Difference between single phase and 3-phase motors

What's the difference between a single phase and a three phase 208V wiring? Does the first has 2 wire only? Can you also identify the wires as to hot, neutral, and ground? This wiring applies to installing an Air conditioning unit. Thanks.

My wife's church recently purchased a used commercial 3 phase griddle(flat top). How can it be wired to use single phase 220/240 V. It's on a 60 AMP breaker.

Supply is from 75 kva transformer, 3 phase delta /y three wire feeding a 30 amp breaker. 100 feet down stream is a junction box that I want to tap and produce a 120 v single phase ( 20 amp CB) supply. The junction box feeds a 6 amp motor

Besides matching the mounts & drives, are there wiring/switching issues changing out a 220-3phase for 220-S-Phase. I am interested in switching motors in a commercial diswasher.