Abstract: Method for controlling a rotor blade adjustment device (14) of a wind turbine or water hydroelectric powerplant (1), wherein the rotor blade adjustment device (14) has a drive (20) which is connected to a rotor blade (8) which is subjected to a flow of wind or water and has the purpose of rotating the rotor blade (8) about a rotor blade axis (15) relative to a rotor hub (7) on which the rotor blade (8) is mounted so as to be rotatable about the rotor blade axis (15), and an electromagnetic brake (34) which is connected to the rotor blade (8) and has the purpose of blocking rotation of the rotor blade (8) about the rotor blade axis (15), wherein the brake (34) is actuated in order to change its activation state at a brake activation time (tB), wherein the drive (20) is actuated to change its driving state at a drive activation time (tA) which has a predetermined chronological offset (?tV) with respect to the brake activation time (tB), and wherein an electric current (IB) which flows through the brake (34) is