B1. The specification of a 8KVA, 400V/200V, 50HZ step-down transformer is shown below: Primary winding impedance R = 0.1 2, X,= 12 Secondary winding impedance R2 = 0.2 2, X2= 0.52 Core resistance = Rm= 20k2 , Magnetizing reactance Xm = 8kN Table B1 (a) Sketch the circuit of the above transformer based on the above (2 marks) specification. Label R1, X, R2, X2, Rm, Xm in the circuit. (b) Calculate the values Ri eq and Xi eg of the transformer referred to the (3 marks) primary side. (c) Calculate the values R2 eg and X2 eq of the transformer referred to the (3 marks) secondary side. (d) Calculate the voltage regulation in percentage at full load with power (5 marks) factor at 0.78 lagging. (e) Calculate the transformer copper loss at half load. (3 marks) (f) Calculate the efficiency of transformer at half load with a lagging power (4 marks) factor of 0.8 and iron loss of 80W.