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+// Electric Machinery and Transformers
+// Irving L kosow 
+// Prentice Hall of India
+// 2nd editiom
+
+// Chapter 9: POLYPHASE INDUCTION (ASYNCHRONOUS) DYNAMOS
+// Example 9-6
+
+clear; clc; close; // Clear the work space and console.
+
+// Given data
+P = 8 ; // Number of poles in the SCIM
+f = 60 ; // Frequency in Hz
+R_r = 0.3 ; // rotor resistance per phase in ohm/phase 
+R_x = 0.7 ; // Added resistance in ohm/phase 
+R_r_total = R_r + R_x ; // Total resistance per phase in ohm
+S_r = 875 ; // Full-load Speed in rpm 
+
+
+// Calculated values from Ex.9-6
+S = 900 ; // Speed in rpm of the rotating magnetic field
+X_lr = 1.08 ; // Locked rotor reactance in ohm
+
+// Calculations
+// case a
+s = (S - S_r)/S ; // Full-load slip,short circuited
+s_r = R_r_total / R_r * s; // New full-load slip with added resistance
+
+S_r_new = S*(1-s_r); // New full-load speed in rpm 
+
+// case b
+// Neglecting constant Kn_t ,since we are taking torque ratios
+T_o = ( R_r / ((R_r)^2 + (X_lr)^2) ); // Original torque
+T_f = ( R_r + R_x) / ( (R_r + R_x)^2  + (X_lr)^2 ); // Original torque
+
+torque_ratio = T_f / T_o ; // Ratio of final torque to original torque
+T_final = 2*torque_ratio ;
+
+// Display the results
+disp("Example 9-6 Solution : ");
+printf(" \n a: The full-load slip,short circuited,is ");
+printf(" \n    s = %.4f \n",s );
+printf(" \n    Since slip is proportional to rotor resistance and since the ");
+printf(" \n    increased rotor resistance is R_r = %.1f + %.1f = %d ,",R_x,R_r,R_r_total);
+printf(" \n    the new full-load slip with added resistance is : ");
+printf(" \n    s_r = %.4f \n",s_r);
+printf(" \n    The new full-load speed is : " );
+printf(" \n    S(1-s) = %.f rpm \n",S_r_new );
+
+printf(" \n b: The original starting torque T_o was twice the full-load torque");
+printf(" \n    with a rotor resistance of %.1f ohm and a rotor reactance of %.2f ohm",R_r,X_lr);
+printf(" \n    (Ex.9-5).The new starting torque conditions may be summarized by the   ");
+printf(" \n    following table and compared from Eq.(9-14),where T_o ");
+printf(" \n    is the original torque and T_f is the new torque.");
+
+printf(" \n    _________________________________________");
+printf(" \n    Condition \t R_r \t X_lr \t T_starting ");
+printf(" \n              \t ohm \t ohm  \t ");
+printf(" \n    _________________________________________");
+printf(" \n    Original : \t %.1f \t %.2f \t 2*T_n ",R_r,X_lr);
+printf(" \n    New      : \t %.1f \t %.2f \t   ?   ",R_r_total,X_lr);
+printf(" \n    _________________________________________\n");
+
+printf(" \n    T_o = %.2f * K_n_t",T_o);
+printf(" \n    T_f = %.3f * K_n_t",T_f);
+printf(" \n    T_f/T_o = %.2f and T_f = %.2f * T_o\n ",torque_ratio,torque_ratio);
+printf(" \n    Therefore,\n    T_f = %.3f * T_n",T_final);