I have 10 identical flowserve water pumps.
They are driven by a 1620 HP ABB electric motor.
In 9 of these pumps I have very low amplitudes of vibration in every direction at electric motor. (0.3 -- 0.5 mm/s)
I supposed this is because of system stifness
But in one of them, specifically in axial direction I have very high levels of vibration (7.1 mm/s at exactly 18x)
This shafts turns at 1180 RPM. So frequency is aproximately 21200 CPM.
This vibration is higher (7.1 mm/s) as close to the shaft I install the accelerometter, and this frequency is not present at pump.
I have attached a picture to show the levels of vibration in two points (closer and further away the shaft).
We have checked shaft alignment tolerances and they are ok.
Please help with these.