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| author | priyanka | 2015-06-24 15:03:17 +0530 |
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| committer | priyanka | 2015-06-24 15:03:17 +0530 |
| commit | b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b (patch) | |
| tree | ab291cffc65280e58ac82470ba63fbcca7805165 /1092/CH8/EX8.2/Example8_2.sce | |
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diff --git a/1092/CH8/EX8.2/Example8_2.sce b/1092/CH8/EX8.2/Example8_2.sce new file mode 100755 index 000000000..19fcee1bc --- /dev/null +++ b/1092/CH8/EX8.2/Example8_2.sce @@ -0,0 +1,74 @@ +// Electric Machinery and Transformers
+// Irving L kosow
+// Prentice Hall of India
+// 2nd editiom
+
+// Chapter 8: AC DYNAMO TORQUE RELATIONS - SYNCHRONOUS MOTORS
+// Example 8-2
+
+clear; clc; close; // Clear the work space and console.
+
+// Given data
+// 3- phase Y-connected synchronous motor
+P = 20 ; // No. of poles
+hp = 40 ; // power rating of the synchronous motor in hp
+V_L = 660 ; // Line voltage in volt
+beta = 5 ; // At no-load, the rotor is retarded 0.5 mechanical degree from
+// its synchronous position.
+X_s = 10 ; // Synchronous reactance in ohm
+R_a = 1.0 ; // Effective armature resistance in ohm
+
+// Calculations
+// case a
+funcprot(0); // To avoid this message "Warning : redefining function: beta"
+alpha = P * (beta/2); // The rotor shift from the synchronous position in
+// electrical degrees.
+
+// case b
+V_p = V_L / sqrt(3); // Phase voltage in volt
+E_gp = V_p ; // Generated voltage/phase at no-load in volt (given)
+E_r = (V_p - E_gp*cosd(alpha)) + %i*(E_gp*sind(alpha));
+E_r_m = abs(E_r);//E_r_m=magnitude of E_r in volt
+E_r_a = atan(imag(E_r) /real(E_r))*180/%pi;//E_r_a=phase angle of E_r in degrees
+
+// case c
+Z_s = R_a + %i*X_s ; // Synchronous impedance in ohm
+Z_s_m = abs(Z_s);//Z_s_m=magnitude of Z_s in ohm
+Z_s_a = atan(imag(Z_s) /real(Z_s))*180/%pi;//Z_s_a=phase angle of Z_s in degrees
+
+I_a = E_r / Z_s ; // Armature current/phase in A/phase
+I_a_m = abs(I_a);//I_a_m=magnitude of I_a in A
+I_a_a = atan(imag(I_a) /real(I_a))*180/%pi;//I_a_a=phase angle of I_a in degrees
+
+// case d
+theta = I_a_a ; // Phase angle between V_p and I_a in degrees
+P_p = V_p * I_a_m * cosd(theta); // Power per phase drawn by the motor from the bus
+P_t = 3*P_p ; // Total power drawn by the motor from the bus
+
+// csae e
+P_a = 3 * (I_a_m)^2 * R_a ; // Armature power loss at no-load in W
+P_d = (P_t - P_a)/746 ; // Internal developed horsepower at no-load
+
+// Display the results
+disp("Example 8-2 Solution : ");
+printf(" \n a: alpha = %d degrees (electrical degrees)\n",alpha );
+
+printf(" \n b: E_gp = %d V also, as given ",E_gp);
+printf(" \n E_r in V/phase = ");disp(E_r);
+printf(" \n E_r = %d <%.1f V/phase \n",E_r_m, E_r_a );
+
+printf(" \n c: Z_s in ohm/phase = ");disp(Z_s);
+printf(" \n Z_s = %.2f <%.1f ohm/phase \n",Z_s_m, Z_s_a );
+printf(" \n I_a in A/phase = ");disp(I_a);
+printf(" \n I_a = %.2f <%.2f A/phase \n ",I_a_m, I_a_a);
+
+printf(" \n d: P_p = %.2f W/phase ",P_p );
+printf(" \n P_t = %.2f W ",P_t);
+printf(" \n Note: Slight variations in power values is due to slight variations");
+printf(" \n in V_p , I_a and theta values from those of the textbook\n");
+
+
+printf(" \n e: P_a = %.f W ",P_a );
+printf(" \n P_d = %.1f hp ", P_d );
+
+
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