Most wind turbines have three main parts:
the tower (the long stem that connects to the ground);
the blades, which connect to a central hub (the rotor);
and the nacelle (a box behind the blades that contains the generator).
Although we talk about "wind turbines," the turbine is only one of the parts inside these machines. For most (but not all) turbines, another key part is a gearbox whose gears convert the relatively slow rotation of the spinning blades into higher-speed motion—turning the drive shaft quickly enough to power the electricity generator. The generator is an essential part of all turbines, which is driven by the turbine's rotor blades.