Design Optimization of Rotor Lock Disc for Horizontal Axis Wind Turbine Generator

This study presents design optimization of rotor lock disc in the generator rotor which was analyzed by applying the respective lateral force taken from machine load calculation for a 2.5 MW permanent magnet direct-drive wind turbine generator. The machine load calculation result was derived from GH Bladed software output. The maximum tensile stress, internal stresses such as von Misses, maximum displacement and corresponding safety factor were calculated in terms of theoretical stress concentration factor due to discontinuity or change in cross-section in the region where the rotor lock is present. The rotor lock disc configuration was optimized to satisfy a safety factor of unity using exhaustive search method and Cosmos works software. Calculation results indicated that the safety factor of rotor lock disc with 40 mm thickness failed when design lateral force taken from the extreme load of rotor locking torque was used. However, the safety factor of the optimized rotor lock disc with 60 mm thickness has been improved when the inner radius and the total arc subtended angle are properly identified.