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Reply to "Marine Diesel generator High vibration in Axial direction at Engine Free End"

Mr. Oli we did not had any damper and the shown gear train sketch is for your guidance.

Mr. Walt for your queries the following are below. Feel free if you need anymore queries. From Engine makers response is very slow.

The 1st video has accelerometer mounted on a thin flange of a cover. It would be good to check mounting location by moving to the engine case/block.

ANS: This cover  flange is for the access to Marin driving gear of Crankshaft. Attached the document. The nearest to Crankshaft position to measure Axial vibration. This flange is robust one and fully secured on to the Engine casing.

If the signal is real and causing accelerometer overloads, then check for dominant frequency in spectrum and view the acceleration-time waveform for impact events.

Ans: The spectrum I will share with you. Rpm 900 and the Axial spectrum with 23.85 mm/s overall recorded and when displaying the value is over the instrument in that position.

If vessel has two D-G, then make comparison measurements including on the auxiliary components (water and oil pumps). Any other signs of poor condition such as cylinder pressures and temperatures and lube oil flow and temperatures?

Ans: Vessel has 3 DGs and No.3 is ok No2 is moderate and No1 is too excessive. Attached around crankshaft vibrations axial, Port side is satisfactory other top, bottom, stbd showing high vibrations.

Appended most of the data and many videos recorded in all 4 points of crankshaft top, bottom, Port and Stbd directions Axial vibrations.



DG1 Vibration reading at Engine NDE Free End

ENGINE NDEHVA
Velocity mm/s / Acceleration g8.79/15.676.57/15.4153/0.01


DG2

ENGINE NDEHVA
Velocity mm/s / Acceleration g14.54/24.638.32/18.9923.93/28.51

DG 3  

6.04/10.25.95/9.8113.3/13.5

Thanks and regards

Chary Tatta

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