11 files changed, 432 insertions, 0 deletions
diff --git a/1445/CH3/EX3.1/Ex3_1.sce b/1445/CH3/EX3.1/Ex3_1.sce
new file mode 100644
index 000000000..f9883c955
--- /dev/null
+++ b/1445/CH3/EX3.1/Ex3_1.sce
@@ -0,0 +1,46 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 1
+
+disp("CHAPTER 3");
+disp("EXAMPLE 1");
+
+//VARIABLE INITIALIZATION
+v_l=400;                         //line voltage in Volts
+r=15;                            //resistance in Ohms
+xc=10;                           //capacitive reactance in Ohms
+
+//SOLUTION
+
+//solution (i)
+v_ph=v_l/sqrt(3);                //phase voltage=(line voltage)/sqrt(3) for star connection
+disp(sprintf("(i) The phase voltage is %.2f V",v_ph));
+
+//solution (ii)
+z_ph=sqrt((r^2)+(xc^2));
+I_l=v_ph/z_ph;                   //phase current = line current for star connection 
+disp(sprintf("(ii) The line current is %.2f A",I_l));
+
+//solution (iii)
+disp(sprintf("(iii) The phase current is %.2f A",I_l));
+
+//solution (iv)
+pow_fact=r/z_ph;
+disp(sprintf("(iv) The power factor of the circuit is %.2f (leading)",pow_fact));
+
+//solution (v)
+p=sqrt(3)*v_l*I_l*pow_fact;
+disp(sprintf("(v) The total power absorbed is %.0f W",p));
+
+//solution (vi)
+va=sqrt(3)*v_l*I_l;
+disp(sprintf("(vi) The apparent power is %.0f VA",va));
+var=sqrt((va^2)-(p^2));
+disp(sprintf("The reactive power is %.0f VAR",var));
+
+//Answers (v) and (vi) are different due to precision of floating point numbers
+
+//END
+
+
+
+
diff --git a/1445/CH3/EX3.11/Ex3_11.sce b/1445/CH3/EX3.11/Ex3_11.sce
new file mode 100644
index 000000000..03c2bf54d
--- /dev/null
+++ b/1445/CH3/EX3.11/Ex3_11.sce
@@ -0,0 +1,68 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 11
+
+disp("CHAPTER 3");
+disp("EXAMPLE 11");
+
+//SOLUTION
+function power_sum=p1(phi);
+power_sum=20*cos(phi);                 //power_sum=p1+p2=20*cos(phi) and in KiloWatts
+endfunction;
+function power_diff=p2(phi);
+power_diff=(20*sin(phi))/sqrt(3);      //power_diff=p1-p2=(20*sin(phi))/sqrt(3) and in KiloWatts
+endfunction;
+
+//solution (a): when phi=0
+power_sum=20*cos(0);                   //eq(i)
+power_diff=(20*sin(0))/sqrt(3);        //eq(ii)
+//solving eq(i) and eq(ii) to get values of p1 and p2
+A=[1 1;1 -1];
+b=[power_sum;power_diff];
+x=inv(A)*b; 
+x1=x(1,:);                             //to access the 1st row of 2X1 matrix 
+x2=x(2,:);                             //to access the 2nd row of 2X1 matrix 
+disp("Solution (a)"); 
+disp(sprintf("P1 + P2 = %d kW",power_sum));
+disp(sprintf("P1 - P2 = %d kW",power_diff));
+disp(sprintf("The two wattmeter readings are %d kW and %d kW",x1,x2));
+
+//solution (b): when phi=30 or %pi/6 (lagging)
+power_sum=20*cos(%pi/6);
+power_diff=(20*sin(%pi/6))/sqrt(3);
+A=[1 1;1 -1];
+b=[power_sum;power_diff];
+x=inv(A)*b; 
+x1=x(1,:);
+x2=x(2,:);
+disp("Solution (b)");
+disp(sprintf("P1 + P2 = %.2f kW",power_sum));
+disp(sprintf("P1 - P2 = %.2f kW",power_diff));
+disp(sprintf("The two wattmeter readings are %.2f kW and %.2f kW",x1,x2));
+
+//solution (c): when phi=60 or %pi/3
