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+// 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 12-19
+
+clear; clc; close; // Clear the work space and console.
+
+// Given data
+V = 220 ; // Rated voltage of SCIM in volt
+f = 60 ; // Frequency in Hz
+P = 4 ; // Number of poles
+PF = 0.85 ; // power factor of capacitor start IM
+// nameplate details
+hp_IM = 5 ; // power rating of IM in hp
+I_L = 28 ; // Rated line current in A
+S_r = 1620 ; // Rotor speed of IM in rpm
+
+// No-load test data
+I_nl = 6.4 ; // No-load line current in A
+V_nl = 220 ; // No-load line voltage in volt
+P_nl = 239 ; // No-load power reading in W
+s_nl = 0.01 ; // No-load slip
+
+// Blocked rotor test
+I_br = 62 ; // Blocked rotor line current in A
+V_br = 64 ; // Blocked rotor voltage in volt
+P_br = 1922 ; // Blocked rotor power reading in W
+s_br = 1 ; // blocked rotor slip(unity) 
+
+// Calculations
+// case a
+R_e1s = P_br / (I_br^2); // Equivalent total resistance of IM in ohm
+
+// case b
+P_in = P_nl ; // Input power to IM in W
+I_1s = I_nl ; // Input current in A
+P_ro = P_in - ((I_1s)^2 * R_e1s); // Rotational losses in W
+
+// case c
+S = (120*f/P); // Speed of synchronous magnetic field in rpm
+S_fl = S_r ; // Full-load rotor speed of IM in rpm 
+s_fl = (S - S_fl)/S ; // Full-load Slip 
+
+LF1 = 1/4 ; // Load fraction
+LF2 = 1/2 ; // Load fraction
+LF3 = 3/4 ; // Load fraction
+LF4 = 5/4 ; // Load fraction
+
+s_LF1 = s_fl*LF1 ; // slip at 1/4 rated load
+s_LF2 = s_fl*LF2 ; // slip at 1/2 rated load
+s_LF3 = s_fl*LF3 ; // slip at 3/4 rated load
+s_LF4 = s_fl*LF4 ; // slip at 5/4 rated load
+
+// case d
+s_o = s_nl ; // No-load slip
+P_rs_LF1 = P_ro * (1 - s_LF1)/(1 - s_o); // Rotational losses in W at s_LF1
+P_rs_LF2 = P_ro * (1 - s_LF2)/(1 - s_o); // Rotational losses in W at s_LF2
+P_rs_LF3 = P_ro * (1 - s_LF3)/(1 - s_o); // Rotational losses in W at s_LF3
+P_rs_fl = P_ro * (1 - s_fl)/(1 - s_o); // Rotational losses in W at full-load slip
+P_rs_LF4 = P_ro * (1 - s_LF4)/(1 - s_o); // Rotational losses in W at s_LF4
+
+// case e
+I1s = I_L ; //  Line current in A
+P_cu_fl = (I1s)^2*R_e1s ; // Equivalent copper loss at full-load slip
+P_cu_LF1 = (LF1)^2 * P_cu_fl ; // Equivalent copper loss at s_LF1
+P_cu_LF2 = (LF2)^2 * P_cu_fl ; // Equivalent copper loss at s_LF2
+P_cu_LF3 = (LF3)^2 * P_cu_fl ; // Equivalent copper loss at s_LF3
+P_cu_LF4 = (LF4)^2 * P_cu_fl ; // Equivalent copper loss at s_LF4
+
+// case f
+Input = V*I_L*PF ; // Input to single phase capacitor start IM
+
+// Efficiency at 1/4 rated load
+eta_LF1 = ( Input*LF1 - (P_rs_LF1 + P_cu_LF1) ) / (Input*LF1) * 100 ;
+
+// Efficiency at 1/2 rated load
+eta_LF2 = ( Input*LF2 - (P_rs_LF2 + P_cu_LF2) ) / (Input*LF2) * 100 ;
+
+// Efficiency at 3/4 rated load
+eta_LF3 = ( Input*LF3 - (P_rs_LF3 + P_cu_LF3) ) / (Input*LF3) * 100 ;
+
+// Efficiency at rated load
+eta_fl = ( Input - (P_rs_fl + P_cu_fl) ) / (Input) * 100 ;
+
