Abstract: A wind turbine or rotor load control compensates for moment imbalance in a wind turbine that includes a rotor having at least two variable pitch blades. The apparatus includes a conventional pitch command logic developing a nominal rotor blade pitch command signal and a moment sensor. The moment sensor can be one or more of a nacelle overturning moment sensor, and a turning moment sensor. An output of this is used as a moment signal. Conversion logic is connected to the moment signal with an output of the conversion logic being calculated individual pitch modulation commands for each of the blades. A combining logic is connected to receive the calculated individual blade pitch modulation commands and to receive a nominal pitch command. An output of the combining logic is individual combined blade pitch commands for each of the blades.

Abstract: Fan relay boards are provided that include terminals configured to receive line power of approximately 115 volts, 208 volts, 230 volts, and 277 volts. The boards are configured to convert the line power to an approximately 24 volt output that is applied to a distribution circuit to select a high, medium, or low fan speed using relays. The boards may be coupled to a control device that designates the fan speed selected by the relays. The boards also may provide an approximately 24 volt power supply to external devices such as electric heaters, valves, and switches.