Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Fan AC Motor adaptive use - problem

  1. Jan 29, 2010 #1
    We have adapted a 60W A/C Fan Motor, 1500 RPM to run two spindles one at 6000 RPM and the other at 500 RPM using pulley & belt. On continuous use the motor heats up excessively and a few fail.

    Load is winding of threads from a Cone to a bobbin.

    I need a few suggestion

    i) Can rewinding the failed motors with a higher gauge copper wire solve the problem.

    ii) How do you determine the load and create specification so that I can buy an appropriate motor capable of handling the load.
  2. jcsd
  3. Jan 29, 2010 #2
    If the motor is properly designed and operating on the correct voltage, changing the wire size will make the motor run hotter.

    Rewind the motor using a higher temperature insulation may be an option.

    Blowing air over the present motor may be a solution.

    Get motor with twice the horse power?
  4. Jan 29, 2010 #3
    AC electric motors on the 60 W range are in an awkward wattage range which is too low for induction motors (usually 1/6 HP-125W) and up. The really low (and cheap) HP motors are called shaded pole, because a resistive copper strap surrounds part of the pole. These get very hot due to the resistive copper strap (needed to produce a starting torque). There are some permanent capacitor start-run ac motors that use capacitors rather than resistance to shift the ac phase. What are details of your motor?

    LOWER gauge wire has LESS resistance. Fractional HP split phase motors use wire resistance to produce a phase shift in the starting coil, so changing wire gauge will change starting torque.

    Start your search in the Grainger catalog:
    http://www.grainger.com/Grainger/motors/ecatalog/N-bii?op=search [Broken]

    Bob S
    Last edited by a moderator: May 4, 2017
  5. Jan 29, 2010 #4
    Rewinding small motors is probably a bad idea because you'll violate the UL/CSA/VDE underwriting. Along with that, you'll have the cost issues.

    When you're uncertain of the load, it's good to try an induction motor that's well defined. Run it at it's rated voltage, and check the shaft RPM and current draw.

    Be careful of shaft loading. If you've got pulleys, but your motor is designed a simple fan, then you're likely to wear out the bearing prematurely. Ball bearings hold up to these radial loads better than the more common sleeve bearing.

    You might go through this site for motors:

    http://www.emersonmotors.com/products/ecatalog.htm [Broken]
    Last edited by a moderator: May 4, 2017
  6. Jan 29, 2010 #5
    Further specification on the motor mentioned Temperature Rise < 75 K [I am unable to figure the temperature rating]

    Also it uses a 2muF 450V capacitor

    Onload Spec
    A = 0.3 A
    P = 60 W
    RPM = 1350

    230 V, 50 Hz Capacitor Motor

    I tried running the motor with no load for 20 minutes and noted temperature 52 C [126 F]. Then used my hand to stop the shaft for a second or two and the motor failed. Is the motor faulty?


    Attached Files:

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook