High Vibration in Pump Drive End Bearing


Thread Starter


1. All 3 BFPs higher shaft vibration is observed about (70 to 80 micron) at the Pump Drive end bearing (both X-Y), but all other bearing point vibrations are in normal range below 30 micron.

2. When all the 3 pumps were running at same speed, similar pattern of vibration reading at the point is noted.

3. Pump suction parameters are also observed but found to be as per design and normal, suction parameters are also changed (Suction pressure 1.4kg/cm2 to 1.8 kg/cm2) to check whether it causes any difference to the vibration at these points. But no variation to the readings is noted.

4. These higher vibration pattern is observed during last 7 days operation, previously the readings on load for the same points were higher than the other points but it was within 40 micron (PP).

5. In pump stand still condition also it is observed that at those points vibration reading of (4-6 micron is observed).

6. All vibration sensors are checked for healthiness by calibration with TK3, also to rule out probability of sensor linearity, sensors/module/cable at those points are altered with other locations. But the same reading at these points were persisting irrespective of sensor/module/cable.

7. For further analysis we arranged analysis group to take readings at different points. At the point of our observation (Pump Driving End) casing vibration in running condition is found as approx. 1.6 mm/sec (RMS).

Please advice for the reason of high vibration.

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Was there any work on all the three BFPs recently?

You mentioned that at pump stand still condition, you are getting a vibration --> could you explain how? As any stand still machine will not have vibration. Again, you mentioned that this is occurring for all three pumps --> have you observed any change in your process parameters like deaerator pressure from which the BFPs are taking suction & the boiler pressure or the high pressure feedwater heaters into which these BFPs are discharging? Again, the vibration values which you have provided are displacement values --> what about the velocity values? Again, have you tried running any of the BFPs on re-circulation & observed any change in vibration?


Thans Manish.

If you give your email add i will provide all the data of Vibration of BFP. Otherwise use my mail address.

with regards

It seems there is a common cause affecting all 3 pumps and it started recently, also it seems there is some background vibration. Is there or has there recently been any structural work taking place around the pump area (including pipe supports)? This could affect the structural stiffness of the whole set-up. If the pumps are floor mounted on solid foundations this is more difficult to explain. Has any other equipment in the area been recently modified or started up?

I would be interested to know the outcome as we have seen vibration issues on various projects.