initial commit / add all books

1 files changed, 99 insertions, 0 deletions

diff --git a/3760/CH5/EX5.1/Ex5_1.sce b/3760/CH5/EX5.1/Ex5_1.sce
new file mode 100644
index 000000000..18c2c993b
--- /dev/null
+++ b/3760/CH5/EX5.1/Ex5_1.sce
@@ -0,0 +1,99 @@
+clc;

+v=220; // rated voltage of alternator

+f=50; // frequency of supply

+r=0.06; // resistance per phase

+p=6; // number of poles

+i=40; // full load current 

+pf=0.8; // lagging power factor

+vt=v/sqrt(3); // rated per phase voltage

+IF=[ 0.2 0.4 0.6 0.8 1 1.2 1.4 1.8 2.2 2.6 3 3.4];

+EA=[ 29 58 87 116 146 172 194 232 261.5 284 300 310];

+subplot(313);

+plot(IF,EA/sqrt(3));

+xlabel('Field current');

+ylabel('open circuit voltage');

+title('open circuit characteristics');

+IF1=[ 0.2 0.4 0.6 0.8 1 1.2 1.4 1.8 ];

+ISC=[ 6.6 13.2 20 26.5 32.4 40 46.3 59 ];

+subplot(323);

+plot(IF1,ISC);

+xlabel('Field current');

+ylabel('short circuit current');

+title('short circuit characteristics');

+ZPF=[ 0 0 0 0 0 0 29 88 140 177 208 230];

+subplot(333);

+plot(IF,ZPF);

+xlabel('Field current');

+ylabel('terminal voltage');

+title('full load zero power factor characteristics');

+disp('EMF method');

+// value of synchronous reactance is taken from given table

+EA1=[ 29 58 87 116 146 172 194 232]

+ZS=EA1./(ISC*sqrt(3));

+disp('synchronous impedance (ohms) is');

+disp(ZS);

+XS=ZS; // RS^2 is negligible

+disp('synchronous reactance (ohms) is');

+disp(XS);

+xs=2.27;

+ia=i*(pf-%i*sqrt(1-pf^2)); // full load current in complex form

+E=vt+ia*(r+%i*xs); // Excitation voltage

+vr=floor(((abs(E)-vt)/vt)*100); 

+printf('Voltage regulation is %f percent\n',vr);

+disp('Mmf method');

+// with ia as reference

+E=vt*(pf+%i*sqrt(1-pf^2))+i*r; // Excitation voltage

+// from fig 5.30 ,E=127 V

+oc=1.69; // current for given excitation voltage obtained from open circuit characteristics

+sc=1.2; // field current required to circulate full load short circuit current

+al=atand(imag(E),real(E)); // angle between ia and E

+Ff=(oc*(-sind(al)+%i*cosd(al)))-sc; // field mmf

+printf('field mmf is %f A\n',abs(Ff));

+// corresponding to Ff,E=163.5 v from O.C.C

+Ef=163.5; 

+vr=((Ef-vt)/vt)*100; 

+printf('Voltage regulation is %f percent\n',vr);

+disp('Zero power factor method');

+// As per the description given in method

+vd=30; // voltage drop armature leakage reactance

+xa=vd/i; // armature leakage reactance

+// with ia as reference

+Er=vt*(pf+%i*sqrt(1-pf^2))+i*(r+%i*xa); // Excitation voltage

+// from fig 5.30 ,E=148.6 V

+oc=2.134; // current for given excitation voltage obtained from open circuit characteristics

+Fa=0.84; // armature mmf from potier triangle

+be=atand(imag(Er),real(Er)); // angle between ia and E

+Ff=(oc*(-sind(be)+%i*cosd(be)))-Fa; // field mmf

+printf('field mmf is %f A\n',abs(Ff));

+// corresponding to Ff=2.797 A,E=169 v from O.C.C

+Ef=169; 

+vr=((Ef-vt)/vt)*100;

+printf('Voltage regulation is %f percent\n',vr);

+disp('New A.S.A method');

+// parameters needed in this method are calculated in part c

+id=0.366; // difference in field current between OCC and air gap line from fig 5.30

+th=acosd(pf);

+ig=1.507; // field current corresponding to rated rated per phase voltage

+Ff=ig+sc*(%i*pf+sqrt(1-pf^2)); // field mmf without saturation

+Ff=abs(Ff)+id; // ield mmf with saturation

+printf('field mmf is %f A\n',Ff);

+// corresponding to Ff=2.791 A,E=169 v from O.C.C

+Ef=169; 

+vr=((Ef-vt)/vt)*100;

+printf('Voltage regulation is %f percent\n',vr);

+disp('Saturated synchronous reactance method');

+// for E=148.5 v (from part c), 

+Era=179.5; // air line gap voltage

+k=Era/abs(Er); // saturation factor

+vdg=100.5; // voltage drop in unsaturated synchronous reactance

+xag=vdg/i; // unsaturated synchronous reactance

+xas=xa+((xag-xa)/k); // saturated synchronous reactance

+// with vt as reference

+Ef=vt+ia*(r+%i*xas); 

+ok=2.15; // resultant mmf from fig 5.30

+Ff=(abs(Ef)/abs(Er))*ok;

+printf('field mmf is %f A\n',Ff);

+// corresponding to Ff=2.78 A,E=169 v from O.C.C

+Ef=169; 

+vr=((Ef-vt)/vt)*100;

+printf('Voltage regulation is %f percent\n',vr);