Multi-Channel Vibration Analysis for Steam Turbines

Tuchner Engineering performs periodic or one-off vibration diagnostics for steam turbines by interfacing with the client’s multi-channel protection system or by installing temporary local sensors for short- or long-term data acquisition.

Objectives of the test:

  1. Periodic assessment of turbine condition to verify that no issues are developing in the turbine or its journal bearings.
  2. Diagnostic vibration analysis to identify mechanical or other sources of abnormal behavior in the turbine.

How the test is performed: connect a multi-channel system to the turbine’s protection rack and proximity probes, together with the turbine’s speed/keyphasor signal, and collect the following data:

  • Shaft displacement levels
  • Displacement spectra
  • Time-waveform (TWF) of displacement
  • Shaft centerline position
  • Rub/contact indications

The above data allow us to generate:

  • Vibration spectra showing dominant frequencies
  • Changes in shaft centerline position over time/operating states
  • Orbit plots of shaft motion within the bearing clearance
  • Bode and Nyquist diagrams to detect natural-frequency issues and resonance excitation
  • Additional diagnostics as needed (e.g., polar plots, run-up/coast-down trends)

The purpose of these tests is twofold: to pinpoint the source of problems in steam turbines and to implement predictive maintenance through periodic testing and comparison of results across time. Findings from these studies can have significant implications for decision-making about continued operation and any maintenance required in the near future.