A 1,000-kw. Wind-driven Electric Generator
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A PLANT which is said to represent the first serious attempt to study the generation of electricity by wind power on such a scale that its practical and economic possibilities may be judged, is described in Engineering of July 31. The plant consists of a two-bladed wind-turbine and a 1,000-kw. alternator mounted on a pintle girder on the top of a lattice steel tower 110 ft. high, and it has been erected on the summit of a 2,000-ft. mountain known as Grandpa's Knob, near Rutland, in the State of Vermont. Though in a sense the plant is experimental, the current generated will be used by the Central Vermont Public Service Corporation. It has been estimated that it will be possible to use the power of the wind for 4,000 hours a year. The blades of the turbine are each 65 ft. long and 11 ft. wide and weigh 15,300 1b. The circle described by the ends of the blades is 175 ft. in diameter and at 28-7 r. p. m. the tip speed is 15-785 ft. per minute. The alternator is driven through gearing and generates three-phase current, 60 cycles and 2,300 volts. The designer of the wind turbine, Mr. P. C. Putnam, has had the assistance of others, and model tests of his turbine were made in the wind tunnel of Stanford University. There are many interesting features in the plant, and so that an exhaustive study of wind variations can be made an anemometer tower 180 ft. high has been erected close by and fitted with three types of anemometers.