EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: sam1275 on July 25, 2018, 02:07:56 pm
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Hello.
There is an AC fan that used to work constantly for a long time, it got stuck several months earlier, I took it apart and cleaned the dust and mud, then add some oil, then it recovers.
But here is a second time, but this time after I make sure it can rotate freely, it still do not work, the motor just vibrates/makes low frequency sound when power is delivered, what could broke and how to troubleshoot it?
Thanks.
Edit: Thank you everyone.
I explained everything in the latest post: https://www.eevblog.com/forum/beginners/electronic-motor-failure/msg1704047/#msg1704047 (https://www.eevblog.com/forum/beginners/electronic-motor-failure/msg1704047/#msg1704047)
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Does it have a capacitor?
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What happens if you give the motor a spin by hand before you apply power?
Does it keep rotating (in the direction you spinned it) or does it coast to a halt.
Is it a low powered fan, which won't cut off your fingers?
Then you might try spinning it after power is applied.
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If it spins freely by hand but just hums when you power it, that's a classic symptom of a PSC motor with a faulty or disconnected run capacitor.
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I never had much luck fixing/cleaning the bearings of such fans.
A clean/re-oil usually lasted about two weeks.
If the bearing/fan got stuck, after a while the thermal fuse would let go.
Those bearings are bush-type synthered bronze bearings, soaked with oil.
Just adding extra oil does not seem to work.
May be if you would boil the bearing in oil it would help. Or just get new bearings.
But then it gets to the point where it is simpler/cheaper to get a new fan, at the end that is what I did.
EDIT:
I did try grease as well, did not really help either.
Good luck, Peter
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I've found that adding grease instead of oil sometimes works well, so long as the bearing has not worn badly from running dry. I used automotive wheel bearing grease.
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What happens if you give the motor a spin by hand before you apply power?
Does it keep rotating (in the direction you spun it) or does it coast to a halt.
Just saying.
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Sorry for the late reply.
Yes it has a capacitor in serial.
It's not a high powered one that will hurt me.
It had a extremely weak force to rotate, not easy to feel.
However everything ended today, after I took off the screws, I pulled it apart, and yes it's really apart, the wire just break completely and everything are in a very aged state that lots of rubber/plastic parts flies everywhere.
I think that's because the long time jamming made the motor too hot. RIP...
Thank you everyone.