Abstract: A method for directing a current generated by a lightning striking a wind turbine is described. The method includes directing the current from a main shaft of the wind turbine to a brake disc attached to the shaft, and directing the current from the brake disc to one of a spark gap and a roller mechanism coupled to a down-conductor at a ground voltage.

Abstract: A method, rotor assembly, and apparatus for ordering blades in a rotatable machine is provided. The rotor assembly includes a disk including a plurality of circumferentially-spaced blade root slots defined therein, and a plurality of blades, each blade including a root, a tip, and an airfoil therebetween, each blade positioned within a pre-determined slot based on a blade map, the blade map generated by a computer system configured to receive a geometric parameter measurement of each blade in a row of blades, determine a shape factor for the row of blades using the geometric parameter measurement of each blade, and determine a sequence map of each blade using the shape factor for the row of blades.