Thread: Discussion Stator coating
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Old Aug 20, 2012, 12:53 AM
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United States, IN, Indianapolis
Joined Oct 2010
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Just came across this thread. Just wanted to chime in a bit on the stator coating with powder process.

I work for a motor manufacturer and we make LARGE, axial flux brushless motors for electric vehicles and military applications.

We occasionally use a powder coating for our stators. The powders do not need to be electrostatically applied. The stator can be heated to the flow temp of the powder and the stator simply dipped in the powder. This generally results in a slightly higher build thickness than you would get applying electrostatically, but with some experimentation could be a viable method for smaller stators.

The powders can also be "flocked" on. Put the powder in a salt shaker, or a real flock dispenser from the hobby shop, heat up the stator to flow temp and shake it on. A re-flow may be needed to even out the coating.

The can also be applied to a hot stator using normal "air" paint guns as long as the air is COMPLETELY dry.

The stator MUST be PRE-HEATED in order to use non-electrostatic methods. the benefit of electrostatically applying the powder is it can be applied to a COLD part.

There are also a few companies that sell electrical coating powders in small quantities. We have a few different "quart size" containers we bought. I will find out where they are from.

Also, normal powder paints should be adequate for insulating stators as long as they are non-metallic. I have worked with both, and as far as I can tell, the "electrical" powders we use, and normal powder paints have no real difference. Especially since all we are really using it for in this application is to prevent mechanical wear on the wire enamel during winding, and vibration when operating. The build thickness is essentially the same on both types.

Harbor Freight sells powder in 16oz containers for $5 of a few different colors that are cheap enough to experiment with.

There are also high-temp, high-build spray epoxies, and lacquers we use for the same process.

@jackerbes -- The most widely use electrical insulating "paper" is Nomex. Its actually the same material used for most of the "CA" hinges used in most planes these days. Find it HERE You can get it adhesive backed as well, which makes it easy!!

Also, Park Electrochemical makes the fiberglass sheet you are looking for, sold under the Nelco brand. You can get it at least down to .006" thick for sure, maybe thinner. Its not expensive and is available in smaller quantities. We used to use the .006 for insulating the bottom of our stator teeth. It can be cut with a pair of scissors and a hobby knife.

Also, I seen the thread on removing epoxy from winding to get them off. The epoxy generally used for this coating is usually Epoxylite, or the Chinese equivalent. It is known as a "Trickle Resin" . It is a very thin air cured resin generally used to simply hold windings or laminations together. Its very thin to provide penetration. Dolphs sells some of these resins in a spray can, as well as some other insulating materials.

EDIT: Look what I found HERE Nelco .006 fiberglass sheet in 12x18 sheet for $2
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Last edited by KKUSA; Aug 20, 2012 at 01:10 AM.
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