1 files changed, 33 insertions, 0 deletions
diff --git a/3760/CH5/EX5.15/Ex5_15.sce b/3760/CH5/EX5.15/Ex5_15.sce
new file mode 100644
index 000000000..8633091ce
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+++ b/3760/CH5/EX5.15/Ex5_15.sce
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+clc;
+v=11000; // rated voltage of motor
+zs=1+10*%i; // per phase synchronous impedance
+ia=100; // armature current at unity power factor
+vt=v/sqrt(3); // per phase voltage
+Ef=sqrt((vt+ia*real(zs))^2+(ia*imag(zs))^2); // excitation EMF from phasor diagram
+al=atand(real(zs),imag(zs));
+de=atand((ia*imag(zs))/(vt+ia)); // load angle
+p=(Ef*vt*sind(de+al)/abs(zs))-((vt^2*real(zs))/abs(zs)^2); // per phase power delivered
+disp('case a');
+Ef1=1.15*Ef; // Excitation EMF after an increment of 15%
+t1=p;
+t2=(vt^2/abs(zs)^2)*real(zs);
+t3=abs(zs)/(vt*Ef1); // terms needed to evaluate load angle
+di=asind((t1+t2)*t3)-al; // load angle
+ia1=(sqrt(vt^2+Ef1^2-2*Ef1*vt*cosd(di)))/abs(zs); // armature current
+pf=p/(vt*ia1); 
+printf('New value of armature current is %f A\n',ia1);
+printf('New value of load angle is %f degrees\n',di);
+printf('New power factor is %f lagging\n',pf);
+disp('case b');
+// at unity pf
+pf=1;
+c1=1+imag(zs)^2;
+c2=2*vt;
+c3=vt^2-Ef1^2; // coefficients of quadratic equation in armature current
+p= [ c1 c2 c3 ];
+ia=roots(p);
+printf('Armature current under given condition is %f A\n',ia(2));
+P=(vt*ia(2)*pf)/1000;
+Pt=P*3; 
+printf('Per phase power delivered is %f KW\n',P);
+printf('Net power delivered is %f KW\n',Pt);