Newly installed Motor Driven Between Bearing pump is vibrating heavly.
Pump Speed=3000 RPM
1.Pump Driving end brg Horizontal vib=26 mm/s
2.Pump Driving end brg Vertical vib= 4.2 mm/s
3.Pump Non-Driving end brg Horizontal vib=25 mm/s
4.Pump Non-Driving end brg Vertical vib= 4.9 mm/s
5.Motor Max Vib=3.4mm/s
6.Alignment is checked by Laser Kit and is within limits.
7.Pump Driving end brg Horizontal & Vertical phase difference is 140 Deg.
8.Pump Non-Driving end brg Horizontal & Vertical phase difference is 37 Deg.
9.Pump Axial maximum vibration=3.8 mm/s
10.Pump Driving & Non-Driving end Bearing Axial vibration is in Phase.
11.All vibration contributed by1X.

Please Comment, What could be the reason of vibration.

quote:

Newly installed Motor Driven Between Bearing pump

Did you check pump mounting. There may be loosened bolt. Since horizontal vibration is extremely high in comparison with vertical vib. level.

Hi bpcl,
woow your horizontal is very high :-)
Ok, please check the natural frequency on horizontal direction..to clarify there is no resonance.
The ratio between Hor/ver more then 3 times.
Your phase difference between NDE & DE is very big (140), normally it's 90 +/- 30 degree.
Looseness or feet weakness problem can be suspected.
Once again, you should check the connecting between pump and piping, is there any excessive stress when installed.

Rahardi
rahardi@softhome.net

Hi bPcl
Check for piping strain problem(excessive tension in one of the piping connections)this cause directional vibration on the pump

Hi bPcl
Some manufacturer gives horizontal locking arrangement in multistage pumps in the barral. Same can be checked. This will help

You may run the motor solo and check the vibration.If ok then the problem is in the pump. Be sure that pump is properly balanced.Check the alignment by rim and face method.Laser alignment tools may sometimes give erroneous data.Probable cause of high horizontal vibration is unbalance.

Regards
Anis

pl check out vibrations of motor..
is the whole assembly of motor & pump installedon same base frame?
I might suggest to strengthenPumpbase frame in horizontal directionthis will sure reduce vibrations.
Most importantly u must check forImpeller unbalance

Check pump for resonance. With the pump shut down, measure the horizontal vibration. I know that sounds silly to check it when it isn't running but it is important to look for vibration that might be coming from near by equipment.

Check the resonant frequencies by hitting the pump with a dead blow hammer or soft face hammer (with the unit shut down) and look for any peaks in the spectrum around 3000 CPM.

Plz check runout of the pump at different place.I think shaft is bend. If bend is there u will get high horizontal vibration

Since this is a new pump it may be a bad impeller.

Run the pump dry. If the vibration goes away it is "Hydraulic unbalance". This means the pump casting was uneven so when it is pumping there is more fluid on one side that the other.

Machining trues up the OD but not the internal cast surfaces.

I have case like this. Shaft is bent (new shaft and length is 1.5 meters).