Dismantling and repairing the motor :o

[jeff-jordan]

Hello bob, I just need to repeat myself: I'm pretty sure that I know why and when the "kissing" between the magnets and the stator happened.
It was in august 2023, when I drove the motor too hot... and the "zing-zing" sound once appeared.

The stator inside the motor can easily reach about 120°C or even more (at high current over a long period), so the diameter of the stator (nickel steel alloy assumed) extends about 0.5mm (compared to 20°C). That's enough to touch prone magnets....

If I had tried to remove the magnets you've spotted, I would have had to use brute force (because they are firmly glued and not loose), and the magnets would not have survived.

And by the way: no need to worry, I already have a spare motor inside my garage.... just in case.

[bob2.0]

Spare motor, nice!

Yes, fair, a stator expanding that much from too hot makes sense rather than rust out.

Hope the refit goes well. Don't use too much sealant! I made a mess of it first time

[jeff-jordan]

Spare motor, nice!
...

Yeah, in 2023 I was lucky enough to get an offer for a new motor for less than €600 (incl. shipping), that's why I jumped at the chance.

[bob2.0]

Spare motor, nice!
...

Yeah, in 2023 I was lucky enough to get an offer for a new motor for less than €600 (incl. shipping), that's why I jumped at the chance.

My strong advice is to keep it dry and warm in storage!

I was thinking to actually put active desiccants within the motor enclosure, cable tied to the stator. As it is meant to be a generally sealed unit, then I figured maybe that would help. In the end, I glued the new magnets on, making sure to fill the gap behind the magnets (as you know), then spray a clear lacquer on them (not sure if it will do much) then also I smeared Dexron over the magnets, just a thin film, figuring it'd go somewhere useful.

Smearing a film of Dexron is something I tried on the 2nd repair iteration, and on the 3rd/final iteration it seemed to be OK and not cause any harm at all. It just disappeared somewhere and left a greasy surface, which is perfect. I considered gear oil and other lubricants too, but Dexron has the highest material and electrical compatibility of any commonly available high shear (gear-bearing) lubricant, so I figured it was probably the least-risk option for that purpose.