+power_sum=20*cos(%pi/3);
+power_diff=(20*sin(-(%pi/3)))/sqrt(3); //leading
+A=[1 1;1 -1];
+b=[power_sum;power_diff];
+x=inv(A)*b; 
+x1=x(1,:);
+x2=x(2,:);
+disp("Solution (c)");
+disp(sprintf("P1 + P2 = %.2f kW",power_sum));
+disp(sprintf("P1 - P2 = %.2f kW",power_diff));
+disp(sprintf("The two wattmeter readings are %.2f kW and %.2f kW",x1,x2));
+
+//solution (d): when phi=90 or %pi/2
+power_sum=20*cos(%pi/2);
+power_diff=(20*sin(%pi/2))/sqrt(3);   //leading
+A=[1 1;1 -1];
+b=[power_sum;power_diff];
+x=inv(A)*b; 
+x1=x(1,:);
+x2=x(2,:);
+disp("Solution (d)");
+disp(sprintf("P1 + P2 = %.2f kW",power_sum));
+disp(sprintf("P1 - P2 = %.2f kW",power_diff));
+disp(sprintf("The two wattmeter readings are %.2f kW and %.2f kW",x1,x2));
+
+//END
diff --git a/1445/CH3/EX3.12/Ex3_12.sce b/1445/CH3/EX3.12/Ex3_12.sce
new file mode 100644
index 000000000..07ceb2454
--- /dev/null
+++ b/1445/CH3/EX3.12/Ex3_12.sce
@@ -0,0 +1,34 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 12
+
+disp("CHAPTER 3");
+disp("EXAMPLE 12");
+
+//VARIABLE INITIALIZATION
+v_l=400;                     //in Volts
+f=50;                        //in Hertz
+w1=2000;                     //in Watts
+w2=800;                      //in Watts
+
+//SOLUTION
+//solution (a)
+p1=w1+w2;
+p2=w1-w2;
+phi=atan((sqrt(3)*p2)/p1);   //this equation comes from two-wattmeter method
+pow_fact=cos(phi);           
+disp(sprintf("(a) The power factor of the circuit is %.3f (leading)",pow_fact));
+
+//solution (b)
+I_l=p1/(sqrt(3)*v_l*pow_fact);
+disp(sprintf("(b) The line current is %.2f A",I_l));
+
+//solution (c)
+v_ph=v_l/sqrt(3);
+z_ph=v_ph/I_l;               //phase current = line current for delta connection
+r_ph=z_ph*pow_fact;
+disp(sprintf("(c) The resistance of each phase is %.2f Ω",r_ph));
+xc=sqrt((z_ph^2)-(r_ph^2)); 
+c=1/(2*%pi*f*xc);
+disp(sprintf("The capacitance of each phase is %.3E F",c));
+
+//END     
diff --git a/1445/CH3/EX3.2/Ex3_2.sce b/1445/CH3/EX3.2/Ex3_2.sce
new file mode 100644
index 000000000..c5a2d35e0
--- /dev/null
+++ b/1445/CH3/EX3.2/Ex3_2.sce
@@ -0,0 +1,24 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 2
+
+disp("CHAPTER 3");
+disp("EXAMPLE 2");
+
+//VARIABLE INITIALIZATION
+v_l=400;                          //line voltage in Volts
+I_l=30;                           //line current in Amperes
+p=12*1000;                        //power absorbed in Watts
+
+//SOLUTION
+v_ph=v_l/sqrt(3);                 //phase voltage = (line voltage)/sqrt(3)
+z_ph=v_ph/I_l;                    //phase current = line current for star connection   
+pow_fact=p/(sqrt(3)*v_l*I_l);     //three-phase power = sqrt(3)*v_l*I_l*pow_fact
+r_ph=z_ph*pow_fact;               //from impedance tringle
+disp(sprintf("The resisatnce of each impedance is %.2f Ω",r_ph));
+x_ph=sqrt((z_ph^2)-(r_ph^2));
+disp(sprintf("The ractance of each impedance is %.2f Ω",x_ph));
+
+//END
+
+
+
diff --git a/1445/CH3/EX3.3/Ex3_3.sce b/1445/CH3/EX3.3/Ex3_3.sce
new file mode 100644
index 000000000..e99995138
--- /dev/null
+++ b/1445/CH3/EX3.3/Ex3_3.sce
