The efficiency of a 75 kVA Transformer having power factor 0.85 at full load will be. Note that full-load Cu loss is 900 W and iron loss is 600 W – Transformer MCQ#54

The efficiency of a 75 kVA Transformer having power factor 0.85 at full load will be: (Other data Full load Cu losses: 900 W, Iron loss: 600 W)

1. 95.75
2. 96.83
3. 97.25
4. 98.05

Solution:

Full load output = kVA * PF = 75 * 0.85 = 63.75 kW

Full load losses = 1200 W + 600 W = 1800 W = 1.8 kW

Full load input = Losses + Output = 63.75 + 1.8 = 65.55 kW

Efficiency = 63.75/65.55 = 0.972 = 97.25%