Question

A transformer consisting of $300$ turns in the primary and $150$ turns in the secondary gives output power of $2.2\, kW$. If the current in the secondary coil is $10\,A$, then the input voltage and current in the primary coil are :

• A. $220\, V$ and $10\,A$
• B. $440\, V$ and $5\,A$
• C. $440\, V$ and $20\, A$
• D. $220\, V$ and $20\, A$

Answer 1

Answer: (B)

Given $N_P = 300, N_s = 150, P_0 = 2200 W$
$I_s = 10A$
$P_0 = V_0 I_0 \; \Rightarrow \; 2200 = V_0 \times 10 \Rightarrow V_0 = 220 V$
$\because \; \frac{V_i}{V_0} = \frac{N_P}{N_s} \; \Rightarrow V_i = 2 \times 220 = 440 V $
Also $P_0 = V_i I_i$
$\Rightarrow \; I_i = \frac{2200}{440} = 5A $