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+//Chapter 7:Synchronous Motor and Brushless DC Motor Drives
+//Example 1
+clc;
+
+//Variable Initialization
+
+//Ratings of the synchronous motor
+Pm1=500*1000   // power rating in W
+f=50           // frequency in HZ
+Vl=3.3*1000    // line voltage in V
+pf=0.8         // power factor lagging
+P=4            // number of poles
+I=10           // field current in A
+Xs=15          // reactance of the windings in ohm
+Rs=0           // resistance of the windings in ohm
+Wms=50*%pi // synchronous speed in rad/sec
+Pm=Pm1/2       // power at half the rated torque when the losses are neglected
+
+//Solution
+V=Vl/sqrt(3)  //phase voltage
+Is=Pm1/(sqrt(3)*Vl*pf)   //rated current
+rad=acos(pf)
+
+Is=Is * (cos(-rad) + sin(-rad)*%i)   //rated current in vector form
+V=V * (cos(0) + sin(0))       //rated phase voltage in rectangular form
+E=V-Is*%i*Xs                  //back emf
+
+//(i) When field current has not changed
+sin_delta=Pm*Xs/(3*abs(V)*abs(E))  
+delta=asin(sin_delta)                 //angle delta
+Is=(V-(abs(E) * (cos(-delta) + sin(-delta)*%i)))/(%i*Xs)   //armature current
+Is1=[]
+Is1(1)=abs(Is)
+Isp=phasemag(Is)
+x=Isp
+n1=x*%pi/180
+power_factor=cos(n1)    //power factor 
+
+//(ii) At unity power factor and rated torque
+cos_phi=1
+Is=Pm1/(3*V)         //since Pm1=3*V*Is
+E1=V-Is*%i*Xs
+If=abs(E1)/abs(E)*I  //field current
+
+//(iii) At the field current of 12.5 A
+If1=12.5      //field current 
+E2=If1/I*abs(E)
+Is=sqrt(E2**2-abs(V)**2)/Xs  //since E2=abs(V-Is*1j*Xs)
+Pm=3*abs(V)*Is*cos_phi            //power output at the given field current
+T=Pm/Wms                          //required torque
+
+//results
+mprintf("i)Armature current :%.2f %.1f ° A",abs(Is1),x)
+mprintf("\nPower factor:%.2f lagging",power_factor)
+mprintf("\nii)Field current at unity power factor at rated torque:%.2f A",If)
+mprintf("\niii)Required torque is:%.1f N-m",T)
+//There is a slight difference in the answer