From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001 From: priyanka Date: Wed, 24 Jun 2015 15:03:17 +0530 Subject: initial commit / add all books --- 1092/CH6/EX6.1/Example6_1.sce | 52 +++++++++++++++++++++++++ 1092/CH6/EX6.2/Example6_2.sce | 53 ++++++++++++++++++++++++++ 1092/CH6/EX6.3/Example6_3.sce | 41 ++++++++++++++++++++ 1092/CH6/EX6.4/Example6_4.sce | 77 +++++++++++++++++++++++++++++++++++++ 1092/CH6/EX6.5/Example6_5.sce | 88 +++++++++++++++++++++++++++++++++++++++++++ 1092/CH6/EX6.6/Example6_6.sce | 51 +++++++++++++++++++++++++ 1092/CH6/EX6.7/Example6_7.sce | 70 ++++++++++++++++++++++++++++++++++ 1092/CH6/EX6.8/Example6_8.sce | 68 +++++++++++++++++++++++++++++++++ 8 files changed, 500 insertions(+) create mode 100755 1092/CH6/EX6.1/Example6_1.sce create mode 100755 1092/CH6/EX6.2/Example6_2.sce create mode 100755 1092/CH6/EX6.3/Example6_3.sce create mode 100755 1092/CH6/EX6.4/Example6_4.sce create mode 100755 1092/CH6/EX6.5/Example6_5.sce create mode 100755 1092/CH6/EX6.6/Example6_6.sce create mode 100755 1092/CH6/EX6.7/Example6_7.sce create mode 100755 1092/CH6/EX6.8/Example6_8.sce (limited to '1092/CH6') diff --git a/1092/CH6/EX6.1/Example6_1.sce b/1092/CH6/EX6.1/Example6_1.sce new file mode 100755 index 000000000..8afa90d79 --- /dev/null +++ b/1092/CH6/EX6.1/Example6_1.sce @@ -0,0 +1,52 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 6: AC DYNAMO VOLTAGE RELATIONS-ALTERNATORS +// Example 6-1 + +clear; clc; close; // Clear the work space and console. + +// Given data +kVA = 1000 ; // kVA rating of the 3-phase alternator +V_L = 4600 ; // Rated line voltage in volt +// 3-phase, Y-connected alternator +R_a = 2 ; // Armature resistance in ohm per phase +X_s = 20 ; // Synchronous armature reactance in ohm per phase +cos_theta_a = 1 ; // Unity power factor (case a) +cos_theta_b = 0.75 ; // 0.75 power factor lagging (case b) +sin_theta_b = sqrt( 1 - (cos_theta_b)^2 ); + +// Calculations +V_P = V_L / sqrt(3) ; // Phase voltage in volt +I_P = ( kVA * 1000 ) / ( 3*V_P ) ; // Phase current in A +I_a = I_P ; // Armature current in A + +// a: At unity PF +E_g_a = ( V_P + I_a * R_a ) + %i*(I_a*X_s); +// Full-load generated voltage per-phase (case a) +E_g_a_m=abs(E_g_a);//E_g_a_m=magnitude of E_g_a in volt +E_g_a_a=atan(imag(E_g_a) /real(E_g_a))*180/%pi;//E_g_a_a=phase angle of E_g_a in degrees + +// b: At 0.75 PF lagging +E_g_b = ( V_P*cos_theta_b + I_a * R_a ) + %i*( V_P*sin_theta_b + I_a*X_s ); +// Full-load generated voltage per-phase (case b ) +E_g_b_m=abs(E_g_b);//E_g_b_m=magnitude of E_g_b in volt +E_g_b_a=atan(imag(E_g_b) /real(E_g_b))*180/%pi;//E_g_b_a=phase angle of E_g_b in degrees + + +// Display the results +disp("Example 6-1 Solution : "); +printf("\n root 3 value is taken as %f , so slight variations in the answer.", sqrt(3)); +printf("\n\n a: At unity PF, \n "); +printf("\n Rectangular form :\n E_g = "); disp(E_g_a); +printf("\n Polar form :"); +printf(" \n E_g = %d <%.2f V/phase ", E_g_a_m , E_g_a_a ); +printf(" \n where %d