March 28, 2007 | Mark Paradies

Equipment Failure “Root Causes”

I was recently sent an article that described how a company, using “root cause analysis”, was able to determine the cause of a recurring motor bearing failure. This particular failure was recurring about every 2 years. After hooking up vibration monitoring gear, they were able to determine that the bearing was nearing failure again. Investigation uncovered that the failure was due to an uninsulated bearing (wrong part) being installed in the motor, allowing circulating electric currents to damage the bearing. Therefore, the root cause was the wrong bearing was installed.

This type of problem would shown up as a Possible Cause using an Equifactor analysis. But TapRooT users know they can’t stop there. “Mechanics installed wrong bearing”, would then be put back into our SnapCharT, and a whole range of questions arise. What was the experience ad training level of the mechanics? Did the procedure specify the correct bearing? Was procedure use required? Why did this bearing fail numerous times before an analysis was performed? Did the manufacturer communicate this possible problem to their customers? Is the correct bearing easy to identify in the supply room? Were supervisors required to inspect thenew installation?

All these questions become obvious once you have a workable SnapCharT that shows the glaring holes in your investigation. With these holes filled, a meaningful TapRooT anlysis can now e conducted.

Root Cause Analysis
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