three blades supported by a hub constituting the rotor The Wind turbines They generally consist of three blades supported by a hub constituting the rotor and installed at the top of a vertical mast. This assembly is fixed by a nacelle that houses a generator. An electric motor makes it possible to orient the rotor so that it is always facing the wind. The blades make it possible to transform the kinetic energy of the wind (energy that a body possesses because of its movement) into mechanical energy (mechanical movement of the blades). The wind rotates the blades between 10 and 25 revolutions per minute. The speed of rotation of the blades depends on their size : the larger they are, the less quickly they rotate. The generator transforms mechanical energy into electrical energy. Most generators need to run at high speeds (1,000 to 2,000 revolutions per minute) to generate electricity. It is therefore first necessary that the mechanical energy of the blades passes through a multiplier whose role is to accelerate the movement of the slow transmission shaft, coupled to the blades, to the fast shaft coupled to the generator. The electricity produced by the generator has a voltage of about 690 volts that cannot be used directly, it is treated through a converter, and its voltage is increased to 20,000 volts. It is then injected into the electricity grid and can be distributed to consumers.