Romax Redesigns Gearbox with DOE


Romax has signed a contract with the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) to perform a major redesign of the research gearbox for the dynamometer testing facility at NREL’s National Wind Technology Center (NWTC).

The gearbox will be redesigned by this summer and rebuilding will commence later in 2012.  Engineering and drafting services provided by Powertrain Engineers Inc. will assist Romax in this project.

In an effort to document and assess the design process, NREL previously completed a redesign/rebuild of two heavily used gearboxes that subsequently underwent in-field operation and dynamometer validation testing. With the help of industry and academic partners, NREL has highlighted significant findings to reduce the number of gearbox failures seen by the wind turbine industry.

Ashley Crowther, the VP Engineering, at Romax’s Wind Technology Center in Boulder, Colorado, is positive about gearbox reliability, saying, “Gearboxes are a reliable workhorse for so many industries, they increase the output velocity and provide a large saving in the costs of the electrical machine.  Programs such as this one at NREL are important as they improve the knowledge across the industry allowing the progression of the wind turbine gearbox into a reliable product.”

The redesign has the primary goal of allowing for the exploration of the effect of design details on the loads and deflections within the gearbox and a secondary goal of improving the design from the previous configuration. Romax has developed a detailed drivetrain engineering model of the current gearbox and performed extensive validation of the model versus a wealth of test data generated so far by the program.

Chris Halse, Engineering Manager at Romax, said, “We have shown by simulation and test several key issues with the 3 pointed mounted arrangement, such as the high sensitivity of the designs to rotor loads, if the gearbox is not correctly supported in the planetary stage. By improving this aspect of the design we can return to simulation and test and demonstrate the engineering approach to ensure future gearboxes don’t have such problems. An original goal of the project was to ensure modelling tools are up to the tasks of predicting gearbox behaviour and we have certainly shown Romax is on top of that.” For more information, visit