In this paper, three typical examples of gear faults for wind turbine gearboxes were presented as case studies. They provided an overview of the significance of SER as a gear health condition indicator. The capture, analysis and trending of SER, which accompanied many classes of gear faults has proven to be an effective diagnostic tool for gear fault detection and severity assessment in wind turbine gearboxes.
Case study #1 and Case study #3 reveals that SER was a reliable defect monitoring parameter for tracking gear defect progression in broken gear tooth failure and gear tooth crack respectively. The proportional increase in SER with gear defect progression was clearly visible ( Fig. 4). The SER was found to be less than 1.5 for healthy gear mesh and more than 3.0 for faulty gear mesh for broken tooth and tooth crack examples as indicated in Case study #1 and Case study #3. In Case study #2, SER was found to be less sensitive towards gear pitting progression due to uniform spread out of pitting formation on all the teeth. SER of 2XGMF were found to be more sensitive than 1XGMF towards gear defects progression in all the three case studies.
The future work is planned at developing an algorithm to publish a gear health severity factor based on the combination of “SER and change of statistical vibration acceleration peak value from healthy to faulty condition” for improved gear health monitoring and gear fault detection.