Question

The primary of a transformer has 400 turns while the secondary has 2000 turns. If the power output from the secondary at 1000 V is 12 kW, what is the primary voltage?

• A. 200 V
• B. 300 V
• C. 400 V
• D. 500 V

Answer 1

Answer: (A)

200 V

Answer 2

$N_{P}=400,\,N_{S} = 2000$ and $V_{S} = 1000\,V.$
$\frac{V_{P}}{V_{S}}=\frac{N_{P}}{N_{S}}$
or,$\quad V_{P} = \frac{V_{S}\times N_{P}}{N_{S}}=\frac{1000\times400}{2000}=200\,V.$