Rotating equipment such as electrical motors, rotary pumps and compressors as well as fans and blowers, are generally designed for smooth operation—with very low vibration as the ideal state.
In this equipment, a severely worn bearing has increased drag, emits more heat, and has lower efficiency because of a mechanical, lubrication, or a wear problem.
Common causes of bearing failure
- Shaft misalignment
- Shaft or component imbalance
- Improper operating conditions or unusual environment
- A heavier load than designed for
- Inadequate or incorrect lubrication
- Ineffective bearing sealing
- Incorrect installation or fit
- Normal wear and tear
- Induced shaft voltages
Before bearings fail, however, the problem is likely to show itself by a telltale vibration. For example, when a roller bearing race becomes pitted, the bearing rollers will cause a vibration each time they pass over the damaged area.
Once bearing failure begins, it also creates a cascade effect that accelerates motor failure. Thirteen percent of motor failures are caused by bearing failure, and more than 60% of the mechanical failures in a facility are caused by bearing wear, but most bearings wear due to shaft misalignment or imbalance than from normal wear. So, learning how to diagnose the root cause and fix it is an important component of any predictive maintenance program because then bearings last for many years.
A test and measurement instrument such as the Fluke 810 Vibration Tester is designed specifically for maintenance professionals to diagnose mechanical problems early, including identifying wear to journal or roller bearings.