need help to fix electric fan

Hello
Trying to figure how to fix this electric fan ,I can feel fan housing vibrating but fan not spinning, if I spin fan blade the fan will spin few seconds.
The fan has 3 speed.
I open the back cover of the fan beside the switch there AC Capactor small plastic black box mark 2.5 uf 250 volt.
mrel

If you spin it by hand with no power applied, does the impeller turn free?

SOunds like a ceiling fan and your starter cap is worn with high ESR.

Buy another (cheap) . THese are plastic film motor start caps.

https://www.amazon.com/Tech-Ceiling-Capacitor-1-5uf-2-5uf/dp/B007XQOG1I

This https://www.hurontel.on.ca/~taitg/pages/cfan.html diagram might help a bit. I'm with everyone else, the capacitor. It only has two leads, right?

Here's https://ceilingfanparts.com/images/capacitor2.htm another source I've used.

I also agree with the check for very easy rotation by hand to see if the bearings need cleaning/greasing. If your in the US, I might be able to send you a small quantity of some really nice grease if you need it.

If the bearings are sintered bronze Oilite sleeve type, I would not use grease, these bearings are porous and if still good, unworn, wash them with Kerosene and soak them overnight in light oil.
Max.

Normally, I would agree, but the stuff I have is light, synhetic, high temperature, non-hydroscopic and expensive. I actually used it
to pack a bearing assembly with 2 oilite bearings within a 1"x2.5"x2.5" space in a gas dryer. 48 YO NOS assembly looked like it was packed with sawdust. I put a brass tipped set screw on the drive pulley which should act as a mechanical fuse. The OEM used grase and Oilite and it lasted 47 years. I wish I knew about the assembly sooner, so it could be part of the PM. The shaft temperature runs at 110 deg. F.

Does the fan have a capacitor, if so it could have failed, and this would cause the symptoms you have described.