Runout Measurements with Non-Contact Probes, and FE Modeling, Tools in Root Cause Analysis (II)

摘要

After a major outage and after individual balancing of turbine and generator rotors, generator rotor had exhibited high vibrations upon a restart. A standard field vibration balancing approach did not yield any results. Five sets of non-contact probes were installed and used as dial indicators to verify the machined and assembled eccentricities. FE modeling and simulations helped to verify the root cause of the vibration problem. The lesson learned from this case is that when balancing rotors individually in high speed balancing facility, machining tolerances at points critical to alignment with other rotors cannot be overlooked and must be evaluated.