1.    A 230/1000V 50 Hz, single phase transformer has the following test data:

Open circuit test (L.V.)

Primary voltage = 230V

Primary current = 1.30 A

Input power = 115W

Short circuit test (H.V.)

Primary voltage = 50 V

Secondary current = 5.55A

Input power = 165 W

a) Determine and sketch the equivalent circuit for the transformer

b) Determine the efficiency of the transformer at full load current at a power factor of unity and 0.8 lagging

Find the percentage regulation at a power factor of unity and 0.8 lagging