@@ -0,0 +1,35 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 3
+
+disp("CHAPTER 3");
+disp("EXAMPLE 3");
+
+//VARIABLE INITIALIZATION
+r_ph=30;                     //resistance of coils in Ohms
+l=0.07;                      //inductance of coils in Henry
+v_l=400;                     //line voltage in Volts
+f=50;                        //frequency in Hertz
+
+//SOLUTION
+
+//solution (a)
+x_ph=2*(%pi)*f*l;            //inductive reactance
+z_ph=sqrt((r_ph^2)+(x_ph^2)); 
+I_ph=v_l/z_ph;               //phase voltage = line voltage for delta connection
+disp(sprintf("(a) The phase current is %.2f A",I_ph));
+
+//solution (b)
+I_l=sqrt(3)*I_ph;            //phase current = (line current)/sqrt(3) for delta connection
+disp(sprintf("(b) The line current is %.2f A",I_l));
+
+//solution (c)
+pow_fact=r_ph/z_ph;
+disp(sprintf("(c) The power factor is %.3f (lagging)",pow_fact));
+
+//solution (d)
+p=sqrt(3)*v_l*I_l*pow_fact;
+disp(sprintf("(d) The power absorbed is %.0f W",p));
+
+//Answer is different due to precision of floating point numbers
+
+//END
diff --git a/1445/CH3/EX3.4/Ex3_4.sce b/1445/CH3/EX3.4/Ex3_4.sce
new file mode 100644
index 000000000..085e72919
--- /dev/null
+++ b/1445/CH3/EX3.4/Ex3_4.sce
@@ -0,0 +1,71 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 4
+
+disp("CHAPTER 3");
+disp("EXAMPLE 4");
+
+//VARIABLE INITIALIZATION
+v_l=866;                              //line voltage in Volts
+z_delta=177-(%i*246);                 //impedance of delta connected load in Ohms
+z_wire=1+(%i*2);                      //impedance of each wire of the line in Ohms
+
+//SOLUTION
+v_ph=v_l/sqrt(3);                     //phase current = (line current)/sqrt(3) for star connection
+z_star=z_delta/3;
+z=z_wire + z_star;
+I=v_ph/z;                             //I_na in rectangular form
+//I_na, I_nb and I_nc are same in magnitude and are the line currents for delta connection or vice-versa
+//function is not used to covert quantities in rectangular form to polar form
+//I_na
+I_na=sqrt((real(I))^2+(imag(I))^2);   //I_na from rectangular to polar form  
+a=atan(imag(I)/real(I));              //angle in radians
+a=a*(180/%pi);                        //radians to degrees
+//I_nb
+I_na=sqrt((real(I))^2+(imag(I))^2);
+b=a-120;                              //lags by 120 degrees
+//I_nc
+I_na=sqrt((real(I))^2+(imag(I))^2);
+c=a-240;                              // lags by another 120 degrees ie.,240 degrees
+disp(sprintf("The line currents are %.3f A (%.2f degrees), %.3f A (%.2f degrees) and %.3f A (%.2f degrees)",I_na,a,I_na,b,I_na,c));
+
+
+//line current lags phase current by 30 degrees, hence (-30)
+//I_AB
+I_AB=I_na/sqrt(3);
+a1=a-(-30); 
+//I_BC
+I_BC=I_na/sqrt(3);
+b1=b-(-30);
+//I_AC
+I_AC=I_na/sqrt(3);
+c1=c-(-30);
+disp(sprintf("The phase currents are %.3f A (%.2f degrees), %.3f A (%.2f degrees) and %.3f A (%.2f degrees)",I_AB,a1,I_BC,b1,I_AC,c1));
+
+//converting z_delta from polar form to rectangular form
+z=sqrt((real(z_delta))^2+(imag(z_delta))^2);
+angle=atan(imag(z_delta)/real(z_delta));
