Dear all
thank alot for your guides and your attention
in this way our group reduced the costs of repairs and maintenance in our factory to 1/3 last year's.
i now our Method and our instruments are not enough and we try to be better.
dear motordoc thank u for Considerations.pdf
help me in my way.
i Have a Boiler Force Draft Fan
Its Bearings are ever in a high temperature and we had to keep its temperature low with Cold Air Blowing

Vahid, is the fan hot so you get heat that way or do the bearings get hot by themselves? If fan is hot add some cooling dishes with fins on the shaft btw. fan and bearing or consider circulation oil for the bearing with a heatexchanger. If the bearings get hot and the fan is not hot, pls post some vibration measurements and machine history. Olov

Dear vahid,

FD fan bearings should not run hot. Can you tell us a bit more about the bearings? Type, clearance class, how they are fitted on shaft and in housing etc.?

Some points to check
1. If shrunk or pressed onto shaft what is the interference, and what is the shaft size?
2. If angular contact bearings are in use are the outer races shimmed? Are they fitted face to face or back to back?
3. If the bearing housing is horizontally split, have you done a blue contact check on the outer race OD, or a trueness check? Result?
4. If the housing is not split, is the outer race held axially tight by the housing cover?
5. When you examine a failed bearing, can you make out how it failed? Some photos would help.

Without some details, we can keep guessing, so help us to help you.

V.Narayan.

What are the RTD bearing temperatures?

What type of oil are you using? (synthetic?)

What is the voltage rating?

Has the motor been repaired in the past?

What type of control are you using?

How long has this been an issue?

Howard