// FUNDAMENTALS OF ELECTICAL MACHINES // M.A.SALAM // NAROSA PUBLISHING HOUSE // SECOND EDITION // Chapter 6 : CONTROL AND STARTING OF A DC MOTORS // Example : 6.1 clc;clear; // clears the console and command history // Given data V_t = 220 // supply voltage in V I_a1 = 10 // dc shunt motor armature current in A N_1 = 900 // speed in rpm R_a = 1 // armature resistance in ohm N_2 = 500 // speed in rpm // caclulations E_b1 = V_t-I_a1*R_a // initial back emf in V R = (E_b1/10)*(1-(N_2/N_1)) // additional value of resistance in ohm // display the result disp("Example 6.1 solution"); printf(" \n additional value of resistance \n R = %.1f ohm \n", R);