3 files changed, 87 insertions, 0 deletions
diff --git a/Working_Examples/293/CH20/EX20.2/eg20_2.sce b/Working_Examples/293/CH20/EX20.2/eg20_2.sce
new file mode 100755
index 0000000..396caca
--- /dev/null
+++ b/Working_Examples/293/CH20/EX20.2/eg20_2.sce
@@ -0,0 +1,36 @@
+//a
+Vt = 230; //(in volts)
+Ia = 73; //armature current (in amps)
+If = 1.6; //feild current (in amps)
+Ra = 0.188; //armature circuit resistance(in ohms)
+n = 1150; //rated speed of the rotor(in rpm)
+Po = 20*746; //output power (in watts)
+
+Ea = Vt - (Ia*Ra); //armature voltage 
+wm = 2*%pi*n/60; //rated speed of the rotor (in rad/sec)
+T = Ea*Ia/wm ; //electromagnetic torque 
+
+disp("a")
+disp(T,"electromagnetic torque = ")
+
+//b
+a = 4; //no. of parallel armature paths 
+p = 4; //no. of poles
+z = 882; //no. of armature conductors
+flux = Ea*60*a/(p*z*n); //flux per pole (in Wb)
+
+disp("b")
+disp(flux,"flux per pole = ")
+
+//c
+Prot = (Ea*Ia) - Po; //rotational loss (in watt)
+disp("c")
+disp(Prot,"rotational losses = ")
+
+//d
+losses = Prot + (Ia^2 * Ra) + (Vt * If) ; 
+Pi = (Ea*Ia) + (Ia^2 * Ra) + (Vt * If); //input power
+efficiency = 1 - (losses/Pi);
+
+disp("d")
+disp(efficiency,"efficiency = ")
+\ No newline at end of file
diff --git a/Working_Examples/293/CH20/EX20.3/eg20_3.sce b/Working_Examples/293/CH20/EX20.3/eg20_3.sce
new file mode 100755
index 0000000..5f7c18b
--- /dev/null
+++ b/Working_Examples/293/CH20/EX20.3/eg20_3.sce
@@ -0,0 +1,13 @@
+// final flux = 0.8*initial flux
+Ia1 = 73; //initial armature current (in amps)
+Vt = 230; //(in volts)
+Ra = 0.188; //armature circuit resistance 
+n1 = 1150; //initial rotor speed (in rpm)
+Ea1 = 216.3; //initial armature voltage 
+
+Ia2 = (1/0.8)*Ia1 ; //final armature current 
+Ea2 = Vt - (Ia2*Ra); //final armature voltage 
+
+n2 = (Ea2/Ea1)*(1/0.8)*n1; //final rotor speed 
+
+disp(n2,"final rotor speed(in rpm) = ")
+\ No newline at end of file
diff --git a/Working_Examples/293/CH20/EX20.4/eg20_4.sce b/Working_Examples/293/CH20/EX20.4/eg20_4.sce
new file mode 100755
index 0000000..c792906
--- /dev/null
+++ b/Working_Examples/293/CH20/EX20.4/eg20_4.sce
@@ -0,0 +1,38 @@
+//a
+rop = 0.4; //ratio of ON time T0 to cycle time Tp
+Vb =550; //rated terminal voltage of the dc motor
+Ia = 30; //current drawn by the motor (in amps)
+Ra = 1; //armature circuit resistance (in ohms)
+ts = 5.94; //torque and speed parameter of the motor (in N-m/A)
+ 
+Vm = rop*Vb; //average value of the armature terminal voltage 
+Ea = Vm - (Ia*Ra); //induced armature voltage 
+
+wm = Ea/ts; //motor speed (in rad/s)
+disp("a")
+disp(wm,"motor speed (in rad/s) = ")
+
+//b
+deltaI = 5; //change of armature current during the ON period 
+La = 0.1; //armature winding inductance (in H)
+To = La*deltaI/(Vb - Ea); //ON time 
+Tp = To/rop; //cycle time 
+
+f = 1/Tp ; //required pulses per second 
+disp("b")
+disp(f,"required pulses per second = ")
+
+//c
+rop = 0.7; //new ratio of ON time T0 to cycle time Tp
+Vm = rop*Vb; //average value of the armature terminal voltage
+Ea = Vm - (Ia*Ra); //induced armature voltage 
+
+wm = Ea/ts; //motor speed (in rad/s)
+disp("c")
+disp(wm,"motor speed with To/Tp equal to 0.7 (in rad/s) = ")
+
+To = La*deltaI/(Vb - Ea); //ON time 
+Tp = To/rop; //cycle time 
+
+f = 1/Tp ; //required pulses per second 
+disp(f,"required pulses per second with To/Tp equal to 0.7 = ")
+\ No newline at end of file