PPT Slide
Section 12.9: The Nonideal Transformer and its Equivalent Circuits cont.
Examples 12.6 and 12.7 cont.
Calculate the transformer’s voltage regulation and efficiency when it serves its rated KVA load at 0.8 lagging power factor
By voltage division, Ep is:
Ep = (10KW || j1.55KW)/[10KW || j1.55KW + (0.2 + j0.45)W]´Vp
But 10KW || j1.55KW = 1.53/81.2° KW >> (0.2 +j0.45)W \ Ep » Vp = 2455/0.7° V.
\ Es = Ep/a = 245.5/0.7° V. and by KVL, VNL = Es = 245.5/0.7° V.
\VR% = [(|VNL|-|VL|)/|VL|]100% = [(245.5-240)/240]´100% = 2.29%