On one of our critical blower, wWe are facing frequent trips due to high vibration on Bentley Nevada probes on gearbox high-speed shaft (12100 RPM). Vibration readings (over the bearing) are high as well on gearbox but we are unable to find the root cause, we have conducted MCSA, perform alignment/ soft foot check but with no success. Oil analysis results came out clean.
Particularly two things we found in spectrum are puzzling us- see spectrum attachment
- Peak at 2LF ( 100 Hz) appears to as a twin peak and not precisely at 100 Hz
- There is a weird peak at 1620 Hz, which is not matching to any of the fault frequency and has been fluctuating/trending up. The same peak is present on all points with differing magnitudes.
If you could please go through the attachments and share your thoughts as to what could possibly be the cause of the problem and what other test (s), we should perform to find the root cause and any thoughts on counter measures.
Please let me know if any other info/ specs are required for the diagnosis of the issue.