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diff --git a/3731/CH6/EX6.1/Ex6_1.sce b/3731/CH6/EX6.1/Ex6_1.sce
new file mode 100644
index 000000000..989f15996
--- /dev/null
+++ b/3731/CH6/EX6.1/Ex6_1.sce
@@ -0,0 +1,52 @@
+//Chapter 6:Induction Motor Drives
+//Example 1
+clc;
+
+//Variable Initialization
+
+//Ratings of the Y-connected induction motor 
+f=50           // frequency in HZ
+Vl=440         //line voltage in V
+P=6            // number of poles
+N=950          //speed in rpm
+
+//Parameters referred to the stator
+Xr_=1.2        // rotor winding reactance in ohm
+Rr_=0.4        // resistance of the rotor windings in ohm
+Rs=0.5         // resistance of the stator windings in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Xm=50          // no load reactance in ohms
+ 
+//Solution
+Ns=120*f/P     //synchronous speed in rpm
+s=(Ns-N)/Ns    //full load slip
+x=sqrt((Rs+Rr_/s)**2+(Xs+Xr_)**2)   //total impedance
+Ir_=(Vl/sqrt(3))/x                  //full load rotor current
+angle=-atan((Xs+Xr_)/(Rs+Rr_/s))    //angle in radian
+
+Ir_=Ir_*(cos(angle)+sin(angle)*%i)                //full load rotor current in rectangular form
+Im=Vl/sqrt(3)/Xm*(-%i)              //magnetizing current
+Is=Ir_+Im                                //full load current
+
+Zf=Rs+Xs*%i+%i*Xm*(Rr_/s+%i*Xr_)/(Rr_/s+%i*(Xr_+Xm))
+Zb=Rs+Xs*%i+%i*Xm*(Rr_/(2-s)+%i*Xr_)/(Rr_/(2-s)+%i*(Xr_+Xm))
+Z=Zf+Zb
+I=(Vl/sqrt(3))/abs(Z)             //motor current
+Wms=2*%pi*Ns/60
+
+//Torque due to positive sequence
+Tp=(1/Wms)*(3*I**2*Xm**2*Rr_/s)/((Rr_/s)**2+(Xr_+Xm)**2)
+
+//Torque due to negative sequence
+Tn=-(1/Wms)*(3*I**2*Xm**2*Rr_/(2-s))/((Rr_/(2-s))**2+(Xr_+Xm)**2)
+T=Tp+Tn          //net torque
+Wm=Wms*(1-s)     //rated speed in in rad/sec
+Tl=0.0123*Wm**2 //required torque of the load
+
+//Results
+var=phasemag(Is)
+mprintf("Full load motor current Is:%.1f %.1f ° A",abs(Is),var)
+mprintf("\nTp:%.2f N-m",Tp)
+mprintf("\nTn:%.3f N-m",Tn)
+mprintf("\n\nSince I:%.2f A and N:%d rpm",I,N)
+mprintf("\nAnd I:%.2f A< Is %.2f A, the motor will run safely",I,abs(Is))
diff --git a/3731/CH6/EX6.10/Ex6_10.sce b/3731/CH6/EX6.10/Ex6_10.sce
new file mode 100644
index 000000000..5c228cb9f
--- /dev/null
+++ b/3731/CH6/EX6.10/Ex6_10.sce
@@ -0,0 +1,62 @@
+//Chapter 6:Induction Motor Drives
+//Example 10
+clc;
+clf();
+//Variable Initialization
+//ratings of the star connected squirrel Induction motor is same as that of Ex-6.9
+f=50           // frequency in HZ
+Vl=400         // line voltage in V
+P=4            // number of poles
+N=1370         // rated speed
+
+//the frequency variation is from 5 Hz to 50 Hz
+fmin=5     
+fmax=50
+//parameters referred to the stator
+Xr_=3.5        // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=3          // resistance of the rotor windings in ohm
+Rs=2           // resistance of the stator windings in ohm
+
+//calculation
+Ns=120*f/P     //synchronous speed
+N1=Ns-N        //increase in speed from no load to full torque rpm
