3 phase typically has a lower power draw on larger industrial equipment, thus why it is used in commercial and industrial applications. The two systems are not exactly compatible, more specifically with electrical motors, they are entirly different. Single phase motors can be hooked up to two legs of a 3 phase electrical supply, but not the other way around.
Also keep in mind that there are 2 type of 3 phase, delta and wye, wye being the most common and what most people refer to. A delta system is grounded differently causing the middle leg to be a higher voltage.
Anyway i don't know what info you are trying to clarify for yourself, but if its something i can answer feel free to PM me.