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-rwxr-xr-x2642/CH3/EX3.1/Ex3_1.sce26
-rwxr-xr-x2642/CH3/EX3.10/Ex3_10.sce38
-rwxr-xr-x2642/CH3/EX3.11/Ex3_11.sce29
-rwxr-xr-x2642/CH3/EX3.12/Ex3_12.sce42
-rwxr-xr-x2642/CH3/EX3.13/Ex3_13.sce29
-rwxr-xr-x2642/CH3/EX3.14/Ex3_14.sce28
-rwxr-xr-x2642/CH3/EX3.15/Ex3_15.sce36
-rwxr-xr-x2642/CH3/EX3.16/Ex3_16.sce33
-rwxr-xr-x2642/CH3/EX3.17/Ex3_17.sce45
-rwxr-xr-x2642/CH3/EX3.2/Ex3_2.sce22
-rwxr-xr-x2642/CH3/EX3.3/Ex3_3.sce27
-rwxr-xr-x2642/CH3/EX3.4/Ex3_4.sce26
-rwxr-xr-x2642/CH3/EX3.5/Ex3_5.sce28
-rwxr-xr-x2642/CH3/EX3.6/Ex3_6.sce31
-rwxr-xr-x2642/CH3/EX3.7/Ex3_7.sce33
-rwxr-xr-x2642/CH3/EX3.8/Ex3_8.sce30
-rwxr-xr-x2642/CH3/EX3.9/Ex3_9.sce34
17 files changed, 537 insertions, 0 deletions
diff --git a/2642/CH3/EX3.1/Ex3_1.sce b/2642/CH3/EX3.1/Ex3_1.sce
new file mode 100755
index 000000000..f0c310134
--- /dev/null
+++ b/2642/CH3/EX3.1/Ex3_1.sce
@@ -0,0 +1,26 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.1
+clc;clear; // clears the console and command history
+
+// Given data
+V_1 = 2200 // primary voltage of transformer in V
+V_2 = 220 // secondary voltage of transformer in V
+N_2 = 56 // number of turns in the secondary coil of transformer
+kVA = 25 // kVA rating of transformer
+
+// caclulations
+a = V_1/V_2 // turn ratio
+N_1 = a*N_2 // number of primary turns
+I_1 = kVA*10^3/V_1 // primary full load current in A
+I_2 = kVA*10^3/V_2 // secondary full load current in A
+
+// display the result
+disp("Example 3.1 solution");
+printf(" \n Number of primary turns \n N_1 = %.0f \n", N_1);
+printf(" \n Primary full load current \n I_2 = %.2f A \n", I_1);
+printf(" \n Secondary full load current \n I_2 = %.1f A \n", I_2);
diff --git a/2642/CH3/EX3.10/Ex3_10.sce b/2642/CH3/EX3.10/Ex3_10.sce
new file mode 100755
index 000000000..2f3d2ebc6
--- /dev/null
+++ b/2642/CH3/EX3.10/Ex3_10.sce
@@ -0,0 +1,38 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.10
+
+
+clc;clear; // clears the console and command history
+
+// Given data
+kVA = 12 // kVA ratingss of transformer
+n = 0.97 // maximum efficiency at unity power factor
+t_1 = 8 // time in hours
+P_1 = 10 // load in kW
+pf_1 = 0.8 // lagging power factor
+t_2 = 10 // time in hours
+P_2 = 15 // load in kW
+pf_2 = 0.90 // leading power factor
+t_3 = 6 // time in hours at no load
+P_3 = 0 // load in kW
+
+// caclulations
+P_01 = kVA*1 // o/p power at full load and unity factor in kW
+P_in1 = (P_01/n) // i/p power at full load
+P_tloss = P_in1-P_01 // total loss in kW
+P_cu = P_tloss/2 // copper loss at 12 kVA P_cu=P_i in kW
+P_024 = P_1*t_1+P_2*t_2+P_3*t_3 // all day o.p power in kWh
+P_i24 = 24*P_cu // iron loss for 24 hours in kWh
+P_cu24 = P_cu*t_1*((P_1/pf_1)/P_01)^2+P_cu*t_2*((P_2/pf_2)/P_01)^2 // copper loss for 24 hours
+P_in24 = P_024+P_i24+P_cu24 // all day i/p power in kWh
+n_allday = (P_024/P_in24)*100 // all day efficiency
+
+// display the result
+disp("Example 3.10 solution");
