actuator for adjusting pitch angle of a rotor blade of a wind turbine rotatably mounted on a rotor hub , comprising a first drive element connectable with the rotor blade , a second drive element in meshing engagement with said first drive element , a lubricating device for lubricating the two drive elements and lubrication controller . a rotor with a rotor hub , on which at least one rotor blade is rotatably mounted , with actuator adjustable pitch angle . a wind turbine comprising such rotor and such actuator . selective lubrication of zero teeth of the gear stage of the actuator considers the rotary position of the drive elements of the gear stage with respect to each other . the lubricating device includes a lubricant passage to selectively supply portion of first drive element and / or portion of second drive element meshing therewith depending on engagement position of drive elements or rotary position of rotor blade .