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+// Example 8.3
+// Determine (a) System active power (b) Power factor of the synchronous motor
+// (c) System power factor (d) Percent change in synchronous field current 
+// required to adjust the system power factor to unity (e) Power angle of the 
+// synchronous motor for the conditions in (d) 
+// Page No. 324
+
+clc; 
+clear;
+close;
+
+// Given data
+
+Php=400;                    // Power in hp
+eta=0.958;                  // Efficiency
+Pheater=50000;              // Resistance heater power 
+Vs=300;                     // Synchronous motor voltage
+eta2=0.96;                  // Synchronous motor efficiency
+Xs=0.667;                   // Synchronous reactnace
+VT=460;                     // 3-Phase supply voltage
+delta=-16.4;                // Power angle
+
+// (a) System active power 
+Pindmot=Php*0.75*746/(eta);   // Motor operating at three quarter rated load
+Psynmot=Vs*0.5*746/(eta2);    // Synchronous motor power  
+Psys=Pindmot+Pheater+Psynmot;
+Psysk=Psys/1000;
+
+// (b) Power factor of the synchronous motor
+Pin=Psynmot;                 // Power input
+Vtph=VT/sqrt(3);             // Voltage per phase
+Ef=-(Pin*Xs)/(3*Vtph*sind(delta));
+// Complex to Polar form...
+
+Ef_Mag=Ef;          // Magnitude part 
+Ef_Ang=delta;       // Angle part 
+Vtph_Mag=Vtph;      
+Vtph_Ang=0;
+////////////
+N01=Ef_Mag+%i*Ef_Ang;      // Ef in polar form 
+N02=Vtph_Mag+%i*Vtph_Ang;  // Vt in polar for
+
+N01_R=Ef_Mag*cos(-Ef_Ang*%pi/180); // Real part of complex number Ef
+N01_I=Ef_Mag*sin(Ef_Ang*%pi/180); //Imaginary part of complex number Ef
+
+N02_R=Vtph_Mag*cos(-Vtph_Ang*%pi/180); // Real part of complex number Vt
+N02_I=Vtph_Mag*sin(Vtph_Ang*%pi/180); //Imaginary part of complex number Vt
+
+FinalNo_R=N01_R-N02_R;
+FinalNo_I=N01_I-N02_I;
+FinNum=FinalNo_R+%i*FinalNo_I;
+// Complex to Polar form...
+
+FN_M=sqrt(real(FinNum)^2+imag(FinNum)^2); // Magnitude part
+FN_A = atan(imag(FinNum),real(FinNum))*180/%pi;// Angle part 
+
+Ia_Mag=FN_M/Xs;          // Magnitude of Ia
+Ia_Ang=FN_A-(-90);       // Angle of Ia
+Theta=0-Ia_Ang;
+FP=cosd(Theta);          // Power factor
+
+
+// (c) System power factor
+ThetaIndMot=acosd(0.891);    // Induction motor power factor
+Thetaheat=acosd(1);          // Heater power factor
+ThetaSyncMot=-34.06;         // Synchronous motor power factor
+Qindmot=tand(27)*Pindmot; 
+Qsynmot=tand(ThetaSyncMot)*Psynmot;
+Qsys=Qindmot+Qsynmot;
+Ssys=Psys+%i*Qsys;         // System variable in complex form
+
+// Complex to Polar form...
+
+Ssys_Mag=sqrt(real(Ssys)^2+imag(Ssys)^2);         // Magnitude part
+Ssys_Ang = atan(imag(Ssys),real(Ssys))*180/%pi;   // Angle part 
+
+FPsys=cosd(Ssys_Ang);                             // System power factor 
+
+// (d) Percent change in synchronous field current required to adjust the 
+// system power factor to unity
+
+Ssynmot=Psynmot-(%i*(-Qsynmot+Qsys));   // Synchronous motor system
+
+// Complex to Polar form...
+
+Ssynmot_Mag=sqrt(real(Ssynmot)^2+imag(Ssynmot)^2);     // Magnitude part
+Ssynmot_Ang=atan(imag(Ssynmot),real(Ssynmot))*180/%pi; // Angle part 
+
+Ssynmot1ph_Mag=Ssynmot_Mag/3;            // For single phase magnitude
+Ssynmot1ph_Ang=Ssynmot_Ang;              // For single phase angle
+
+Iastar_Mag=Ssynmot1ph_Mag/Vtph;          // Current magnitude
+Iastar_Ang=Ssynmot1ph_Ang-0;             // Current angle
+
+IaNew_Mag=Iastar_Mag;
+IaNew_Ang=-Iastar_Ang;
+
+IaXs_Mag=IaNew_Mag*Xs;
+IaXs_Ang=IaNew_Ang-90;
+
+// Convert these number into complex and then perform addition
+// Polar to Complex form
+
+// Y=29.416<-62.3043 //Polar form number
+IaXs_R=IaXs_Mag*cos(-IaXs_Ang*%pi/180);  // Real part of complex number
+IaXs_I=IaXs_Mag*sin(IaXs_Ang*%pi/180);   // Imaginary part of complex number
+Efnew=Vtph+IaXs_R+%i*IaXs_I;
+// Complex to Polar form...
+
+Efnew_Mag=sqrt(real(Efnew)^2+imag(Efnew)^2);     // Magnitude part
+Efnew_Ang=atan(imag(Efnew),real(Efnew))*180/%pi; // Angle part 
+
+DeltaEf=(Efnew_Mag-Ef)/Ef; 
+
+// (e) Power angle of the synchronous motor
+deltasynmot=Efnew_Ang;
+
+// Display result on command window
+printf("\n System active power  = %0.1f kW ",Psysk);
+printf("\n Power factor of the synchronous motor = %0.3f leading ",FP);
+printf("\n System power factor = %0.3f lagging ",FPsys);
+printf("\n Percent change in synchronous field current = %0.2f Percent ",DeltaEf*100);
+printf("\n Power angle of the synchronous motor = %0.2f deg ",deltasynmot);