Analysis vibration of pump

The vibration is very low at 0.016 mm/sec RMS Velocity. The dominant vibration frequency on motor is not an integer order of shaft speed. Perhaps the pump was off, and the vibration is from a background source! What makes you think there is a problem to be analyzed?

Walt

Walt Strong posted:

The vibration is very low at 0.016 mm/sec RMS Velocity. The dominant vibration frequency on motor is not an integer order of shaft speed. Perhaps the pump was off, and the vibration is from a background source! What makes you think there is a problem to be analyzed?

Walt

Thanks my friends 

what make me think there is a problem to do the analysis is that the pump is running and the rms is very low 

perhaps there is a problem of the device Skf or accelerometer 

I assume you have 50-Hz power and 4-pole motor-pump are direct coupled with horizontal shaft. The spectrum you provided is for motor outboard vertical (MOV) or motor non-drive end, correct? Why not measure overall vibrations in the vertical, horizontal and axial at all (4) of the bearings to get the "big picture", and also look at spectra to see if 60-Hz is dominant at the other measurement points. You could also try another accelerometer (or cable) or another meter/analyzer for comparison -- called Sanity Check". Other data checks include measuring on another machine that you have previous data and it is stable over time, hand-held or desk-top vibration calibrator, or send instruments to calibration/repair vendor.

Walt

Walt Strong posted:

I assume you have 50-Hz power and 4-pole motor-pump are direct coupled with horizontal shaft. The spectrum you provided is for motor outboard vertical (MOV) or motor non-drive end, correct? Why not measure overall vibrations in the vertical, horizontal and axial at all (4) of the bearings to get the "big picture", and also look at spectra to see if 60-Hz is dominant at the other measurement points. You could also try another accelerometer (or cable) or another meter/analyzer for comparison -- called Sanity Check". Other data checks include measuring on another machine that you have previous data and it is stable over time, hand-held or desk-top vibration calibrator, or send instruments to calibration/repair vendor.

Walt

Thanks again 

it’s 60 hz power motor-pump fuel coupled in horizontal position 

the spectrum is for mov position 

Okay, so you have to be careful whether the dominant peak is at 2xSS or 60-Hz electrical noise. Are you using a portable analyzer and accelerometer, permanent accelerometer with portable analyzer, or permanent on-line system? Permanent sensors and monitors can develop electrical faults. Time-synchronous averaging with a tachometer trigger would indicate whether the 60-Hz is really 2xSS or not. All of my other comments are in play. The real vibration could be that low at that location and in vertical direction, so measure all of the other locations as part of YOUR analysis.

Walt

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