The compressor manufacturer requested data acquisition and diagnostics support after experiencing 2 compressor failures due to wiped bearings shortly after the initial start-up of the newly installed compressor.  The compressor manufacturer was especially concerned about the possibility of the shaft critical and aerodynamic noise within the compressor contributing to an oil whirl condition.

The MAARS Model 5000 was attached to a proximity probe and accelerometer (used on gearbox) buffered outputs and key phaser output in the control room building.

After establishing this fact the team began to explore the operating envelope of the compressor.  During this time it was found that there were certain operating conditions where a vibration amplitude oscillation could be induced.  Thanks to the Model 5000's ability to acquire data simultaneously on several channels, a phase oscillation was also identified.  In addition, the vibration was found to “swap ends” on the compressor.  The combination of these characteristics led to a diagnosis of a light seal rub.  Automatic controls were programmed to avoid this operating condition.