skeetab5780 wrote: ↑
Jun 18 2019 8:12am
Dui, ni shuo de dui wrote: ↑
Jun 17 2019 9:01pm
It might be a little late, but to solve your magnet problem, have you thought about using some kevlar wire all around the rotor?
Just dip them in epoxy and as long as they don't touch the stator there should be no way that your magnets will fly off again.
that could work? ive never worked with Kevlar and have no clue how thin it could be but there is not much room for error in these motors, they don't work very well at low rpm either unless you use the stock controller. Very odd setup
if anything I would probably try to adapt a stronger motor to the bike, but there is nowhere to put it except exactly where it is...
I never tried myself and it was just a wild thought, but I searched afterwards and it seems like some companies are actually doing it so I guess it does work.
An alternative could be to use some carbon fiber wire, which is easier to find and very cheap, so I'd say go for that instead.
https://www.arnoldmagnetics.com/product ... psulation/
Yes, it is extremely thin, thinner than a hair actually. If you wrap it tight and take your time to avoid the fibers crossing each other I think the size difference will barely be noticeable. Pretty sure it could work, the only important things would be:
1) to wind the carbon as tight as possible, so build some kind of jig (a crank fixed on the rotor shaft, two planks and it's done)
2) to use some high temp epoxy, so that it can last a long time. That shouldn't be an issue, a lot of motor windings are epoxied so I think it should be easy to find.
3)Make sure that your bearings are still OK, if you have any play in them then the carbon might come into contact with the iron of the coils.
It shouldn't cost you a lot, I don't think it is very difficult to do and it might be the solution in your case. I think your original magnet gluing was very close to be sufficient, otherwise it would have exploded in a few seconds. But you managed to get a few rides before the magnets flew off, so just adding a tiny bit of strenght would be likely to solve the problem. In this case, with the carbon fiber, I think you'll at least double the strenght if not more, given that the shear forces won't be on the same axis anymore so it should be reliable. Might worth a try, fitting a bigger motor in this tight spot is a much bigger challenge.