Wind Turbine Components

Wind turbines come in many sizes and configurations. But no matter if they are big or small, horizontal-axis or vertical-axis, every wind turbine function on the same principle: extracts energy from wind, transfers this harvested energy into a spinning shaft which turns an alternator or generator to produce electricity.

So the basic components of a wind turbine are:
  • Blades or rotor, which converts the energy in the wind to rotational shaft energy.
  • Nacelle that houses a drive train, usually including a gearbox, a generator , support bearings and some other parts.
  • Tower, that supports the rotor and the drive train.
  • Ground-mounted electrical equipments, including electrical cables, controls and interconnection equipment.

Most traditional wind turbines have three large steel blades, but the rules are not set in stone. New blade designs and materials are constantly experimented and sometimes proven more efficient than the traditional ones.

The power available to harvest from the wind largely depends on both the wind speed and the area that is swept by the turbine blades.
  • for a double wind speed the energy available increases by a factor of 8.
  • for a double rotor diameter the energy available increases by a factor of 4.

However is not possible to harvest all the energy and turn it into electricity. By the Betz Limit formula there is a maximum of 59.26% that can be extracted from the available power. Also no alternator or generator is 100% efficient in converting the energy into electricity, and factors like friction, magnetic drag and electrical resistance losses will further reduce the wind turbine efficiency.
This means that no small wind turbines are 100% efficient even when running at maximum speed.

This is the reason why the rotor diameter and the generator model are the most important factors when choosing a wind turbine model. Hopefully realistic expectations will help you make the right choice and avoid unsubstantiated claims and products.

For more information check out How To Build A Wind Generator Guide.

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