What are some advantages of 3-phase power over 1-phase power?

Answer 1

There are several advantages of 3-phase power over single phase power. First, with 3-phase power, more power can be transferred with the same amount of wire (meaning the amount of copper used in all of the conductors transferring that power) as with single or 2-phase power. Also, power is transferred more "evenly" with 3-phase power because the "next peak" is closer than it is with single and 2-phase power. The 3-phase motors run more smoothly than those run on fewer phases. Also, there are motor design considerations (one being control of the direction of rotation) regarding the motor that make 3-phase power more attractive. Use the link to the Wikipedia article on 3-phase power and skim it. It isn't long and it is quite readable.

Answer 2

Three phase power uses 3 conductors (or sometimes 4) for the equivalent power of 3 circuits, that in single phase would require 6 conductors. This is possible because the voltages and current are 120 electrical degrees apart in time and so sum to zero.

In addition, because of the timing of the phase voltages and currents a very simple (and therefore cheap) induction motor can be run on the 3 phase supply. Single phase induction motors are more complex, less efficient, larger and more expensive.

For similar reasons 3 phase Transformers are more cost-effective than single phase.

Answer 3

The 3 phase system has an advantage for the single phase system for sure, the 3 phase system has more power than the single phase system, such that p=3vicos(theta).

Answer 4

It can carry twice the energy in terms of volts and amperage with the addition of only one wire to the single phase system