Assessment of gear damage monitoring techniques using vibration measurements

Each gear damage monitoring technique has its merits and limitations. This paper experimentally investigates the sensitivity and robustness of the currently well-accepted techniques: phase and amplitude demodulation, beta kurtosis and wavelet transform. Four gear test cases were used: healthy gears, cracked, filed and chipped gears. The vibration signal was measured on the gearbox housing and processed, online, under three filtering conditions: general signal average, overall residual and dominant meshing frequency residual. Test results show that beta kurtosis is a very reliable time-domain diagnostic technique. Phase modulation is very sensitive to gear imperfections, but other information should be used to confirm its diagnostic results. Continuous wavelet transform provides a good visual inspection especially when residual signals are used. The diagnosis based only on dominant meshing frequency residual, however, should not be used independently for gear health condition monitoring, it may give false alarms.