+printf(" \n All day efficiency \n n_allday = %.0f percent \n", n_allday);
+
diff --git a/2642/CH3/EX3.11/Ex3_11.sce b/2642/CH3/EX3.11/Ex3_11.sce
new file mode 100755
index 000000000..ea9938e0e
--- /dev/null
+++ b/2642/CH3/EX3.11/Ex3_11.sce
@@ -0,0 +1,29 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.11
+
+
+clc;clear; // clears the console and command history
+
+// Given data
+V_1 = 200 // voltage in V
+f = 50 // frequency in Hz
+I_0 = 0.6 // single phase current in A
+P_0 = 80 // power in W
+
+// caclulations
+cos_phi0 = P_0/(V_1*I_0) // power factor
+sin_phi0 = 0.74 // from above expression
+I_w = I_0*cos_phi0 // working component of no load current in A
+I_m = I_0*sin_phi0 // working component of no load current in A
+R_0 = V_1/I_w // no load circuit resistance in ohm
+X_0 = V_1/I_m // no load circuit reactance in ohm
+
+// display the result
+disp("Example 3.11 solution");
+printf(" \n No-load circuit resistance \n R_0 = %.2f ohm \n", R_0);
+printf(" \n No-load circuit reactance \n X_0 = %.1f ohm \n", X_0);
diff --git a/2642/CH3/EX3.12/Ex3_12.sce b/2642/CH3/EX3.12/Ex3_12.sce
new file mode 100755
index 000000000..6d743ace0
--- /dev/null
+++ b/2642/CH3/EX3.12/Ex3_12.sce
@@ -0,0 +1,42 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.12
+
+
+clc;clear; // clears the console and command history
+
+// Given data
+kVA = 25 // kVA ratings of transformer
+V1 = 2200 // primary side voltage in V
+V2 = 220 // secondary side voltage in V
+V_1 = 40 // voltage at high voltage side in V
+I_1 = 5 // current at high voltage side in A
+P = 150 // power at high voltage side in W
+
+// caclulations
+Z_01 = V_1/I_1 // reactance to primary sidec in ohm
+R_01 = P/I_1^2 // resistance to primary side in ohm
+phi = acosd(R_01/Z_01) // power factor angle
+X_01 = Z_01*sind(phi) // impedance to primary side in ohm
+a = V1/V2 // turn ratio
+Z_02 = Z_01/a^2 // reactance to secondary side in ohm
+R_02 = R_01/a^2 // resistance to secondary side in ohm
+X_02 = X_01/a^2 // impedance to secondary side in ohm
+I_2 = kVA*10^3/V2 // secondary side current in A
+E_2 = V2+I_2*Z_02 // secondary induced voltage in V
+VR = ((E_2-V2)/V2)*100 // voltage regulation
+
+// display the result
+disp("Example 3.12 solution");
+printf(" \n Resistance to primary side \n Z_01 = %.2f ohm \n", Z_01);
+printf(" \n Resistance to primary side \n R_01 = %.1f ohm \n", R_01);
+printf(" \n Impedance to primary side \n X_01 = %.2f ohm \n", X_01);
+printf(" \n Reactance to secondary side \n Z_02 = %.2f ohm \n", Z_02);
+printf(" \n Resistance to secondary side \n R_02 = %.2f ohm \n", R_02);
+printf(" \n Impedance to secondary side \n X_02 = %.3f ohm \n", X_02);
+printf(" \n oltage regulation \n VR = %.0f percent \n", VR);
+
diff --git a/2642/CH3/EX3.13/Ex3_13.sce b/2642/CH3/EX3.13/Ex3_13.sce
new file mode 100755
index 000000000..3ce3efd85
--- /dev/null
+++ b/2642/CH3/EX3.13/Ex3_13.sce
@@ -0,0 +1,29 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.13
+
