Turbomachinery Vibration Analysis using data from online vibration monitoring systems

Subba Rao Ganti, CM Engineer, Qatargas


Turbomachinery (Steam & Gas Turbines, Centrifugal Compressors etc.) of Oil & Gas, Petrochemcial and Power indusries are, in general, provided with state of the art vibration montoring systems to monitor and protect the equipment from catastrophic failure due to high vibration. Also, the online vibration monitoring systems have the facility to store the vibration data for analysis and troubleshooting. In this paper, case studies are presented for diagnosing machinery problems like mislaignment, rotor instability, rubbing of rotating components with stationary components etc. Online vibration data is analyzed using various plots like vibration trends, polar, bode, shaft centerline, casecade, waterfall and orbits to identify various machinery malfunctions.

1. Importance of various vibration data plots in diagnosing machinery malfunctions.
2. Corelating different vibration plots in arriving at the most probale cause for hihg vibration.
3. Diagnosis of malfunctions like misalignment, rubbing etc.


35 years of work experience out of which 30 years is in condition monitoring of rotating machinery of Oil & Gas, Petrochemical and Power Industries. Experience in vibration data collection, analysis and dynamic balancing of all types of rotating machinery including large turbo- machinery like steam turbines (up to 500 MW) and gas turbines (frame 9E & 9FA of GE make), centrifugal compressors (Elliott, Nuvo Pignone etc.).
Vibration Specialist Category IV – certified by the Vibration Institute, USA according to the ISO 18436: Part-2 Vibration Condition Monitoring and Diagnostics