Gearbox Reliability Collaborative Phase 3 Gearbox 2 Test Report

Many gearboxes in wind turbines have not been achieving their expected design life; however, they commonly meet or exceed the design criteria specified in current standards in the gear, bearing, and wind turbine industry as well as third-party certification criteria. The cost of gearbox replacements and rebuilds, as well as the downtime associated with these failures, has elevated the cost of wind energy. The National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) was established by the U.S. Department of Energy in 2006; its key goal is to understand the root causes of premature gearbox failures and improve their reliability. The GRC uses a combined gearbox testing, modeling, and analysis approach disseminating data and results to the industry and facilitating improvement of gearbox reliability. This test report describes the recent tests of GRC gearbox 2 in the National Wind Technology Center dynamometer and documents any modifications to the original test plan. In this manner, it serves as a guide to interpret the publicly released data sets with brief analyses to illustrate the data.