First slide

Transformer

Question

A transformer having efficiency of 90% is working on 200 V and 3 kW power supply. If the current in the secondary coil is 6 A, the voltage across the secondary coil and the current in the primary coil respectively are

Moderate

A

300 V, 15 A
B

450 V, 15 A
C

450 V, 13.5 A
D

600 V, 15 A

Solution

Here,
Efficiency of the transformer, $η = 90 %$
Input power, $P_{i n} = 3 k W = 3 \times 10^{3} W = 3000 W$
Voltage across the primary coil, $V_{p} = 200 V$
Current in the secondary coil, $I_{s} = 6 A$
$A s P_{i n} = I_{p} V_{p}$
$∴$ Current in the primary coil,
$I_{p} = \frac{P_{in}}{V_{p}} = \frac{3000 W}{200 V} = 15 A$
$η = \frac{P_{out}}{P_{in}} = \frac{V_{S} I_{s}}{V_{p} I_{p}}$
$∴ \frac{90}{100} = \frac{6 V_{s}}{3000} or V_{s} = \frac{90 \times 3000}{100 \times 6} = 450 V$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App