A power transmission line feeds input power at 2.3 kV to a step down transformer with its primary winding having 3000 turns. The output power is delivered at 230 V by the transformer. The current in the primary of the transformer is 5 A and its efficiency is 90%. The winding of transformer is made of copper. The output current of transformer is ____ A.

Step-down transformer: $$V_p = 2300$$ V, $$N_p = 3000$$, $$V_s = 230$$ V, $$I_p = 5$$ A, efficiency = 90%.

$$\frac{N_s}{N_p} = \frac{V_s}{V_p} = \frac{230}{2300} = \frac{1}{10}$$, so $$N_s = 300$$.

Input power = $$V_p I_p = 2300 \times 5 = 11500$$ W.

Output power = $$0.9 \times 11500 = 10350$$ W.

$$I_s = \frac{P_s}{V_s} = \frac{10350}{230} = 45$$ A.

The output current is 45 A.