Fiber Optic Speed Sensor For Gas Turbine Engine Control

Allison Gas Turbine Division of General Motors Corporation, with Teledyne Ryan Electronics, has developed and demonstrated a fiber optic speed sensor (FOSS) for application to advanced fiber optic based control systems for gas turbine engines. The subject FOSS is capable of measuring turbine engine rotational speed throughout a speed range of 0-22,000+ rpm, which is equivalent to a sensor bandwidth of approximately 25 KHz. The principle of operation is based on directly sensing the pressure pulses generated by passing turbine blades via a pressure tube, a diaphragm at the top of the pressure tube, and a fiber optic microbend transducer affixed to the diaphragm. Transceiver electronics/optoelectronics are remotely located.