View Full Version : Stator Teeth

06-20-2009, 08:27 PM
Please don't laugh at me for the dumb question. I probably already
know the answer; but I wanted to make sure.
The stator teeth from the diy brushless suppliers are coming with
the enamel covering the edge of the teeth. Will this have a big
impact on the performance of these motors and should I sand off
the coating to clean up the teeth?
Also, some of my stator teeth are not clean from laying around
for awhile. Should I sand them with fine sandpaper or emery cloth
to shine them up?
Thanks for the advice,

06-21-2009, 11:19 PM
The enamel insulation is there to prevent the (insulated!) winding wires against shorting/knicking against the otherwise sharp edges. No effect on performance, don't worry.
Rust is no problem, just extra insulation, you don't have to shine them up. By sanding/filing the rust you may create burs on the laminations, those can create electric contacts between the otherwise insulated laminations -> higher eddy currents -> higher losses. Read posts #4 and #5 in this thread, about laminations, insulation and eddy currents:

If you have not done so yet, read this rewinding introduction (
-> knowledge base
-> basic overview (1-5)

More stator insulation methods in item #16 to #25 of first post in this "Tips and tricks, checks and tests, may keep you from frying yer ESC and/our controller" thread:

All manufacturers use enamel, usually green or blue, e.g. Kontronik: (
-> Site Map
-> repairs, tuning
-> power Pyro Kontronik

07-04-2009, 08:14 AM
Thanks much Ron,
I feel honored it is you answering me.
I wasn't worried so much about the
extra insulation, just the rust on the
"head" of the stator teeth. It is easier
to understand thinking magnetic.
I guess it was just the "electrician" in me that
worried about the rust. I am too used
to wanting everything clean and shiny :o.