Rotor Condition Monitoring Using Fibre Optic Sensing Technology

This paper reports a feasibility study of fibre Bragg Grating (FBG) sensing application for condition monitoring the rotor structure in electric machines. The work examines the potential of using individual FBG heads embedded on the rotor structure to simultaneously infer localised information on both the rotor thermal and mechanical operating conditions. To this end, experiments were undertaken on an FBG array instrumented rotor cage of an operating squirrel cage induction machine. The paper reports the details of the in-situ FBG sensor design, installation and calibration procedures and explores the information contained in the observed measurements. The findings demonstrate that the attained in-situ measurements contain simultaneous information on the examined rotor’s thermal and mechanical operating conditions thus providing a step forward in understanding the potential of FBG based rotor condition monitoring applications.