+Wms=2*%pi*Ns/60
+s=(Ns-N)/Ns    //full load slip
+Tmax=54.88   //maximum torque as obtain from Ex-6.9
+
+//to obtain the plot between the voltage and the frequency
+K=0
+k=[]
+frequency=[]
+line_voltage=[]
+for i=0:9
+K=K+0.1
+f1=K*f
+x=2*K*Wms*Tmax/3
+y=Rs+sqrt((Rs)**2+(K*(Xs+Xr_))**2)
+Vl_square=3*x*y
+Vl=sqrt(Vl_square)
+k($+1)=K
+frequency($+1)=f1
+line_voltage($+1)=Vl
+end
+disp(k,"K:")
+disp(frequency,"f:in Hz")
+disp(line_voltage,"Vl:in V")
+
+//Plotting the values of line voltage Vl vs f 
+plot(frequency,line_voltage,'b')
+xlabel('f,Hz')
+ylabel('Line voltage,volts')
+xgrid(2)
+title('Line voltage  vs Frequency characteristic')
+//for constant V/f ratio
+x=[0,10,20,30,40,50]
+y=[0,80,160,240,320,400]
+plot(x,y,'--')
+str=["$\underleftarrow{\huge{Constant V/f  ratio}}$"]
+xstring(21,160,str)
+
+mprintf("\nHence for a constant breakdown torque at all frequencies,")
+mprintf("\nV/f ratio has to be progressively increased with increase in frequency")
diff --git a/3731/CH6/EX6.11/Ex6_11.sce b/3731/CH6/EX6.11/Ex6_11.sce
new file mode 100644
index 000000000..5a3b1ed97
--- /dev/null
+++ b/3731/CH6/EX6.11/Ex6_11.sce
@@ -0,0 +1,50 @@
+//Chapter 6:Induction Motor Drives
+//Example 11
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected squirrel Induction motor are same as that of Ex-6.9
+f=50           // frequency in HZ
+Vl=400         // line voltage in V
+P=4            // number of poles
+N=1370         // rated speed
+
+//Parameters referred to the stator
+Xr_=3.5        // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=3          // resistance of the rotor windings in ohm
+Rs=2           // resistance of the stator windings in ohm
+
+//Solution
+Ns=120*f/P     //synchronous speed
+N1=Ns-N        //increase in speed from no load to full torque rpm
+Wms=2*%pi*Ns/60 //synchronous speed
+s=(Ns-N)/Ns    //full load slip
+D=Ns-N        //drop in speed from no load to full load torque at 50 Hz
+
+//(i)When the frequency is 30 Hz and 80% of full load torque
+f1=30          //given frequency in Hz
+d=D*0.8        //drop in speed from no load to 80% full load torque
+Ns1=120*f1/P   //synchronous speed at the given frequency f1=30 Hz
+N1=Ns1-d       //required motor speed 
+
+//(ii)When the speed is 1000 rpm for a full load torque
+N2=1000       //given speed in rpm
+Ns2=N2+D      //synchronous speed
+f2=P*Ns2/120   //required frequency
+
+//When the speed is 1100 rpm and the frequency is 40 Hz
+N3=1100       //given speed in rpm
+f3=40         //given frequency in Hz
+Ns3=120*f3/P  //synchronous speed at the given frequency f1=40 Hz
+D1=Ns3-N3     //drop in speed from no load to N1=1100 rpm
+x=(Rs+Rr_/s)**2+(Xs+Xr_)**2
+Tf=(3/Wms)*(Vl/sqrt(3))**2*(Rr_/s)/x      //full load  torque
+T1=D1/D*Tf    //required torque 
+
+
+//results
+mprintf("(i)Hence the required motor speed is :%d rpm",N1)
+mprintf("\n(ii)Hence the required frequency is :%.2f Hz",f2)
+mprintf("\n(iii)Hence the required torque is :%.2f N-m",T1)
