Text: In three phase systems the additional phase are carried by extra wires. a three phase system has 4 wires. Ground, 120degrees, 240 degrees, and 360 degrees. Now for the electricity to reach your home of course you only need 3. in single phase systems you only need one wire. A 240 volt (peak to peak) signal (or what ever you want to call it) is sent to your home and is put through a 1 to 1 transformer. for 120 volts you take the center tap to one side and get 120 volts. for the full 240 you take both outer end and get the full amount. If you have three inverters that are phase locked your can produce three phase power. And if you really wanted to be fancy you can use 4 phases (80 degrees), 5 phases (64 degrees), 6 phases (60 degrees), and 8 phases (40 degrees). The more phases you want the more wires you need. The benefit of additional phases is better external motor control, slightly more torque at lower speeds, and slightly more efficiency. The big draw back is increased complexity, and diminishing returns. I don't know of anyone who has built motors and generators with more than 3 phases, it is entirely possible however.

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