My fan motor is not spinning.

Discussion in 'General Electronics Chat' started by electron_prince, Apr 27, 2014.

  1. electron_prince

    Thread Starter Member

    Sep 19, 2012
    93
    3
    Hello all,
    last year I tried to start my old fan and it wasn't starting. Then I tried to rotate the fans by my hands with power on to the motor and I felt like there is some torque which is acting in the reverse direction (i.e trying to prevent the fan to rotate). I am not exactly sure whether it was some mechanical jamming or there is some electrical torque built up in a reverse direction. Then I turned off the power to the motor and I rotated the fans like 25-30 times in the correct direction ( I even can feel the torque but as I rotate more and more the torque decreases) and then I powered on the fan and it started spinning. The speed of the motor gradually went down and in like 2 hours it stopped.
    Everyday I used to do the same thing, spin it for 25-30 times with power off and then it starts. But after few days it's completely dead.

    Now this year, I tried to spin the motor and I didn't feel any opposing torque or jamming. But the fan is still dead i.e not starting on power supply. What could be wrong with the fan? Is it the condenser/capacitor?


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  2. Brevor

    Active Member

    Apr 9, 2011
    279
    54
    It looks like a POS, I think you need a new fan. If you feel resistance when you turn it by hand the bearings are probably dry and worn out.
     
  3. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,761
    1,099
    Agreed. You probably needed a new one several years ago! Shame to disturb the spider at the top of the pic :)
     
  4. ErnieHorning

    Member

    Apr 17, 2014
    67
    17
    You're probably right though, the condenser is likely bad from reading your description. But even if you replace it and the motor starts running again, you're probably also right in that the mechanical jamming (bearings) will fail and seize the motor permanently shortly thereafter.

    You could spend the money and attempt to fix the motor (and you may succeed) but in the end you likely spend the same amount of money and you will still have an old motor that more likely to fail again.
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,494
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    +1 on the lack of maintenance, these usually have Oilite bronze bearings that eventually dry up.
    You may have a job buying a 'Condenser' these days. :p
    Max.
     
  6. ian field

    Distinguished Member

    Oct 27, 2012
    4,412
    782
    The spider did it.
     
  7. electron_prince

    Thread Starter Member

    Sep 19, 2012
    93
    3
    lol, I too saw that spider in the picture while posting that pic here but I thought (s)he is going to be overlooked by people. I didn't know that (s)he has an attractive personality to capture everybody's view. :p

    Seriously, I don't need that motor/fan whole year except in summer so I need to store it in a store room. Here summers are extremely hot and you need a fan even in places where you spend just 10 minutes a day. That is why I was trying to save some money. :p

    Anyway, I'll buy a new one :)
     
  8. wayneh

    Expert

    Sep 9, 2010
    12,083
    3,022
    Good idea. You'll save more on electricity by not using so much just to turn against an old bearing. Is that a "swamp cooler"? You might do well to find a fan or motor that is better suited to rough (high humidity) service.
     
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,494
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    I went to one site where that were advertising these types 24" extraction fans, the guy on the promotion video obviously a salesman, "120v and 130Hp" !!:eek:
    I think he missed the fraction notation.:p
    Max.
     
  10. #12

    Expert

    Nov 30, 2010
    16,247
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    Lovely old motor, but you proved the bearings are bad, a long time ago, and now it isn't even trying? I think it has a bad winding. Even if the condenser is bad, you should be able to feel a tiny vibration and the motor would "try" when you move it by hand with the power on. (Insert funeral music here.)
     
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Even you too? :confused:
    Max.:)
     
  12. #12

    Expert

    Nov 30, 2010
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    What? Using the words of the OP is somehow wrong?
    Just trying to communicate. :D
     
  13. MaxHeadRoom

    Expert

    Jul 18, 2013
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    OK we'll let it go this time, OK. :)
    Max.
     
  14. Lundwall_Paul

    Member

    Oct 18, 2011
    220
    19
    A lot of old fan motors can be disassembled and the bearings can be cleaned and lubed. Then it will last many more years. If the bearings are shot you may be able to replace them.
     
  15. #12

    Expert

    Nov 30, 2010
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    Thank you. :D
     
  16. Brownout

    Well-Known Member

    Jan 10, 2012
    2,375
    998
    I don't get it. We can't say condenser anymore?

    No country for old farts?
     
  17. #12

    Expert

    Nov 30, 2010
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    As long as this is droning on, the word "condenser" was one of the worst puzzles of my young life. What can a capacitor possibly condense and why would anybody call it that???

    Then I met air conditioners.
    The part where water condenses is called the evaporator and other end (the hot coil) is called the condenser. Go figure. :D
     
  18. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The automotive guys still use it for some reason, I guess it just stuck with them?
    It virtually dissapeared from the Electrical/Electronic scene around 1950, apart from a few hold-outs.
    Max.
     
  19. ErnieHorning

    Member

    Apr 17, 2014
    67
    17
    The capacitor was invented in the year 1746, by a Dutch scientist named as Van Mussenbrock. Initially, it was known be the name ‘Leyder Jar’, as it was made using a glass jar filled with water. This jar was charged with static electricity. This jar was capable of storing electric charge in a very small space, and hence the name ‘condenser’ was born.

    I’ll look this stuff up, so you won’t have to. :p
     
  20. #12

    Expert

    Nov 30, 2010
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    That reminds me of the old beliefs about the "ether" that radio waves were supposed to travel through. So, a capacitor seems to condense electricity to fit more of it in a small space. That makes sense if I just think about how my grandmother viewed the world and add a couple of centuries. :D
     
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