High frequency vibration was recently observed on an overhanging fan . The accl versus freq spectrum is attached herewith. Any reasons? Turbulence, piping vibration or anything else?
Regards.

Zoom your spectrum in on the peak labeled 70.3 and see if there are sidebands around it. This may be a bearing natural frequency being rung by the inner race defect. The sideband spacing will show you the cause.

Can you post an autocorrelated time wave form?

Zoomed spectrum indeed shows BPFI to the left of 70.3X but we have got another big peak at 106.947X and 60.443X. WThere is a plethora of high frequency peaks. Can anyone shed light on high frequency vibration diagnostic techniues?
Regards.

While you have identified defects within the spectra, the amplitudes are extremely low and I would probably not make a fuss about this at this time. The running speed shown is 2920? You are viewing the data in g's rms. I would prefer to look at it in velocity. What does the history look like? Does the waterfall appear to be getting worse over time? Take a good look at all of your data to come to a solid decision.

Regards,