3.1 What is the purpose of a transformer? The purpose of a transformer is to transfer electrical energy between two or more circuits through electromagnetic induction - NSC Electrical Technology Electronics - Question 3 - 2017 - Paper 1

The secondary phase current ( $I_2$) is equal to the secondary line current:

$I_2 = I_L \approx 182.32 \, A$

The input power (P) can be calculated using the formula:

$P = \sqrt{3} V_{L} I_L \cos \theta$

where,

• $V_{L} = 380 \, V$
• $I_L = 182.32 \, A$
• $ext{power factor} = 0.9$

Substituting the values, we approximate:

$P = \sqrt{3} \times 380 \times 182.32 \times 0.9 \approx 107999.32 \, W$

Thus, the input power to the clinic is approximately 108 kW.

The secondary winding of a step-down transformer requires a thicker wire to handle the higher current that results from the lower voltage. A thicker wire reduces resistive losses due to its larger cross-sectional area, enabling it to efficiently carry higher currents without overheating and ensures the integrity and longevity of the transformer.