1. Diesel Generator Alternator End bearing Vertical / Horizontal / Axial vibration readings taken and the tri-axial spectrum below analysis:

Horizontal vibration reading:

1. The value recorded 22.06 mm/s RMS and 1X is 18.9 mm/s is the dominant fundamental frequency at shaft speed 720rpm.the IACS recommended for DG vibration satisfactory value is 18mm/s RMS.

2. The 1X indicating unbalance and comparing with vertical reading 2X is dominant of misalignment too.

3. The 1X is 6.547 mm/s RMS and 2X is 13.66mm/s on total vibration of 16.97 mm/s RMS indicating misalignment is dominant.

4. The causes of the high vibration is resultant effect of unbalance and misalignment due to soft foot are appearing significant.

5. The Axial vibration reading total showing 9.692mm/s and the rotor bars 30 nos. indicating defect of bent rotor bars with side bands.

6. Conclusion: once the soft foot corrected, the further vibration recorded and corrective actions suggested accordingly.

2. DG No.1 Engine Free End:

1. Engine side vibrations on tri-axial HVA readings 6.768/6.259/4.318mm/s RMS are in well limits of 18 mm/s RMS at load.

2. The engine side combustion forces and inertia forces registered harmonic components are well in limits.

3. The engine vibrations are in satisfactory order.

Engine side G forces and time wave with FFT spectrum:

3. Turbocharger DG No.1 Vibration analysis:

Observations:

1. The turbocharger at variable rpm with load and at higher ranges 15000-25000 rpm showing low amplitudes and appearing in satisfactory condition.

2. The Total overall tri axial vibrations on Vertical/Horizontal / Axial directions recorded on load running 4.809/ 6.664/ 12.29 mm/s RMS are well in satisfactory limits.

3. The IACS limits appended in this report are 45mm/s in velocity RMS value and 2.5g forces on acceleration value.

DG NO.1 Turbocharger accelration analysis:

The acceleration values recorded on VHA directions are 1.102/ 0.7672/ 1.805 g RMS

DG No.1 General Vibrations recorded on 3rd September 2015 Recommendations:

1. The DG running condition is satisfactory.2. The dominant frequencies on alternator end are the cause of concern and the 1X is high in Horizontal direction

above the IACS limit and total vibration is also exceeding the limit.3. The vertical misalignment is indicating due to soft foot effect.4. The engine side and turbocharger side total and unique components showing satisfactory performance.

RECOMMENDATIONS:

1. The DG No.1 soft foot to be corrected.2. The vibrations once again checked after correction for the unbalance in rotor, as rotor bars frequency showing in

axial direction defect of bent rotor bars.3. After the corrective actions the results are to be analyzed.

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the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.

The acceleration values are well in limits and turbocharger is operating in satisfactory

condition.

Industry legend on 1X Dominant interpretations:

Force Unbalance will be in-phase and steady. Amplitude due to unbalance will increase by the square of speed (3x speed increase = 9x higher vibration. 1x RPM always present and normally dominates the spectrum. Can be corrected by placement of only one balance weight in one plane at rotor Centre of gravity (CG)

Mechanical Looseness is indicated by either type A, B or C spectra.

Type 'A' is caused by structural looseness/weakness of machine feet, baseplate or foundation, also by deteriorated grouting, loose hold-down bolts at the base and distortion of the frame or base (i.e Soft Foot).

Phase analysis may reveal approx. 180° phase difference between vertical measurements on the machine foot, baseplate and base itself.

Type 'B' is generally caused by loose pillow block bolts, cracks in the frame structure or bearing pedestal.

Type 'C' is normally generated by improper fit between component parts which will cause many harmonics due to nonlinear response of loose parts to dynamic forces from the rotor. Causes a truncation of time waveform. Type 'C' is often caused by a bearing liner loose in its cap, excessive clearance in either a sleeve or rolling element bearing or a loose impeller on a shaft. Type 'C' phase is often unstable and may vary widely from one measurement to the next, particularly if the rotor shifts position on the shaft from one start-up to the next. Mechanical looseness is often highly directional and may cause noticeably different readings if you compare levels at 30° increments in the radial direction all the way around one bearing housing. Also note that looseness will often cause subharmonic multiples at exactly 1/2 or 1/3 x rpm (.5x, 1.5x, 2.5x etc.)