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/CH9/EX9.9/Example9_9.sce | 77 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) create mode 100755 1092/CH9/EX9.9/Example9_9.sce (limited to '1092/CH9/EX9.9') diff --git a/1092/CH9/EX9.9/Example9_9.sce b/1092/CH9/EX9.9/Example9_9.sce new file mode 100755 index 000000000..647a6926d --- /dev/null +++ b/1092/CH9/EX9.9/Example9_9.sce @@ -0,0 +1,77 @@ +// Electric Machinery and Transformers +// Irving L kosow +// Prentice Hall of India +// 2nd editiom + +// Chapter 9: POLYPHASE INDUCTION (ASYNCHRONOUS) DYNAMOS +// Example 9-9 + +clear; clc; close; // Clear the work space and console. + +// Given data +P = 8 ; // Number of poles in the SCIM +f = 60 ; // Frequency in Hz +S_r = 875 ; // Full-load Speed in rpm with rotor short-circuited +R_r = 0.3 ; // rotor resistance per phase in ohm/phase +R_x = 0.7 ; // Added resistance in ohm/phase +R_x_a = 1.7 ; // Added resistance in ohm/phase (case a) +R_x_b = 2.7 ; // Added resistance in ohm/phase (case b) +R_x_c = 3.7 ; // Added resistance in ohm/phase (case c) +R_x_d = 4.7 ; // Added resistance in ohm/phase (case d) + +// Calculations +S = (120*f)/P ; // Speed in rpm of the rotating magnetic field +s_o = (S - S_r)/S ; // Slip at rotor speed 875 rpm + +// case a +s_r_a = s_o * (R_r + R_x_a)/R_r; // Rated slip +S_r_a = S * (1 - s_r_a); // Full-load speed in rpm for added resistance R_x_a + +// case b +s_r_b = s_o * (R_r + R_x_b)/R_r; // Rated slip +S_r_b = S * (1 - s_r_b); // Full-load speed in rpm for added resistance R_x_b + +// case c +s_r_c = s_o * (R_r + R_x_c)/R_r; // Rated slip +S_r_c = S * (1 - s_r_c); // Full-load speed in rpm for added resistance R_x_c + +// case d +s_r_d = s_o * (R_r + R_x_d)/R_r; // Rated slip +S_r_d = S * (1 - s_r_d); // Full-load speed in rpm for added resistance R_x_d + +// Display the results +disp("Example 9-9 Solution : "); + +printf(" \n Slip s_r = s_o*(R_r+R_x)/R_r \n Rotor speed S_r = S_o*(1-s)\n"); + +printf(" \n Calculated value of s_o = %f , instead of 0.0278(textbook)",s_o) +printf(" \n so slight variations in the answers below.\n"); + +printf(" \n a: When R_x = %.1f ohm ",R_x_a); +printf(" \n s_r = %.3f \n S_r = %.1f rpm \n",s_r_a,S_r_a ); + +printf(" \n b: When R_x = %.1f ohm ",R_x_b); +printf(" \n s_r = %.3f \n S_r = %.1f rpm \n",s_r_b,S_r_b ); + +printf(" \n c: When R_x = %.1f ohm ",R_x_c); +printf(" \n s_r = %.3f \n S_r = %.1f rpm \n",s_r_c,S_r_c ); + +printf(" \n d: When R_x = %.1f ohm ",R_x_d); +printf(" \n s_r = %.3f \n S_r = %.1f rpm \n",s_r_d,S_r_d ); + +printf(" \n This example,verifies that slip is proportional to rotor resistance"); +printf(" \n as summarized below."); + +printf(" \n ___________________________________________________________________"); +printf(" \n R_T(ohm) = R_r+R_x \t\t Slip \t\t Full-load Speed(rpm)"); +printf(" \n ___________________________________________________________________"); +printf(" \n Given \t\t\t Given \t\t Given \t\ "); +printf(" \n 0.3 \t\t\t 0.0278 \t 875 "); +printf(" \n 0.3+0.1 = 1.0 \t\t 0.0926 \t 817"); +printf(" \n ___________________________________________________________________"); +printf(" \n Given \t\t\t Calculated \t Calculated \t\ "); +printf(" \n a. %.1f + %.1f = %.1f \t\t %.3f \t\t %.1f ",R_r,R_x_a,R_r+R_x_a,s_r_a,S_r_a); +printf(" \n b. %.1f + %.1f = %.1f \t\t %.3f \t\t %.1f ",R_r,R_x_b,R_r+R_x_b,s_r_b,S_r_b); +printf(" \n c. %.1f + %.1f = %.1f \t\t %.3f \t\t %.1f ",R_r,R_x_c,R_r+R_x_c,s_r_c,S_r_c); +printf(" \n d. %.1f + %.1f = %.1f \t\t %.3f \t\t %.1f ",R_r,R_x_d,R_r+R_x_d,s_r_d,S_r_d); +printf(" \n ___________________________________________________________________"); -- cgit