18 files changed, 515 insertions, 0 deletions
diff --git a/1319/CH8/EX8.1/8_1.sce b/1319/CH8/EX8.1/8_1.sce
new file mode 100644
index 000000000..75bf78051
--- /dev/null
+++ b/1319/CH8/EX8.1/8_1.sce
@@ -0,0 +1,28 @@
+//Find the percentage slip and poles of the motor
+
+clc;
+clear;
+
+p=12;
+n=500;
+nlim=1440;
+f=p*n/120;
+c=1;
+
+while(c>0) // Used to find out the poles of the motor nearest to the full load slip
+    P=2*c;
+    N=120*f/P;
+    g=(5/100)*N;
+    if((N-nlim)>(0.05*N))
+        c=c+1;
+    else
+        c=0;
+    end
+end
+
+slip=(N-nlim)*100/N;
+
+printf('The Number of poles of the induction motor is %g \n',P)
+printf('The percentage slip is %g percent \n',slip)
+
+
diff --git a/1319/CH8/EX8.10/8_10.sce b/1319/CH8/EX8.10/8_10.sce
new file mode 100644
index 000000000..03f7b85c3
--- /dev/null
+++ b/1319/CH8/EX8.10/8_10.sce
@@ -0,0 +1,36 @@
+//To determine parameters of an 3 phase delta connected 4 pole induction motor
+
+clc;
+clear;
+
+V=440;
+f=50;
+p=4;
+E2=150;
+Nr=1450;
+
+Ns=120*f/p;
+
+s=(Ns-Nr)/Ns;
+
+rf=s*f; // Rotor frequency
+
+Eir=s*E2; // Rotor induced EMF per phase
+gc=1;
+
+// To find the GCD of both the voltages
+for i=E2:-1:1
+    a=modulo(V,i);
+    b=modulo(E2,i);
+    if(a==0&b==0)
+        gc=gc*i;
+        break;
+    end
+end
+
+printf('The parameters for a motor running at 1450 rpm are \n')
+printf('i) The slip = %g percent \n',s)
+printf('ii) The frequency of the rotor induced EMF =%g Hz \n',rf)
+printf('iii) The rotor induced EMF per phase = %g V \n',Eir)
+printf('iv) Stator to rotor turn ratio = %g : %g \n',V/gc,E2/gc)
+
diff --git a/1319/CH8/EX8.11/8_11.sce b/1319/CH8/EX8.11/8_11.sce
new file mode 100644
index 000000000..92abc9545
--- /dev/null
+++ b/1319/CH8/EX8.11/8_11.sce
@@ -0,0 +1,19 @@
+// Determine the shaft power of 6 pole Induction Motor
+
+clc;
+clear;
+
+f=50;
+p=6;
+rf=120/60; // Rotor Frequency
+T=150; // Full Load torque
+
+s=rf/f;
+
+Ns=120*f/p;
+
+Nr=Ns*(1-s);
+
+Ps=2*%pi*Nr*T/60; // Shaft power
+
+printf('The shaft power of the motor = %g kW \n',Ps/1000)
diff --git a/1319/CH8/EX8.12/8_12.sce b/1319/CH8/EX8.12/8_12.sce
new file mode 100644
index 000000000..7e8c87979
--- /dev/null
+++ b/1319/CH8/EX8.12/8_12.sce
@@ -0,0 +1,31 @@
+// Motor parameters at a load power factor
+
+clc;
+clear;
+
+p=4;
+f=50;
+V=400;
+pf=0.8;
+Nr=1440;
+Pm=20*(10^3); // Mechanical Power Developed
+Ns=120*f/p;
+s=(Ns-Nr)/Ns;
+
+rf=s*f; // Rotor frequency
+
+Pstat=1000; //Stator Loss
+
+// Power input to the rotor = Mechanical Power Developed / (1-s)
+
+Pirot=Pm/(1-s); // Rotor Power Input
+
+Pi=Pirot+Pstat; // Power input to stator
+
+Il=Pi/(sqrt(3)*V*pf); // Line Current
+
+printf('For a 4 pole motor running at 1440 rpm and 0.8 p.f \n')
+printf('i) Rotor Current frequency = %g Hz \n',rf)
+printf('ii) Total input if stator loss is 1000W = %g kW \n',Pi/1000)
+printf('iii) The line current = %g A \n',Il)
+
diff --git a/1319/CH8/EX8.13/8_13.sce b/1319/CH8/EX8.13/8_13.sce
new file mode 100644