+// Efficiency at 5/4 rated load
+eta_LF4 = ( Input*LF4 - (P_rs_LF4 + P_cu_LF4) ) / (Input*LF4) * 100 ;
+
+// case g
+// since eta is calculated in percent divide it by 100 for hp calculations
+P_o_LF1 = (Input*LF1*eta_LF1/100)/746 ; // Output hp at 1/4 rated load
+P_o_LF2 = (Input*LF2*eta_LF2/100)/746 ; // Output hp at 1/2 rated load
+P_o_LF3 = (Input*LF3*eta_LF3/100)/746 ; // Output hp at 3/4 rated load
+P_o = (Input*eta_fl/100)/746 ; // Output hp at 1/4 rated load
+P_o_LF4 = (Input*LF4*eta_LF4/100)/746 ; // Output hp at 5/4 rated load
+
+// case h
+hp = P_o ; // Rated output horsepower
+S_fl = S_r ; // Full-load rotor speed in rpm
+T_o = (P_o*5252)/S_fl ; // Outpue torque at full-load in lb-ft
+T_o_Nm = T_o * 1.356 ; // Outpue torque at full-load in N-m
+
+// Display the results
+disp("Example 12-19 Solution : "); 
+
+printf(" \n a: Equivalent total resistance of IM :\n    R_e1s = %.1f Ω \n",R_e1s);
+
+printf(" \n b: Rotational losses :\n    P_ro = %.1f W \n ",P_ro);
+
+printf(" \n c: Slip at rated load : s = %.1f \n    Slip,",s_fl);
+printf(" \n    s at %.2f rated load = %.3f",LF1,s_LF1);
+printf(" \n    s at %.2f rated load = %.3f",LF2,s_LF2);
+printf(" \n    s at %.2f rated load = %.3f",LF3,s_LF3);
+printf(" \n    s at %.2f rated load = %.3f \n ",LF4,s_LF4);
+
+printf(" \n d: Rotational losses :\n ");
+printf(" \n    P_r at at %.2f rated load = %.1f W ",LF1,P_rs_LF1);
+printf(" \n    P_r at at %.2f rated load = %.1f W ",LF2,P_rs_LF2);
+printf(" \n    P_r at at %.2f rated load = %.1f W ",LF3,P_rs_LF3);
+printf(" \n    P_r at at full load = %.1f W ",P_rs_fl);
+printf(" \n    P_r at at %.2f rated load = %.1f W \n ",LF4,P_rs_LF4);
+
+printf(" \n e: At full-load, P_cu = %d W \n",P_cu_fl);
+printf(" \n    P_cu at %.2f rated load = %.2f W",LF1,P_cu_LF1)
+printf(" \n    P_cu at %.2f rated load = %.2f W",LF2,P_cu_LF2)
+printf(" \n    P_cu at %.2f rated load = %.2f W",LF3,P_cu_LF3)
+printf(" \n    P_cu at %.2f rated load = %.2f W \n",LF4,P_cu_LF4)
+
+printf(" \n f: Full-load input = %.f W \n",Input);
+printf(" \n    Efficiency :\n    η at %.2f rated load = %.1f percent \n",LF1,eta_LF1);
+printf(" \n    η at %.2f rated load = %.1f percent \n",LF2,eta_LF2);
+printf(" \n    η at %.2f rated load = %.1f percent \n",LF3,eta_LF3);
+printf(" \n    η at rated load = η_fl = %.1f percent \n",eta_fl);
+printf(" \n    η at %.2f rated load = %.1f percent \n",LF4,eta_LF4);
+printf(" \n    Please note: Calculation error for η_fl in textbook.\n");
+
+printf(" \n g: Output horsepower :\n    P_o at %.2f rated load = %.3f hp \n",LF1,P_o_LF1);
+printf(" \n    P_o at %.2f rated load = %.3f hp \n",LF2,P_o_LF2);
+printf(" \n    P_o at %.2f rated load = %.3f hp \n",LF3,P_o_LF3);
+printf(" \n    P_o at rated load = %.3f hp \n",P_o);
+printf(" \n    P_o at %.2f rated load = %.3f hp \n",LF4,P_o_LF4);
+
+printf(" \n h: Output torque at full-load :\n    T_o = %.1f lb-ft",T_o);
+printf(" \n    T_o = %.2f N-m ≃ %.1f N-m",T_o_Nm,T_o_Nm);