DESIGN OF PITCH GEARBOX FOR 4MWCLASS WIND TURBINE

The pitch gearbox for 4MW-class wind turbine is comprised of a triple-gear planetary system. It is a component that keeps wind turbine blades rotating at a constant speed by adjusting their angles, and should have a life span of at least 20 years. This study analyzed the design stability and vibrational characteristics of pitch gearbox components for 4MW-class wind turbine. Design stability was secured by performing stress analysis of the housing and carriers under actual loads and extreme loads, specified in Load Duration Distribution (LDD), through finite element analysis. The natural frequencies and mode shapes of the pitch gearbox were also analyzed. There was found to be significant deformation of the third planetary gear for the first and second mode shapes, of the second planetary gear for the third and fourth mode shapes, and of the first planetary gear for the fifth and sixth mode shapes. Critical speed was assessed based on analysis of excitation source in relation to mass imbalance and excitation source. In the range of operation of the pitch gearbox, that is, 260rpm – 320rpm, critical speed did not exist.