diff --git a/3731/CH6/EX6.12/Ex6_12.sce b/3731/CH6/EX6.12/Ex6_12.sce
new file mode 100644
index 000000000..c4bbd4eb9
--- /dev/null
+++ b/3731/CH6/EX6.12/Ex6_12.sce
@@ -0,0 +1,52 @@
+//Chapter 6:Induction Motor Drives
+//Example 12
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor are same as that of Ex-6.9
+f=50           // frequency in HZ
+Vl=400         //line voltage in V
+P=4            // number of poles
+N=1370         //rated speed
+
+//Parameters referred to the stator
+Xr_=3.5        // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=3          // resistance of the rotor windings in ohm
+Rs=2           // resistance of the stator windings in ohm
+
+//Solution
+Ns=120*f/P     //synchronous speed
+N1=Ns-N        //increase in speed from no load to full torque rpm
+
+//(i)When f1=30Hz and 80% of full load
+Ns=120*f/P
+f1=30          //frequency 
+N2=0.8*N1      //increase in speed from no load to 80% of full torque rpm
+Ns1=f1/f*Ns
+N=Ns1+N2       //machine speed
+
+//(ii)At a speed of 1000rpm
+N2=1000         //given speed in rpm
+N3=N2-N1        //synchronous speed
+f3=P*N3/120     //required frequency
+
+//(iii)When frequency is 40Hz and speed is 1300 rpm
+f4=40          //frequency in hz
+N2=1300        //speed in rpm
+Ns=120*f4/P    //required synchronous speed in rpm
+N4=N2-Ns       //increase in speed from no load speed in rpm
+Tf=25.37       //full load torque as calculated in Ex-6.11
+Tm=-N4/N1*Tf   //motor torque
+
+//(iv) when the motor is under dynamic braking
+
+
+//Results
+
+mprintf("(i)Required speed is :%d rpm",N)
+mprintf("\n(ii)Required frequency is:%d Hz",f3)
+mprintf("\n(iii)Required motor torque :%.2f N-m",Tm)
+mprintf("\n(iv)The value of the frequency,speed and motor torque calculated in (i),(ii) and(iii)")
+mprintf("    \nwill be the same when the motor is operated under dynamic braking")
diff --git a/3731/CH6/EX6.13/Ex6_13.sce b/3731/CH6/EX6.13/Ex6_13.sce
new file mode 100644
index 000000000..e2b1a1b86
--- /dev/null
+++ b/3731/CH6/EX6.13/Ex6_13.sce
@@ -0,0 +1,30 @@
+//Chapter 6:Induction Motor Drives
+//Example 13
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor are same as that of Ex-6.9
+f=50           // frequency in HZ
+Vl=400         //line voltage in V
+P=4            // number of poles
+N=1370         //rated speed
+
+//Parameters referred to the stator
+Xr_=3.5        // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=3          // resistance of the rotor windings in ohm
+Rs=2           // resistance of the stator windings in ohm
+
+//Solution
+Wms=4*%pi*f/P
+f1=60          //frequency in Hz during speed control of the motor
+K=f1/f         //the value of K at 60Hz 
+x=Rs+sqrt(Rs**2+K**2*(Xs+Xr_)**2)
+Tmax_=3/(2*K*Wms)*(Vl/sqrt(3))**2/x       //torque at 60 Hz frequency
+z=Rs+sqrt(Rs**2+(Xs+Xr_)**2)
+Tmax=3/(2*Wms)*(Vl/sqrt(3))**2/z          //maximum torque
+ratio=Tmax_/Tmax  //ratio
+
+//Result
+mprintf("Ratio of Motor breakdown torque at 60Hz to rated torque at 50Hz is:%.3f",ratio)
