initial commit / add all books

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diff --git a/3760/CH6/EX6.37/Ex6_37.sce b/3760/CH6/EX6.37/Ex6_37.sce
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+clc;

+P=20000; // rated power of induction motor

+v=400; // rated voltage of motor

+f=50;  // frequency

+m=3; // number of phases

+p=4; // number of poles

+r1=0.2; // stator resistance

+x=0.45; // stator/rotor leakage reactance

+xm=18; // magnetising reactance

+s=0.04; // slip

+pg=P/(1-s); // air gap power

+pr=s*pg; // rotor copper loss

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

+ve=(vp*xm)/(x+xm); // Thevenin  voltage

+re=(r1*xm)/(x+xm); // Thevenin resistance

+xe=(x*xm)/(x+xm); // Thevenin reactance

+// using Thevenin's theorrm and rotor copper loss expression we get a quadratic equation in r2 (rotor resistance) whose terms are

+t1=pr/s^2; 

+t2=((2*pr*re)/s)-(m*ve^2);

+t3=pr*((xe+x)^2+re^2);

+t=[ t1 t2 t3];

+r2=roots(t);

+disp('case a');

+ws=(4*%pi*f)/p; // synchronous speed

+Tm=(m*ve^2)/(ws*2*(re+sqrt(re^2+(x+xe)^2)));

+printf('Maximum internal torque is %f Nm\n',Tm);

+Ti=(m*ve^2*r2(1))/(ws*((re+r2(1))^2+(x+xe)^2));

+printf('Initial starting torque is %f Nm\n',Ti);

+disp('case b');

+sm=r2(1)/(sqrt(re^2+(xe+x)^2));

+printf('Slip at maximum torque is %f ',sm);