A wind power installation with a rotor, a generator for generating electric power, at least one rotatably mounted rotor blade displaceable about its longitudinal axis for adjusting the angle of attack, and an auxiliary generator for generating electric power for at least one consumer, characterized in that the auxiliary generator produces electricity for a controller for the rotor blade adjustment and for a drive for adjusting the angle of attack of at least one rotor blade at a lower range of rotational speed in comparison to the rotational speed in normal operation, wherein the controller for the angle of attack is controlled or regulated for sustained operation in the range of the rotational speed.