engineering recuitment GATE IN Test Series 2023-24 Mock Test Electrical Machines Transformer Efficiency of a Transformer
A 120 kVA, 2000/200 V transformer has the following parameters:
R1 = 0.75 Ω, X1 = 0.8 Ω, R2 = 0.0045 Ω, X2 = 0.008 Ω
The total transformer losses at full load is 4 kW and the load that achieve the transformer maximum efficiency is 57.73% of the rated load. Which of the following statements is/are true?1
The equivalent impedance referred to primary is 1.2 Ω + j 1.6 Ω
2
The half load copper losses of the transformer are 1.5 kW
3
The total losses of the transformer at maximum efficiency is 2 kW
4
The maximum efficiency of the transformer at 0.8 pf lag is 96.5%