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+//CHAPTER 8- DIRECT CURRENT MACHINES
+//Example 22
+
+disp("CHAPTER 8");
+disp("EXAMPLE 22");
+
+//VARIABLE INITIALIZATION
+N1=600;                       //in rpm
+v=230;                        //in Volts
+I_l1=50;                      //line current in Amperes
+r_a=0.4;                      //armature resistance in Ohms
+r_f=104.5;                    //field resistance in Ohms
+drop=2;                       //brush drop in Volts
+
+//SOLUTION
+
+//solution (i)
+I_l2=5;
+I_a1=I_l1-(v/r_f);
+E_b1=v-(I_a1*r_a)-drop; 
+I_a2=I_l2-(v/r_f);
+E_b2=v-(I_a2*r_a)-drop; 
+N2=(E_b2/E_b1)*N1;
+N2=round(N2);
+disp(sprintf("(i) The speed at no load is %d rpm",N2));
+
+//solution (ii)
+I_l2=50;
+N2=500;
+E_b2=(N2/N1)*E_b1; 
+dif=v-drop;                   //difference
+I_a2=I_l2-(v/r_f); 
+r_se=((dif-E_b2)/I_a2)-r_a;
+disp(sprintf("(ii) The additional resistance is %f Ω",r_se));
+
+//solution (iii)
+phi1=1;                       //it is an assumption
+I_a3=30;
+N2=750;
+E_b3=v-(I_a3*r_a)-drop;
+phi2=(E_b3/E_b1)*(N1/N2)*phi1;
+red=((1-phi2)*100*phi1)/phi1;
+disp(sprintf("(iii) The percentage reduction of flux per pole is %f %%",red));
+
+//END  
+