diff --git a/3731/CH6/EX6.14/Ex6_14.sce b/3731/CH6/EX6.14/Ex6_14.sce
new file mode 100644
index 000000000..292b73078
--- /dev/null
+++ b/3731/CH6/EX6.14/Ex6_14.sce
@@ -0,0 +1,16 @@
+//Chapter 6:Induction Motor Drives
+//Example 14
+clc;
+
+mprintf("When operating at a frequency K times rated frequency f then")
+mprintf("\nIm**2=[((Rr_/Ksf)**2+(2*pi*Lr_)**2)/((Rr_/Ksf)**2+(2*pi*Lm+2*Pi*Lr_)**2)]*Is**2----(1)")
+mprintf("\nSince Im is constant for constant flux,")
+mprintf("\nK*s*f=constant--------(2)")
+mprintf("\nK*Wms*s=constant-------(3) which is the slip speed")
+mprintf("\ns*K=constant----------(4)")
+mprintf("\nThereofre for a frequency K*f")
+mprintf("\nT=(3/K/Wms)*[(Is*K*Xm)**2*(Rr_/s)/((Rr_/s)**2+K**2*(Xm+Xr_)**2]")
+mprintf("\nT=(3/K/Wms*s)*[(Is*Xm)**2*(Rr_)/((Rr_/s/K)**2+(Xm+Xr_)**2]-------(5)")
+mprintf("\nHence for a given slip speed (K*Wms*s),K*s is constant and from (1) for a given K*s*f and constant flux")
+mprintf("\noperation Is is fixed. Now from (5) T is also fixed. Thus, motor develps a constant torque and draws a")
+mprintf("\nconstant current from the inverter at all frequencies for a given slip speed")
diff --git a/3731/CH6/EX6.15/Ex6_15.sce b/3731/CH6/EX6.15/Ex6_15.sce
new file mode 100644
index 000000000..55fb9a151
--- /dev/null
+++ b/3731/CH6/EX6.15/Ex6_15.sce
@@ -0,0 +1,62 @@
+//Chapter 6:Induction Motor Drives
+//Example 15
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor 
+f=50           // frequency in HZ
+Vl=400         //line voltage in V
+P=4            // number of poles
+N=1370         //rated speed
+//Parameters referred to the stator
+Xr_=3.5        // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=3          // resistance of the rotor windings in ohm
+Rs=2           // resistance of the stator windings in ohm
+Xm=55          // magnetizing reactance in ohm
+
+//Solution
+Wms=4*%pi*f/P
+Ns=120*f/P     //synchronous speed in rpm
+s=(Ns-N)/Ns    //full load slip
+x=%i*Xm*(Rr_/s+%i*Xr_)
+y=Rr_/s+%i*(Xr_+Xm)
+Z=Rs+%i*Xs+x/y        //total motor impedance
+Isf=(Vl/sqrt(3))/abs(Z)                  //full load stator current
+Irf_=Isf*(%i*Xm)/(Rr_/s+%i*(Xr_+Xm))          //full load rotor current
+Tf=(3/Wms)*abs(Irf_)**2*Rr_/s                 //full load  torque
+N1=Ns-N        //full load slip speed
+//(i) When the motor is operating at 30Hz
+f1=30          //given frequency in Hz
+//At rated slep speedvalue of torque and stator current is same as the rated value
+T=Tf 
+Is=abs(Isf)    
+Ns1=f1/f*Ns    //synchronous at f1=30Hz
+N2=Ns1-N1      //required motor speed at 30Hz
+
+//(ii)At a speed of 1200 rpm
+N3=1200       //speed in rpm
+Ns1=N3+N1     //required synchronous speed
+f1=Ns1/Ns*f   //required frequency at N2=1200rpm
+
+//(iii)When speed-torque curves are assumed to be straight lines at 30Hz at half the rated motor torque
+f2=30          //frequency in Hz
+N1_=N1/2       //slip at half the rated torque
+Ns1=f2/f*Ns    //synchronous at f1=30Hz
+N4=Ns1-N1_     //required motor speed
