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+// Electric Machinery and Transformers
+// Irving L kosow 
+// Prentice Hall of India
+// 2nd editiom
+
+// Chapter 4: DC Dynamo Torque Relations-DC Motors
+// Example 4-17
+
+clear; clc; close; // Clear the work space and console.
+
+// Given data
+V_a = 230 ; // Rated armature voltage in volt
+P = 10 ; // Rated power in hp
+S = 1250 ; // Rated speed in rpm
+R_A = 0.25 ; // Armature resistance in ohm
+R_p = 0.25 ; // Interpolar resistance
+BD = 5 ; // Brush voltage drop in volt
+R_s = 0.15 ; // Series field resistance in ohm
+R_sh = 230 ; // Shunt field resistance in ohm
+phi_1 = 1 ;// Original flux per pole
+
+// Long-shunt cumulative connection
+I_l = 55 ; // Line current in A at rated load 
+phi_2 = 1.25 ; // Flux increased by 25% due to long-shunt cumulative connection
+I_ol = 4 ; // No-load line current in A
+S_o = 1810 ; // No-load speed in rpm
+
+// Calculations
+R_a = R_A + R_p ; // Effective armature resistance in ohm
+I_f = V_a / R_sh ; // Field current in A in shunt winding
+I_a = I_ol - I_f ; // Armature current in A for shunt connection
+E_c_o = V_a - ( I_a * R_a + BD ); // No-load BACK EMF in volt for shunt connection
+E_c_o1 = V_a - ( I_a * R_a + I_a * R_s + BD ); // No-load BACK EMF in volt for
+// long shunt cumulative connection
+S_n1 = S_o * ( E_c_o1 / E_c_o ); // Speed at no load
+
+I_f = V_a / R_sh ; // Field current in A in shunt winding
+I_a_lsh = I_l - I_f ; // Armature current in A
+E_c_full_load = V_a - ( I_a_lsh * R_a + BD ); // No-load BACK EMF in volt at
+// full-load for long-shunt cumulative connection 
+
+E_c_full_load_lsh = V_a - ( I_a_lsh * R_a + I_a_lsh * R_s + BD ); // BACK EMF in volt 
+// at full-load for long-shunt cumulative motor 
+
+S_r = S_o * ( E_c_full_load / E_c_o ); // Speed at rated load for shunt connection
+S_r_lsh = S_n1 * ( E_c_full_load_lsh / E_c_o1 ) * ( phi_1 / phi_2 ); 
+// Speed at rated load for shunt connection
+
+P_d = E_c_full_load * I_a_lsh ; // Internal power in watts
+hp = P_d / 746 ; // Internal horse power
+
+T_shunt = ( hp * 5252 ) / S_r ; // Internal torque @ full-load for shunt motor
+
+I_a1 = I_a_lsh; // Armature current for shunt motor in A
+I_a2 = I_a_lsh; // Armature current for long-shunt cumulative motor in A
+T_comp = T_shunt * ( phi_2 / phi_1 ) * ( I_a2 / I_a1); // Internal torque 
+// at full-load for long-shunt cumulative motor in A
+
+Horsepower = ( E_c_full_load_lsh * I_a_lsh ) / 746 ; // Internal horsepower of
+// compound motor based on flux increase
+
+// Display the results
+disp(" Example 4-17 Solution : ");
+printf(" \n a: S_n1 = %d rpm \n", S_n1 );
+printf(" \n b: S_r = %d rpm \n", S_r_lsh );
+printf(" \n c: Internal torque of shunt motor at full-load : ");
+printf(" \n    T_shunt = %.2f lb-ft ", T_shunt );
+printf(" \n    T_comp = %.2f lb-ft \n", T_comp );
+printf(" \n d: Horsepower = %.1f hp \n", Horsepower );
+printf(" \n e: The internal horsepower exceeds the rated horsepower because ");
+printf(" \n    the power developed in the motor must also overcome the internal");
+printf(" \n    mechanical rotational losses. ");