+clc;clear; // clears the console and command history
+
+// Given data
+kVA = 120 // kVA ratings of autotransformer
+V1 = 2200 // lower part voltage of autotransformer in V
+V2 = 220 // upper part voltage of autotransformer in V
+
+// caclulations
+I_pq = kVA*10^3/V2 // currents of respective windings
+I_qr = kVA*10^3/V1 // currents of respective windings
+I_1 = I_pq+I_qr // current in primary side in A
+V_2 = V1+V2 // voltage across the secondary side in V
+kVA_1 = I_1*V1/1000 // kVA ratings of autotrnsformer
+kVA_2 = I_pq*V_2/1000 // kVA ratings of autotrnsformer
+
+
+// display the result
+disp("Example 3.13 solution");
+printf(" \n kVA ratings of autotrnsformer \n kVA_1 = %.0f kVA \n", kVA_1);
+printf(" \n kVA ratings of autotrnsformer \n kVA_2 = %.0f kVA \n", kVA_2);
+
diff --git a/2642/CH3/EX3.14/Ex3_14.sce b/2642/CH3/EX3.14/Ex3_14.sce
new file mode 100755
index 000000000..b585a9279
--- /dev/null
+++ b/2642/CH3/EX3.14/Ex3_14.sce
@@ -0,0 +1,28 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.14
+
+clc;clear; // clears the console and command history
+
+// Given data
+E_1 = 500 // secondary induced voltages in V
+E_2 = 450 // secondary induced voltages in V
+kVA_1 = 100 // kVA ratings of transformer
+kVA_2 = 200 // kVA ratings of transformer
+Z_1 = 0.05 // impedance of transformer
+Z_2 = 0.08 // impedance of transformer
+
+// caclulations
+Z1 =Z_1*E_1/(kVA_1*10^3/E_1) // actual impedance of 1st transformer in ohm
+Z2 = Z_2*E_2/(kVA_1*10^3/E_2) // actual impedance of 2nd transformer in ohm
+Z = %i*(Z1+Z2)
+I_c = (E_1-E_2)/(Z) // value of the circulating current
+
+// display the result
+disp("Example 3.14 solution");
+printf(" \n Value of the circulating current \n I_c = %.3f<%.f A \n", abs(I_c),atand(imag(I_c),real(I_c)));
+
diff --git a/2642/CH3/EX3.15/Ex3_15.sce b/2642/CH3/EX3.15/Ex3_15.sce
new file mode 100755
index 000000000..5f9a94737
--- /dev/null
+++ b/2642/CH3/EX3.15/Ex3_15.sce
@@ -0,0 +1,36 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.15
+
+clc;clear; // clears the console and command history
+
+// Given data
+V_L1 = 11 // three-phase transformer supply in kV
+I_P1 = 6 // three-phase transformer current in A
+a = 11 // turns ratio
+
+// caclulations
+// delta-wye
+V_dP2 = V_L1*10^3/a // phase voltage at secondary side in V
+V_dL2 = sqrt(3)*V_dP2 // line voltage at secondary side in V
+I_dP1 = a/sqrt(3) // phase current in the primary in A
+I_dL2 = a*I_dP1 // line current in secondary in A
+//Wye delta connection
+V_wP1 = V_L1*10^3/sqrt(3) // phase voltage at primary in V
+V_wP2 = V_wP1/a // phase voltage at secondary in V, V_L2=V_P2
+I_wP2 = a*I_P1 // phase current in secondary in A
+I_wL2 = sqrt(3)*I_wP2 // line current in secondary in A
+
+// display the result
+disp("Example 3.15 solution");
+printf(" \n For delta-wye connection-");
+printf(" \n Phase voltage at secondary side \n V_dL2 = %.f V \n", V_dL2);
+printf(" \n Line voltage at secondary side \n I_dL2 = %.2f A \n", I_dL2);
+printf(" \n For wye-delta connection-")
