Abstract: A control system for obtaining maximum power output from electrical generating water pumping, flywheel storage and like systems comprising a wind-driven prime mover coupled to an electrical generator over an extended range of wind velocities is described. The maximum electrical output power is obtained by synchronizing the speed of the generator, and hence the speed of the prime mover, with the maximum power output of the prime mover. Since the maximum output power of a wind-driven prime mover is proportional to the third power of the wind velocity, and is a function of an angular velocity-dependent power coefficient, means are provided for detecting the angular velocity of the prime mover and generating a signal proportional to the cube of said wind velocity.