered any magnetic monopoles to date. There are some interesting theoretical speculations about them, but they're not something that one is going to be able to find and produce to put into an art sculpture.

 

[Locrian]

Hi all!

i'm a design student, trying to find out about the feasibility of a project I'm working on...

http://i.1asphost.com/s2mega/magnet.jpg

the concept goes like this: a "bowl" structure, lined with electromagnets, all with the same polarity facing towards the centre of the bowl, levitates a large chrome-finished ball (built as light as possible from perhaps fibre-glass or any other light-weight material, to lessen the load on the mechanism), within which is magnet/electromagent constructs which give the object an opposite polarity, which brings me to my first question:

1. is it possible to have entirely a single polarity on an magnetically charged object? either negatively or positively...

No, it is not possible. Or, to be more accurate, no one else has ever managed it. If you succeed, expect an A and a nobel prize.

if it is impossible then...

a second concept involves a cable running from the base of the ball to the base of the bowl, holding it while its negative pole is on the underside of the ball, repelled by the positive pole facing up at the bottom of the bowl, but held in place by the cable. theoretically i think is is quite sound... i hope.

Eh? If the negative pole is on the bottom of the ball and the positive pole is on the top of the bowl they will attract. I'm not sure what you could mean here. I can say that trying to get a magnet to "float" on another magnet, almost no matter how you rig it up, is extremely difficult. I would expect failure, even with a lot of work.

4. is there a magnetic-field retardant material that could force the field to not radiate off the side of the sculpture, possibly ripping zips and gold teeths off unsuspecting viewers?

The force of a magnet tends to fall off roughly as distance cubed. I don't think gold is even magnetic, is it? In any case, I wouldn't worry about it. You won't need to make it that strong. I had the misfortune of working with really really strong magnets recently, and they are awful, but you are dealing with electromagnets. Just don't turn the voltage up so high.

a professor in physics informed me about the concept of an induction coil, where a coil is twisted in such a way that the topmost last turn is REVERSED, and that, he says, creates a zone of zero force (or something similar) in the centre of the coil, where a metallic object (non-magnetic) may be levitated.

6. is an induction coil feasible on such a large scale? and its implications? power drain?

Well the power drain will depend on how much voltage you apply. This sounds like the most reasonable of all your ideas, but will still be a lot of hard work, and I can't say how it will turn out.

thank you so much for enduring throught this rather long problem, any any any assistance that you may offer would be rewarded with my eternal gratitude! it is rather urgent, too...

thank you again, and in advance!

If it is urgent, I think you may be in a bind. Good luck though

 

[pervect]

It's indeed impossible to do magnetic levitation with static fields, this is known as Earnsahw's theorem. With feedback though, this theoretical problem isn't necessarily an obstacle, but there are a lot of design difficulties. I have a lot of doubt about the proposed "bowl" project, though. Basically it's going to be technically challenging, so the person who builds it is going to need to be able to do his own design work.

One thing that turned up in a websearch was somewhat interesting

http://www.amasci.com/maglev/maglev.html

specifically the feedback stablizied multi-coil cradle.

This was an active simulation of the passive Meisner effect. I suspect it'd be very difficult to get the ball to float above the top of the bowl with this (or any) approach though, getting it to float inside the bowl, below the top but above the bottom, would probably be possible with enough effort. Getting it to work at all is going to take a lot of effort and technical saaavy, though, as the author points out, it's not really a beginner's project, and I get the impression the original poster here(s2mega) _is_ a beginner.

 

[s2mega]

Thanks very much Locrian and pervect, for taking the time out to humor this beginner here! indeed i am what you might term a beginner, or perhaps someone standing by the starting block might be more appropriate...

locrian i meant the positive facing the positive, oops :p but i think u got the gist.

the urgency is not in construction, but in conceptualisation... cos basically I'm only working on a concept, and even myself doubt the possibility of it being built... technically, financially and practically it all sounds very edgy, this concept...

attached is a diagram of my really simplified concept, which, by all practicality, sounds and looks much much simpler than an induction coil. except that i think it's a bit of a cop-out by needing to have a cable to stabilise the ball. and the 2nd magnet. grrr.
http://i.1asphost.com/s2mega/mg2.jpg

locrian could you perhaps point me to a site with info on the induction coil concept? only I've searched for a while and have only been turning up stuff on electric sparks and spikes (pretty patterns but not what i need...)

