Creating Three Phase Power

It turns out that creating three-phase power occurs quite naturally from geometry. With that in mind, take a look at the physical layout of the coils and magnets in our wind turbine, shown again in Figure 6-3. The turbine's black rotor disk has six magnets that are physically arranged 60 degrees apart from one another, and the north-south orientation of the poles alternates from one magnet to the next.

60 degrees

Figure 6-3

Wind Turbine Magnet Arrangement

60 degrees

Inside the base, or stator, of the turbine are three coils of wire. In the schematic in Figure 6-4, the coils are wired such that they look like an upside-down letter "Y". This arrangement is called a "Wye" coil arrangement. It's also called a "Star" arrangement, as well, because it looks like a three-pointed star (but you'll have to use your imagination, somewhat). Notice that the coils are separated by 120 degrees, like the numbers on a clock face at the hours of 12, 4 and 8.

Figure 6-4

Wye Coil Arrangement

Figure 6-4

Wye Coil Arrangement

As the wind turbine spins, the magnets pass over each coil in turn. From the point of view of one coil, a changing magnetic field is seen. This changing magnetic field induces a changing current in the coil of wire. With three coils and six magnets, the resulting output waveform is three-phase AC.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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