Wideband Fiber Bragg Grating Accelerometer Suitable for Health Monitoring of Electrical Machines

A fiber Bragg grating (FBG) accelerometer suitable for health monitoring of electrical machines has been proposed. A polymer composite material is used to design the cantilever of the accelerometer. Thus it is ensured that there are no conducting parts in the accelerometer. Detailed finite element analysis of the cantilever is done to optimize the sensitivity and the resonant frequency. The sensitivity is significantly improved compared to the conventional FBG accelerometer having similar bandwidth of operation. Two different configurations, one having sensitivity 14.4 pm/g with resonant frequency 444 Hz, and the other having sensitivity 7.5 pm/g with resonant frequency 940 Hz have been designed and fabricated. The wide band optical accelerometers will enable monitoring of vibration modes of critical components of electrical machines and more importantly using commercially available standard FBG interrogators, instead of using any complex interrogation techniques. A good match between the simulation and experimental results was observed.