// Electric Machinery and Transformers // Irving L kosow // Prentice Hall of India // 2nd editiom // Chapter 14: TRANSFORMERS // Example 14-12 clear; clc; close; // Clear the work space and console. // Given data(from Example 14-11) V_1 = 2300 ; // Primary voltage in volt V_2 = 230 ; // Secondary voltage in volt I_2 = 2174 ; // Secondary current in A I_1 = 217.4 ; // Primary current in A // calculated values from Example 14-11 Z_2 = 0.00316 ; // Secondary internal impedance in ohm Z_1 = 0.316 ; // Primary internal impedance in ohm // Calculations alpha = V_1 / V_2 ; // Transformation ratio // case a Z_L = V_2 / I_2 ; // Load impedance in ohm // case b Z_p = V_1 / I_1 ; // Primary input impedance in ohm Zp = (alpha)^2 * Z_L ; // Primary input impedance in ohm // Display the results disp("Example 14-12 Solution : "); printf(" \n a: Load impedance :\n Z_L = %.4f ohm \n ", Z_L ); printf(" \n b: Primary input impedance : "); printf(" \n (method 1) :\n Z_p = %.2f ohm \n ",Z_p ); printf(" \n (method 2) :\n Z_p = %.2f ohm \n ",Zp ); printf(" \n c: The impedance of the load Z_L = %.4f Ω, which is much greater",Z_L); printf(" \n than the internal secondary impedance Z_2 = %.5f Ω .\n ",Z_2); printf(" \n The primary input impedance Z_p = %.2f Ω,which is much greater",Z_p); printf(" \n than the internal primary impedance Z_1 = %.3f Ω .\n",Z_1); printf(" \n d: It is essential for Z_L to be much greater than Z_2 so that the "); printf(" \n major part of the voltage produced by E_2 is dropped across the "); printf(" \n load impedance Z_L. As Z_L is reduced in proportion to Z_2, the "); printf(" \n load current increases and more voltage is dropped internally "); printf(" \n across Z_2.");