wala namang problema dun ah. 230vac pa din makuha mo na voltage dun at 60hz pa din.... ang mahalaga sa 3phase system eh yung load balancing. halimbawa, kung sa factory mo eh meron kang 3 load na single phase at ang wattage nya eh sabihin natin na 10,000watts, ang connection nun sa line eh yung load 1 sa L1 & L2 yung load 2 eh sa L2 & L3 at yung load 3 eh L1 & L3. para balanse yung current mo sa 3 phase.
Hindi ko pa rin magets. Mathematically, you'll definitely get either more or less than 230V output if you use two 230V out of phase lines.
Your answer just assumes you'll get 230V 60Hz single phase from using 2 230 live lines which are out of phase w/o any explanation.
Ang pagkaka-intindi ko, in order to get lets say a single phase 230V from a three-phase system is by tapping only one line lets say L1, and feeding it to a 1:1 transformer. The output of the transformer is center-tapped and the center tap is earth grounded. This way, you get 2 115V on each line that adds up to a 230V output.
I'm not an electrical engineer so I'm not sure of my understanding.