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//CHAPTER 8- DIRECT CURRENT MACHINES
//Example 14
disp("CHAPTER 8");
disp("EXAMPLE 14");
//VARIABLE INITIALIZATION
v_t=220; //in Volts
I_l=196; //in Amperes
s_loss=720; //stray loss in Watts
r_f=55; //shunt field ressitance in Ohms
eff=88/100; //efficiency
//SOLUTION
p_o=v_t*I_l;
p_i=p_o/eff; //electrical input
tot_loss=p_i-p_o;
I_f=v_t/r_f;
I_a=I_l+I_f;
cu_loss=v_t*I_f; //shunt field copper loss
c_loss=cu_loss+s_loss; //constant loss
arm_loss=tot_loss-c_loss; //armature copper loss
r_a=arm_loss/(I_a^2);
disp(sprintf("The armature resistance is %f Ω",r_a));
//for maximum efficiency, armature loss = constant loss =>(I_a^2)*r_a=c_loss
I_a=sqrt(c_loss/r_a);
disp(sprintf("The load current corresponding to maximum efficiency is %f A",I_a));
//END
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