Ceiling Fan suddenly become dead slow


My ceiling fan which became a little slower after 1 year, has now become dead slow to the point it hardly spins. Specially last night when electricity went off due to load shedding, it almost failed to spin on ups and I saw that it was putting so much load on ups that lights of ups were gone dim and ups started sounding link "drann drann".

I suspect its capacitor has gone bad and will be changing it today. Any other cause which can raise such problem? I pray its not the winding of the fan which has gone bad :(


most probably capacitor need replacement

As stated above, capacitor needs to be changed. Are you using modified/square wave UPS?

Main winding, Run winding, capacitor and bearing seizure can all be causes.


Thanks all.

As suspected, capacitor was the culprit. I have changed capacitor and its working fine now. Asad bro, I think I am using modified square wave ups as its local kit IB4 from Imran Brothers Lahore Hall road and their 15+15 module.

One more think I want to ask is how much fix volt should I set for the output of UPS. Currently its set for 245v. If I bring it down to 220v then transformer starts giving buzzing sound and as I go up to 250v then transformer becomes soundless.

Why this behaviour ?


ups output should be 225V to 230V max (this is the standard accepted voltage range in the 208-240V category) .. since on heavier load it will come down to 220 or 218V. this happens with all desi ups and even some imported ones as well. anything above 230V would stress the home appliances.

you can use a stabilizer on the OUTPUT of the ups to convert the 250V to 225V :P JK..

Unless you use a full sine wave UPS, you will have recurring issues with fan capacitors having short life, dimmers getting damaged, CFL lamps getting damaged frequently, LCD PSU supplies blowing capacitors (strictly depends on quality of PSU inside LCD), and other numerous small issues with various appliances.

yes , modified wave or square wave is only good for emergency / temporary use . If you want permanent use (like people do in regular electric load shedding) then it is better to buy a sine wave inverter than to burn expensive gadgets which will give him more loss in the long run .

ohh people have so much knowledge over here regarding any product :o and get well soon Mr. Fan :D

Thanks all for your valuable feedback and lovely comments :)

The thing is that only APC comes in mind if we think about sine wave but it's expensive, plus hard to repair. I have seen people running lots of LCD and other stuff on desi ups without any problem to devices, even a company CEO is running his entire office load including many PC and laptops on desi ups.

Setting 225v as out reduces fan speed.

higher voltage to ANY motor based device will increase its speed/performance upto a point then it will overload and burn it.. the fan is designed to run at 225v, at that specific speed.. so compare the speed of fan at 220V wapda and 220V ups, and then tell if there is a difference.

Desi UPS are the worst of their kind, they generally are square wave,with least control on battery charging and discharging thresholds. You should at least go for a modified sign wave UPS. For a 24V battery bank, it will cost you around 12k-13k for a good chinese one (affordability).

1 Like

So forum is back again :slight_smile:
@farhan_ds bro you are right about the over voltage overloading fan but a ups guy told me that the modified square wave voltage of desi ups are a bit low as compared to wapda voltage hence we can assume that 250 volts of desi ups are almost equal to 220 volts of wapda. Don’t know if its true or not.