Author Topic: Stand Fan And Floor Fan Cannot Start Turning  (Read 19149 times)

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Offline Boris_yo

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Stand Fan And Floor Fan Cannot Start Turning
« on: July 18, 2013, 05:39:01 pm »
These fans are old I would say and as time passed, they started to refuse to start at low speed levels. There are in total 3 speed levels on each and as more time passes, fans require higher speed levels to start turning. Recently both fans start only on final 3rd speed level and one of fans, starts barely turning and it takes less than minute to start turning normally. I can however reduce speed level to 2 on one of them and it keeps spinning at lower speed but should I set it on 1st speed level, it soon stops turning. You can hear z-z-z-z-z sound as fan struggles to start turning.

I am wondering why this is happening fans. Do fans have starter or their motor gets weaker after a while? Is there something I can fix or it is time for me to get new fans?

Finally, when buying new fan does it matter with how many paddles in order to ensure fans durability? I fans with 3 and 5 paddles.
 

Offline SeanB

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #1 on: July 18, 2013, 06:05:05 pm »
You need a new 2.2uF 275v capacitor in the fan, it has gone low in value, and as well the grease in the bushings has gone hard, and needs to be relubed with regular engine oil. Some have a split capacitor with 3 leads, one section is 0.5uF, the other is 1.5uF. Easy to tell as it has 3 leadout wires.

As to blade number, it makes no difference, the motors inside are likely the same cheap motors made by assorted small vendors using the same patterns, they are all cheap and nasty.
 

Offline Boris_yo

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #2 on: July 18, 2013, 06:22:42 pm »
Must I give fan's current capacitor time to discharge in order to not get electrocuted? Is this task of replacing capacitor feasible for DIY'er in home repair like me?
 

Offline SeanB

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #3 on: July 18, 2013, 06:30:06 pm »
Discharges in under a second, and is easy to replace, it is a black rectangular device at the rear, either with a single screw holding it down or just taped in place.
 

Offline IanB

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #4 on: July 18, 2013, 07:18:21 pm »
Before you look at electrical issues, make sure the fan blades spin freely without any resistance. If the bearings are gummed up then no electrical cure will help.
« Last Edit: July 18, 2013, 11:06:09 pm by IanB »
I'm not an EE--what am I doing here?
 

Offline bilko

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #5 on: July 18, 2013, 08:45:29 pm »
It definitely sounds like the bearings need cleaning and oiling. A couple of drops of sewing machine oil works well.
 

Offline Smokey

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #6 on: July 18, 2013, 08:58:43 pm »
Fans are dust magnets.  That dust gets into the oil/grease and makes dust paste which has huge friction.  Clean up the mechanical bits and it should run fine.  Just don't forget to replace the oil/grease.
 

Offline SeanB

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #7 on: July 19, 2013, 06:21:46 pm »
The grease used is poor quality ( I think they make it out of old cooking oil that is rancid, just boiled and mixed with clay) and goes hard and polymerises with time, but as well the capacitors are not good and slowly go low in capacitance, compounding the problems.
 

Offline Boris_yo

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #8 on: July 19, 2013, 08:29:17 pm »
You know this because you reverse-engineered fans?
 

Offline bilko

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #9 on: July 19, 2013, 09:10:40 pm »
Its called servicing and maintenance  ;)
 

Offline SeanB

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #10 on: July 20, 2013, 04:59:42 am »
It's called being an electrician and having a lot of fans around in a hot country. I do white goods at work, but do not do it private or for free. I meet these slow fans a lot, though often they are so poorly put together it is easier to buy a new one as the plastic parts will have gone so brittle that they shatter when touched.
 

Offline G7PSK

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #11 on: July 20, 2013, 03:35:25 pm »
Most of these fans run in oilite bushes (http://en.wikipedia.org/wiki/Oilite) they dry up after a while and the bearing becomes tight, its best to replace them but often not worth the cost of doing so. You can in such cases just mix some oil an benzine, about 80% oil in the mix and wash the bearings in petrol or benzine and then soak in the mixture over night, works in most cases sometimes after doing so the bearing will rattle because although the motor stops due to sticky bearings the bush has actually worn. If the bearing are small ball races these are very often sealed and the only sensible thing is to replace them any good bearing supplier should stock them, if there is no number written on the inner race just take the inside shaft dia. and the outer dia. and the width and you should be able to find a match, most bearings are an off the shelf item very few are made a special size.
« Last Edit: July 20, 2013, 03:40:09 pm by G7PSK »
 

Offline Boris_yo

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #12 on: August 13, 2013, 06:47:33 pm »
@SeanB Attached is the picture of motor after I took off plastic covering of my 12 year old fan. You mentioned capacitor but there isn't any that I could find.
 