+printf(" \n Phase voltage at secondary side \n V_wL2 = %.2f V \n", V_wP2);
+printf(" \n Line current in secondary side \n I_wL2 = %.2f A \n", I_wL2);
+
diff --git a/2642/CH3/EX3.16/Ex3_16.sce b/2642/CH3/EX3.16/Ex3_16.sce
new file mode 100755
index 000000000..9ab6e7a35
--- /dev/null
+++ b/2642/CH3/EX3.16/Ex3_16.sce
@@ -0,0 +1,33 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.16
+
+
+clc;clear; // clears the console and command history
+
+// Given data
+V_b = 220 // voltage in V
+f = 50 // frequency in Hz
+S_b = 600 // power ratings
+R = 3 // resistance in ohm
+X_L = 5 // inducatnce in ohm
+Z = R+X_L // impedance
+
+// caclulations
+I_b = S_b/V_b // base value of current in A
+Z_b = V_b^2/S_b // base value of impedance in ohm
+R_pu = R/Z_b // per unit value of resistance in ohm
+X_Lpu = X_L/Z_b // per unit value of impedance in ohm
+Z_pu = abs(Z)/Z_b // per unit of value of impedance in ohm
+Z_pu = R_pu+%i*X_Lpu // per unit of value of impedance in ohm NOTE:alternative method
+
+// display the result
+disp("Example 3.16 solution");
+printf(" \n Per unit value of resistance \n R_pu = %.3f ohm \n", R_pu);
+printf(" \n Per unit value of impedance \n X_Lpu = %.3f ohm \n", X_Lpu);
+printf(" \n Per unit of value of impedance \n Z_pu = %.3f<%.f \n", abs(Z_pu),atand(imag(Z_pu),real(Z_pu)));
+
diff --git a/2642/CH3/EX3.17/Ex3_17.sce b/2642/CH3/EX3.17/Ex3_17.sce
new file mode 100755
index 000000000..e963b79f3
--- /dev/null
+++ b/2642/CH3/EX3.17/Ex3_17.sce
@@ -0,0 +1,45 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.17
+
+
+clc;clear; // clears the console and command history
+
+// Given data
+S_b1 = 100 // base apparent power
+V_bT11 = 220 // voltage of 1st transformer in kV
+V_bT12 = 132 // voltage of 1st transformer in kV
+X_T1 = 0.02 // impedance of 1st transformer in pu
+S_b2 = 50 // base apparent power
+V_bT21 = 132 // voltage of 2nd transformer in kV
+V_bT22 = 66 // voltage of 2nd transformer in kV
+X_T2 = 0.05 // impedance of 2nd transformer in pu
+X_L = 4 // line impedance in ohm
+P = 50 // power absorded in MW
+pf = 0.6 // lagging power factor from transmission line
+Z_p = 0.32*%i //Reactance of transformer in ohm
+
+// caclulations
+S_b = S_b1 //Base power(MW)
+V_b = V_bT11 //Base voltage(kV)
+a = V_bT11/V_bT12 // turn ratio for 1st transformer
+Vb_line = (V_bT11/a) // base voltage of line in kV
+Zb_line = Vb_line^2/S_b1 // base impedance of line in ohm
+Xpu_line = X_L/Zb_line // per unit reactance of line
+Xpu_T1 = X_T1*(V_bT11/V_b)^2*(S_b/S_b1) // 1st grid transformer ,the per unit reactance
+Vb_load = (V_bT12/(V_bT12/V_bT22)) // load side base voltage in kV
+Xpu_load = X_T2*(V_bT22/Vb_load)^2*(S_b/S_b2) // second load transformer ,the per unit reactance
+I_b = S_b*1000/(sqrt(3)*Vb_load) // base current
+I_L = S_b2*1000/(sqrt(3)*V_bT22*pf) // actualcurrent in load in A
+I_Lpu = I_L/I_b // per unit value of the load
+V_L = V_bT22/V_bT22 //per unit value of the voltage at the load terminal(bus4)
