Some Motors Incompatible with Statorade / Ferrofluid cooling?

Electric Motors and Controllers
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amberwolf   100 GW

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by amberwolf » May 01 2020 12:11am

j bjork wrote:
Apr 30 2020 12:24pm
I think it would be interesting to hear if people had problems without statoraid too.
viewtopic.php?p=1551213#p1541839

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by madin88 » May 01 2020 6:22am

amberwolf wrote:
May 01 2020 12:11am
j bjork wrote:
Apr 30 2020 12:24pm
I think it would be interesting to hear if people had problems without statoraid too.
viewtopic.php?p=1551213#p1541839
There have been some cases i know with QSV2 (Cromotors) but those had the rectangular magnets which make a gap to the back iron which leads to lower adhesive strength and heat shedding compared to the curved magnets used on V3.
We had a few cases in the company i was working and we got replacement magnets sent from Cromotor or a new Rotor sent that time. They also mentioned something about production failure and i have thought they maybe have forgotten to clean the surfaces properly before aplying the glue, because when milling, turning, drilling there often are oily coolants used.

I found the photos from mxus repair. Statorade used was "Type B"
Everything which is brown color is what from FF. It looks like rust but there was no.
The biggest part seems to got soaked up by the stator lams and wood sticks which hold the widings down. It was easy to wipe clean and also the rest of the glue went off easy.

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by j bjork » May 01 2020 6:27am

Thanks,I was a bit unclear in my comment. I saw your post, what I meant was that it would be interesting to hear from those who had problems without statoraid too.

Statoraid did a lot of difference for me in how hard I could ride before it overheated, but I don't think the outer shell has ever been more than about 50 degrees C. I have hubsinks too now, but they didn't do much difference.

Edit, it was a response to Amberwolfs post.

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by hias9 » Jan 28 2021 10:06pm

Do you guys also have rust at the bearings when using Statorade?

This is the Chinese bearing (left side) after a bit over a year with Statorade. Technically it was still ok.
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The bearing (right side) in the background is a FAG bearing after less than 2 months with Statorade.
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I seal the cover plates using a high temperature silicone motor sealant.

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by DogDipstick » Jan 29 2021 12:13am

hias9 wrote:
Jan 28 2021 10:06pm
Do you guys also have rust at the bearings when using Statorade?

This is the Chinese bearing (left side) after a bit over a year with Statorade. Technically it was still ok.
Image

The bearing (right side) in the background is a FAG bearing after less than 2 months with Statorade.
Image

I seal the cover plates using a high temperature silicone motor sealant.
Condensation gets in there as a vapor ( through the wire, ) or wicks into the motor (through the wire). Condenses, causes rust. Gets in as a vapor, condenses, cannot get out then.

This is what I like a good volume of ATF ( instead of statoraid) or that orange insulation varnish that some coat the insides of the motor with.

Mine did this. First time I opened it.. it was clean..( to fix the halls, reseal) but the second time ( after a fix, halls, reopened) I saw a good amount of condensation.... H20.... not getting out.. ( maybe 20-30mL) So I upped the ATF i used to about 250ml and the problem went away.

It means the hub is well sealed. If you had a vent hole this wouldn't happen either.. but it is inherent....

Vapor is tough to completely protect against.. and once it gets in and becomes liquid.. it cannot get out.

Who cares about little surface rust on the exterior
of a bearing shell. Its not like the rust is reaching the cage or the race, or teh rollers (balls).
83.1v of Ironhorse XC.. :) :bolt: by Chevy :bolt: :D Broke 10 horsies :twisted: (... no.. down to 'bout 20% now... again....On another note... Anybody know how to diagnose broken ribs? ..Asking for a friend... ).. :? Waddyamean? You cant tell me how many amperes/Ft.^2 of the plate ?!?!? :x 1 (pound / second) Horse Power = 338.24 M^2 Kg^2 / Sec^4 ( :twisted: prove me wrong :twisted: ) :| (gottenymoem4115thangs?Yall?) :confused: Fabricator @ BSECo. Inc.

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by hias9 » Jan 29 2021 2:19am

What you see on the pictures are the interior sides of the bearings.
On the exterior sides there was only very little rust even after 1.5 years of use.

My side covers are sealed so the only way for moisture to get inside the motor would be via the cable. However so far I never noticed any moisture when I opened up the motor.

