How can we move a marble inside a rotating tire?

Question

I'm doing a hobby project.. that is to generate AC electric inside a tire (or rotating rim).

A marble (magnet) will move inside the rotating tire (or rim), which its inner layer will be covered with coils.. there shall be a relative movements which can induce the voltage. As the tire/rim rotates, the marble will also rotating.

Problem is, i can't figure out how to make that marble move inside the rotating tire.

Or, does anyone else have any idea on how to induce voltage from a rotating tire (besides using the dynamo attached at the side of the tire). The voltage must be induced from INSIDE the tire)

Answer 1

That marble will stay stuck to the point inside the tire that is the most out-of-balance, trying to balance it. It will not act as an independant dynamo/generator. So sorry.

Answer 2

Don't use a marble...use a bar magnet that spins freely on a low friction track which is attached to the hub. That magnet (hopefully) will stay at the low point of the hub (even when the hub is spinning), then the coils (secured to the hub) will move past the bar magnet. Note a marble won't work because as it spins, its field will spin, so the net change in field will be 0. Also, the coils should have a length shorter than the magnet, so that there is a net change in flux with time (which generates the emf)

Answer 3

Is it ok to actually stick a few magnets to the inside of the inner wall of the tyre then pick up your AC from a small wire loop mounted on the steering arm or suspension , outside the tyre? The AC is still beng induced by a source inside the tyre but you can actually use the electricity this way.

Alternately , if you really want the electricity inside the tyre, put your loops inside the tyre and stick a magnet on the chassis/steering arm/brake caliper.

best of luck - Mike