Steven Katz, president of Emerson Bearing, writes an excellent article on bearing failure and analysis:
The main function of any rolling bearing is to decrease friction which could be caused from any elements related to the rotation in order to maximize the power efficiency that could have been converted from torque power into heat power. So the main function of the bearing is to decrease the "converted to heat" power.
The accurate diagnosis of a bearing failure is imperative to prevent repeat failure and additional expense.
Rolling bearings are precision machine elements found in a wide variety of applications. They are typically very reliable even under the toughest conditions. Under normal operating conditions, bearings have a substantial service life, which is expressed as either a period of time or as the total number of rotations before the rolling elements or inner and outer ring fatigue or fail. Less than one percent (0.35 percent, specifically.) of rolling bearings do not reach their expected life. (Source: FAG Bearing Antriebtechnik 18 from 1979.)
PREMATURE BEARING FAILURE
When a bearing does fail prematurely, it is usually due to causes that could have been avoided. For this reason, the possibility of reaching conclusions about the cause of a defect by means of studying its appearance is very useful. It’s most important to correct the causes and prevent future failures and the costs that follow.
Please read the whole thing.
The L&S Electric Reliability Team provides several bearing analysis services. Contact us today to learn the many ways we can help you.