+angle=angle*(180/%pi); 
+
+//line voltages for load or phase voltages for the delta load-
+//v_AB
+v_AB=I_AB*z;
+a2=a1+angle;
+//v_B
+v_BC=I_BC*z;
+b2=b1+angle;
+//v_AC
+v_AC=I_AC*z;
+c2=c1+angle;
+disp(sprintf("The phase voltages for the delta load are %.3f A (%.2f degrees),  %.3f A (%.2f degrees) and %.3f A (%.2f degrees)",v_AB,a2,v_BC,b2,v_AC,c2));   
+
+p_AB=(I_AB^2)*real(z_delta); 
+p_load=3*p_AB;   
+disp(sprintf("The power absorbed by the load is %.2f W",p_load));
+p_l=3*(I_na^2)*real(z_wire);
+disp(sprintf("The power dissipated by the line is %.2f W",p_l));
+p=p_load+p_l;
+disp(sprintf("The total power supplied by 3-ϕ source is %.2f W",p));
+
+//Answers may be slightly different due to precision of floating point numbers
+
+//END
diff --git a/1445/CH3/EX3.5/Ex3_5.sce b/1445/CH3/EX3.5/Ex3_5.sce
new file mode 100644
index 000000000..2804e3e92
--- /dev/null
+++ b/1445/CH3/EX3.5/Ex3_5.sce
@@ -0,0 +1,25 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 5
+
+disp("CHAPTER 3");
+disp("EXAMPLE 5");
+
+//VARIABLE INITIALIZATION
+w1=5000;                       //reading of 1st wattmeter in Watts
+w2=-1000;                      //reading of 2nd wattmeter in Watts
+
+//SOLUTION
+
+//solution (a)
+p1=w1+w2;
+disp(sprintf("(a) The total power is %d W",p1));
+
+//solution (b)
+p2=w1-w2;
+phi=atan((sqrt(3)*p2)/p1);     //this equation comes from two-wattmeter method 
+pow_fact=cos(phi);            
+disp(sprintf("(b) The power factor of the load is %.3f", pow_fact));
+
+//END
+
+
diff --git a/1445/CH3/EX3.6/Ex3_6.sce b/1445/CH3/EX3.6/Ex3_6.sce
new file mode 100644
index 000000000..52cdce49a
--- /dev/null
+++ b/1445/CH3/EX3.6/Ex3_6.sce
@@ -0,0 +1,34 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 6
+
+disp("CHAPTER 3");
+disp("EXAMPLE 6");
+
+//VARIABLE INITIALIZATION
+v_l=3300;                     //line voltage in Volts
+p_out=1500*735.5;             //output power in Watts (1 metric horsepower= 735.498W)
+eff=0.85;
+pow_fact=0.81;
+
+//SOLUTION
+
+//solution (a)
+p_in=p_out/eff;
+disp(sprintf("(a) The motor input is %.2f kW",p_in/1000));
+
+//solution (b)
+I=p_in/(sqrt(3)*v_l*pow_fact);//phase current = line current for star connection
+disp(sprintf("(b) The line and phase current of the alternator is %.2f A",I));
+
+//solution (c)
+I_l=I;
+I_ph=I_l/sqrt(3);             //phase current = (line current)/sqrt(3) for delta connection
+disp(sprintf("(c) The line current of the motor is %.2f A",I_l));
+disp(sprintf("The phase current of the motor is %.2f A",I_ph));
+
+//Answers may be different due to precision of floating point numbers
+
+//END
+
+
+
diff --git a/1445/CH3/EX3.7/Ex3_7.sce b/1445/CH3/EX3.7/Ex3_7.sce
new file mode 100644
index 000000000..3371d0fe9
--- /dev/null
+++ b/1445/CH3/EX3.7/Ex3_7.sce
@@ -0,0 +1,33 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 7
+
+disp("CHAPTER 3");
+disp("EXAMPLE 7");
+
+//VARIABLE INITIALIZATION
+v_ph=200;                            //phase voltage in Volts
+r1=5;                                //in Ohms
+r2=8;                                //in Ohms
