//Problem 21.20: A 240 V shunt motor takes a total current of 30 A. If the field winding resistance Rf = 150 ohm and the armature resistance Ra = 0.4 ohm. determine (a) the current in the armature, and (b) the back e.m.f. //initializing the variables: Rf = 150; // in Ohms Ra = 0.4; // in Ohms I = 30; // in Amperes V = 240; // in Volts //calculation: //Field current If If = V/Rf //Supply current I = Ia + If //Hence armature current, Ia Ia = I - If //Back e.m.f. E = V - Ia*Ra E = V - (Ia*Ra) printf("\n\n Result \n\n") printf("\n (a) current in the armature is %.1f A ",Ia) printf("\n (b) Back e.m.f. E is %.2f V ",E)