Dismantling and repairing the motor :o

[jeff-jordan]

I think for pushing the stator out of the rotor, the approach of TwisterMax would be the most elegant way.



Just a few thoughts for the reverse process (haven't done it so far and don't know if it really works this way):

I would try to lay one or two layers of wooden planks between the stator (lying flat at two thick wooden beams at the ground, upside down beer crate will do the job as well) and the rotor, so that the two parts couldn't snap together.
Then centering the axle into the bearing of the rotor and applying the 3-legged puller, so that it's center reaches the tip of the axle.
Afterwards I would try to take out the planks between stator and rotor. The puller should then prevent that the two parts snap together.

Then I would gently loosen the puller (here in fact used as a pusher ) while the magnetic pull should merge both parts in a controlled way.


update: Hehe... , TwisterMax was faster with his post.

[bob2.0]

Thank you, yes, I think I will revert to that.

I had some success and some less success with it this morning. I cut the sealant easily with this method;-

WhatsApp Image 2025-01-25 at 13.44.47.jpeg (189.25 KiB) 2948 mal betrachtet

But after that success I made the error of continuing to hammer, thinking the sealant went deeper than that, but I must be up against an inner flange. A few razors shattered and flew off into the garage somewhere. I really do not like sharp things flying around a garage full of motorcycles! I could not find one piece, I hope it landed safely somewhere. The sealant only goes in <8mm from the edge.

The mistake I made was thinking I could lift the lid up and off the bearing, but it must be quite well pressed in, it is not going anywhere, so I strapped under the table, but there was too much give in my webbing and the table cracked at a weak point (not structural, just cosmetic, hence that is why it broke).

So, yes, thank you, the above will be my method. It just looks awkward to actually hold the wheel in a good way without it dropping on the other side, but I have those guide bolts.

I am not sure I have a puller that large, if I do I doubt the bolt length is enough, but I will buy one if I need to.

[bob2.0]

I have used my bearing extractor and several encyclopedias to do this job with relative ease.

I was keen to take time to create a process that was readily reversible. I want to do this backwards to reinstall the stator safely and without bashing the bearing interface.

I think perhaps this motor has been open before, and that is why the bearing surface was the problem, it got bashed and not well sealed. This corrosion was why it was reluctant to move. Maybe this is useful information for people reinstalling their motors?

Once this was freed, removal of the stator using the guide bolts was very easy and not much force. I think they kept the stator very central and it did not scrape across the magnets.

Now it is out, I see several anomalies, the question is which, if any or all, are important ones?

[bob2.0]

The fundamental reason why the motor was binding seems to have been the one bottom magnet shown here.

I think it is probably just a very slight scratch in the plating on the back of the magnet, that over time has bubbled up and pushed the magnet out, into the path of the stator.

The question is what to do about this? Is it possible to remove the magnet and try to stop the rusting? Surely, it will only get worse if I don't do that? I don't believe it will come out easily, more likely in pieces.

What to do about this?

Do you think this has been very recent (since I went through water 2 months ago) or a long standing issue? I think it is something over a long time, I am not seeing evidence of liquid water getting in.

The alternative explanation might be that it was always like this, with the magnet slightly proud, and very slowly wore away, and the corrosion there is the dust from the magnet?

[jeff-jordan]

Thank you for the pictures!
Seems that the stator and the magnet once kíssed each other slightly.

Its likely that this was caused by the stator getting really hot (driving with (too) much current over a longer period).

Let's make a rough calculation.
Stainless steel has an expansion coefficient of 16E-6.
Let's assume it got really hot, 190°C at an ambient temperature of 10°C.
So a stator with a diameter of 33cm (LP size) will expand: 0.0010032m or 1.0032mm. And a millimeter is not insignificant.

Now what to do?

I wouldn't touch the magnets at the ring, unless they got loose. They are very, very brittle and, due to the magnetic repulsion, you won't be able to put or glue them back at the rim.
Furthermore, it's unlikely to get replacement parts and a new motor would eventually be necessary.