+r3=10;                               //in Ohms
+
+//SOLUTION
+I1=v_ph/r1;
+I2=v_ph/r2;
+I3=v_ph/r3;
+disp(sprintf("The current in the three phases are %d A, %d A and %d A",I1,I2,I3));
+
+I_x=0+I2*(sqrt(3)/2)-I3*(sqrt(3)/2); //x-component of the three currents =>I_x = I1*cos(90) + I2*cos(30) + I3*cos(30)
+I_y=I1-(I2*0.5)-(I3*0.5);            //y-component of the three currents =>I_y = I1*sin(90) + I2*sin(30) + I3*sin(30)
+I=sqrt((I_x^2)+(I_y^2));
+disp(sprintf("The neutral current is %.2f A",I));
+
+p1=v_ph*I1;                          //power consumed in 1st phase
+p2=v_ph*I2;                          //power consumed in 2nd phase
+p3=v_ph*I3;                          //power consumed in 3rd phase
+disp(sprintf("The power consumed in the three phases are %d W, %d W and %d W",p1,p2,p3));
+
+p=p1+p2+p3; 
+disp(sprintf("The total power is %d W",p));
+
+//END
+
diff --git a/1445/CH3/EX3.8/Ex3_8.sce b/1445/CH3/EX3.8/Ex3_8.sce
new file mode 100644
index 000000000..bfc910b2f
--- /dev/null
+++ b/1445/CH3/EX3.8/Ex3_8.sce
@@ -0,0 +1,34 @@
+//CHAPTER 3- THREE-PHASE A.C. CIRCUITS
+//Example 8
+
+disp("CHAPTER 3");
+disp("EXAMPLE 8");
+
+//VARIABLE INITIALIZATION
+v_ph=230;                               //in Volts and in polar form 
+z=8+(%i*6);                             //in Ohms and in rectanglar form
+
+//SOLUTION
+//converting z from rectangular form to polar form
+z_mag=sqrt(real(z)^2+imag(z)^2);  
+phi=atan(imag(z)/real(z));              //atan() gives output in radians
+
+I_ph=v_ph/z_mag;
+I_l=sqrt(3)*I_ph;
+disp(sprintf("The line current is %.2f A",I_l));
+
+pow_fact=cos(phi);
+disp(sprintf("The power factor is %.2f",pow_fact));
+
+p=sqrt(3)*v_ph*I_l*pow_fact;           //phase volt=line volt in delta connection(v_l=v_ph)
+disp(sprintf("The power is %.2f W",p));
+
+var=sqrt(3)*v_ph*I_l*sin(phi); 
+var=var/1000;                          //from VAR to kVAR   
+disp(sprintf("The reactive power is %.2f kVAR",var));
+
+va=sqrt(3)*v_ph*I_l;
+va=va/1000;                            //from VA to kVA
+disp(sprintf("The total volt amperes is %.2f kVA",va));
+
+//END
diff --git a/1445/CH3/EX3.9/Ex4_9.sce b/1445/CH3/EX3.9/Ex4_9.sce
new file mode 100644
index 000000000..037cea75c
--- /dev/null
+++ b/1445/CH3/EX3.9/Ex4_9.sce
@@ -0,0 +1,28 @@
+//CHAPTER 4- MEASURING INSTRUMENTS
+//Example 9
+
+disp("CHAPTER 4");
+disp("EXAMPLE 9");
+
+//VARIABLE INITIALIZATION
+I=50;                     //in Amperes
+v=230;                    //in Volts
+rev=61;                   //revolutions
+t=37/3600;                //from seconds to hours
+m_c=500;                  //meter constant in rev/kwh
+pow_fact=1;               //since load is purely resistive
+
+//SOLUTION
+E1=(v*I*t*pow_fact)/1000; //energy consumed in 37 seconds in kWh
+E2=rev/m_c;               //energy consumption registered by meter
+err=(E2-E1)/E1;
+err=err*100;              //percentage error
+disp(sprintf("The percentage error is %.2f %%",err));
+if(err<0) then
+disp("The negative sign indicates that the meter will run slow");
+end
+
+//END
+
+
+