and locrian, perhaps magnetic power DOES fall off quite a lot with distance, but if u regard that the proposed structure would be 5-6 metres in diameter, the magnetic field would rather have to be at least that powerful, right? and for a aesthetic structure, it shouldn't cause passer-by grief...
therefore I'm asking about a magnetic-retardant material to block that magnetism. is something magnetically retardant employed in maglev trains? like the japanese metro? or is the magnetic rail's field not that large at all?

pervect, that site IS quite interesting. delving deeper. still can't find the coil thing though...

on the unipolar magnet theory... what happens if a ball of electromagnets is rigged like that? (in the above attached file)
just a thought :)

and just one more thing, my lecturer told me that he saw once on discovery a truly spokeless bicycle wheel... that is to say that there were no spokes between the hub of the wheel, and the outer rim where the rubber is. he said he saw some guy put his hand between the hub and the rim and did what a magician would do to their floating assistants... i could not turn up anything in my search (spokeless wheel = flat bicycle wheels with spokes replaced by a disc. darnit), but has anyone heard of this before?

 

[pervect]

A picture of the device operating is at
http://www.amasci.com/maglev/levgif.html

Note that it's not a bowl shape, but a 'v', the magnet being levitated was small and skinny, and that this particular version had it's share of problems

This particular version was only marginally stable, and the bar magnet would remain levitated for several seconds before oscillations built up and ejected it from the device.

 

[Gza]

Does the levitation have to occur with electromagnetism, or can you use another physical principal? The reason I ask is, I was at the mall today and saw this hemispherical object being levitated effortlessly off the ground (about 10-11 feet up) and upon closer inspection saw a fan underneath generating the lift to raise the structure. It was pretty neat looking, I think you might be able to buy it from the sharper image, or one of those types of stores. Just an idea .

 

[s2mega]

Does the levitation have to occur with electromagnetism, or can you use another physical principal? The reason I ask is, I was at the mall today and saw this hemispherical object being levitated effortlessly off the ground (about 10-11 feet up) and upon closer inspection saw a fan underneath generating the lift to raise the structure. It was pretty neat looking, I think you might be able to buy it from the sharper image, or one of those types of stores. Just an idea .

hm~ i was given the same advice by a friend...
could work on the same principle as the straw and ping pong ball thing... slight wobbling...
i just wanted to make it outta magnetics cos that'd be REALLY technologically impressive... just for the sake of BEING impressive... :p

and also i envisioned it as a "magnetic wishing well"... ppl can throw their money where no fish's going to eat it... haha, there'd be much more problems than that though :p


could anyone answer my question about whether this construction would turn out a unipolar sort of magnet? (on the left of the image)

http://i.1asphost.com/s2mega/mg2.jpg

 

[enigma]

Unless the cable is very stiff, the ball will bend the cable and attempt to turn itself upside down.

The thing would probably work if you just use the upper magnet and scrap the lower one.

Depending on the size of the device, you're going to need really powerful magnets. The 0.1T magnets I've got in my lab have a range (are able to hold themselves up against gravity) of a few cm at most.

Make sure that you build the device out of something non-magnetic. I'd recommend aluminum or stainless steel.

 

[enigma]

and locrian, perhaps magnetic power DOES fall off quite a lot with distance, but if u regard that the proposed structure would be 5-6 metres in diameter,

You're not going to be able to move it if it's that big.

Iron is really heavy. The base to one of the transducers in my lab is a cylinder ~10cm dia and 7-8cm high. It weighs 10lbs.

I'm sure something that huge would also be enormously expensive. The materials cost alone may be a few hundred dollars, and that's not including the cost for machining.

 

[s2mega]

You're not going to be able to move it if it's that big.

Iron is really heavy. The base to one of the transducers in my lab is a cylinder ~10cm dia and 7-8cm high. It weighs 10lbs.

I'm sure something that huge would also be enormously expensive. The materials cost alone may be a few hundred dollars, and that's not including the cost for machining.

hm? actually when i read "enormously expensive", i thought at least thousands of dollars... but when u said a few hundred i went... "HUH??"
cost issues i don't want to think about now since if it EVER got picked it'll be a big corporate park feature anyway (if EVER EVER EVER...), but i wanted to know if it was feasible in operation and safety issues...

would a magnet configured like this in a ball float above a bowl of like-poled magnets? or would it simply cancel itself out?

and there's no ways of getting a light electro-magnet material? must it be iron?

 

[agkusumo]

Dear s2mega, I'm working at an EPC Oil&Gas company and not quiet an engineer. If you don't have any objection, I just wondering about status of your project in 2004.