one thing i can't understand about three phase generation,is that in single phase motors, pumps, general lighting and power etc there is a neutral to provide the difference in potential to enable voltage to flow, but in three phase equipment where is the difference?
I know there is 0 voltage within the neutral in a fully balanced 3 phase delta setup,so how does the current return back to the transformer to complete the circuit?

does it return through one of the two other phases when at 0 potential due to the phase displacement of 120 degrees? [Linked Image]