Offline M. András

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #13 on: August 13, 2013, 06:53:36 pm »
lol its the black screwed rectangular thing
 

Offline SeanB

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #14 on: August 13, 2013, 07:41:25 pm »
Standard 1u5 unit, common on these units. Clip the black and white leads to it close to it and replace it. It probably will measure well under 1uF if you measure capacitance. The motor normally stops turning at about the 500n mark.
 

Offline Boris_yo

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #15 on: August 14, 2013, 10:06:52 am »
How do I measure capacitance? All I have is multimeter.
 

Offline IanB

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #16 on: August 14, 2013, 01:23:32 pm »
You don't. You simply obtain a replacement capacitor of the same specifications and fit it. Assuming the motor has no other problems like stuck bearings or burned out coils it will now work.
I'm not an EE--what am I doing here?
 

Online Shock

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #17 on: August 14, 2013, 01:51:30 pm »
Fixing the mechanical problem first does save time :)

How do I measure capacitance? All I have is multimeter.

http://bit.ly/16PwAIK

Cap will cost you around $5 plus shipping all the specs are right there on the capacitor.
You should read up on how capacitors work, how to read their specs, and how to safely discharge them.
I am concerned if your repairing things like this to use or sell, as lack of knowledge on appliance repair can easily kill someone.


 


« Last Edit: August 14, 2013, 01:56:00 pm by Shock »
Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 87V, 117, 27/FM       >>> WANTED STUFF <<<
Oszilloskopen: Lecroy 9314, Phillips PM3065, Tektronix 2215a, 314
 

Offline MrAureliusR

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #18 on: August 14, 2013, 02:26:37 pm »
I am concerned if your repairing things like this to use or sell, as lack of knowledge on appliance repair can easily kill someone.

+1 to this. It seems the OP isn't even reading the replies to this topic, someone specifically mentioned the cap was a 'black box with either a single screw or tape holding it down' and then posted a picture with that exact description stating he couldn't find the cap...
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Offline Boris_yo

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #19 on: August 16, 2013, 01:18:53 am »
I have found black rectangular capacitor although the problem now is that before I did anything, the fan stopped working. Initially it took it warm up time to start spinning and at that time I could barely hear motor working. Now however it does not work and nothing can be heard from it. Maybe bearings are stuck? In addition to bad capacitor this can be another problem.
 

Online Shock

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #20 on: August 16, 2013, 04:23:27 am »
Think to yourself...  how could I test if the bearings are stuck?
Soldering/Rework: Pace ADS200, Pace MBT350
Multimeters: Fluke 87V, 117, 27/FM       >>> WANTED STUFF <<<
Oszilloskopen: Lecroy 9314, Phillips PM3065, Tektronix 2215a, 314
 

Offline G7PSK

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #21 on: August 16, 2013, 07:44:05 am »
I would say that the bearings were tight and now that you have persisted in running the fan despite all the information given, the windings have given up the ghost which is why you cant hear any sound from the fan motor. :-BROKE
 

Offline dr_p

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #22 on: August 16, 2013, 07:51:49 am »
Ghost or no ghost, it's not dead until the magic smoke is released. :D
 

Offline David_AVD

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #23 on: August 16, 2013, 07:54:15 am »
"If at first you don't succeed... run the bastard into the ground until it doesn't work at all !"   :-DD
 

Offline SeanB

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Re: Stand Fan And Floor Fan Cannot Start Turning
« Reply #24 on: August 17, 2013, 06:11:00 am »
Those motors are about the only thing into which the cheap ass manufacturers actually put a thermal fuse, typically a 112C unit. Buried in the windings inside, it is possible to replace it, but you will find it difficult to do. I keep a small packet of around a dozen for that. Typically though if the windings have gotten that hot that the fuse melts then they themselves will fail later.
 


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