ahilito

Hi,

I'm just trying a set of Reelights for the first time and I am confused, is the light supposed to make a very slight contact with the magnets or narrowly avoid it. In the instructions it says that it's supposed to be 1-3mm away from the magnets - I think I have a bit over a 1mm distance and at the moment it feels as though the magnets both get pulled into contact with the magnets, so the lights flash and everything is good. But I'm confused because all of the talk was about frictionless.

Thanks

prathmann

There shouldn't be any actual contact. But note that 'frictionless' does not mean 'dragless'. There will still be some drag on the wheel rotation as the magnets pass by the wire loops and generate electricity.

ahilito

ok, guess I'll have to add another spacer or more.

Thanks!

fietsbob

Its electricity by Induction , A magnet and a coil of copper wire pass by each other within the range of the magnetic field.

https://en.wikipedia.org/wiki/Electromagnetic_induction

ahilito

yes, I knew something like this existed, even if I sucked at physics... but I've got the light as far out as possible with a spacer and it's still rubbing up against it slightly so I started to lose faith in my vague memory of physics

fietsbob

You got the basic one that all attaches to the Hub axle & spokes? https://www.reelight.com/en/products/sl100/

Looigi

Ah. The videos finally explain how these work. I wondered how they did this without moving parts but now I see they do have moving parts. Eddy currents in the rim turn a magnetic rotor in the light which in turn passes coils to generate the power for the lights. The only friction loss is that in the bearings for the rotor. There certainly are electrical losses, including the resistive losses due to the eddy currents in the rim.