Analysis of bearing vibration monitoring

The analysis of rotor vibration monitoring is essentially a process of pattern recognition in the changes of bearing vibrations during normal operation and under test conditions. The probable cause of any change can usually be identified in general terms although the exact cause is rarely predicted without a physical investigation of the rotor. Nevertheless, such analysis can predict some types of shaft integrity problems and has prevented catastrophic failure in the past. The paper describes the vibration changes which are characteristics of typical balance problems which occur in turbine generators. Simple mechanical unbalance, thermal unbalance, rubbing effects, nonsynchronous vibrations, and shaft integrity are covered