Powdercoating as core insulation?

will it work?
I found out that black has the biggest electrical ressistance and it is able to keep up to 220°C when it is properly cured.
What are the cons?

Do you mean insulation over the windings? If so, the question is "how do you get it evenly between the wires, lams, etc, once it's already been wound?"

Not over, under. Between windings and core plates, instead of cloath/paper/foil...

Does it stay completely hard until it reaches that temperature, or does it get progressively softer as it gets hotter?

I don't know much about powdercoating's high-temp characteristics, but f it is like most epoxies I've dealt with it starts to get softer as it reaches or exceeds the boiling point of water. If that were to happen in this case, vibration and magnetic fields pushing and pulling would be able to eventually squish the powdercoating out of the way of windings rubbing against the edges of laminations/etc., and that would probably be bad.

I guess it depends on the hardness of the stuff at high temps.

Also, how well does powdercoating stay on edges before baking? If it is like most stuff, edges will have the least coating, and that is the most important place to be heavily coated if you're wrapping wire around stator lams, for instance, if it were replacing the normal plastic or paper/etc used to keep wire from scraping/scratching/rubbing on those edges.

Epoxy resin is often used.

In this case, wouldn't you want to use whichever method gives the best thermal path?

Exactly thermal conductivity is the issue so I was thinking thinner - better. I can do epoxy but it came out thick. I tryed to delute it and to make thinn layer as powdercoat with same electrical resistance but then is no good because it became fragile and cracks easily. Today I will try acetone/epoxy. 50:50

My brother has his own business dealing in polymerics. I could ask him about formulations, if you like?

Great, Please do.

I found out that this insulation layer is the biggest thermal bridge in stator and it makes difference in temperature, for example in x5306 difference at temps. higher then 100°C difference between wire and core plates temperature is up to 22°C

I know that there is special epoxy for electronics with high thermal conductivity and high electrical resistance but I can't get around here bottle or two...

Something like this, perhaps: http://www.epotek.com/sscdocs/datasheets/T7110.PDF

exactly!
Now, how can I buy some?

I found this comparator:
http://www.polytec-pt.com/ger/_files/Thermally_Conductive_Adhesive_Selector_Guide.pdf

T905 has twice the thermal conductivity of T7110 and higher operating temp (200 deg. C.)...

Encapsulate the whole winding for the water cooled version?

I will just say that making windings with tube is PITA.

I would have thought that potting the windings was feasible...

This is Luke's territory - I'm sure he'll weigh in....

Miles said:

I would have thought that potting the windings was feasible...

This is Luke's territory - I'm sure he'll weigh in....

Click to expand...

I'm thinking.... But its been ~36hrs of awake time me, I'm buried in trying to finish up paperwork at work, and my mind is stuck on crafting strategy for winning the import drag racing event I'm in this Saturday.

You can use a thin layer of epoxy resin on the sides of the stator teeth, but make epoxy plates in the same shape as the stator sheets for both ends of the stator. This will reduce the risk of a shortcut between wire and stator.

Or, as I mentioned earlier in the 12kW-motor thread you could make aluminium cooling plates ( with smooth edges against shortcuts) for both ends of the stator stack to improve copper cooling.

-Olaf
A link quite useful for you:
http://www.powercroco.de/statorisolieren.html