I would clean up everything from fine steel particles that rubbed off from the stator and coating dust that rubbed of from the magnets.
Maybe it's a good idea to use some adhesive tape to remove the magnetized dust from the poles and the magnets.
Then make sure that there are no proud elevations (from flush rust?) at the stator.

Don't know if it is possible or a good idea to put a thin layer of temperature resistant coating at the stator.
Maybe just a thin layer of diesel will protect the surface from catching some flash rust (yes, even stainless steel catches it).

To prevent that it'll happen again, It might be considered to install a temperature sensor (like a kty84-130, which is supported by the fardriver controller) at the stator (touching the coils).
I would even sacrifice the wires for the spare hall sensors for that, if there is no easy way to install an additional wire for that.
The controller could then be configured to monitor the temperature and limit it to a safe value (by reducing the current).

These are just my ideas about it. It's only from a theoretical point of view. Until now, as far as I know (haven't opened my E-Odin motor so far), I haven't been challenged with that issue. But who knows...

Maybe some other users like (dominik, TwisterMax, AmpSauger ...) have some experience at this topic.

[bob2.0]

There was a slight binding when I got the bike in the summer.

I thought it was the rear brake, never really investigated it. Now I know this, I am sure it was like this before.

I have driven flat out until the battery got too low, several times. It would not have got hotter, so I would definitely have made it worse, if it was that. Or maybe I stopped it getting worse by gradually grazing off the material and warming out the humidity, until recently when I let it stand over Christmas?

Play in the bearings would result in this effect too. The bearing on the one side seems OK, but I could buy reduced radial clearance bearings? Would that be an idea? Maybe the axle has tilted if one has worn more?

I can't see how motorbike axle bearings would get warm that it needs even a 'normal' tolerance, I think they are low speed and low forces by bearing standards.

I will remove the brake disc again because I can see there is a lot of messy work to be done here. I might even take the tyre off.

I think I will have to;-
- gently sand off those other magnets showing initial pitting,
- use rust remover on that magnet and elsewhere, carefully, and wash it off thoroughly,
- brush-paint up those edges to seal them, and maybe have to remove the panel on the other side too, check those edges and paint,
- measure the height of all the magnets, and sand that one back to give clearance,
- very thin spray on the radial surfaces of the magnets, I think it has to be done, might all wear off again.

I might also cut gaskets instead of using sealant, I think a good gasket would reduce humidity ingress at the edges.

You mention the stator, that is the next 'anomaly' which I will now post about.

Summary for your inputs good idea/bad idea? (thank you!);-
1. Derust magnet edges, and paint/seal (both sides)?
2. Measure radial height of, and sand back, the faces of the proud magnet(s)?
3. Thin spray-paint of magnet faces?
4. Replace bearings with low radial clearance variants (if available)

[bob2.0]

FYI; the rest of the magnets;

[bob2.0]

The stator; here is a typical image, it is similar all the way around.

The laminations are slightly splayed at the edges, and rusty in places.

I'd have thought a good quality motor would have tight laminations, fixed in place. I guess ... not good quality?

[bob2.0]

The Black one could be a second hall sensor set.

Yes, it was another set of Hall sensors;

To prevent that it'll happen again, It might be considered to install a temperature sensor (like a kty84-130, which is supported by the fardriver controller) at the stator (touching the coils).
I would even sacrifice the wires for the spare hall sensors for that, if there is no easy way to install an additional wire for that.

It seems I do have such 'spare wiring'!

[dominik]

After 9 years, when I had melted the phase wires, the magnets of my QS60V5000W were totaly rusty.
My stator had a lot of scratches, but it never felt like it was sticking together.
I sanded both with sandpaper grit 240 and 1000 and put clear laquer onto them, installed thicker phase wires with higher rated temperature isolation and a temperature sensor and raised the controller limits.