Rotor blade adjustment device for a wind turbine

Abstract

A wind turbine includes a rotor having adjustable rotor blades for driving a generator and an adjusting device for the rotor blades provided with an actuator that comprises at least an excitation winding. The adjusting device includes a torque-reducing device that automatically reduces drag torque of the actuator. The torque-reducing device includes a current divider that switches the current through the excitation winding in such a manner that the current flows completely through the excitation coil when the motor is in operation and the current only partly flows through the excitation coil when coasting (slip operation). As a result, when coasting, the magnetization of the excitation winding is reduced about the adjusting device, whereby the increase of the speed torque characteristic curve can be determined, thus improving the ratio of the adjusting device when coasting.

Dependencies are inferred from the claim text.