My ceiling fan speed has gone low currently.

First check the regulator

Then Power supply by tester into FAN motor

By changing condensor of same rating

even , it is not recetified

Take help of electrician to check the fan motor or bearing

Checking is not very complex , it is very simple .

This may be an often overlooked cause but it was the problem in my case. I had a fan which has a 400 mm sweep. A few months ago I sent it for rewinding and after it came back started running slower than before. The rewinding agency and the local electrician concluded and tried to convince me that factory original winding has an edge over a refurbished job and hence the lack of speed. After a lot of tinkering I compared it to the same fan installed in my bedroom and found out that the blade angles may be the culprit. It so happened that while removing the fan and refitting it, the blades got twisted and two out of four actually drooped a bit lower than the recommended angle. I spent 30 mins adjusting the angle an the position of the four blades using a reference point from the (dangled a thread and marked where each blade should be touching the leading the trailing edge) and to my surprise a small adjustment to the blades made a significant increase to the RPM. I should have noticed the fan actually getting hotter when ever I touched it in the past and I often disregarded it thinking of it as a result of extended run periods. It was not, it was a result of higher aerodynamic drag. Point to remember is that ceiling fans are not high in torque (they are medium to high RPM motors ) and hence they cannot cut through the air efficiently if the blade angles are not optimal. Hence even a slight misalignment of the blade angle can cause a significant drop in RPM and air flow.. I also noticed that all fans in my house were running much slower than before and found out the second reason. Our domestic helper often holds the blades while cleaning it and this ends up bending them and altering the angle of sweep which creates un-desired drag and lower RPM, some were actually wobbling. The wobble was caused due to one blade being out of position and this causes the anchor eye bolt to grind. As for the capacitor it either works as expected or does not, there is no degradation that you wont notice and a factory supplied capacitor works minimum 3-4 years with out any problems considering normal domestic usage. And putting a higher capacity capacitor makes no big difference for domestic fans but you must ensure they are rated correctly. Check again, and adjust the blades and it may just solve your problem.