Dismantling and repairing the motor :o

[dominik]

The magnet in between gets touched by the stator, or is this only dust?

[jeff-jordan]

Looks like the magnet between the two 3packs moved over to the other side, curious.

Are the magnets still firmly glued to the rim, or has something got loose?
I assume that the black stuff ist some kind of magnetic dust that has enriched at the (loose?) middle and the new magnets.

Ist there any loss of flux at the new magnets?

[bob2.0]

Yes, that is what I am seeing. The magnet between the new ones has kissed the stator and twisted.

The way I see it, the magnets either side were the highest point and that middle one was lower but still too high.

There was no way to tell it was too high until it was the only one of the three left.

So, I can forgive myself for this!

Actually, it would have been impractical to try to glue the new magnets without that one in place. So in any case, it's reasonable to have put it back together once the new ones were glued in.

I think what has happened is that it was really just ever so slightly kissing the stator, but after 100 miles of constant touching it began to move and then twist

It has not yet demagnetised, which leaves me with a quandry. If it comes off in one piece, should I sand it down and reglue that one back in, or use new magnets? The new magnets are slightly weaker so I don't know if having 3 slots of new magnets together might be a problem.

I'm also looking at the one to the right, too, in case that one is high. I think, maybe, like I have just done, make a repair and if it gets worse then just have to do the job again? It didn't actually take very long, now I know how to do it.

[bob2.0]

Magnet removed, and cleaned.

Before (backside), after cleaning (lots of pitting) and the 'front'.

The field has weakened, but not reversed anywhere. Particularly, it is weak right in the middle and up towards the end with the most wear.

I'm unsure if to use this or the new magnets. I don't think there is a big difference in strength, what worries me is that if I use the new magnets then there will be a 4mm gap between them rather than just the 2mm, and I am wondering how big a gap we can go before the Hall effect sensors give a bad signal.

[jeff-jordan]

... and I am wondering how big a gap we can go before the Hall effect sensors give a bad signal.

I don't think that it'll make a big difference. The sensors are "latched" ones, so they remain triggered until they detect a reversed magnetic field.

[bob2.0]

Before

After

That makes sense on the reversing polarity thing, which is why it failed before when there was no reversal for 3 magnets.

[jeff-jordan]

I'm wondering if it might be a good idea to glue some kind of "spacer" between the (two kissing) 3packs?

[bob2.0]

It would be nice to have the right size magnets, but I think it is OK to have gaps because if any condensate gets in then there is a place for it to go rather than under the magnets.

I think the only reason that last one moved was simply because of all the rust underneath and it getting hit on the stator. I don't think it would have helped if the gap had been filled.

It's got me worrying about the other magnets, but if I keep pulling them off then I'll end up with replacing all of them!

I'll save the ones I take off, if I can avoid breaking them (the first one was too rusty, it snapped) and if I have enough I'll get them remagnetised, some how.

I do have worry about a few others. I will just have to see how it goes. I can do this again in the future, like a service item, check the insides of the motor for rusting. It's not a difficult job once you are familiar with it. TBH, it is not really any more difficult than taking a back wheel off a regular motorbike.

[jeff-jordan]

... I can do this again in the future, like a service item, check the insides of the motor for rusting. It's not a difficult job once you are familiar with it. TBH, it is not really any more difficult than taking a back wheel off a regular motorbike.

Now that you are quite familiar with dismantling the motor, can you describe or sum up your "method" with all the required hints what to do and what not (e.g. squeeze your fingers)? Or even publish it in a short youtube video?

I think, sooner or later, we all need to have a look inside... even if it's only for inspection.

[bob2.0]

[Now that you are quite familiar with dismantling the motor, can you describe or sum up your "method" with all the required hints what to do and what not (e.g. squeeze your fingers)? Or even publish it in a short youtube video?

I think, sooner or later, we all need to have a look inside... even if it's only for inspection.

Far more familiar than I want to be!

Sure, of course. Busy just this week, I won't do it straight away, anyway in case there is a 3rd time and I "learn more".

I cleaned up the stator and decided just to put it back together. It'll get another 24hrs curing before I try to run it.