A single phase transformer rated 1.2kV/120V, 7.2kVA hasprimary-referred parameters Req= r1+ a r2= 1Ω andXeq = x1+ a2 x2 =4Ω when neglecting exciting current. At rated voltage itscore loss may be assumed to be 40W for all the load curent.
(a) Determine theefficiency and regulation of the transformer when it delivers 7.2kVA at V2=120Vand power factor of 0.8 lagging.
(b)Repeat (a) at powerfactor of 0.8 leading.
(c)Determine maximumefficiency of the transformer at rated voltage and 0.8 powerfactor, and determine the kVA load level at which the maximum efficiencyoccurs.