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diff --git a/Working_Examples/2777/CH6/EX6.31/Ex6_31.sce b/Working_Examples/2777/CH6/EX6.31/Ex6_31.sce new file mode 100755 index 0000000..7cd049b --- /dev/null +++ b/Working_Examples/2777/CH6/EX6.31/Ex6_31.sce @@ -0,0 +1,75 @@ +
+// ELECTRICAL MACHINES
+// R.K.Srivastava
+// First Impression 2011
+// CENGAGE LEARNING INDIA PVT. LTD
+// CHAPTER : 6 : SYNCHRONOUS MACHINES
+
+// EXAMPLE : 6.31
+
+clear ; clc ; close ; // Clear the work space and console
+
+
+// GIVEN DATA
+
+Pi = 2*10^6; // Power input in Volt-Amphere
+v = 6.6*10^3; // Operating voltage in Volts
+
+
+// CALCULATIONS
+
+I = Pi/(v*sqrt(3)); // Rated current in Amphere
+V = v/sqrt(3); // Phase voltage in Volts
+xs = v/(I*sqrt(3)); // Synchronous reactance in Ohms
+
+// For case (a) 0.8 pf lagging
+
+pf_a = 0.8; // Power factor
+pfa_a = acosd(pf_a); // Power factor angle in degree
+a_a = (V + (I*xs*sind(pfa_a)));
+b_a = (I*xs*cosd(pfa_a));
+E_a = sqrt(a_a^2 + b_a^2); // Induced EMF in Volts
+delta_a = atand(b_a/a_a); // Torque (power) angle in degree
+P_a = (3*V*E_a*sind(delta_a))/(xs*10^6); // Power developed in MVA
+
+// For case (b) 0.8 pf leading
+
+pf_b = 0.8; // Power factor
+pfa_b = acosd(pf_b); // Power factor angle in degree
+a_b = (V - (I*xs*sind(pfa_a)));
+b_b = (I*xs*cosd(pfa_b));
+E_b = sqrt(a_b^2 + b_b^2); // Induced EMF in Volts
+delta_b = atand(b_b/a_b); // Torque (power) angle in degree
+P_b = (3*V*E_b*sind(delta_b))/(xs*10^6); // Power developed in MVA
+
+// For case (c) UPF
+
+pf_c = 1.0; // Power factor
+pfa_c = acosd(pf_c); // Power factor angle in degree
+a_c = V;
+b_c = I*xs;
+E_c = sqrt(a_c^2 + b_c^2); // Induced EMF in Volts
+delta_c = atand(b_c/a_c); // Torque (power) angle in degree
+P_c = (3*V*E_c*sind(delta_c))/(xs*10^6); // Power developed in MVA
+
+
+disp("EXAMPLE : 6.31: SOLUTION :-");
+printf("\n For Case (a) 0.80 lagging Power factor \n Induced EMF, EMF = %.2f V \n",E_a)
+printf("\n Power (Torque) angle = %.2f degree \n",delta_a)
+printf("\n Power developed, P = %.1f MVA \n",P_a)
+printf("\n For Case (b) 0.80 leading Power factor \n Induced EMF, EMF = %.f V \n",E_b)
+printf("\n Power (Torque) angle = %.2f degree \n",delta_b)
+printf("\n Power developed, P = %.3f MVA \n",P_b)
+printf("\n For Case (c) Unity Power Factor \n Induced EMF, EMF = %.1f V \n",E_c)
+printf("\n Power (Torque) angle = %.2f degree \n",delta_c)
+printf("\n Power developed, P = %.1f MVA \n",P_c)
+printf("\n\n [ TEXT BOOK SOLUTION IS PRINTED WRONGLY ( I verified by manual calculation )]\n" );
+printf("\n WRONGLY PRINTED ANSWERS ARE :- xs = 20.14 instead of %.2f Ohms \n ",xs);
+printf("\n For Case (a) 0.80 lagging Pf (a.1) E = 6561.42 instead of %.2f V \n ",E_a);
+printf("\n (a.2) delta = 25.45 instead of %.2f degree \n ",delta_a);
+printf("\n For Case (b) 0.80 leading Pf (b.1) E = 3290 instead of %.1f V \n ",E_b);
+printf("\n (b.2) delta = 58.98 instead of %.2f degree \n ",delta_b);
+printf("\n (b.3) Power developed = 1.617 instead of %.3f MVA \n ",P_b);
+printf("\n For Case (c) UPF (c.1) E = 5190.2 instead of %.2f V \n ",E_c);
+printf("\n (c.2) delta = 42.77 instead of %.2f degree \n ",delta_c);
+printf("\n In all the three cases from Calculation of the Synchronous reactance (xs), rest all the Calculated values in the TEXT BOOK is WRONG because of the Synchronous reactance (xs) value is WRONGLY calculated and the same used for the further Calculation part \n")
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