index 000000000..9d6332655
--- /dev/null
+++ b/1319/CH8/EX8.13/8_13.sce
@@ -0,0 +1,19 @@
+// To determine the auto tranformer ratio and starting torque
+
+clc;
+clear;
+
+V=400;
+f=50;
+p=4;
+sfl=4/100;
+
+Ria=2.5; // Ratio of starting current to full load current (Auto transformer)
+Rir=4; // Ratio of starting current to full load current ( For the Rated Voltage)
+
+x=sqrt(Ria/Rir);
+
+Rt=((x*Rir)^2)*sfl; // Ratio of starting torque to full load torque;
+
+printf('The auto-transformer ratio = %g \n',x)
+printf('The starting torque at the above transformer ratio = %g percent of full load torque \n',100*Rt)
diff --git a/1319/CH8/EX8.14/8_14.sce b/1319/CH8/EX8.14/8_14.sce
new file mode 100644
index 000000000..85ec3cb21
--- /dev/null
+++ b/1319/CH8/EX8.14/8_14.sce
@@ -0,0 +1,18 @@
+//To determine the starting torque in terms of full load torque
+
+clc;
+clear;
+
+sfl=4/100;
+
+Rir=5; // Ratio of starting current to the full load current at rated voltage
+
+x=70.7/100; // Auto transformer tapping
+
+Rsd=((Rir)^2)*sfl/3; // Ratio of the starting load to full load torque for a star -delta starter
+
+Ra=((x*Rir)^2)*sfl; // Ratio of the starting load to full load torque for an 70.7% tapped auto transformer
+
+printf('The starting torque in terms of full load torque by \n')
+printf('i) Star-Delta starter = %g Tfl \n',Rsd)
+printf('ii) An auto-tranformer starter with 70.7 percent tapping = %g Tfl \n',Ra)
diff --git a/1319/CH8/EX8.15/8_15.sce b/1319/CH8/EX8.15/8_15.sce
new file mode 100644
index 000000000..ba5f4d806
--- /dev/null
+++ b/1319/CH8/EX8.15/8_15.sce
@@ -0,0 +1,21 @@
+// Stator input of 3 phase 4 pole induction motor
+
+clc;
+clear;
+
+p=4;
+f=50;
+Pd=4000; // Power Developed
+Nr=1440;
+Ps=320;// Stator loss
+
+Ns=120*f/p;
+
+s=(Ns-Nr)/Ns;
+
+Pir=Pd/(1-s); // Power to the rotor
+
+Pi=Pir+Ps; // The input to the stator
+
+printf('The stator input of a 440V 3 phase 4 pole induction motor = %g W \n',ceil(Pi))
+
diff --git a/1319/CH8/EX8.16/8_16.sce b/1319/CH8/EX8.16/8_16.sce
new file mode 100644
index 000000000..1eb9e5832
--- /dev/null
+++ b/1319/CH8/EX8.16/8_16.sce
@@ -0,0 +1,36 @@
+// Motor parameters of a 6 pole motor with 40 hp mechanical power
+
+clc;
+clear;
+
+f=50;
+p=6;
+Pd=40*735.5; // Mechanical Power developed
+V=500;
+Nr=960;
+pf= 0.8; // Lag
+Pm=1500; // Mechanical Loss
+
+Ns=120*f/p;
+
+s=(Ns-Nr)/Ns;
+Ps=1800; // Stator Loss
+
+Po=Pd-Pm; // Power Output
+
+Pir=Pd/(1-s); // Power input to rotor
+
+Prc=s*Pir; // Copper Loss of the Rotor
+
+Pi=Pir+Ps; // Power input to the stator
+
+eff=Po*100/Pi;
+
+Il=Pi/(sqrt(3)*V*pf);// Line Current
+
+printf('For a 6 pole 3 phase motor at 500V with a power factor of 0.8 lag \n')
+printf('i) Rotor Copper Loss = %g W \n',Prc)
+printf('ii) Total input to stator if the stator loss is 1500W = %g W \n',Pi)
+printf('iii) The line Current = %g A \n',Il)
+printf('iv) Efficiency = %g percent \n',eff)
+
diff --git a/1319/CH8/EX8.17/8_17.sce b/1319/CH8/EX8.17/8_17.sce
new file mode 100644
