No, very large single-speed industrial motors are synchronous motors, not squirrel-cage (induction). These motors cannot start spinning on any number of phases: they can only run at the synchronous speed (which is dictated by the power line frequency and the number of poles in the motor). And it's not a short; it just doesn't run at all if you supply power to it; it only works once it's at the synchronous speed. These motors are used because they're the most efficient type of AC motor. Induction motors have "slip" of around 3% IIRC.