+
+//(iv) When the motor is operating at 45hz  and braking torque is equal to rated torque
+f3=45          //given frequency in Hz
+N1_=-N1        //slip speed when braking at rated torque
+Ns1=f3/f*Ns    //synchronous at f1=45Hz
+N5=Ns1-N1_     //required motor speed
+
+
+//results
+mprintf("(i)At 30Hz the required value of Torque is T:%.2f N-m",T)
+mprintf("\nStator current is Is:%.4f A",Is)
+mprintf("\nMotor speed is :%d rpm",N2)
+mprintf("\n(ii)Required inverter frequency is :%.2f Hz",f1)
+mprintf("\n(iii)Required motor speed at 30Hz is:%d rpm",N4)
+mprintf("\n(iv)Required motor speed at 45Hz is:%d rpm",N5)
diff --git a/3731/CH6/EX6.16/Ex6_16.sce b/3731/CH6/EX6.16/Ex6_16.sce
new file mode 100644
index 000000000..5767f58a4
--- /dev/null
+++ b/3731/CH6/EX6.16/Ex6_16.sce
@@ -0,0 +1,59 @@
+//Chapter 6:Induction Motor Drives
+//Example 16
+clc;
+
+//Variable Initialization
+
+//Ratings of the Delta connected slipring Induction motor
+f=50           // frequency in HZ
+Vl=400         //line voltage in V
+P=6            // number of poles
+SR=2.2         //ratio of stator to rotor
+
+//Parameters referred to the stator
+Xr_=1          // rotor winding reactance in ohm 
+Rr_=0.2        // resistance of the rotor windings in ohm
+s=0.04         // given slip when motor runs at full load
+
+//Solution
+Ns=120*f/P     //synchronous speed
+Wms=2*%pi*Ns/60
+x=(Rr_/s)**2+Xr_**2
+Tf=(3/Wms)*(Vl)**2*(Rr_/s)/x      //full load  torque
+K=Tf/(Ns*(1-s))**2
+N=850                  //speed of the motor in rpm
+Tl=K*N**2              //torque at the given speed N
+s=(Ns-N)/Ns            //slip at the given speed N
+y=Tl*(Wms/3)/Vl**2     //y=X/(X**2+Xr_**2) and X=(Re+Rr_)/s
+
+mprintf("\nThe torque at the given speed of 850rpm is:%d N-m",Tl)
+mprintf("\nWith a slip of s:%.2f",s)
+mprintf("\nTo find the external resistance connected the given quadratic equation is X**2-6.633X+1=0")
+mprintf("\nWith X=(Re-Rr_)/s where Re is the required external resistance") 
+
+a = 1
+b = -1/y
+c = 1
+
+//Discriminant
+d = (b**2) - (4*a*c)
+
+X1 = (-b-sqrt(d))/(2*a)
+X2 = (-b+sqrt(d))/(2*a)
+
+//Results
+mprintf("\nThe solutions for X are %.4f and %.4f",X1,X2)
+Re1=X1*s-Rr_
+Re2=X2*s-Rr_
+
+if (Re1>0) then :
+mprintf("\nThe number Re1:%.3f ohm is feasible",abs(Re1))
+R=Re1/SR**2
+mprintf("\nRotor referred value of the external resistance is:%.3f ohm",R)
+end
+
+if (Re2>0) then
+mprintf("\nThen  Re2:%.3f ohm is feasible",abs(Re2)) 
+R=Re2/SR**2
+mprintf("\nHence Rotor referred value of the external resistance is:%.3f ohm",R) 
+end
diff --git a/3731/CH6/EX6.17/Ex6_17.sce b/3731/CH6/EX6.17/Ex6_17.sce
new file mode 100644
index 000000000..8aafafe27
--- /dev/null
+++ b/3731/CH6/EX6.17/Ex6_17.sce
@@ -0,0 +1,40 @@
+//Chapter 6:Induction Motor Drives
+//Example 17
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor 
+f=50           // frequency in HZ
+Vl=440         //line voltage in V
+P=6            // number of poles
+Ns=120*f/P     //synchronous speed
