Question

Example 3.8: Two electric Furnaces are supplied with single-phase circuit at 100 V from

& 3-phase, 13,750 V supply by means of two single-phase Scott-connected transformers with

similar seco;z dary windings when the load on main transformer is 625 kW and on the teaser

is 1000 kW, zohat current will flow in each of 3-phase lines at unity power factor ?

Answer 1

Transformer coefficient $k=\frac{N_1}{N_2}=\frac{13750}{100}=137.5$

Then $\frac{\sqrt{3}}{2}\times 137.5=119.08$

The furnace current is $I_a=\frac{625\times 10^3}{100\times 1}=6250$ A

Similarly, $I_b=\frac{1000\times 10^3}{100\times 1}=10000$ A

On the three-phase side, $I_A=\frac{6250}{119.08}=52.49$ A.