+V_gb = I_Lpu*exp(%i*acos(pf))*Z_p + 1 // per unit value of bus voltage
+V_gba = abs(V_gb)*V_bT11 // actual value of grid to bus voltage
+
+// display the result
+disp("Example 3.17 solution");
+printf(" \n Actual value of grid to bus voltage \n V_gba = %.2f kV \n", V_gba);
diff --git a/2642/CH3/EX3.2/Ex3_2.sce b/2642/CH3/EX3.2/Ex3_2.sce
new file mode 100755
index 000000000..30cd6af41
--- /dev/null
+++ b/2642/CH3/EX3.2/Ex3_2.sce
@@ -0,0 +1,22 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.2
+clc;clear; // clears the console and command history
+
+// Given data
+V_1 = 220 // voltage in V
+N_1 = 150 // number of turns in the primary coil of transformer
+N_2 = 300 // number of turns in the secondary coil of transformer
+f = 50 // frequency in Hz
+
+// caclulations
+a = N_1/N_2 // turn ratio
+phi_m = V_1/(4.44*f*N_1) // mutual flux in Wb
+
+// display the result
+disp("Example 3.2 solution");
+printf(" \n Mutual flux \n phi_m = %.2e Wb \n", phi_m);
diff --git a/2642/CH3/EX3.3/Ex3_3.sce b/2642/CH3/EX3.3/Ex3_3.sce
new file mode 100755
index 000000000..7f8988bd5
--- /dev/null
+++ b/2642/CH3/EX3.3/Ex3_3.sce
@@ -0,0 +1,27 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.3
+clc;clear; // clears the console and command history
+
+// Given data
+V_1 = 2200 // primary voltage of transformer in V
+V_2 = 220 // secondary voltage of transformer in V
+I_0 = 0.5 // no-load current in A
+P_0 = 350 // absorbed power by transformer
+
+// caclulations
+phi = acos(.32)
+sin_phi = sin(phi)
+cos_phi = P_0/(V_1*I_0) // no-load power factor
+I_w = I_0*cos_phi // iron loss component of current A
+I_m = I_0*sin_phi // magnetizing component of current A
+
+
+// display the result
+disp("Example 3.3 solution");
+printf(" \n The iron loss component of current A \n I_w = %.2f A \n", I_w);
+printf(" \n The magnetizing component of current A \n I_m = %.2f A \n", I_m);
diff --git a/2642/CH3/EX3.4/Ex3_4.sce b/2642/CH3/EX3.4/Ex3_4.sce
new file mode 100755
index 000000000..295de1627
--- /dev/null
+++ b/2642/CH3/EX3.4/Ex3_4.sce
@@ -0,0 +1,26 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.4
+clc;clear; // clears the console and command history
+
+// Given data
+N_1 = 450 // number of turns in the primary coil of transformer
+N_2 = 45 // number of turns in the secondary coil of transformer
+Z_L = 3 // load impedance in Ω
+V_1 = 15 // primary coil voltage of transformer in V
+
+// caclulations
+a = N_1/N_2 // turn ratio
+Z_1 = a^2*Z_L // load impedance referred to primary ohm
+I_1 = V_1/Z_1 // primary current in A
+
+
+// display the result
+disp("Example 3.4 solution");
+printf(" \n Turn ratio \n a = %.0f \n", a);
+printf(" \n Load impedance referred to primary \n Z_1 = %.0f Ω \n", Z_1);
+printf(" \n Primary current \n I_1 = %.2f A \n", I_1);
diff --git a/2642/CH3/EX3.5/Ex3_5.sce b/2642/CH3/EX3.5/Ex3_5.sce
new file mode 100755
index 000000000..a88344b6e
--- /dev/null
+++ b/2642/CH3/EX3.5/Ex3_5.sce
