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Why aren't the coils in electric motors insulated?

  1. Feb 29, 2012 #1
    In all the electric motors I have taken apart, the coils on the armature have never been insulated. This has always confused me because, how could the coil make a sufficient magnetic field if it shorts out to the adjacent wires from lack of insulation?
     
  2. jcsd
  3. Feb 29, 2012 #2

    DaveC426913

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    Are you sure they're not coated in a thin layer of clear sheathing?
     
  4. Feb 29, 2012 #3
    I have suspected that but I do not know for sure. I was wondering if anyone else could confirm. :]
     
  5. Feb 29, 2012 #4
    They are insulated with a think transparent layer of insulator.
     
    Last edited: Feb 29, 2012
  6. Feb 29, 2012 #5
    No, I don't think it's transparent.

    Magnet wire is coated with a thin layer of enamel. The color is usually gold, making it appear similar to bare copper. It also comes in other colors, such as red and green.
     
  7. Feb 29, 2012 #6
    Cool thanks guys!
     
  8. Feb 29, 2012 #7
    Thanks a lot. Do you know how to remove the insulation before soldering? Or is it removed by the heat while soldering? I usually use flame to remove the insulation first. Sometimes just scratching them by a knife! I wonder if there was a more efficient way.
     
  9. Feb 29, 2012 #8

    DaveC426913

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    Wire strippers are the correct way.
     
  10. Feb 29, 2012 #9
    Yes, there is a more efficient way. You can buy a machine that is designed for removing the insulation. However, the price is probably too high for the hobbyest. I used such a machine many years ago when I worked for a motor manufacturer. At home I usually just lay it on a flat hard surface and scrape it with a sharp knife. I've never had much luck with using wire strippers on magnet wire.
     
  11. Feb 29, 2012 #10

    Pengwuino

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    How do you use wire strippers to take off such a thing layer?
     
  12. Feb 29, 2012 #11

    DaveC426913

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    Mm. Good point. It's not designed to be stripped like regular electrical wire, is it? It won't just slide off.
     
  13. Feb 29, 2012 #12

    AlephZero

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    Modern "enamelled" wire usually has a plastic coating that will burn off cleanly during soldering. The wire in old motors etc uses "real" enamel which needs to be scraped off with a knife blade or fine sandpaper.

    There are electrically powered tools available to do this on an "industrial" scale.
     
  14. Mar 1, 2012 #13
    Apparently some types of enamel could be stripped by placing the wire on aspirin tablet and heating with a soldering iron (or so the urban legend says). Never tried it myself though.
     
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