Lucky,
I assume you are correct that your machines require single phase, in which case they need the neutral (4th current carrying conductor)
Btw, I think people sometimes confuse phasing with voltage, but they are somewhat independent.? Aussie three phase is 400v, and single phase is 230v.? In the US, it's 240v or 208v, and 120v single phase.
Fwiw, Aussie system is more analogous to our 208v.? Note that 120 * sqrt(3) =~ 208, and 230 * sqrt(3) =~ 400.? Not mere coincidence!
