motor repairs

Discussion in 'General Electronics Chat' started by caulfield6, Feb 26, 2012.

  1. caulfield6

    Thread Starter New Member

    Dec 15, 2011
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    Hi,
    Just been given a task to fix a fan. The motor is running slow and very hot. Ive been looking on the motor itself, and couldnt find much in the way of markings or anything and was wondering if anyone could help point to a place where I might be able to get a new motor.

    The only things on it are a label with:
    220v-240v
    50hz
    0.13a
    IEC 355 ( i think this is the shape/frame size)
    a funky circuit diagram.

    and 0348 written on the bottom of the chassis.

    Im trying now to open it. If anyone could reccomend a place to get a replacement, or anything to look for when i open it that would be appreciated.

    Pat
     
  2. #12

    Expert

    Nov 30, 2010
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    Look for dry bushings. A spot of oil has saved many a fan at my house.
     
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Look if you find capacitors in there. Check their values.

    Is the rotor turning ok when you turn it by hand or is there a lot of resistance?
     
  4. caulfield6

    Thread Starter New Member

    Dec 15, 2011
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    the rotor turns ok when i do it. the capacitor which is also part of the circuit diagram but seperate is a 1.0uf and is correct size.
    The bearings seem to be well oiled. Ill have a look at the bushes now.
     
  5. caulfield6

    Thread Starter New Member

    Dec 15, 2011
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    what would be the best type of lubricant to use. Would wd40 be ok?
     
  6. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Just to make sure: You measured the capacitor value, right?
     
  7. #12

    Expert

    Nov 30, 2010
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    A slow, hot, motor with good bearings is a sign of bad windings. Keep looking. If you don't find anything else wrong it means the motor is dead.
     
    strantor likes this.
  8. caulfield6

    Thread Starter New Member

    Dec 15, 2011
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    read what it said on the side. 1uf +- 10%.. looking now for multimeter to test it.
     
  9. caulfield6

    Thread Starter New Member

    Dec 15, 2011
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    that was my first thought too with The bad windings. Hence i was looking to find where i could get a new one.
    I couldnt find any bad windings, and when i opened it, was kind of overwhelmed. Thought looking in all that for one bad winding was a pointless ordeal.
    Looking at the rotor the bushings on it, seem to have some shiny spots, is it possible that it could be rubbing against the bushings?

    Couldnt find multimeter. how could the cap's value make that much difference. It was working a while back, so i wouldnt think that the problem was with it?

    I have a feeling that the fan blades got caught on some junk in the vent, and caused it to overheat? Is this possible?
     
  10. #12

    Expert

    Nov 30, 2010
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    Nobody finds the bad winding and repairs it. You have to get the whole thing re-wound.
    Rubbing is possible, but not the likely cause of failure.
    If the capacitor goes open or shorted, that will affect the running of the motor. They go bad suddenly.

    Overheating is a very likely cause of blistered insulation, causing a partial short in the windings.
     
  11. caulfield6

    Thread Starter New Member

    Dec 15, 2011
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    Also have now realised that the actuator(?) whichis in parallel with the motor doesnt work properly either (its supposed to open the flaps). Yet it is power across it.
    So the cap is looking more and more like the culprit.

    Ive just oiled with WD40 and put it back together. Ill suss out how to check the cap.

    Anyone know an easy way to do it with a multimeter, which unfortunately doesnt have capacitance. Id be thinking checking the time it takes to charge?
    I really dont have the energy to work the maths at the moment.
     
  12. #12

    Expert

    Nov 30, 2010
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    WD-40 is NOT A LUBRICANT!

    Do not pretend that WD-40 can oil a motor!
     
    shortbus likes this.
  13. #12

    Expert

    Nov 30, 2010
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    Put the multimeter on a high resistance scale, like 100k, and watch it take a moment to stabilize. If it doesn't hesitate, either the capacitor is bad or you need to use a higher ohm scale.
     
  14. caulfield6

    Thread Starter New Member

    Dec 15, 2011
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    If i put it on the lowest scale (200ohm max) it fluctuates between 26-40 ohms and hasnt stopped yet.
    If i put it on the higher scales, it still continues fluctuating and doesnt stop.

    Does this mean it is a busted capacitor?
     
  15. #12

    Expert

    Nov 30, 2010
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    That looks like a bad capacitor. It should hesitate, then go to infinite ohms.

    ps, it should also not be connected to anything except the meter at one end (or both ends).
     
    caulfield6 likes this.
  16. caulfield6

    Thread Starter New Member

    Dec 15, 2011
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    replaced the cap, and got a new multimeter to test them out. The both function fine.
    Leaves me at the motor.
    The final question is where can i get a similar motor. Or even just coils and brushes.
     
  17. #12

    Expert

    Nov 30, 2010
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    No help from me. I'm in USA. You have 240 V @ 50 Hz. Probably England. The Brits will wake up in a few hours. They can probably help.
     
  18. caulfield6

    Thread Starter New Member

    Dec 15, 2011
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    Oh.. whoops. yeh... Im in Australia. Anywhere online that you know of?
     
  19. #12

    Expert

    Nov 30, 2010
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    Not me.

    ps, you should go to your account settings and put in "Austrailia" or "Kangaroo Land" or something like that.
     
    caulfield6 likes this.
  20. caulfield6

    Thread Starter New Member

    Dec 15, 2011
    13
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    Totally riding my kangaroo to school tomorrow. While my kookaburra flies ahead.
    Thanks for the help. I appreciate it.
     
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