The primary and secondary windings of a 40-kVA, 6600/250-V, single-phase transformer have resistances of 10 Ģ and 0.02 Ģ respectively. The leakage reactance of the transformer referred to the primary is 35 Ģ. Calculate:
a) The primary voltage required to circulate full-load current when the secondary is short-circuited.
b) The full-load regulations at i) unity ii) 0.8 lagging p.f. Neglect the no-load current.
Calculate:
c) F.L. efficiency at unity p.f.
d) The secondary terminal voltage when supplying full-load secondary current at p.f. i) 0.8 lag ii) 0.8 lead for the 4-kVA, 200/400 V, 50 Hz, 1-phase transformer of which the following are the test figures: Open circuit with 200 V supplied to the primary winding-power 60 W. Short-circuit with 16 V applied to the h.v. winding-current 8 A. power 40 W.