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Use different size wire in electro clutch?

Discussion in 'Electrical Engineering' started by DaveC, Dec 17, 2009.

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  1. DaveC

    DaveC Guest

    The coil in an industrial electromagnetic clutch (connecting the flywheel to
    the drive mechanism) has gone open-circuit. So it is being rewound by a motor
    rewind shop.

    I was just informed that the original wire was about 12 ga. (maybe slightly
    larger; original was metric) but it was rewound using 10 ga.

    Should I be worried about this change in wire size? Will this change the
    magnet's strength significantly? The current draw?

    Here's the original schematic:


    "F" is the clutch coil. The machine isn't currently wired to mains so the
    clutch's exact operating voltage isn't known. The transformer voltage that
    supplies the rectifier bridge seems to be 32 v (per label on the schematic).
    Here's photos of the clutch. (The coil is imbedded in a groove in the metal
    cylinder.) ::






    Will this change in wire size cause me troubles?

  2. Eeyore

    Eeyore Guest

    Why do Americans persist in using stupid AWG that no-one else in the
    world uses except to entertain you ?

    Have you never heard of mm^2 ?

  3. Forget how to convert Graham?


    I don't think 10 awg will be a problem, as long as the # of turns is the
    same. Measure the current to be sure.

  4. James Sweet

    James Sweet Guest

    You paint with a wide brush. I'd be perfectly content to use metric, and
    end up using both systems regularly but it's not as if it's up to me
    what the whole country uses.
  5. Eeyore

    Eeyore Guest

    Oh I can convert. Trouble is, IME a single gauge can cover a range of
    CSAs. Plus it's pointlessly and wastefully time consuming.

  6. Rich Webb

    Rich Webb Guest

    Mostly inertia, of course. On the other hand, the AWG scale is right
    simple to use to swag the nominal wire resistance, given that it's a log
    scale and starting with AWG 10 = 1 ohm/1000 feet (yeah, "feet" but ...).
  7. Sjouke Burry

    Sjouke Burry Guest

    And you dont care about the rest of the world?
    If you want a clear answer ask a clear question.
    Dont hide behind obscure local encodings.
  8. krw

    krw Guest

    Forget the dumb donkey. He's just another jealous Europeon.
  9. krw

    krw Guest

    The subject excites you?
    Everyone knows that 42 is in base 13. ;-)
  10. krw

    krw Guest

  11. I like the way Peter Sellers says "pressurized firkins" in "The Magic
  12. Fred Abse

    Fred Abse Guest

    Metric magnet wire (enameled copper wire to you) is usually specced in
    diameter, rather than cross sectional area.
  13. Fred Abse

    Fred Abse Guest

    "About 12 gauge" is hardly an engineering statement. Didn't they use
    a micrometer?

    Possibly 2mm diameter.

    (maybe slightly
    #12 wire is 2.053mm dia. #10 is 2.588.

    Best practice would be to wind for the same number of amp-turns as before.

    From wire tables, changing from #12 to #10 wire,the resistance of the same
    number of turns will decrease by a factor of approximately 0.6. The
    current will correspondingly increase by a factor of approximately 1.6,
    hence so will the amp-turns, assuming the supply voltage stays constant.
    How much the strength of the magnet will increase depends upon the
    magnetic properties of the magnet iron. If the magnet was originally
    operated close to saturation, the increase in pulling strength may not be
    very much.

    The power dissipated in the copper is proportional to current squared,
    hence 1.6 for the same voltage. The coil will run hotter.

    There's also the issue of supply regulation. Will the transformer supply
    the increased current without significant voltage drop?

    Why did they rewind it using #10? Didn't they have any #12? I'm surprised
    they didn't have metric sizes, there are a lot of Japanese and European
    motors around.
  14. krw

    krw Guest

    No, my position is pretty safe.
  15. Guest

    Guest Guest

    Otherwise agreed.
    Any world wide "Standard"agreement is an extended version of what is going
    on in Copenhagen- politicians and special interests drag it out indefinitely
    as it is important to get ones first class travel to expensive
    places -preferrably in a warm place with cheap booze.
  16. Eeyore

    Eeyore Guest

    The USA is 'supposed' to be metricated. hy you choose to be so backward never
    fails to amaze me. Any given wire gauge covers a wide range of
    cross-sectional areas. At least you know what you're getting with mm2.

  17. Eeyore

    Eeyore Guest

    It is indeed. AWG does not specify an explicit conductor CSA.

    TOTALLY universal except for the USA, Liberia and Burma / Myanmar, both somewhat
    backward countries you have chosen to retain compatability with. Some might say the
    USA is rather backward too. The high level of belief in religion is one pointer to

    Conversion is a waste of time and a source of errors. There is only ONE system of
    units I need for engineering.

    And what did you get from going to the Moon ?

    Furthermore we have ESA
    and Galileo

    It knocks spots off GPS.

  18. Eeyore

    Eeyore Guest

    Oh dear ! Is that how it was specified ? At what temperature btw ?


    due to the hugely increased level of spam please make the obvious adjustment to my
    email address
  19. Eeyore

    Eeyore Guest

    What an absurd comment. Do you have 12 fingers so you can count in inches to the
    foot ?

  20. Eeyore

    Eeyore Guest

    LOL ! Give me a thou over a 'mil' anyday. Only the Americans could confuse a
    metric prefix with an old unit.

    Not to mention that if you use the word 'mil' in the UK it means a millimetre.

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