Over the past couple of years, motor vibration problems have skyrocketed. You’ve been tasked with figuring out why. One of your first steps was to analyze the motor failure and replacement history. It turns out these failures tend to occur at the same installations, within a few months of a motor replacement. But in a few cases, the trend simply stopped even though nothing was changed other than the motor itself.
The motor shop post-mortems show bearing issues such as galling, but there’s no evidence of undesired current flow through the bearings. What should you look at, next?
Compare the names of the crews for the motor installations that show a continuing failure trend to those of the crews for the motors installations in which the trend inexplicably stopped. The evidence is strongly suggestive of installation errors by someone hired in the last two years.
For example, a poorly trained technician might use the motor shaft as a lifting point for moving the motor or a leveraging point for adjusting its position. For the typical motor, this puts undue stress on the bearings; they aren’t designed for lateral loads of that magnitude. Use the proper handling points (e.g., lifting eyes), instead.
When this sort of error doesn’t appear to break anything, poorly trained people assume it’s OK. They don’t see that the soft Babbitt bearing has been permanently deformed and its increased eccentricity means decreased longevity.
Also, closely investigate how the newly installed motor is being lubricated.
