A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5A and its efficiency is 90 %, the output current (in ampere) would be:

Question

A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5A and its efficiency is 90 %, the output current (in ampere) would be: (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

Efficiency, η = (Pout/Pin) = (Vs Is/Vp Ip) ⇒ 0.9 = (230 × Is/2300 × 5) ⇒ Is = 0.9 × 50 = 45 A Output current = 45 A

Efficiency, η=Pin​Pout​​=Vp​Ip​Vs​Is​​ ⇒0.9=2300×5230×Is​​ ⇒Is​=0.9×50=45A Output current =45A

Efficiency, $η = \frac{P _{o u t}}{P _{in}} = \frac{V _{s} I _{s}}{V _{p} I _{p}}$
$\Rightarrow 0.9 = \frac{230 \times I _{s}}{2300 \times 5}$
$\Rightarrow I_{s} = 0.9 \times 50 = 45 A$
Output current $= 45 A$