Superconductors in Brushless motors

[wilz1234]

Recently in school (yes i am a 15 year old) we have been looking at superconductors and how powerful they can be (ie: the maglev train, or making strawberrys levatate :) ). Would it not be possible to make brushless motors using superconductors. I imagine someone will have thought of this already but its still interesting to know.
If Brushless motors turned out that so much more efficient than brushed motors, and superconductive metals have much lower resistance in them because of the 'cooper theory' then maybe they'd be even more efficient than normal brushless motors. I know it seems near to impossible to get the coils down to a low enough temperature :eek: but im sure there must be a way. ;) Perhaps liquid helium? with the whole thing sealed and insulated?

Heres some links about superconductors:
http://en.wikipedia.org/wiki/Superconductors
http://en.wikipedia.org/wiki/BCS_theory

Let me know what you guys think. Probably just another crazy idea! :D

[Tom Harper]

Will,

Great idea!

You have a lot of years ahead of you to work on it.

[wilz1234]

Maybe, just not time at the moment, or the money.

[vintage1]

The classic way is to make the windings out of superconducting tube and run liquid something through them to cool.
But for most purpose sour motors are good enough without.

[BMatthews]

Yes, superconductors are a good idea.

But I'm afraid you missed out on a few things.

While there would be an insignificant amount of heat generated by the all but non existant DC resistance the motor is still doing real work that consumes watts of power. And no motor gives out all the watts it takes in. The DC resistance is only one aspect of the general inefficiencies. So that means that some of the current flowing in the motor will be going to producing heat. So the temperature would soon rise unless it's kept cool. It's not practical to have the motor sitting in a pool of liquid gas as a coolant so arrangements would need to be made to have these liquids be fed through the motor to hold the temperature down to what is needed. And the temperatures would only stay low for as long as the liquid is kept cold. And the only practical way the liquid gas stays cold is to carry the heat away by evaporating. So you'd have to see just how much liquid would be needed perflight and arrange that as a total loss evaporative coolant.

And this would also require a far smaller than normal flask with some very fancy insulative material to hold this liquid. And of course the motor would need to be contained in it's own flask to hold away the much warmer outside temperatures.

So work out the numbers and get back to us would you?

Far from making fun of your idea this is a great brain teaser. By the time you figure out all the questions and come up with the answers you'll know a LOT more about a lot of things that, while they have no practical use, will make you the hit of many parties.... :D

[Mister UHU]

Would it not be possible to make brushless motors using superconductors.

Let me know what you guys think. Probably just another crazy idea! :D



No, it is not a crazy idea.

Superconducting motors have already been made.
Check the internet, there are photos etc,
this is an area of active R&D.
I have even seen an experimental one dating back to the 1960s,
made in Britain, (when Britain still did R&D).

For modelling purposes, it would be rather impractical.
There might only be a few very small niche applications.
And the cost would be much greater than existing motors.

[Accu157]

Don't you have to induce a magnetic field into a superconductor to make it accept the current? The only superconducting coil I know of is a closed loop... Maybe you can make loops of superconducting coils and induce current into it somehow?

I think you can get a cheaper high temperature ceramic superconductor. Well, I don't know if it will be cheaper, but you will not need liquid helium, you will only need liquid nitrogen. Liquid helium is also a superfluid (no friction), and can also be a superconductor itself, so choose wisely.

[downunder]

I think you might have to wait for a while until they reach the "holy grail" of a room temperature (or better) superconductor. From memory the best so far only needs liquid nitrogen temperatures but that's still a far cry for room temperature. The limiting then then for the power of the motor will be how fast the battery can discharge to keep the current going and probably the mechanical strength of the coils themselves.

[Accu157]

I don't know if I'd want to work around a room temperature superconductor just yet... Unless I could somehow turn it on and off. "Phantom" magnetic charges building up from a DC appliance, that would be scary. :eek: Leave the house on vacation for a week and the next thing you know your superconductor is up to 12 teslas.

[wilz1234]

thanx for the feedback guys!