Thank you for comments and internet link. I think I better understand. Our Municipal emergency 911 building has a 3Ph-3Ph,480 volt UPS. The 30 battery, battery bank (408 VDC) cabinet has two cables leading to the adjacent UPS inverter. I wasn't initally aware that the inverter could create 480V,3Ph,4W,AC from 2 wire 408V DC. I knew it was able to convert DC to AC.
