A bearing has a random life due to a complex set of factors that determine the life of a bearing.
SKF confirms that bearing life is random even when bearings are operating under same conditions.
"Under controlled laboratory conditions, seemingly identical bearings operating under identical conditions have different endurance lives".
So what to do now? If the bearing application and design is correct we cannot determine the life of the bearing. We suggest focusing the on Essential Care of the bearing and equipment it's part of.
Let's imagine that you have a large centrifugal pump. You can preserve the life of the bearings by:
- Use of correct bearing specification according to OEM
- Store the bearing correctly
- Mount the bearing correctly
- Make sure that shaft and bearing housing have the correct tolerance
- Operate the equipment within its limits and avoid overload, and cavitation
- Align the shafts and couplings within
- Balance impeller to avoid vibration
- Select and use the correct lubricant/oil
- Make sure that the oil is clean and avoid moisture, chemicals, and contaminants
- Make sure that the oil is not breaking down and keeps properties and additives
- Prevent overheating of the pump
If we implement procedures to preserve the conditions of the bearings we have maximized the bearing life and reliability.
Now we need to figure out what procedures are needed when the bearing begins to fail and its condition deteriorates. Predicting when the bearing is failing is not extending the life of the bearing but give us time plan and schedule downtime when it impacts the operations the least. Based on the criticality and industry we could use the Condition Monitoring Standards (CMS by IDCON) or we could use FMEA and RCM to determine the condition monitoring procedure. How often should you measure? Let's save that for another time since the life of the bearing does not changewhen we do condition monitoring.