Generator rotor and TG bearing to ground isolation
Generator rotor and TG bearing to ground isolation
(OP)
What are the standards for isolating the turbine and generator bearings? It has been my thought that all the bearing pedestals should be isolated from ground. Is that correct?





RE: Generator rotor and TG bearing to ground isolation
RE: Generator rotor and TG bearing to ground isolation
Another question: I have had difficulty determining the difference, on one occasion I should say, between a fatque failure and an arcing failure in a steam turbine bearing. The bearing babbet failed several times on a 20 year old machine. Of course the root cause could have been arcing which preceeded a fatique failure. We addressed the problem as if both could have occurred. What has been your experience?
RE: Generator rotor and TG bearing to ground isolation
I have seen both contact fatigue failures and surface pitting from arcing of large T/G bearings in service. Typically, contact fatigue failures of babbit will exhibit rather abrupt or distinct fracture surfaces or breakout of babbit material with no surface pits or local arcing damage. Babbit failure can also occur in regions that were puddle repaired, if not done correctly. Normally, with electrical arcing you will see a localized region or band of surface pits that are distinct and can become deep over time.