Wind power, converted into mechanical energy imparted to the turbine, is transferred to a shaft at the center or hub of the turbine.
Since the circumference of the turbine is greater than the circumference of the shaft, the torque in the shaft is substantially increased while the relative speed at the outside circumference of the shaft is proportionally decreased.
This increase in torque is important because the torque is needed to overcome the electromagnetic resistance of the generator or alternator.
Generators and alternators are fundamentally the same device. They both have a center shaft upon which is wound coils of wire known as an armature. Around the armature and separated from it, are two, or in some cases more, coils of wire called field coils.
When an electric current passes through the field coils a magnetic field develops. As the armature rotates, driven by the turbine shaft, its wire coils pass through these magnetic fields and a secondary current is induced into the armature windings.
In an alternator, the current is drained off directly through devices called slip rings. Alternators produce alternating current (A/C).
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