Mini projeto torre eolica

How to build a WIND TURBINE
Axial flux alternator windmill plans 8 foot and 4 foot diameter machines © Hugh Piggott -May 2003

How to build a wind generator - the axial flux alternator windmill plans - May 2003 version © Hugh Piggott

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Introduction
Blades These plans describe how to build two sizes of machine. The diameter of the larger wind-rotor is 8 feet [2.4 m]. The smaller machine has 4' diameter [1.2 m]. The diameter is the width of the circular area swept by the blades. The energy produced by wind turbines depends on the swept area more than it does on the alternator maximum output. Alternator The plans describe how to build a permanent magnet alternator. The alternator can be wired for 12, 24 or 48-volt battery charging. Essentially this choice only affects the size of wire and the number of turns per coil. But the tower wiring for the 12-volt version will be much heavier than the others. And the stator for the small machine is different in thickness. The alternator design is integrated into a simple tower-top mounting arrangement (called a 'yaw bearing'). A tail vane faces the turbine into the wind. A built in rectifier converts the electrical output to DC, ready to connect to a battery. Small wind turbines need low speed alternators. Low speed usually also means low power. The large machine alternator is exceptionally powerful because it contains 24 large neodymium magnets. The power/speed curve for a very similar design is shown below. Maximum output is about 500 watts under normal circumstances, but it is capable of more than 1000 watts for short periods. The starting torque (force required to get it moving) is very low because there are no gears, nor are there any laminations in the alternator to produce magnetic drag. This means that the wind turbine can start in very low winds and produce useful power. Power losses are low in low winds so the best possible battery charge is available. In higher winds the alternator holds down the