Disassemble a Magic Pie 3

[d8veh]

I'm trying to fix a Magic Pie 3, which has had salty water in it. I have removed the covers. Now I need to remove the stator from the rotor and later reassemble them. I'm a little worried about damaging the magnets when I reassemble it. Does anybody have any tips for how to do this?

Before I disassembled it, I tested with an ebike tester. One hall is not switching, which should be easy to fix, but one phase was not generating when I turned the motor. As it's a three phase motor, I would have expected to lose two phases if one had a short. Can anybody think of a failure mode that would cause loss of generation on only one phase (as shown by the tester)?

This is what I found inside. I wouldn't recommend that anybody use one of these motors on wet winter roads, when they put salt down:

 

[Punx0r]

No idea about the phase issue, but you just need to be a little brave separating the motor. It will scuff the magnets and laminations a little, it just can't be helped. How I do it is to hold the rim at opposing sides, place the axle against the ground and push the rim down squarely. Or, support the rim on wooden blocks, stand on it, grab the motor shaft and pull upwards.

 

[d8veh]

Thanks for that. It's all fixed now. I was a bit worried about reassembling with no bearings to guide it in, but it went back easily without damage. I cleaned it up, derusted it and fixed the hall sensor. Interestingly, with my normal reliable sendor/sensorless controllers, it wouldn't work with or without the sendors connected. It took an old KU120 to finally get it going. I think there must be some conduction through the salt that was/is causing the problems. I couldn't clean it out of the windings. Maybe I should rinse it in fresh water. First, I'll run it a bit with the KU120 and see how it goes.

 

[Punx0r]

I wouldn't hesitate to wash it in hot water if you suspect there's salt in there. If it's hot it'll dry before any corrosion can take place.