Oil Splash Bearing Compare to Greased Roller bearing for 750 kW Electrical Motor. 1

[harrasi2012]

Dear All,

We are in the process of slecting an electrical motor 750 kW rating for harsh, desert sandy environment at E&P installation. I would like to have your kind opinion on the selection of splash oil type bearing compare to greased roller bearing. kindly advise the pros & cons of each.

also advsie on vibration monitoring requirment of each slection. currently we are proposing casing velocity meter on each bearing.

 

[electricpete]

One advantage of grease: more effective at excluding contaminants.

Advantage of oil is that it tends to be better at lubricating the bearing.

Different types of maintenance requirements: grease requires continual regreasing, oil requires checking levels and tending to leaks.

The balance shifts towards oil as the size and speed of the bearing goes up. As the D*N (diameter times speed) increases, grease is less and less suitable. The D*N limits for thrust bearings also a little lower than for radial. And additionally if you just keep adding grease without replacing the whole cavity (which is typically tough to do), the cavity can get full, most of grease dry, lubrication conditions deteriorate further... so chances of getting 20+ years life without replacement on 3600rpm 6313 is much better when oil-lubricated than when grease lubricated.

Perhaps if you tell us more details of type of bearings we can give info. You can also check many references available regarding D*N limits of greased bearings.

If you are concerned about contamination, grease is not the only way to protect bearing. You can use fancier seal like INPRO seal (although those tend to cost more).


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