Aeroderivative Gas Turbines

Vibration early warning system (VEWS)

Conventional engine shut-down systems for vibration protection of aeroderivative gas generators and power turbines are usually not appropriate for protecting the machines against primary component damage or malfunction. Consequences often seen are substantial secondary damage to the engine as a result of, for example, ball or roller bearing failure. Other effects may typically be various blade or vane damage, root fretting or blade rubbing.

Conventional engine shutdown systems do not activate until a certain unbalance is released. The nature of the signals related to bearing and blade-pass are too small in energy and lie in too high a frequency range to be monitored by conventional engine protection systems. This application note discusses the importance of the early detection and trending of vibration from primary component damage and taking necessary actions to prevent secondary damage to the engine. The use of SKF systems for this application is considered together with the potential benefits of expanding the system to integrated performance monitoring.