A wind turbine can harness the renewable energy source of wind. To do this, the wind turbine needs a generator to convert the kinetic power into electrical energy. The type of generator installed in the wind turbine should be chosen based on the turbine’s location. Different sites will have different wind speed measurements, which will affect your choice of both turbine and generator.
Personal Wind Turbine Generators
o If you plan to build a wind turbine yourself for your home, you may consider installing a brushed DC (direct current) motor, which can usually be found in surplus stores or even in household items like an old treadmill. This motor comes in a variety of shapes and sizes and is easily driven. The brushed DC motor operates by a stationary magnetic field surrounding the rotor. When the rotor’s windings are energized, it also creates a magnetic field, when then creates opposite poles and the rotor begins to turn. The energy continually builds and switches poles so the rotor continues to spin; this process is called commutation.
o The induction generator is one of the most common types of electrical generators used in wind turbines and works by converting the kinetic force of the wind turning the turbine blades into electrical energy. When the amount of magnetic flux varies in the conducting loop, electrical voltage is induced into the loop. Closing the loop and attaching it through an external load causes the induced voltage to create a flow of electric current. Normally an induction motor should run at 1,500 revolutions per minute or higher, so typically you will also need gearing.
Permanent Magnet Alternators
o Permanent magnet alternators, or PMAs, are used in a variety of power systems, including wind turbines. They do not need to continually create a magnetic field to operate, so they do not waste energy. A PMA has a set of permanent magnets, typically mounted on the rotor, and a set of electromagnets, typically mounted on the stator. PMAs can have an efficiency rating between 60 and 95 percent, normally operating at approximately 70 percent.