Question

A transformer operating at primary voltage $8 \,kV$ and secondary voltage $160 \,V$ serves a load of $80\, kW$. Assuming the transformer to be ideal with purely resistive load and working on unity power factor, the loads in the primary and secondary circuit would be

• A. $800\, \Omega$ and $1.06 \,\Omega$
• B. $10 \,\Omega$ and $500\, \Omega$
• C. $800\, \Omega$ and $0.32\, \Omega$
• D. $1.06\, \Omega$ and $500\, \Omega$

Answer 1

Answer: (C)

$ \frac{\left(8 \times 10^3\right)^2}{R_P}=80 \times 10^3 $
$ R_P=800\, \Omega$
$\frac{(160)^2}{R_S}=80 \times 10^3$
$ R_S=0.32\, \Omega$