Handling Bearing Trouble...

There is a noise coming from near a bearing. Sounds like trouble. If you are not lucky, it's going to be downhill from here. Unattended to, the following effects can be expected in the near future: increase in vibration, oil analysis showing metal residue, high bearing temperature, smoke!! and finally, bearing failure

?Needless to say, we should not let this course run. To begin with, we should not find ourselves in this position. That’s the whole purpose of preventive maintenance. If you already have ongoing preventive maintenance activity, then this event must be recorded for future reference. If such events occur in assets of the same asset class, then it would be a good cue to make changes in the Maintenance plan for the said asset class. We’ll discuss this in a later article.

Now that we are facing the situation, it’s time for a hands-on approach. Check vibrations, and temperature data of the bearing. If there is no data acquisition system, take periodic readings. Do lube oil analysis for changes in oil quality and keep an eye on lube oil temperature. Take baseline values. Therein lies the importance of solid condition monitoring and data acquisition systems. It’ll inform us of changes ahead of time and ensure the machines don’t fail catastrophically. It is important to set warning limits to know if trouble is ahead, and establishing initial values is crucial for setting limits such as alarms and warnings. Understanding the rate of change of a parameter is essential.

If the parameters are stable, we can make an informed decision about keeping the machine running. This depends on the criticality of the machine to the operation, replaceability, allowable downtime, etc. If the parameters are increasing, it's better to go for corrective maintenance. Once corrective action is taken, which could be replacing the bearing (not an easy task with heavy machinery), we might want to ensure this doesn’t happen again. Root cause analysis is the tool we need.

What are the main causes of bearing failure?

• Dirt and moisture ingress into the bearing
• Operation with a misalignment
• Insufficient lubrication
• Overloading
• Corrosion

We’ll discuss each cause in detail in future articles.