//Caption:Determine the KVA rating of auto transformer with additive and subtractive polarity also find the efficiency at full load and unity power factor //Exa:3.13 clc; clear; close; P=120*1000;//in watts V1=2400;//in volts V2=240;//in volts I1=P/V1;//in amperes I2=P/V2;//in amperes KVA_1=V1*(I1+I2)/1000; P_trans=V2*I2/1000; P_cond_1=KVA_1-P_trans; P_loss_1=((1/0.98)-1)^2*P_trans; Eff_a=1-(P_loss_1/KVA_1) disp(KVA_1,'KVA Rating of transformer with additive polarity (in KVA)='); disp(Eff_a*100,'Efficiency of auto transformer with additive polarity (in %)='); KVA_2=V1*(I2-I1)/1000; P_trans=V2*I2/1000; P_cond_2=KVA_2-P_trans; P_loss=((1/0.98)-1)^2*P_trans; Eff_s=1-(P_loss/KVA_2) disp(KVA_2,'KVA Rating of transformer with subtractive polarity (in KVA)='); disp(Eff_s*100,'Efficiency of auto transformer with subtractive polarity (in %)=');