+
+//Parameters referred to the stator
+Xr_=1.2        // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=0.4        // resistance of the rotor windings in ohm
+Rs=0.5         // resistance of the stator windings in ohm
+Xm=50          // magnetizing reatance
+a=3.5          // stator to rotor turns ratio
+delta=0        // duty ratio  at the given breakdown torque
+Sm=1           // slip at standstill
+
+//Solution
+
+//Slip at maximum torque without an external resistance is Sm=Rr_/sqrt(Rs**2+(Xs+Xr_)**2)   
+//When an external resistanc Re referred to the stator is connected 
+x=Sm*sqrt(Rs**2+(Xs+Xr_)**2)     //x=Re+Rr_
+Re=x-Rr_
+y=0.5*a**2*(1-delta)    // y=0.5*a**2*R*(1-delta)   //y=Re
+R=Re/y
+
+//(Ns-N)/Ns
+//(Ns/Ns)-(N/Ns)
+Sm=(Ns/Ns)-(1/Ns)
+c=(x*Sm-Rr_)/(0.5*a**2*R)  //c=(1-delta)
+delta=1-c                  //given duty ratio
+
+//Results
+mprintf("Variation of the duty ratio is:%.3f*N*10**(-3)",delta*1000)
+mprintf("\nHence the duty ratio must change linearly with speed N")
diff --git a/3731/CH6/EX6.18/Ex6_18.sce b/3731/CH6/EX6.18/Ex6_18.sce
new file mode 100644
index 000000000..622d76165
--- /dev/null
+++ b/3731/CH6/EX6.18/Ex6_18.sce
@@ -0,0 +1,79 @@
+//Chapter 6:Induction Motor Drives
+//Example 18
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor 
+f=50         // frequency in HZ
+Vl=440       // line voltage in V
+P=6          // number of poles
+N=970        // rated speed
+n=2          // ratio of stator to rotor
+Sm=0.25      // it is given the speed range is 25% below the synchronous speed which is proportional to the Slip
+
+//Parameters referred to the stator
+Xr_=0.4      // rotor winding reactance in ohm
+Xs=0.3       // stator winding reactance in ohm
+Rr_=0.08     // resistance of the rotor windings in ohm
+Rs=0.1       // resistance of the stator windings in ohm
+alpha=165    // maximum value of the firing angle in degress
+
+//Solution
+Ns=120*f/P   // synchronous speed
+Wms=2*%pi*Ns/60
+//(i) transformer turns ratio
+al=alpha*(%pi/180)
+a=-Sm/cos(al)  //since  Sm=a*math.cos(alpha)   
+m=n/a        //since a=n/m where m is the transformer ratio
+
+//(ii)When speed is 780 rpm and firing angle is 140 degrees
+N1=780           //given speed
+alpha1=140       //given firing angle
+s1=(Ns-N1)/Ns    //slip at the given speed N1
+Vd1=(3*sqrt(6)/%pi)*s1*(Vl/sqrt(3))/n
+al1=alpha1*(%pi/180)
+Vd2=(3*sqrt(6)/%pi)*(Vl/sqrt(3))/m*cos(al1)
+Rs_=Rs*(1/n)**2   //stator resistance referred to the rotor
+Rr=Rr_*(1/n)**2   //rotor resistance referred to the rotor
+Rd=0.01           //equivalent resistance of the DC link inductor
+Id=(Vd1+Vd2)/(2*(s1*Rs_+Rr)+Rd)
+T1=abs(Vd2)*Id/s1/Wms     //required torque
+
+//(iii)when speed is 800rpm and firing angle is half the rated motor torque
+N1=800           //given speed
+s=(Ns-N)/Ns      //rated slip
+x=(Rs+Rr_/s)**2+(Xs+Xr_)**2
+Trated=(3/Wms)*(Vl/sqrt(3))**2*(Rr_/s)/x          //rated torque
+T_half=Trated/2        //half rated torque