is magnitude and %.2f is phase angle\n",E_g_a_m,E_g_a_a); + +printf(" \n b: At 0.75 PF lagging , \n "); +printf("\n Rectangular form :\n E_g = "); disp(E_g_b); +printf("\n Polar form :"); +printf(" \n E_g = %d <%.2f V/phase ", E_g_b_m , E_g_b_a ); +printf(" \n where %d is magnitude and %.2f is phase angle\n",E_g_b_m,E_g_b_a); diff --git a/1092/CH6/EX6.2/Example6_2.sce b/1092/CH6/EX6.2/Example6_2.sce new file mode 100755 index 000000000..fecdf70b8 --- /dev/null +++ b/1092/CH6/EX6.2/Example6_2.sce @@ -0,0 +1,53 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 6: AC DYNAMO VOLTAGE RELATIONS-ALTERNATORS +// Example 6-2 + +clear; clc; close; // Clear the work space and console. + +// Given data +kVA = 1000 ; // kVA rating of the 3-phase alternator +V_L = 4600 ; // Rated line voltage in volt +// 3-phase, Y-connected alternator +R_a = 2 ; // Armature resistance in ohm per phase +X_s = 20 ; // Synchronous armature reactance in ohm per phase +cos_theta_a = 0.75 ; // 0.75 PF leading (case a) +cos_theta_b = 0.40 ; // 0.40 PF leading (case b) +sin_theta_a = sqrt( 1 - (cos_theta_a)^2 ); // (case a) +sin_theta_b = sqrt( 1 - (cos_theta_b)^2 ); // (case b) + +// Calculations +V_P = V_L / sqrt(3) ; // Phase voltage in volt +I_P = ( kVA * 1000 ) / ( 3*V_P ) ; // Phase current in A +I_a = I_P ; // Armature current in A + +// a: At 0.75 PF leading +E_g_a = ( V_P*cos_theta_a + I_a * R_a ) + %i*( V_P*sin_theta_a - I_a*X_s); +// Full-load generated voltage per-phase (case a) +E_g_a_m=abs(E_g_a);//E_g_a_m=magnitude of E_g_a in volt +E_g_a_a=atan(imag(E_g_a) /real(E_g_a))*180/%pi;//E_g_a_a=phase angle of E_g_a in degrees + +// b: At 0.40 PF leading +E_g_b = ( V_P*cos_theta_b + I_a * R_a ) + %i*( V_P*sin_theta_b - I_a*X_s ); +// Full-load generated voltage per-phase (case b ) +E_g_b_m=abs(E_g_b);//E_g_b_m=magnitude of E_g_b in volt +E_g_b_a=atan(imag(E_g_b) /real(E_g_b))*180/%pi;//E_g_b_a=phase angle of E_g_b in degrees + + +// Display the results +disp("Example 6-2 Solution : "); +printf("\n root 3 value is taken as %f , so slight variations in the answer.", sqrt(3)); +printf("\n\n a: 0.75 PF leading, \n "); +printf("\n Rectangular form :\n E_g = "); disp(E_g_a); +printf("\n Polar form :"); +printf(" \n E_g = %d <%.2f V/phase ", E_g_a_m , E_g_a_a ); +printf(" \n where %d is magnitude and %.2f is phase angle\n",E_g_a_m,E_g_a_a); + +printf(" \n b: At 0.40 PF leading , \n "); +printf("\n Rectangular form :\n E_g = "); disp(E_g_b); +printf("\n Polar form :"); +printf(" \n E_g = %d <%.2f V/phase ", E_g_b_m , E_g_b_a ); +printf(" \n where %d is magnitude and %.2f is phase angle\n",E_g_b_m,E_g_b_a); diff --git a/1092/CH6/EX6.3/Example6_3.sce b/1092/CH6/EX6.3/Example6_3.sce new file mode 100755 index 000000000..ad2f089a5 --- /dev/null +++ b/1092/CH6/EX6.3/Example6_3.sce @@ -0,0 +1,41 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 6: AC DYNAMO VOLTAGE RELATIONS-ALTERNATORS +// Example 6-3 + +clear; clc; close; // Clear the work space and console. + +// Given data +// From