initial commit / add all books

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diff --git a/3760/CH6/EX6.48/Ex6_48.sce b/3760/CH6/EX6.48/Ex6_48.sce
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+clc;

+P=4500; // rated power of induction motor

+V=400; // rated voltage of motor

+f=50; // frequency

+m=3; // number of phases

+// no load test results

+Vo=400; // applied line voltage

+io=4.2; // no load line current

+Po=480; //  power input

+// blocked rotor test

+vb=215; // line voltage

+ib=15; // line current

+pb=1080; // input power

+rs=1.2; // rotor resistance referred to stator per phase

+nt=2; // stator to rotor turns ratio

+pfo=Po/(sqrt(3)*io*Vo); // no load power factor

+pfb=pb/(sqrt(3)*ib*vb); // short circuit power factor

+isc=(V/vb)*(ib*sqrt(3)); // per phase short circuit current

+iop=io/sqrt(3); // per phase no load current

+x=1; // scale 1 A= 1 cm

+// circle diagram is drawn in fig 6.38

+disp('case a');

+// value of maximum torque at starting is not given

+// now we note Bf=4.6 and B'f=1.25 using these values external resistance to be inserted is calculated

+re=(4.6/1.25)*1.2; // external resistance

+printf('External resistance referred to rotor is %f ohms\n',re/nt^2);

+// as per the construction we obtain OB=11.24 which is needed to calculate starting line current

+is=11.24*sqrt(3); 

+printf('Starting current is %f A\n',is);

+// angle OBB'=45.5 which is needed to calculate power factor

+pf=cosd(45.5);

+printf('power factor is %f lagging\n',pf);

+pps=x*V; // per phase power scale

+fp=P/m; // full load power per phase

+disp('case b');

+// now torque is 1.25 times full load torque

+// now we note NK=2.9 and N'K=2.1 using these values external resistance to be inserted is calculated

+re=(2.9/2.1)*1.2; // external resistance

+printf('External resistance referred to rotor is %f ohms\n',re/nt^2);

+// as per the construction we obtain ON=14.35 which is needed to calculate starting line current

+is=14.35*sqrt(3); 

+printf('Starting current is %f A\n',is);

+// angle ONN'=58.3 which is needed to calculate power factor

+pf=cosd(58.3);

+printf('power factor is %f lagging\n',pf);

+disp('case c');

+// we obtain OH=5.35 which is per phase output current

+// thetag=41.3

+opf=cosd(41.3); 

+printf('Operating power factor is %f leading\n',opf);

+po=m*5.35*V*opf; 

+printf('Output power is %f KW\n',po/1000);

+// we note HL=3.95 and Ha=4.90 which is needed for efficiency

+ne=3.95/4.9; 

+printf('Induction generator efficiency is %f percent',ne*100);