index 000000000..cfa9d003f
--- /dev/null
+++ b/1319/CH8/EX8.17/8_17.sce
@@ -0,0 +1,53 @@
+//To determine parameters of 4 pole induction motor considering circuit parameters
+
+clc;
+clear;
+
+R1=0.5;
+R2=0.35;
+X1=1.2;
+X2=X1;
+Xm=25;
+f=50;
+p=4;
+
+Pd=25*735.5; // Power Developed
+Prl=800;// Rotational Losses
+V=400;
+Vph=V/sqrt(3);
+
+Ns=120*f/p;
+s=2.5/100;
+Nr=(1-s)*Ns;
+rf=s*f; // Rotor Frequency
+
+Z1=R1+(%i*X1);
+Z2=(R2/s)+(%i*X2);
+Zm=%i*Xm;
+
+Z2m=(Zm*Z2)/(Zm+Z2);
+
+Zeff=Z1+Z2m; // Effective Impedance
+
+Is= Vph/Zeff; // Stator Current
+
+Psc= 3*(abs(Is)^2)*R1; // Copper Loss in the Stator
+Ztheta= atand(imag(Zeff)/real(Zeff)); // Phase angle of impedance
+Ctheta= atand(imag(Is)/real(Is)); // Phase angle of current
+
+pf= cosd(Ctheta);// Lagging Power Factor 
+Ir=Is*(Zm/(Zm+Z2));// Rotor Current
+
+Prc= 3*(abs(Ir)^2)*R2; // Rotor Copper Loss
+
+Pim= sqrt(3)*V*abs(Is)*cosd(Ctheta); // Power input to the motor
+Pom= Pim-Prc-Psc-Prl; // Power Output to the motor
+
+eff=Pom*100/Pim; // Efficiency
+
+printf('For a rotor slip of 2.5 percent at rated voltage and frequency \n');
+printf('i) The motor speed = %g rpm \n',Nr)
+printf('ii) The stator Current = %g /_%g A \n',abs(Is),Ctheta)
+printf('iii) The p.f = %g lagging \n',pf)
+printf('iv) The efficiency = %g percent \n',eff)
+
diff --git a/1319/CH8/EX8.18/8_18.sce b/1319/CH8/EX8.18/8_18.sce
new file mode 100644
index 000000000..3fd725e0e
--- /dev/null
+++ b/1319/CH8/EX8.18/8_18.sce
@@ -0,0 +1,36 @@
+//Stator Current and pf and efficiency of a motor operating at 0.03 slip
+
+clc;
+clear;
+
+V=400;
+Vph=V/sqrt(3);
+R1=0.2;
+R2=0.15;
+X1=%i*0.5;
+X2=%i*0.3;
+
+s=3/100;
+
+Ptl=2000; // Total Losses
+
+Z1=R1+X1;
+Z2=(R2/s)+X2;
+Zt=Z1+Z2; // Total Impedance of the circuit
+
+Is= Vph/Zt; // Stator Current
+
+Ctheta=atand(imag(Is)/real(Is)); // Phase angle of stator current
+
+pf= cosd(Ctheta); // Power factor lagging
+
+Pi=sqrt(3)*V*abs(Is)*cosd(Ctheta);
+
+Po=Pi-Ptl; // Power Output
+
+eff=Po*100/Pi;
+
+printf('For a 3 phase, 4 pole, 400V Induction Motor operating at 3 percent slip \n')
+printf('i) The Stator current = %g /_%g A \n',abs(Is),Ctheta)
+printf('ii) The p.f = %g lagging \n',pf)
+printf('iii) The efficiency = %g percent \n',eff)
diff --git a/1319/CH8/EX8.2/8_2.sce b/1319/CH8/EX8.2/8_2.sce
new file mode 100644
index 000000000..5011b1189
--- /dev/null
+++ b/1319/CH8/EX8.2/8_2.sce
@@ -0,0 +1,19 @@
+//To calculate motor speed and its slip
+
+clc;
+clear;
+
+f=50;
+sf=3/2;
+s=sf/f;
+
+p=8;
+N=120*f/8;
+
+Nr=poly([0 1],'Nr','c'); // Actual Speed Variable
+
+x=(750*s)-(750-Nr); // Equation To find the Actual Speed
+
+Nr=roots(x); // Actual Speed Constant
+
+printf('The motor runs at a speed of %g rpm and has a slip of %g \n',ceil(Nr),s)
diff --git a/1319/CH8/EX8.3/8_3.sce b/1319/CH8/EX8.3/8_3.sce
new file mode 100644
index 000000000..a50431a0d
--- /dev/null
+++ b/1319/CH8/EX8.3/8_3.sce
@@ -0,0 +1,36 @@
+// To Calculate Parameters of a 3 phase 4 pole induction machine.