Ex.6-1 and Ex.6-2 we have V_P and E_g values as follows +// Note : approximated values are considered when root 3 value is taken as 1.73 +// as in textbook +V_P = 2660 ; // Phase voltage +E_g_a1 = 3836 ; // E_g at unity PF (Ex.6-1 case a) +E_g_b1 = 4814 ; // E_g at 0.75 PF lagging (Ex.6-1 case b) + +E_g_a2 = 2364 ; // E_g at 0.75 PF leading (Ex.6-2 case a) +E_g_b2 = 1315 ; // E_g at 0.40 PF leading (Ex.6-2 case b) + +// Calculations +VR_a = ( E_g_a1 - V_P )/V_P * 100 ; // voltage regulation at unity PF (Ex.6-1 case a) +VR_b = ( E_g_b1 - V_P )/V_P * 100 ; // voltage regulation at 0.75 PF lagging (Ex.6-1 case b) + +VR_c = ( E_g_a2 - V_P )/V_P * 100 ; // voltage regulation at 0.75 PF leading (Ex.6-2 case a) +VR_d = ( E_g_b2 - V_P )/V_P * 100 ; // voltage regulation at 0.40 PF leading (Ex.6-2 case b) + +// Display the results +disp("Example 6-3 Solution : "); +printf(" \n a: At unity PF : "); +printf(" \n VR = %.1f percent \n ", VR_a ); + +printf(" \n b: At 0.75 PF lagging : "); +printf(" \n VR = %.2f percent \n ", VR_b ); + +printf(" \n c: At 0.75 PF leading : "); +printf(" \n VR = %.2f percent \n ", VR_c ); + +printf(" \n d: At 0.40 PF leading : "); +printf(" \n VR = %.1f percent \n ", VR_d ); diff --git a/1092/CH6/EX6.4/Example6_4.sce b/1092/CH6/EX6.4/Example6_4.sce new file mode 100755 index 000000000..1e9a42df0 --- /dev/null +++ b/1092/CH6/EX6.4/Example6_4.sce @@ -0,0 +1,77 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 6: AC DYNAMO VOLTAGE RELATIONS-ALTERNATORS +// Example 6-4 + +clear; clc; close; // Clear the work space and console. + +// Given data +kVA = 100 ; // kVA rating of the 3-phase alternator +V_L = 1100 ; // Line voltage of the 3-phase alternator in volt + +// dc-resistance test data +E_gp1 = 6 ; // generated phase voltage in volt +V_l = E_gp1 ; // generated line voltage in volt +I_a1 = 10 ; // full-load current per phase in A +cos_theta_b1 = 0.8 ; // 0.8 PF lagging (case b) +cos_theta_b2 = 0.8 ; // 0.8 PF leading (case b) +sin_theta_b1 = sqrt( 1 - (cos_theta_b1)^2 ); // (case b) +sin_theta_b2 = sqrt( 1 - (cos_theta_b2)^2 ); // (case b) + +// open-circuit test data +E_gp2 = 420 ; // generated phase voltage in volt +I_f2 = 12.5 ; // Field current in A + +// short-circuit test data +I_f3 = 12.5 ; // Field current in A +// Line current I_l = rated value in A + +// Calculations +// Assuming that the alternator is Y-connected +// case a : +I_a_rated = (kVA*1000)/(V_L*sqrt(3)); // Rated current per phase in A +I_a = sqrt(3)*I_a_rated ; // Rated Line current in A + +R_dc = V_l/(2*I_a1); // effective dc armature resistance in ohm/winding +R_ac = R_dc * 1.5 ; // effective ac armature resistance in ohm.phase +R_a = R_ac ; // effective ac armature resistance in ohm.phase from dc resistance test + +Z_p = E_gp2 / I_a ; // Synchronous impedance per phase +X_s = sqrt( Z_p^2 - R_a^2 ); // Synchronous reactance per phase + +// case b : +V_p = V_L / sqrt(3); // Phase voltage in volt (Y-connection) + +// At 0.8 PF lagging +E_gp1 = ( V_p*cos_theta_b1 + I_a_rated * R_a ) + %i*( V_p*sin_theta_b1 + I_a_rated * X_s); +E_gp1_m=abs(E_gp1);//E_gp1_m=magnitude of E_gp1 in volt +E_gp1_a=atan(imag(E_gp1) /real(E_gp1))*180/%pi;//E_gp1_a=phase angle of E_gp1 in degrees +V_n1 = E_gp1_m ; // No-load voltage in volt +V_f1 = V_p ; // Full-load voltage in volt +VR1 = ( V_n1 - V_f1 )/ V_f1 * 100; // percent voltage regulation at 0.8 PF lagging + + +// At 0.8 PF leading +E_gp2 = ( V_p*cos_theta_b2 + I_a_rated * R_a ) + %i*( V_p*sin_theta_b2 - I_a_rated*X_s); +E_gp2_m=abs(E_gp2);//E_gp2_m=magnitude of E_gp2 in volt +E_gp2_a=atan(imag(E_gp2) /real(E_gp2))*180/%pi;//E_gp2_a=phase angle of E_gp2 in degrees +V_n2 = E_gp2_m ; // No-load voltage in volt +V_f2 = V_p ; // Full-load voltage in volt +VR2 = ( V_n2 - V_f2 )/V_f2 * 100 ; // percent voltage regulation at 0.8 PF leading + +// Display the results +disp("Example 6-4 Solution : "); +printf(" \n Assuming that the alternator is Y-connected "); +printf(" \n a: R_dc = %.1f ohm/winding ", R_dc ); +printf(" \n R_ac = %.2f ohm/phase ", R_ac ); +printf(" \n Z_p = %.2f ohm/phase ", Z_p ); +printf(" \n X_s = %.2f ohm/phase \n", X_s ); + +printf(" \n b: At 0.8 PF lagging "); +printf(" \n Percent voltage regulation = %.1f percent \n", VR1 ); + +printf(" \n At 0.8 PF leading "); +printf(" \n Percent voltage regulation = %.1f percent ", VR2 ); diff --git a/1092/CH6/EX6.5/Example6_5.sce b/1092/CH6/EX6.5/Example6_5.sce new file mode 100755 index 000000000..2dfac51b0 --- /dev/null +++ b/1092/CH6/EX6.5/Example6_5.sce @@ -0,0 +1,88 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 6: AC DYNAMO VOLTAGE RELATIONS-ALTERNATORS +// Example 6-5 + +clear; clc; close; // Clear the work space and console. + +// Given data +kVA = 100 ; // kVA rating of the 3-phase alternator +V_L = 1100 ; // Line voltage of the 3-phase alternator in volt + +// dc-resistance test data +E_gp1 = 6 ; // generated phase voltage in volt +V_l = E_gp1 ; // generated line voltage in volt +I_a1 = 10 ; // full-load current per phase in A +cos_theta_b1 = 0.8 ; // 0.8 PF lagging (case b) +cos_theta_b2 = 0.8 ; // 0.8 PF leading (case b) +sin_theta_b1 = sqrt( 1 - (cos_theta_b1)^2 ); // (case b) +sin_theta_b2 = sqrt( 1 - (cos_theta_b2)^2 ); // (case b) + +// open-circuit test data +E_gp2 = 420 ; // generated phase voltage in volt +I_f2 = 12.5 ; // Field current in A + +// short-circuit test data +I_f3 = 12.5 ; // Field current in A +// Line current I_l = rated value in A + +// Calculations +// Assuming that the alternator is delta-connected +// case a : +I_a_rated = (kVA*1000)/(V_L*sqrt(3)); // Rated current per phase in A +I_L = I_a_rated ; // Line current in A + +V_p = E_gp2 ; // Phase voltage in volt +V_l = V_p ; // Line voltage in volt (from short circuit data) + +I_p = I_L / sqrt(3) ; // Phase current in A (delta connection) +I_a = I_p ; // Rated current in A + +Z_s = V_l / I_p ; // Synchronous impedance per phase +R_dc = E_gp1/(2*I_a1); // effective dc armature resistance in ohm/winding +R_ac = R_dc * 1.5 ; // effective