BABBITTED BEARING HEALTH ASSESSMENT

Abstract

Within most plants there is often a desire to extend the time between outages. Several factors determine this but one to consider is the bearings ability to run for the extended time. This Tutorial will address common bearing failure mechanisms, tools available to diagnose these problems and ways to use that information to make decisions on continued operation. Evaluation consists of analysis of Condition Monitoring information coupled with rotor dynamic analysis and computerized bearing modeling. A case study will be presented that details the evaluation of a distressed bearing. Analysis allowed the user to determine they could slightly reduce running speed (to limit vibration to a certain level) and continue to run to the scheduled outage date. There will then be a discussion on bearing robustness and ways to design bearings for long life. A case study will be presented where an Ethylene plant desired to extend the time between outages but the existing bearings prohibited that. The determination was made that upgrading the bearings to a more robust design would allow the extended time between outages.