Planetary gear sets power loss modeling: Application to wind turbines

Power losses in any geared-transmission can be attributed to gear-mesh and bearing-contact frictional effects and the interaction of rolling element bearings and gears with the lubricating medium. In this paper, a composite power loss model combining a non-uniform load distribution model with a local friction coefficient at any point of contact and oil drag formulations has been developed. A design sensitivity study has been carried out that examines how the design parameters of planetary gear sets and bearings and lubricant properties influence performance. The accuracy of these models was assessed by comparing predicted results to published measured values taken from planetary gear sets and parallel axis gear set experiments.