ac armature resistance in ohm.phase + +// R_eff in delta = 3 * R_eff in Y +R_eff = 3 * R_ac ; // Effective armature resistance in ohm +R_a = R_eff ; // effective ac armature resistance in ohm.phase from dc resistance test + +X_s = sqrt( Z_s^2 - R_a^2 ); // Synchronous reactance per phase + +V_p = V_L ; // Phase voltage in volt (delta-connection) + +// At 0.8 PF lagging +E_gp1 = ( V_p*cos_theta_b1 + I_a * R_a ) + %i*( V_p*sin_theta_b1 + I_a*X_s); +E_gp1_m=abs(E_gp1);//E_gp1_m=magnitude of E_gp1 in volt +E_gp1_a=atan(imag(E_gp1) /real(E_gp1))*180/%pi;//E_gp1_a=phase angle of E_gp1 in degrees +V_n1 = E_gp1_m ; // No-load voltage in volt +V_f1 = V_p ; // Full-load voltage in volt +VR1 = ( V_n1 - V_f1 )/ V_f1 * 100; // percent voltage regulation at 0.8 PF lagging + + +// At 0.8 PF leading +E_gp2 = ( V_p*cos_theta_b2 + I_a * R_a ) + %i*( V_p*sin_theta_b2 - I_a*X_s); +E_gp2_m=abs(E_gp2);//E_gp2_m=magnitude of E_gp2 in volt +E_gp2_a=atan(imag(E_gp2) /real(E_gp2))*180/%pi;//E_gp2_a=phase angle of E_gp2 in degrees +V_n2 = E_gp2_m ; // No-load voltage in volt +V_f2 = V_p ; // Full-load voltage in volt +VR2 = ( V_n2 - V_f2 )/V_f2 * 100 ; // percent voltage regulation at 0.8 PF leading + +// Display the results +disp("Example 6-5 Solution : "); +printf(" \n Assuming that the alternator is delta-connected : \n "); +printf(" \n a: I_p = %.3f A ", I_p ); +printf(" \n Z_s = %.2f ohm/phase ", Z_s ); +printf(" \n R_eff in delta = %.2f ohm/phase ", R_eff ); +printf(" \n X_s = %.1f ohm/phase \n", X_s ); +printf(" \n R_eff, reactance and impedance per phase in delta is 3 times") +printf(" \n the value when connected in Y. \n") + +printf(" \n b: At 0.8 PF lagging "); +printf(" \n Percent voltage regulation = %.1f percent \n", VR1 ); + +printf(" \n At 0.8 PF leading "); +printf(" \n Percent voltage regulation = %.1f percent \n", VR2 ); +printf(" \n Percentage voltage regulation remains the same both in Y and delta connection."); diff --git a/1092/CH6/EX6.6/Example6_6.sce b/1092/CH6/EX6.6/Example6_6.sce new file mode 100755 index 000000000..74dbed591 --- /dev/null +++ b/1092/CH6/EX6.6/Example6_6.sce @@ -0,0 +1,51 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 6: AC DYNAMO VOLTAGE RELATIONS-ALTERNATORS +// Example 6-6 + +clear; clc; close; // Clear the work space and console. + +// Given data +// 3-phase Y-connected alternator +E_L = 11000 ; // Line voltage generated in volt +kVA = 165000 ; // kVA rating of the alternator +R_p = 0.1 ; // Armature resistance in ohm/per phase +Z_p = 1.0 ; // Synchronous reactance/phase +Z_r = 0.8 ; // Reactor reactance/phase + +// Calculations +E_p = E_L / sqrt(3); // Rated phase voltage in volt +I_p = (kVA * 1000)/(3*E_p); // Rated current per phase in A + +// case a +I_max_a = E_p / R_p ; // Maximum short-circuit current in A (case a) +overload_a = I_max_a / I_p ; // Overload (case a) + +// case b +I_steady = E_p / Z_p ; // Sustained short-circuit current in A +overload_b = I_steady / I_p ; // Overload (case b) + +// case c +Z_t = R_p + %i*Z_r ; // Total reactance per phase +I_max_c = E_p / Z_t ; // Maximum short-circuit current in A (case b) +I_max_c_m=abs(I_max_c);//I_max_c_m=magnitude of I_max_c in A +I_max_c_a=atan(imag(I_max_c) /real(I_max_c))*180/%pi;//I_max_c_a=phase angle of I_max_c in degrees +overload_c = I_max_c_m / I_p ; // Overload (case a) + +// Display the results +disp("Example 6-6 Solution : "); +printf("\n root 3 value is taken as %f , so slight variations in the answer.\n", sqrt(3)); +printf(" \n a: I_max = %d A ", I_max_a ); +printf(" \n overload = %.1f * rated current \n", overload_a ); + +printf(" \n b: I_steady = %d A ", I_steady ); +printf(" \n overload = %.2f * rated current \n", overload_b ); + +printf(" \n c: Rectangular form :\n I_max = "); disp(I_max_c); +printf(" \n Polar form :"); +printf(" \n I_max = %d <%.2f A ", I_max_c_m , I_max_c_a ); +printf(" \n where %d is magnitude and %.2f is phase angle\n",I_max_c_m,I_max_c_a); +printf(" \n overload = %.3f * rated current \n", overload_c ); diff --git a/1092/CH6/EX6.7/Example6_7.sce b/1092/CH6/EX6.7/Example6_7.sce new file mode 100755 index 000000000..81d6cae8d --- /dev/null +++ b/1092/CH6/EX6.7/Example6_7.sce @@ -0,0 +1,70 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 6: AC DYNAMO VOLTAGE RELATIONS-ALTERNATORS +// Example 6-7 + +clear; clc; close; // Clear the work space and console. + +// Given data +kVA = 100 ; // kVA rating of the 3-phase alternator +V_L = 1100 ; // Line voltage of the 3-phase alternator in volt + +// dc-resistance test data +E_gp1 = 6 ; // generated phase voltage in volt +V_l = E_gp1 ; // generated line voltage in volt +I_a1 = 10 ; // full-load current per phase in A +cos_theta = 0.8 ; // 0.8 PF lagging +sin_theta = sqrt( 1 - (cos_theta)^2 ); // + +// open-circuit test data +E_gp2 = 420 ; // generated phase voltage in volt +I_f2 = 12.5 ; // Field current in A + +// short-circuit test data +I_f3 = 12.5 ; // Field current in A +// Line current I_l = rated value in A + +// Calculated data from Ex.6-4 +I_L = 52.5 ; // Rated line current in A +I_a = I_L ; // Rated current per phase in A +E_gp = 532 + %i*623 ; // Generated voltage at 0.8 PF lagging +X_s = 4.6 ; // Synchronous reactance per phase +V_p = 635 ; // Phase voltage in volt + +// Calculations +// case a +P_T = sqrt(3) * V_L * I_L * cos_theta ; // Total output 3-phase power + +// case b +P_p_b = P_T / 3 ; // Total output 3-phase power per phase + +// case c +E_gp_m=abs(E_gp);//E_gp_m=magnitude of E_gp in volt +E_gp_a=atan(imag(E_gp) /real(E_gp))*180/%pi;//E_gp_a=phase angle of E_gp in degrees + +// case d +theta = acos(0.8)*180/%pi; // phase angle for PF in degrees +theta_plus_deba = E_gp_a ; // phase angle of E_gp in degrees +deba = theta_plus_deba - theta ; // Torque angle in degrees + +// case e +P_p_e = (E_gp_m/X_s)*V_p*sind(deba); // Approximate output power/phase (Eq.(6-10)) + +// case f +P_p_f = E_gp_m * I_a * cosd(theta_plus_deba); // Approximate output power/phase (Eq.