1 files changed, 71 insertions, 0 deletions
diff --git a/1092/CH12/EX12.8/Example12_8.sce b/1092/CH12/EX12.8/Example12_8.sce
new file mode 100755
index 000000000..26d2bafb1
--- /dev/null
+++ b/1092/CH12/EX12.8/Example12_8.sce
@@ -0,0 +1,71 @@
+// Electric Machinery and Transformers
+// Irving L kosow 
+// Prentice Hall of India
+// 2nd editiom
+
+// Chapter 12: POWER,ENERGY,AND EFFICIENCY RELATIONS OF DC AND AC DYNAMOS
+// Example 12-8
+
+clear; clc; close; // Clear the work space and console.
+
+// Given data
+V = 240 ; // Voltage rating of dc shunt motor in volt
+P_hp = 5 ; // Power rating of dc shunt motor in hp
+S_fl = 1100 ; // Speed in rpm of the dc shunt motor
+R_a = 0.4 ; // Armture resistance in ohm
+R_f = 240 ; // Field resistance in ohm
+eta = 0.75 ; // Full-load efficiency
+
+// Calculations
+// case a
+V_L = V ; // Load voltage
+P_o = P_hp * 746 ; // Power rating of dc shunt motor in W
+I_L = P_o / (eta*V_L); // Rated input line current in A
+
+V_f = V ; // Voltage across field winding in volt
+I_f = V_f / R_f ; // Field current in A
+I_a = I_L - I_f ; // Rated armature current in A
+
+// case b
+V_a = V ; // Voltage across armature in volt
+E_c = V_a - I_a*R_a ; // back EMF in volt
+P_d = E_c * I_a ; // Power developed by the armature in W
+
+// case c
+P_r = P_d - P_o ; // Rotational losses in W at rated load
+
+// case d
+// At no-load
+P_o_nl = 0 ;
+P_r_nl = P_r ; // Rotational losses in W at no load
+P_d_nl = P_r_nl ;
+
+// case e
+I_a_nl = P_d_nl / V_a ; // No-load armature current in A
+
+// case f
+E_c_nl = V ; // No-load voltage in volt
+E_c_fl = E_c ; // Full-load voltage in volt
+S_nl = (E_c_nl / E_c_fl)*S_fl ; // No-load speed in rpm
+
+// case g
+SR = (S_nl - S_fl)/S_fl * 100 ; // Speed regulation
+
+// Display the results
+disp("Example 12-8 Solution : ");
+
+printf(" \n a: Rated input line current :\n    I_L = %.2f A \n ",I_L);
+printf(" \n    Rated armature current :\n    I_a = %.2f A \n ",I_a );
+
+printf(" \n b: E_c = %.1f V \n ",E_c );
+printf(" \n    Power developed by the armature at rated load :\n    P_d = %d W \n ",P_d);
+
+printf(" \n c: Rotational losses at rated load :\n    P_r = %d W \n ", P_r );
+
+printf(" \n d: At no-load, P_o = %d W ; therefore\n\t\tP_d = P_r = %d W \n",P_o_nl,P_r);
+
+printf(" \n e: No-load armature current :\n    I_a(nl) = %.2f A \n ",I_a_nl );
+
+printf(" \n f: No-load speed :\n    S_nl = %.f rpm \n ",S_nl );
+
+printf(" \n g: Speed regulation :\n    SR = %.1f percent ",SR );