customer has pretty large natural gas 2-stage compressor. Vibrations on LP DE bearing are slowly rising and now reached dangerously high level. vibrations at gearbox DE, which is rigidly coupled to compressor are low, showing some reaction to the vibration changes at compressor. NDE bearing vibrations are also low. No bearing temperature changes. No serious load changes. Vibrations just went down ones, August-September 2010, we were thinking about some temperature influence, but now it is 20-30degC colder than in summer, vibrations are still growing.
Major component is 1X, no phase changes since train was commissioned 3 years ago. I was suspecting bearing deterioration (1X, no changes on other bearings, gradual vibrations growth), but bearings can't improve (!). Contaminations (fouling)will, in theory, produce the same pattern, but shouldn't vectors change
Lost, need your opinion.