The following data were obtained or a 30-kva, 60 hz, 2400-240V transformer tested at 60hz.
Voltage (V),                  Current(A),              Power(W)
O.C. Test       240V,                               3.0 A,                       230 W
S.C. Test        70V,                                18.8 A,                     1050 W
a). determine the primary voltage when 12.5 A at 240 V is taken from the low voltage side supplying a load of 0.8 p.f. lagging.
b). Compute the efficiency and regulation in part (a)