+
+clc;
+clear;
+
+V1=200;
+R2=0.1;
+X2=0.9;
+f=50;
+p=4;
+s=4/100;
+a=0.67; // The Ratio of rotor to stator turns
+
+P=((a*V1)^2)*R2*(1-s)*s/(((R2)^2)+((s*X2)^2)); // Power Delivered referred to the rotor side ( Mechanical Power)
+
+N=120*f/p;// Rated Speed
+
+N1=N*(1-s);// Speed at 4% slip
+
+T4=P*60/(2*%pi*N1); // Total Torque at 4% slip
+
+sm=floor((R2/X2)*1000)/1000; // Condition for Maximum Torque
+
+Pmax=((a*V1)^2)*R2*(1-sm)*sm/((R2^2)+((sm*X2)^2));// Power at maximum torque
+
+Nmax=ceil(N*(1-sm)); // Speed at Maximum Torque
+
+Tmax=Pmax*60/(2*%pi*Nmax); // Maixmum Torque
+
+// Please Note that the answers are accurate and no quantities are neglected as in the text book.
+printf('a) Total torque at 4 percent slip = %g Nm \n',T4)
+printf('b) Total Mechanical Power at 4 percent slip = %g watts or %g H.P \n',P,(P/735))
+printf('c) Maximum Torque = %g Nm \n',Tmax)
+printf('d) Speed at maximum torque = %g rpm \n',Nmax)
+printf('e) Maximum Mechanical Power = %g watt or %g H.P \n',Pmax,(Pmax/735))
+
diff --git a/1319/CH8/EX8.4/8_4.sce b/1319/CH8/EX8.4/8_4.sce
new file mode 100644
index 000000000..c3c27ddbb
--- /dev/null
+++ b/1319/CH8/EX8.4/8_4.sce
@@ -0,0 +1,24 @@
+//Calculation of slip from losses
+
+clc;
+clear;
+
+eff=0.9; // Efficiency
+P=50*735; // Load in watts
+x=poly([0 1],'x','c'); // Rotor Copper Loss Variable
+
+tx=(x+x+x+(x/3)); // Total loss
+
+loss=((P+tx)*eff)-P; // Equation to calculate x
+
+x=roots(loss); // Rotor Copper Loss Constant
+
+s=poly([0 1],'s','c'); // Variable for slip
+slip=(P*s)-(x*(1-s));// Gives the variable equation of slip
+
+s=roots(slip); // Numerical Value of slip
+
+printf('The slip of an induction motor of 0.9 efficiency at 50 HP load = %g \n',s)
+
+
+
diff --git a/1319/CH8/EX8.5/8_5.sce b/1319/CH8/EX8.5/8_5.sce
new file mode 100644
index 000000000..0a2915010
--- /dev/null
+++ b/1319/CH8/EX8.5/8_5.sce
@@ -0,0 +1,39 @@
+//Tapping of an auto transformer to limit current in squirrel cage motor
+
+clc;
+clear;
+
+V=400; // Line to line voltage
+Vph=V/sqrt(3); // Phase voltage
+Z=1.54; // Standstill impedance
+Ifl=30;// Full Load Current
+Imax=75; // Max current which can be taken by the line
+s=4/100; // Full load slip
+
+t=poly([0 1],'t','c'); // Variable for tapping percent of normal voltage
+
+Is=t*(Vph/(100*Z)); // Starting current in the motor
+
+Ias=(t/100)*Is; // Current on supply side of the auto transformer
+
+Tap=Ias-Imax; // Equation to find t
+
+t=roots(Tap);// Numerical Value for t
+
+if(imag(sqrt(t(1))))
+    t=t(2);
+else
+    t=t(1);
+end
+
+
+Ism=Imax*100/t; // Starting current in the motor (Numerical Value)
+
+st=((Ism/Ifl)^2)*s; // Starting torque to full load torque ratio
+
+printf('The tapping provided to the auto transformer = %g percent of Normal Voltage \n',t)
+
+printf('The starting torque available is %g times the full load torque \n',st)
+
+
+
diff --git a/1319/CH8/EX8.6/8_6.sce b/1319/CH8/EX8.6/8_6.sce
new file mode 100644
index 000000000..971a09443
--- /dev/null
