I am running into this problem of an AC electric motor in a vertical electric motor driven centrifugal sea cooling pump configuration. The overall velocity vibration of the motor NDE is oscillating from 2.8mm/s RMS to 13.5mm/s RMS as picture below.
The overall velocity of Pump NDE is also oscillating from 0.6mm/s to 1.8mm/s.
Have you guys encountered this behavior and could you please suggest me the possible causes and share your related experiences about this case.
I've also attached some spectrum and time waveform, motor-pump arrangement drawing in the attached file. (Noted for this vertical configuration, V direction refer to the direction inline with suction/discharge piping, H direction is the direction perpendicular to V direction)
Kind regards and success.