Abstract

PurposeThis study explores the use of acoustic emissions (AE) for detection of ring gear cracks in wind turbine gearboxes (WTG) by means of experimental measurements and signal analysis.MethodsAE measurements were conducted on two full-size WTG, from which one was in a healthy condition and the other one had a crack in one tooth from the ring gear. We analyzed the AE signals using various signal processing techniques, including envelope spectrum, cyclostationarity and wavelet packed decomposition (WPD).ResultsNo amplitude modulations could be identified using envelope spectrum in the AE signals. Instead, the cyclostationarity and WPD analyses revealed AE energy in higher frequencies that can be related to the crack. Besides, a proposed approach based on AE burst characterization was able to distinguish among normal and fault-related bursts.ConclusionIf appropriate signal processing techniques and specific analysis approaches are employed, the AE analysis has great potential for its application on condition monitoring of WTG.