AC motor experts?
Not rc related at all, but you are smart people here and I bet can help. Two unrelated(?) ac motor questions.
First, why would an ac motor whose speed is controled by the line frequency (60hz here) run slow? Bearing/bushings are clean and lubed, motor shaft is clean and lubed, in this particular case there are no contacting brushes(sorry my motor understanding/terminology is lacking). This particular example is a home turntable. I have two with this issue. These are 30+ year old motors and turn consistently but slower.
Second, home room fans. Almost all my newer home fans start to slow down after a year or two until eventually they stop turning on their own. I clean off any dust and goo from the motor and have tried lubing them with light oil, medium oil and grease. Fairly soon(days to months) later they have the same problem again. This does not happen with fans I have that are 30 years old! Any wisdom as to how to properly lubricate them? Or what has changed over the decades?
I appreciate any wisdom! Thanks.