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Replacing Aluminium windings for Motors with copper wires

  1. Jul 11, 2010 #1
    Good Day,

    I have defective Aluminium windings motor.

    As you know Aluminium is very difficult to winding.

    So, I want to use Copper wire to re-winding the motor.

    How can I do that?

    What size should I use and what will be the number of turns?

    Someone told me that you can use Copper by reducing 15% from the sectional area of Aluminium wire.

    Another one gave me this table:

    [PLAIN]http://img401.imageshack.us/img401/2595/tablebf.jpg [Broken]

    Copper Diamet mm Aluminium Diameter mm
    0.3 0.3795
    0.35 0.44275
    0.4 0.506
    0.45 0.56925
    0.5 0.6325
    0.55 0.69575
    0.6 0.759
    0.65 0.82225
    0.7 0.8855
    0.75 0.94875
    0.8 1.012
    0.85 1.07525
    0.9 1.1385
    0.95 1.20175
    1 1.265
    1.05 1.32825
    1.1 1.3915
    1.15 1.45475
    1.2 1.518
    1.25 1.58125
    1.3 1.6445

    I need your advice, please.
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Jul 11, 2010 #2
    This table shows that the aluminum to copper cross section area ratio should be 1.6:1


    so the diameter ratio should be about 1.265:1, as per your table.

    Bob S
  4. Jul 12, 2010 #3
    Thank you

    So, I can use that table without changing the number of turns.

  5. Aug 22, 2011 #4
    Currently, I am using that table, and it is very good , no excessive heat.
  6. Aug 28, 2011 #5
    You could probably improve the motor characteristics slightly by going to a slightly larger diameter copper wire, but if you change the number of turns, you will change both the coil inductance (important in ac motors) and the Tesla per amp. Also, in some ac induction motors (split phase), wire resistance is an important part of the design. Also, in some dc brush motors (shunt wound), wire resistance is important.

    Bob S
  7. Aug 29, 2011 #6


    User Avatar
    Gold Member

    Though I doubt it's relevant to this apparently one time fix:

    Copper and aluminum have different coefficients of expansion and heat conductivity. Aluminum wiring when attached to electrical terminations not designed to accommodate the difference has been shown to cause electrical fires through on/off power cycling, causing the connection to loosen over time thus increasing resistance which accelerates the mechanical issue to the point of connection failure.
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