Ceiling Fan question

Discussion in 'General Electronics Chat' started by Gdrumm, Jan 4, 2014.

  1. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
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    36
    The string of a party ballon got caught in the fan.
    It locked up.
    I was able to remove the string, but the fan turned very slow.

    I took it down, and disassembled it, and checked what I could.
    One red wire from the 5 wire cap tested below the 5% allowable in microfarads.

    I changed the cap with a used but good spare of the same type (5 wire).
    It made no difference.

    Basically, now when I turn on the power to bench test it, the fan locks up like a brake, and it humms.
    Forward or reverse makes no difference; fast, medium or slow, makes no difference.

    Does anyone have a speculation about what is wrong with the fan?

    I see no visual evidence of damage.

    Thanks for reading, and all replys welcome.

    Gary
     
    Last edited: Jan 4, 2014
  2. inwo

    Well-Known Member

    Nov 7, 2013
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    315
    If it's connected properly and turns free, it must be a bad winding.

    Some fans are impedance protected, but maybe not all.:(
     
  3. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
    684
    36
    Thanks, for the reply.

    Winding wires are coated, so what's the best way to test for bad winding?

    Can I scratch off some coating and test for continuity?

    Can you explain impedance protection a little more?

    Is it a fail safe, similar to a thermal fuse?

    What would it look like, and is it replaceable / repairable?

    Thanks,
    Gary
     
    Last edited: Jan 4, 2014
  4. inwo

    Well-Known Member

    Nov 7, 2013
    2,435
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    I can't think of a good way to test windings unless you could compare resistance to known value.

    Someone else may come up with a way to "ring" the windings.

    Impedance protected means a motor is designed to not burn out if rotor is locked. The locked rotor impedance is high enough to limit current to a safe value.

    I really don't know how common it is in ceiling fans.

    Any chance of mis-wiring?

    You could disconnect all the controls and switches and connect windings only with one known good capacitor.
     
  5. wayneh

    Expert

    Sep 9, 2010
    12,153
    3,059
    Are you sure the bearings are OK and the fan is really spinning freely? It wouldn't take much resistance to prevent rotation.
     
  6. Gdrumm

    Thread Starter Distinguished Member

    Aug 29, 2008
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    It seems the outer ring is warped?
    During a spin I an hear rubbing, and I can see a gap difference from side to side.

    I guess it's time to replace it.

    Thanks,
    Gary
     
  7. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    Some use ball, others employ sleeve bearings, which may or may not be a self-centering type... How old is the unit..?

    In the event the invasion of the ribbon skewed a dry sleeve bearing, or damaged the end-play washers in some way, it would refuse to turn freely.
    is the gap difference in the verge betwixt stator and rotor ? it may be it's just misaligned...
     
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