Cut-in Note: A Blade Element Estimation of the Cut-in Wind Speed of a Small Turbine

摘要

As the wind speed increases form zero, small turbines will cut-in only when the aerodynamic torque acting on the blades exceeds the resistive torque of the generator and drive system. This Note describes the sue of standard blade element theory to calculate the cut-in wind Speed, at which rotation commences, using the apparent near-universality of aerofoil flit and Drag at high incidence. The starting torque is shown to depend on the "chord-pitch" integral That, in turn, is a function only of the blade geometry.