(6-9)) + +// Display the results +disp("Example 6-7 Solution : "); +printf("\n root 3 value is taken as %f , so slight variations in the answer.\n", sqrt(3)); +printf(" \n a: P_T = %d W \n", P_T ); +printf(" \n b: P_p = %.2f W \n", P_p_b ); +printf(" \n c: E_gp = %d <%.2f V \n", E_gp_m, E_gp_a ); +printf(" \n where %d is magnitude in V and %.2f is phase angle in degrees.\n",E_gp_m,E_gp_a); +printf(" \n d: Torque angle, deba = %.2f degrees \n", deba ); +printf(" \n e: P_p = %d W \n", P_p_e ); +printf(" \n f: P_p = %d W ", P_p_f ); + + diff --git a/1092/CH6/EX6.8/Example6_8.sce b/1092/CH6/EX6.8/Example6_8.sce new file mode 100755 index 000000000..c3afce4d2 --- /dev/null +++ b/1092/CH6/EX6.8/Example6_8.sce @@ -0,0 +1,68 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 6: AC DYNAMO VOLTAGE RELATIONS-ALTERNATORS +// Example 6-8 + +clear; clc; close; // Clear the work space and console. + +// Given data + +kVA = 100 ; // kVA rating of the 3-phase alternator +V_L = 1100 ; // Line voltage of the 3-phase alternator in volt +S = 1200 ; // Synchronous speed in rpm + +// dc-resistance test data +E_gp1 = 6 ; // generated phase voltage in volt +V_l = E_gp1 ; // generated line voltage in volt +I_a1 = 10 ; // full-load current per phase in A +cos_theta = 0.8 ; // 0.8 PF lagging +sin_theta = sqrt( 1 - (cos_theta)^2 ); // + +// open-circuit test data +E_gp2 = 420 ; // generated phase voltage in volt +I_f2 = 12.5 ; // Field current in A + +// short-circuit test data +I_f3 = 12.5 ; // Field current in A +// Line current I_l = rated value in A + +// Calculated data from Ex.6-4 & Ex.6-7 +I_L = 52.5 ; // Rated line current in A +I_a = I_L ; // Rated current per phase in A +E_gp = 532 + %i*623 ; // Generated voltage at 0.8 PF lagging +E_g = 819 ; // E_g = magnitude of E_gp in volt +X_s = 4.6 ; // Synchronous reactance per phase +V_p = 635 ; // Phase voltage in volt +deba = 12.63 ; // Torque angle in degrees + +// Calculations +// case a +T_p_a = ( 7.04 * E_g * V_p * sind(deba) ) / (S*X_s); // Output torque per phase in lb.ft +T_3phase_a = 3 * T_p_a ; // Output torque for 3-phase in lb.ft + +// case b +omega = S * 2*%pi *(1/60); // Angular frequency in rad/s +T_p_b = ( E_g * V_p * sind(deba))/(omega*X_s); // Output torque per phase in lb.ft +T_3phase_b = 3 * T_p_b ; // Output torque for 3-phase in lb.ft + +// case c +T_p_c = T_p_a * 1.356 ; // Output torque per phase in N.m +T_3phase_c = 3 * T_p_c ; // Output torque for 3-phase in N.m + +// Display the results +disp("Example 6-8 Solution : "); +pi = %pi; +printf(" \n Slight variations in the answers are due to value of pi = %f ",pi); +printf(" \n and omega = %f, which are slightly different as in the textbook.\n",omega); +printf(" \n a: T_p = %d lb-ft ",T_p_a); +printf(" \n T_3phase = %d lb-ft \n", T_3phase_a); + +printf(" \n b: T_p = %.1f N-m ",T_p_b); +printf(" \n T_3phase = %.1f N-m \n", T_3phase_b); + +printf(" \n c: T_p = %.1f N-m ",T_p_c); +printf(" \n T_3phase = %.1f N-m \n", T_3phase_c); +printf(" \n Answers from cases b and c almost tally each other "); -- cgit