+++ b/1319/CH8/EX8.6/8_6.sce
@@ -0,0 +1,21 @@
+//To find the total mechannical power and rotor copper loss
+
+clc;
+clear;
+
+P=60*(10^3); // Power input
+Pstat=1*(10^3);// Stator Losses
+Pirot=P-Pstat;// Rotor Input
+s=3/100;// Running slip
+
+Prc=poly([0 1],'Prc','c'); // Variable for rotor copper loss
+// Prc = I2^2 * R2
+
+rloss=(Pirot*s)-(3*Prc);
+
+Prc=roots(rloss); // Numerical Value of rotor loss per phase;
+
+Pm=Pirot-(3*Prc); // Mechanical power developed
+
+printf('The rotor loss per phase = %g W \n',Prc)
+printf('The Mechanical Power developed = %g kW \n',Pm/1000)
diff --git a/1319/CH8/EX8.7/8_7.sce b/1319/CH8/EX8.7/8_7.sce
new file mode 100644
index 000000000..3e08e89f3
--- /dev/null
+++ b/1319/CH8/EX8.7/8_7.sce
@@ -0,0 +1,37 @@
+// To determine the starting torque and current using different starters
+
+clc;
+clear;
+
+// Rated Parameters of the motor
+V=400; // Delta connected
+P=50*735.5; // Power developed
+N=750; // Speed
+
+Ifl=50; // Full Load current
+Z=2.5; // Impedance per phase
+sf=4.5/100; // Slip
+f=50;
+
+Tfl=P*60/(2*%pi*N);
+ 
+deff('y=curr(x)','y=(sqrt(3))*x/Z');
+
+deff('a=stor(b)','a=((b/Ifl)^2)*sf*Tfl');
+
+//Case 1
+I1=curr(V);
+T1=stor(I1);
+
+//Case 2
+I3=curr(70*V/100);
+T3=stor(I3);
+
+T2=Tfl*((1/sqrt(3))^2); // Case 2 torque
+I2=I1;
+
+printf('The starting torque and the starting current using different starters are : \n')
+
+printf('i) D.O.L starter = %g Nm and %g A \n',T1,I1)
+printf('ii) Star-delta starter = %g Nm and %g A \n',T2,I2)
+printf('iii) An auto transformer starter with 70 percent tapping = %g Nm and %g A \n',T3,I3)
diff --git a/1319/CH8/EX8.8/8_8.sce b/1319/CH8/EX8.8/8_8.sce
new file mode 100644
index 000000000..fdba08319
--- /dev/null
+++ b/1319/CH8/EX8.8/8_8.sce
@@ -0,0 +1,19 @@
+// To actual rotor speed and the rotor frequency at 3 percent slip
+
+clc;
+clear;
+
+P=2;
+f=50;
+V=400;
+Vph=V/sqrt(3);
+s=3/100;
+
+Ns=120*f/P;
+
+Nr=Ns*(1-s);
+
+rf=s*f; // Rotor Frequency
+
+printf('The Actual rotor speed = %g rpm \n',Nr)
+printf('The rotor frequency = %g Hz \n',rf)
diff --git a/1319/CH8/EX8.9/8_9.sce b/1319/CH8/EX8.9/8_9.sce
new file mode 100644
index 000000000..e755e1a07
--- /dev/null
+++ b/1319/CH8/EX8.9/8_9.sce
@@ -0,0 +1,23 @@
+// To determine the various parameters of a 3 phase 400V 6 poles Induction Motor
+
+clc;
+clear;
+
+f=50;
+p=6;
+s=3/100;
+V=400;
+
+N=120*f/p; // Synchronous speed
+Ns=0; // Speed of stator
+rf=s*f; // Rotor Frequency
+Nr=N*(1-s); // Rotor speed
+Nrs=N-Ns; // Speed of Rotor field wrt stator
+Nrr=120*rf/6; // Speed of rotor field wrt rotor
+Nrmsm=0; // Speed of rotor field wrt stator field
+
+printf('i) The speed of the rotor = %g rpm \n',Nr)
+printf('ii) The frequency of rotor current = %g Hz \n',rf)
+printf('iii) The Speed of the rotor magnetic field w.r.t the stator = %g rpm \n',Nrs)
+printf('iv) The speed of the rotor magnetic field w.r.t the rotor = %g rpm \n',Nrr)
+printf('v) The speed of the rotor magnetic field w.r.t the stator magnetic field = %g rpm \n',Nrmsm)