Fiber optic strain system for ball bearings

A dual wavelength test setup using fiber Fabry Perot interferometer (FFPI) strain sensors was assembled in order to monitor ball bearings using analog and digital approaches simultaneously. The high sensitivity of the FFPI sensors allowed for the measurement of strain forces affecting roller element bearings. Tests were carried out to compare the time waveforms for load comparisons and their respective spectra of generated bearing frequencies to expected values of such bearings. Further tests were conducted to assess the effects of imbalance added to the shaft, rotational speed, and impulses on the rotor system. Positions of observed spectral peaks show good agreement with predictions. These results indicate that fiber optic sensors can provide a unique capability for bearing monitoring in today´s machinery.