@@ -0,0 +1,28 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.5
+clc;clear; // clears the console and command history
+
+// Given data
+V_1 = 400 // primary voltage of transformer in V
+V_2 = 100 // secondary voltage of transformer in V
+I_0 = 0.4 // no-load current in A
+I_2 = 100 // load draws current in A
+cos_phi0 = 0.3 // power factor lagging from the supply
+cos_phi2 = 0.6 // power factor lagging from the secondary
+
+// caclulations
+phi0 = acosd(0.3)
+phi2 = acosd(0.6)
+phi1 = phi0-phi2
+a = V_1/V_2 // turn ratio
+I_2! = I_2/a // secondary current equivalent to the primary
+I_1 = sqrt((I_2!^2)+(I_0^2)+(2*I_2!*I_0*cosd(19.4))) // primary current in A
+
+// display the result
+disp("Example 3.5 solution");
+printf(" \n Primary current \n I_1 = %.2f A \n", I_1);
diff --git a/2642/CH3/EX3.6/Ex3_6.sce b/2642/CH3/EX3.6/Ex3_6.sce
new file mode 100755
index 000000000..63857c585
--- /dev/null
+++ b/2642/CH3/EX3.6/Ex3_6.sce
@@ -0,0 +1,31 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.6
+clc;clear; // clears the console and command history
+
+// Given data
+V_1 = 2000 // primary voltage of transformer in V
+V_2 = 400 // secondary voltage of transformer in V
+kVA = 200 // kVA rating of transformer
+R_1 = 3 // primary resistance in Ω
+X_1 = 12 // primary reactance in Ω
+R_2 = 0.3 // secondary resistance in Ω
+X_2 = 0.1 // secondary reactance in Ω
+
+// caclulations
+a = V_1/V_2 // turn ratio
+R_01 = R_1+(a^2*R_2) // total resistance referred to primary side Ω
+X_01 = X_1+(a^2*X_2) // total reactance referred to primary side Ω
+Z_01 = sqrt((R_01^2)+(X_01^2)) // equivalent impedance reffered to primary side in Ω
+R_02 = R_2+(R_1/a^2) // total resistance referred to secondary side Ω
+X_02 = X_2+(X_1/a^2) // total reactance referred to secondary side Ω
+Z_02 = sqrt((R_02^2)+(X_02^2)) // equivalent impedance reffered to secondary side in Ω
+
+// display the result
+disp("Example 3.6 solution");
+printf(" \n Equivalent impedance reffered to primary side \n Z_01 = %.1f Ω \n", Z_01);
+printf(" \n Equivalent impedance reffered to secondary side \n Z_02 = %.2f Ω \n", Z_02);
diff --git a/2642/CH3/EX3.7/Ex3_7.sce b/2642/CH3/EX3.7/Ex3_7.sce
new file mode 100755
index 000000000..876496b4f
--- /dev/null
+++ b/2642/CH3/EX3.7/Ex3_7.sce
@@ -0,0 +1,33 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.7
+clc;clear; // clears the console and command history
+
+// Given data
+V_1 = 200 // primary voltage of transformer in V
+V_2 = 400 // secondary voltage of transformer in V
+R_1 = 0.3 // primary resistance in Ω
+X_1 = 0.6 // primary reactance in Ω
+R_2 = 0.8 // secondary resistance in Ω
+X_2 = 1.6 // secondary reactance in Ω
+I_2 = 10 // secondary supply current in A
+cos_phi2 = 0.8 // power factor lagging
+
+// caclulations
+a = V_1/V_2 // turn ratio
+phi2 = acosd(0.8)
+sin_phi2 = sind(phi2)
+R_02 = R_2+(R_1/a^2) // total resistance referred to secondary side Ω
+X_02 = X_2+(X_1/a^2) // total reactance referred to secondary side Ω