There is no rust at other locations, only at and around the bearings and on the axle where the bearings sit.
I never had this rust before I used Statorade.
The bearing on the second picture shown from the inside is not even 2 months in use.
On the same picture, if you look at the axle where the left bearing would sit, you can see that the rust is coming from the inside of the motor.

So probably some Statorade splashes around while riding and a bit of it stays on the parts which are ferromagnetic. And it seems to be corrosive.

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by DogDipstick » Jan 29 2021 2:39am

hias9 wrote:
Jan 29 2021 2:19am
What you see on the pictures are the interior sides of the bearings.
On the exterior sides there was only very little rust even after 1.5 years of use.

My side covers are sealed so the only way for moisture to get insid
I mean the bearing, outside.. but yes this is still located inside the motor. The bearing has a seal and a seal holds the bearing lubrication. The exterior face of the race is not any function.

Another place water could have entered, or oil escaped, is around the small diameter axle race, and the large diameter cover race. If you did not seal those, you must, for complete seal. Hubs usually come with a very cheap seal here ( at least my Qs motors do come with tiny seal washer, not a labyrinth seal....

Yes probally through the wire... water entrained... but also, ... consider this...

Water can make it around the bearing. From the outside environment. If you look at the shaft in a transmission, engine, you always see a seal that encompasses this part to the environment.. and the races can certainly let water in... not only the wire. Teh place where the cover meets the bearing, or the axle meets the bearing. Water entrance. I seal this too, anaerobic.

Good luck, friend.
83.1v of Ironhorse XC.. :) :bolt: by Chevy :bolt: :D Broke 10 horsies :twisted: (... no.. down to 'bout 20% now... again....On another note... Anybody know how to diagnose broken ribs? ..Asking for a friend... ).. :? Waddyamean? You cant tell me how many amperes/Ft.^2 of the plate ?!?!? :x 1 (pound / second) Horse Power = 338.24 M^2 Kg^2 / Sec^4 ( :twisted: prove me wrong :twisted: ) :| (gottenymoem4115thangs?Yall?) :confused: Fabricator @ BSECo. Inc.

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by hias9 » Jan 29 2021 3:01am

Does not really look like water entrance in my case. Never noticed any moisture when I opened it and never had this rust from the inside on the bearings before using Statorade. Anybody using Statorade having the same issue?

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by serious_sam » Jan 29 2021 4:54am

Statorade is oil based. It does not cause rust.

Your hub has moisture in it.

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by hias9 » Jan 29 2021 1:49pm

So maybe the problem was caused by sealing the cover plates which I did when I added the Statorade.
I might need to drill a vent hole which would be opened after riding to let any moisture escape.

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by amberwolf » Jan 29 2021 10:30pm

Remember that Statorade (all ferrofluid) is made of very fine particles of iron-based substances, embedded in a fluid of one sort or another. Whenever any of those particles are washed out of that fluid by water ingress, the water will eventually corrode those particles, and make a fine rust out of it that may also go along with the water wherever the water itself comes in or goes out.


Another issue that could cause bearing corrosion when there is no evidence of water intrusion into the motor is simple bearing seal failure (or lack of seals) so that water gets in teh bearing itself, even if it doens't get any further.

A more complicated and probably very unlikley cause of bearing corrosion is if there is an electrical connection thru the bearing, accidental or otherwise, so current (even a tiny one) is flowing thru the bearing itself. This isnt' a likely problem, as it would require that statorade/ff be present and electrically conductive, *and* that there be a short from a wire or winding to the stator laminations, *and* that the stator laminations are electrically isolated from the axle, *and* that either battery negative or positive be shorted at least to some degree to the frame, *and* that the axle be electrically connected to the frame. If any of those is not true, there is no electrical path thru the bearing itself (or the path is higher resistance than other paths so current wouldnt' flow thru the bearing itself).

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Re: Some Motors Incompatible with Statorade / Ferrofluid cooling?

Post by hias9 » Jan 29 2021 11:00pm

I think the first theory is the most realistic one. On the second picture you can also see little points of rust on the aluminium cover plate. Probably some of the iron-based particles of the ferrofluid got there.

The bearings (both the original Chinese ones and the ones I use) are sealed on both sides. On the second picture, the bearing in the background is a FAG bearing less than two months in use.
I would also say that an electric connection through the bearing would be extremely unlikely.

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