Need help fixing electric fan

Discussion in 'General Electronics Chat' started by mrel, Oct 27, 2015.

  1. mrel

    Thread Starter Active Member

    Jan 20, 2009
    97
    1
    1. Hello
      Trying to figure how to fix this electric fan ,I can feel fan housing vibrating but fan not spinning, if I spin fan blade the fan will spin few seconds.
      The fan has 3 speed.
      I open the back cover of the fan beside the switch there AC Capactor small plastic black box mark 2.5 uf 250 volt.
      mrel
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,061
    3,834
    Generally, there are a few possibilities.
    1) the oil-impregnated bushing on the motor is dried out and has high friction (usually if not used in a long time).

    2) the capacitor has failed (often from not being used but can just get worse with age and fail)

    3) the power switch fails - builds up oxides (looks like "carbon" but it is black copper oxide) and high resistance on the switch. "High" can only be a few ohms or tens of ohms on your ohm meter but enough to cause a problem.

    If the blade turns easily by hand, and the switch has reasonably low resistance, I would focus on the capacitor.
     
    Roderick Young likes this.
  3. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,795
    951
    Add some oil to the shaft. If the back end is not accessible, then minor disassembly is required.

    I've fixed many many fans this way. The fact that you can spin it by hand and it works for a short while is a good indicator it needs lube.
     
    Roderick Young likes this.
  4. #12

    Expert

    Nov 30, 2010
    16,338
    6,823
    If the switch is good, and the oil and the capacitor don't fix it, the motor windings are bad.:(

    I have never bought a 20 inch box fan. I find them set out on trash day, replace the fuse, oil the bearings, and use them for years.:p
     
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