NREL Gearbox Reliability Collaborative

The NREL/ DOE Gearbox Reliability Collaborative has been reviewing the design process of wind turbine gearboxes in order to identify ways to improve the reliability of this fundamental component. As part of this effort, two 750-kilowatt (kW) gearboxes were removed from an operating population and redesigned and rebuilt to meet current megawatt (MW) power standards using state-of-the-art technology. To date, 300+ hours of operational data, including over 125 signals, have been collected in the field and from NREL dynamometer testing on a 750-kW wind turbine platform. This data includes both internal and external loads, motions, deflections and other response during a broad range of operating modes and conditions. This paper compares measured gearbox response in the NREL dynamometer to gearbox response during field testing. It then describes the way in which dynamometer testing has been improved to better represent field loading conditions. Conclusions and recommendations are made for augmented dynamometer testing.