+E_2 = (V_2*cos_phi2+I_2*R_02)+(%i*(V_2*sin_phi2+I_2*X_02)) // no-load voltage
+V_r = (abs(E_2)-V_2)/V_2*100 // voltage regulation
+
+// display the result
+disp("Example 3.7 solution");
+printf(" \n Voltage regulation \n V_r = %.0f percent \n", V_r);
+
+
diff --git a/2642/CH3/EX3.8/Ex3_8.sce b/2642/CH3/EX3.8/Ex3_8.sce
new file mode 100755
index 000000000..eca25ca92
--- /dev/null
+++ b/2642/CH3/EX3.8/Ex3_8.sce
@@ -0,0 +1,30 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.8
+clc;clear; // clears the console and command history
+
+// Given data
+P_i = 1 // iron loss of transformer in kW
+P_cu = 2 // copper loss of transformer in kW
+kVA = 200 // kVA ratingss of transformer
+pf = 0.95 // power factor
+
+// caclulations
+P_cu1 = (3/4)^2*P_cu // copper loss at 1/2th of full load in kW
+P_cu2 = (1/2)^2*P_cu // copper loss at 1/2th of full load in kW
+P_01 = (3/4)*kVA*P_i // o/p power at 3/4 full load and unity power factor in kW
+P_in1 = P_01+P_i+P_cu1 // i/p power at 3/4 full load and unity power factor in kW
+n_1 = (P_01/P_in1)*100 // efficiency at 3/4 full load and unity power factor
+P_02 = (1/2)*kVA*pf // o/p power factor at1/2 full load and 0.95 power factor in kW
+P_in2 = P_02+P_i+P_cu2 // i/p power at 1/2 full load and 0.95 power factor in kW
+n_2 = (P_02/P_in2)*100 // efficiency at 1/2 full load and 0.95 power factor
+
+// display the result
+disp("Example 3.8 solution");
+printf(" \n Efficiency at 3/4 full load and unity power factor \n n_1 = %.2f percent \n", n_1);
+printf(" \n Efficiency at 1/2 full load and 0.95 power factor \n n_2 = %.2f percent \n", n_2);
+
diff --git a/2642/CH3/EX3.9/Ex3_9.sce b/2642/CH3/EX3.9/Ex3_9.sce
new file mode 100755
index 000000000..5b1b69703
--- /dev/null
+++ b/2642/CH3/EX3.9/Ex3_9.sce
@@ -0,0 +1,34 @@
+// FUNDAMENTALS OF ELECTICAL MACHINES
+// M.A.SALAM
+// NAROSA PUBLISHING HOUSE
+// SECOND EDITION
+
+// Chapter 3 : TRANSFORMER AND PER UNIT SYSTEM
+// Example : 3.9
+
+
+clc;clear; // clears the console and command history
+
+// Given data
+P_i = 350 // iron loss of transformer in W
+P_cu = 650 // copper loss of transformer in W
+kVA = 30 // kVA ratingss of transformer
+pf = 0.6 // power factor
+
+// caclulations
+P_tloss = (P_i+P_cu)*10^-3 // total full load loss in kW
+P_out = kVA*pf // o/p power at full load in kW
+P_in = P_out+P_tloss // i/p power at full load
+n_1 = (P_out/P_in)*100 // efficiency at full load
+kVA_out = kVA*sqrt(P_i/P_cu) // o/p kVA corresponding to maximum efficiency
+P_01 = kVA_out*pf // o/p power in W
+P_tloss1 = 2*P_i // maximum efficiency iron loss=copper loss in W
+P_in1 = P_01+P_tloss1*10^-3 // i/p power in kW
+n_2 = (P_01/P_in1)*100 // efficiency
+
+// display the result
+disp("Example 3.9 solution");
+printf(" \n Efficiency at full load \n n_1 = %.2f percent \n", n_1);
+printf(" \n Out put power \n P_01 = %.1f kW \n", P_01);
+printf(" \n Efficiency \n n_2 = %.2f percent \n", n_2);
+
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