+s1=(Ns-N1)/Ns          //given slip at speed N1=800rpm
+Vd1=(3*sqrt(6)/%pi)*s1*(Vl/sqrt(3))/n
+Vd2=(3*sqrt(6)/%pi)*(Vl/sqrt(3))/m
+Id=(Vd1+Vd2)/(2*(s1*Rs_+Rr)+Rd)
+T=abs(Vd2)*Id/s1/Wms     //required torque
+
+//since the given torque is half of the rated value
+//To find the find the firing angle we assumed cos(alpha1)=-X
+//The given quadratic equation is X**2-0.772X+0.06425=0
+a = 1
+b = -0.772
+c = 0.06425
+//Discriminant
+d = (b**2) - (4*a*c)
+
+X1 = (-b-sqrt(d))/(2*a)
+X2 = (-b+sqrt(d))/(2*a)
+alpha1=-acos(X2)   //since cos(alpha1)=-X where alpha1 is radians
+alpha1=alpha1*(180/%pi)
+alpha1=180+alpha1            //required firing angle
+
+
+//Results
+mprintf("(i)Transformer ratio is:%.3f",m)
+mprintf("\n(ii)Required torque is :%.2f N-m",T1)
+//There is a slight difference in the answer for the torque due to accuracy
+mprintf("\n(iii)The half rated torque at the given speed of %d rpm is:%.2f N-m",N1,T_half)
+mprintf("\nWith a slip of s:%.1f",s1)
+mprintf("\nThe solutions for X are %.4f and %.4f",X1,X2)
+mprintf("\nFor X1:%.4f the motor is unstable so we use X2:%.4f",X1,X2)
+mprintf("\nHence the required firing angle is :%.1f °",alpha1)
diff --git a/3731/CH6/EX6.19/Ex6_19.sce b/3731/CH6/EX6.19/Ex6_19.sce
new file mode 100644
index 000000000..3eaf445d3
--- /dev/null
+++ b/3731/CH6/EX6.19/Ex6_19.sce
@@ -0,0 +1,75 @@
+//Chapter 6:Induction Motor Drives
+//Example 19
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor is same as that of Ex-6.17
+f=50           // frequency in HZ
+Vs=440         // line voltage in V
+P=4            // number of poles
+//Parameters referred to the stator
+Xr_=1.2        // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=0.4        // resistance of the rotor windings in ohm
+Rs=0.5         // resistance of the stator windings in ohm
+Xm=50          // magnetizing reatance
+a=3.5          // stator to rotor turns ratio
+
+//Solution
+Ns=120*f/P              // synchronous speed in rpm
+Wms=2*%pi*Ns/60     // synchronous speed in rad/s
+
+//(i)When motor speed is 1200rpm with a voltage of 15+0j V
+
+V=15*(cos(0)+sin(0)*%i)
+N1=1200  //speed in rpm
+Vr_=a*V          //rotor voltage
+s1=(Ns-N1)/Ns    //slip at the given speed N1=1200 rpm
+Z=Rs+Rr_/s1+%i*(Xs+Xr_)                   //total impedance
+Ir_=(Vs/sqrt(3)-Vr_/s1)/Z            //rotor current
+phi_r=atan(imag(Vr_),real(Vr_))-atan(imag(Ir_),real(Ir_))//angle between Vr_ and Ir_
+Pr=3*(abs(Ir_))**2*Rr_                    //rotor copper loss
+P1=3*abs(Vr_)*abs(Ir_)*cos(phi_r)    //power absorbed by Vr_
+Pg=(Pr+P1)/s1              //gross power 
+T=Pg/Wms                   //required motor torque
+
+//(ii)when motor speed is 1200rpm with a unity power factor 
+N1=1200  //speed in rpm
+Ir_=abs(Ir_)
+Ir_=Ir_*(cos(0)+sin(0)*%i)//machine is operating at unity power factor
+x=Ir_*Z                      //x=(Vs-Vr_/s1)*phi_r   where phi_r is the angle between Vr_ and Ir_
+
+//x=a+b
+d=(Vs/sqrt(3)-Vr_/s1*cos(phi_r))**2
+e=(Vr_/s1*sin(phi_r))**2
+f=x/(d+e)
