Points should be consider for new transformer installation: Location Environmental impact Soils condition Survey of land Ventilation Grounding Wiring Fluid check Inspection
Here auto transformer change voltage from 600 V to 200 V. Voltage ratio (a) = 600/200 = 3 kVA rating of the auto-transformer = (a/(a - 1))*(kVA rating of auto transformer) = (3/2)*20 = 30 kVA
EXAMIANS