Proper bearing lubrication 1

[soupsamich]

I was wondering if there was any solid idea's or evidence on motor bearing lubrication procedure. I have read several different recommendations on the proper way to grease a motor bearing. Some say shut the unit down to grease, but the majority that I can find say lube it while running. I'm on the running side of things, but wanted some more feedback. Thanks.

 

[jmoritz]

The optimum way to relubricate any bearing is while it's running - helps to spread it around instead of dumping it out or leaving dry areas.

Sometimes however this is just not possible.

 

[Hippo41]

I agree, lube whilst running is best. But ensure that you don't overgrease, use compatible lubricants and ensure that the grease has some way of escaping from the bearing (i.e. you don't fill it).

You will notice some temperature rise, bu th ebearing should settle sown to it's original running temp once it has purged the excess.

How much and how often can be advised by your bearing supplier. The old formula's in the books are good standby's, but modern lubricants are far better than the old ones on which these are based.


Lester Milton
NBC Group Ltd, Telford, Shropshire, UK

 

[rickwsykes]

The best way to grease any bearing is while it is running. The simple method is to grease slowly, counting the number of pumps until a thin film of grease is visable around the seal. Then you have established your own "rule of thumb" for that particular area of your plant. There are 2 important things to keep in mind:
1. The bearing cannot have a mechanical seal. The grease must be able to flow out past the seal without creating internal pressure. I have seen a bearing go from 25C to 82C in about 2 minutes due to over greasing. The oil will flow out of the grease and then the grease is useless and will provide no lubrication. If unchecked, the bearing will then fail.
2. In motor bearings, a very good long-term grease is needed. One with a type II or III base oil or even a PAO. The grease must be able to last for up to 6 months. Over-greasing of these bearings can cause oil leakage into the windings and subsequent motor failure due to internal grounding. The oil attracts conductive particles and arcs across the small cracks in the winding insulation.

 

[motorman]

For whatever its worth, years and years ago my company's instruction books said to grease while the motor was running. This avoids the possibility of grease getting around the internal seal and getting piled up inside the motor. Then… some worker got his hand in the coupling and sued everybody. Needless to say, no motor manufacture will tell you to do anything while the motor is running… not even wipe it down.

 

[wallygator]

Beyond written proceedures, has anyone had experience with "acoustic lubrication" tools like Ultra-Lube?
link:

http://www.UVLM.com

Thanks,
Wally

 

[Texaco]

I think you will find oil mist lubrication is far easier and has fewer problems than grease. Users say that their MTBR is significantly improved when they switch to oil mist. It is interesting that we have automated so many of our processes but perform the lubrication function pretty much the same way that we did at the start of the Industrial Revolution. The lubrication can be automated too.