Keeping a wheel spinning using as little electrical energy as possible

[Laguna2]

Hello.

This question has kept me up all night: What mechanism would keep a wheel spinning using as little electrical energy as possible?

Let's say we have a toy car (could be anything that involves a wheel) that is already in motion and moving with a constant velocity. What would you build to keep the wheels spinning at that velocity and uses as little electrical energy as possible? (It must be with electricity)

I have a few ideas but I have no idea which uses the least amount of electricity:

#1
Using a regular motor to spin the wheel
http://www.scooter-tuning.com/variator3.jpg

#2
Using the principal of Walschaerts valve gear using electricity instead of steam.
[PLAIN]http://upload.wikimedia.org/wikipedia/commons/0/08/Walschaerts_motion.gif

#3
This is the tricky one: Using magnetism. Use electromagnets to give the wheel a 'kick' to keep it going. Make current run through the electromagnets at certain points to induce the kick and stop the current when not at that particular point (to save energy).


Which one would require the least amount of electricity? If you can think of any other method that would meet the criteria better please share :)

 

[xts]

Let's say we have a toy car (could be anything that involves a wheel)

What is it makes a pretty important (actually - critical!) issue.
Your problem is to engineer the most efficient electric motor, feasible to use in your particular case. The solution will be quite different if your wheel is the London Eye, a hard disc for your laptop, a gyroscope stabilizing V1 missile, or gramophone.

 

[Laguna2]

I see... Let's take a case where I'm sitting on a chair holding the spinning wheel at arms length. I'm twisting the wheel so I will rotate on the chair. Now I just need the wheel to keep spinning to keep rotating.

What then would require the least amount of energy?

 

[xts]

You use a well beared bicycle wheel for that purpose?

I may guess that small electric motor, like those used in toys, with appropriate transmission, might be quite efficient and easiest to implement solution.

 

[Laguna2]

I'm not concerned about it being easy to implement. I need the most efficient method of keeping that wheel spinning regardless of the contstruction.
That's also why I asked for other ideas :)

 

[DaveC426913]

I'm not concerned about it being easy to implement. I need the most efficient method of keeping that wheel spinning regardless of the contstruction.
That's also why I asked for other ideas :)

Well, in addition to whatever mechanism you use to spin it up, a heavy flywheel will offset much in the way of losses.