Windmill yaw and speed controls

Abstract

A yaw control device automatically aligns a windmill. A spur gear displaces a motor-driven worm gear mounted between balanced springs when an external turning moment is applied to the windmill. Displacement of the worm gear moves an actuator arm positioned between switches in the motor power supply circuit, closing one of the switches and thereby activating the motor to drive the spur gear in opposition to the turning moment. An idler gear can be operatively positioned between the spur and worm gears. The worm gear is mounted on the rotatable shaft of a bracket pivotally connected to the spur or idler gear axis or is mounted on splined shaft rotatably supported by fixed bearings. The actuator arm is rigidly connected to the worm gear bracket or is pivotally mounted adjacent the worm gear. In an alternative embodiment, the worm gear is connected to the windmill for movement therewith about a fixed spur gear. In a further alternative embodiment, a torque sensor in the drive shaft of a motor connected through gears to the windmill senses the externally applied turning moment. In still further embodiments, proximity switches and idler pulleys sense slack in a drive belt and control a drive motor in response thereto. A windmill speed control has panels pivotally mounted in the rotor blades. Panel control arms are pivotally connected to control rods biased radially inwardly by springs.