Question

The full load voltage drop in a 1-phase transformer is 2% and 4% respectively due to resistance and leakage reactance. Then the voltage drop is maximum at __________

(a) 0.45 lagging

(b) 0.45 leading

(c) 0.9 lagging

(d) 0.9 leading

I got this question in class test.

The above asked question is from Transformer Losses and Efficiency in portion Transformers of Electrical Machines

Answer 1

The correct choice is (a) 0.45 lagging

To elaborate: Z = 4.47; cosθ = percentage r/percentage z = 2/(4.47) = 0.45.