An electrical generator 46 is driven by a circular rim 30 of a wind turbine 10 in response to atmospheric wind. The generator and its driving wheel 50 are supported on a tiltable platform 60 that is movable on a guide track 56 by linear actuator 66 in response to electronic sensors 76, 77. The bellows 74 biases the tiltable platform upwardly to maintain the generator driving wheel 50 in contact with the circular rim of the turbine wheel.