I am a graduate engineer and have been set a small task to work out the current (primary side) in a 2 phase 30kVA 415:650 transformer. The 2 phases have been utilized from a 3 phase source and are hence 120 degrees out of phase. I understand had it been a 3 phase 30kVA transformer I could calculate my current by 30kVA / 415 / route*3 = 42A. If it was a single phase then simply 30kVA / 415 = 73A. However if I am only using 2 phases from a 3 phase source yet still need to produce 30kVA of power, how do I calculate the line current? Thanks in advance.