US Patent 8672797 Power train for wind turbine

A geared power train (100) for use in a wind turbine application to maximize a step-up ratio within a radial space that is defined by the planetary gearing system ring gear size. The geared power train (100) is configured as a split-compound planetary gearing system with a closed-carrier flex-pin planetary system in a high-torque stage (Stage 1) for receiving driving torque via an input shaft (IN) from a wind turbine, and an open-carrier flex-pin planetary system in a low-torque stage (Stage 2) coupled to the high-torque stage (Stage 1) for delivering the driving torque to an electrical generator via an output shaft (OUT).