A single-phase transformer rated at 3000 kVA, 69 kV / 4.16 kV, 60 Hz has a total internal impedance Zp of 127 Ω referred to the primary side. Calculate the primary current if the secondary is accidentally short-circuited.

In a single-phase transformer, the number of turns per volt is 8. The primary voltage is 110 V and the secondary voltage is 25 V. Determine the number of turns in the primary winding (N1) and secondary winding (N2).

Consider a 20 kVA, 2200/200 V, 50 Hz single-phase transformer. Test results are: OC Test: 220 V, 4.2 A, 150 W (LV side) SC Test: 88 V, 10 A, 366 W (HV side) Determine the voltage regulation at full load with 0.8 lagging power factor.