I went to a shop and picked up a "refurbished" alternator. I saw the work area and noticed that they seem to partially spray paint the stators on their refurbished alternators. Mainly the main body and a bit of the wiring.

I was wondering why they would do this?


It could be a cosmetic thing (which isn't necessarily bad), but the "good" reason for doing this is to renew the insulation on the alternator windings. The stator of the alternator is made up of three coils of densely wound wires with a relatively thin coating of insulation (which allows the wires to be closely packed making for a smaller, higher output, alternator).

If the insulation is mostly intact then recoating the coils can help to extend the life of the alternator (or motor, same principles apply). A common brand is Glyptal which is a brick red color.

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  • How do you know what spray paint they used? – Moab Aug 9 '16 at 21:51
  • @Moab Back in the day ('80s) the stuff we use was called Glyptol or something close to that. – dlu Aug 9 '16 at 22:20
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    It just looked like standard plain spray paint to me. But I can imagine that since it's only 12 volts just a thin layer of spray paint could be sufficient to keep it from shorting to the case or the next wire in the winding, now that I think about it. – Robert S. Barnes Aug 10 '16 at 5:34

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