1 files changed, 59 insertions, 0 deletions
diff --git a/1092/CH4/EX4.18/Example4_18.sce b/1092/CH4/EX4.18/Example4_18.sce
new file mode 100755
index 000000000..06fa4b366
--- /dev/null
+++ b/1092/CH4/EX4.18/Example4_18.sce
@@ -0,0 +1,59 @@
+// Electric Machinery and Transformers
+// Irving L kosow 
+// Prentice Hall of India
+// 2nd editiom
+
+// Chapter 4: DC Dynamo Torque Relations-DC Motors
+// Example 4-18
+
+clear; clc; close; // Clear the work space and console.
+
+// Given data
+P = 25 ; // Power rating of a series motor in hp
+V_a = 250 ; // Rated voltage in volt
+R_a = 0.1 ; // Armature ckt resistance in ohm
+BD = 3 ; // Brush voltage drop in volt
+R_s = 0.05 ; // Series field resistance in ohm
+I_a1 = 85 ; // Armature current in A (case a)
+I_a2 = 100 ; // Armature current in A (case b)
+I_a3 = 40 ; // Armature current in A (case c)
+S_1 = 600 ; // Speed in rpm at current I_a1
+R_d = 0.05 ; // Divertor resistance in ohm
+
+// Calculations
+E_c2 = V_a - I_a2 * ( R_a + R_s ) - BD ; // BACK EMF in volt for I_a2
+E_c1 = V_a - I_a1 * ( R_a + R_s ) - BD ; // BACK EMF in volt for I_a1
+
+S_2 = S_1 * ( E_c2 / E_c1 ) * ( I_a1 / I_a2 ); // Speed in rpm at current I_a2
+
+E_c3 = V_a - I_a3 * ( R_a + R_s ) - BD ; // BACK EMF in volt for I_a3
+
+S_3 = S_1 * ( E_c3 / E_c1 ) * ( I_a1 / I_a3 ); // Speed in rpm at current I_a3
+
+// When divertor is connected in parallel to R_s
+R_sd = ( R_s * R_d ) / ( R_s + R_d ); // Effective series field resistance in ohm
+
+E_c2_new = V_a - I_a2 * ( R_a + R_sd ) - BD ; // BACK EMF in volt for I_a2
+S_2_new = S_1 * ( E_c2_new / E_c1 ) * ( I_a1 / ( I_a2 / 2 ) ); // Speed in rpm 
+// at current I_a2
+
+E_c3_new = V_a - I_a3 * ( R_a + R_sd ) - BD ; // BACK EMF in volt for I_a3
+S_3_new = S_1 * ( E_c3_new / E_c1 ) * ( I_a1 / ( I_a3 / 2 ) ); // Speed in rpm 
+// at current I_a3
+
+// Display the results
+disp(" Example 4-18 Solution : ");
+printf(" \n a: S_2 = %d rpm \n", S_2 );
+printf(" \n b: S_3 = %d rpm \n", S_3 );
+printf(" \n c: The effect of the divertor is to reduce the series field current");
+printf(" \n    (and flux) to half their previous values. ");
+printf(" \n    S_2 = %d rpm ", S_2_new );
+printf(" \n    S_3 = %d rpm \n", S_3_new );
+
+printf(" \n    The results may be tabulated as follows : \n ");
+printf(" \n     Case \t I_a in A \t S_o in rpm \t S_d in rpm ");
+printf(" \n    ________________________________________________________");
+printf(" \n      1    \t   %d       \t   %d         \t   ___ ", I_a1 , S_1  );
+printf(" \n      2.   \t   %d       \t   %d         \t   %d ", I_a2 , S_2 , S_2_new );
+printf(" \n      3.   \t   %d       \t   %d       \t   %d ", I_a3 , S_3 , S_3_new );
+