Advanced Capacitive-Sensor Turbine- Blade-Monitoring System

An electronic system that includes a capacitive proximity sensor is under development as a prototype of instrumentation systems for real-time monitoring of vibrations of turbine blades and shafts. Because vibrations are caused by stresses that can induce fatigue and/or are sometimes associated with damage, monitoring of vibrations can provide information needed to detect damage, detect incipient fatigue failures, and alter turbine operating parameters to prevent or postpone failures. The design of this system overcomes the frequency-response and spatial-resolution limitations of prior capacitive-sensor-based turbine-monitoring systems. Its resolution is comparable to that of optical-sensor-based turbine-monitoring systems used in testing turbines at temperatures below their operating temperatures; however, unlike optical sensors, capacitive sensors can withstand high turbine operating temperatures [in some cases, >2,000 °F (>1,100 °C)].