Ceiling Fan Capacitor

[RD_Atlanta]

Perhaps someone could provide some direction.
- Ceiling fan, 25 years old, used 2/3 of every year but very clean.
- Temps dropping so I shut it off one night.
- The next day, after starting it the motor area began producing a subtle but strange noise that I can only describe as imagine two Phillips head screwdrivers and occasionally one of the screwdriver shafts slides down the other (a clean metallic scraping). The repetition is random. Only happens wen the motor is running (the bearings are fine). I tightened all mechanical components.
- Then the medium speed (the speed it is mostly run on) started slowing.

I'm glad to replace the capacitor (image attached). But for the life of me I can't reason out what I'm hearing or why. Can a failing capacitor cause such a strange noise as this?

Thank you for any input.

[stj]

Re: Ceiling Fan Capacitor

if you turn it by hand is there any friction or wobble?
the thing in the picture looks like it's for interference suppression

[RD_Atlanta]

Re: Ceiling Fan Capacitor

Thank you. Sorry, I was not aware of inclusion of interference protection.
There is a second block labeled 4L (photo attached). Would that be a run capacitor? Do you know what 4L indicates?
The subtle noise seems to me to be excited by motor magnetism as far as I can tell. It spins very free by hand and has no wobble.

[R_J]

Re: Ceiling Fan Capacitor

It is likely 4µf 250vac, they are listed everywhere as fan capacitor

[abhi.1981]

Re: Ceiling Fan Capacitor

Sometimes a worn out lower shaft creates noise as it moves freely inside the bearing ring. There is a spring on the shaft which prevents slippage.

[DrewPhillips]

Re: Ceiling Fan Capacitor

Sometimes the motor will spin freely by hand, but the bearing is stuck due to dried-out grease and the shaft is just slipping in the bearing's inner race. Disassemble, clean out the old grease (lacquer thinner works well), re-grease (synthetic is best) and reassemble.

If you are lazy like me, skip the cleaning and just oil the bearing well with synthetic (such as Mobil 1 or equivalent) which will solubilize the hardened grease. You may need to first pry out the seal(s) if any. Rotate the shaft a few turns and visually verify no relative motion between the inner race and shaft to ascertain that the bearing is indeed free. I oiled a squeaky fan like this (without first removing the old grease) in 2012 and now it is still running fine and quietly. The synthetic oil does not lubricate any better than conventional oil, but is much more resistant to gumming up.