+theta=atan(imag(f),real(f))//required angle in radian
+theta=theta*180/%pi
+//Now we should solve for the quadratice equation for the rotor current
+//  0.9*Ir_**2 + 50.8*Ir_ + 90.12 = 0
+a1 = 0.9
+b1 = 50.8
+c1 = 90.12
+
+//Discriminant
+d = (b1**2) - (4*a1*c1)
+
+Ir_1 = (-b1-sqrt(d))/(2*a1)
+Ir_2 = (-b1+sqrt(d))/(2*a1)
+
+Ir_=Ir_2           //Ir_2 is chosen because for Ir_1 the motor is unstable
+Vr_sin_phi_r=abs(Ir_)/2.083
+Vr_cos_phi_r=s1*(Vs/sqrt(3)+2.5*Vr_sin_phi_r)
+Vr_=Vr_cos_phi_r+%i*Vr_sin_phi_r   //total rotor voltage referred to the stator
+Vr_=Vr_/a                          //total  rotor voltage referred to the rotor
+var=atan(imag(Vr_),real(Vr_))
+phase=var*180/%pi
+
+//Results
+mprintf("(i)The torque is :%.2f N-m and since it is negative the motor is operating in regenerative braking ",T)
+mprintf("\n(ii)Now theta θ:%.2f ◦",theta)
+mprintf("\nThe solution for Ir_ are %.3f and %.3f",Ir_1,Ir_2)
+mprintf("\nWe choose Ir_:%.3f A since higher value corresponds to unstable region",Ir_2)
+mprintf("\nHence the required voltage magnitude is Vr:%.2f V,phase:%.1f ◦",Vr_,phase)
+//There is a slight difference in the answers due to accuracy
diff --git a/3731/CH6/EX6.2/Ex6_2.sce b/3731/CH6/EX6.2/Ex6_2.sce
new file mode 100644
index 000000000..9944263ea
--- /dev/null
+++ b/3731/CH6/EX6.2/Ex6_2.sce
@@ -0,0 +1,75 @@
+//Chapter 6:Induction Motor Drives
+//Example 2
+clc;
+
+//Variable Initialization
+//Ratings of the Delta connected Induction motor
+f=50           //frequency in HZ
+Vl=2200        //line voltage in V
+P=8            //number of poles
+N=735          //rated speed in rpm
+
+//Parameters referred to the stator
+Xr_=0.55        // rotor winding reactance in ohm
+Xs=0.45         // stator winding reactance in ohm
+Rr_=0.1         // resistance of the rotor windings in ohm
+Rs=0.075        // resistance of the stator windings in ohm
+
+//Solution
+Ns=120*f/P     //synchronous speed in rpm
+s=(Ns-N)/Ns    //full load slip
+x=sqrt((Rs+Rr_/s)**2+(Xs+Xr_)**2)   //total impedance
+Ip=(Vl)/x                  //full load phase current
+Il=sqrt(3)*Ip         //full load line current
+Wms=2*%pi*Ns/60        
+Tl=(1/Wms)*(3*Ip**2*Rr_/s) //full load torque
+
+//(i)if the motor is started by star-delta switching
+y=sqrt((Rs+Rr_)**2+(Xs+Xr_)**2)
+Ist=(Vl/sqrt(3))/y                //Maximum line current during starting
+Tst=(1/Wms)*(3*Ist**2*Rr_)             //Starting torque
+ratio1=Tst/Tl                          //ratio of starting torque to full load torque
+z=Rs+sqrt(Rs**2+(Xs+Xr_)**2)
+Tmax=3/(2*Wms)*(Vl/sqrt(3))**2/z  //maximum torque
+ratio2=Tmax/Tl                         //ratio of maximum torque to full load torque
+
+//(ii) If the motor is started using auto transformer
+y=sqrt((Rs+Rr_)**2+(Xs+Xr_)**2)
+Ist1=Vl*sqrt(3)/y         //starting current direct online
+aT=sqrt(2*Il/Ist1)        //transofrmation ratio
+Ilst=2*Il/aT                   //starting motor line current
+Ipst=Ilst/sqrt(3)         //starting motor phase current
+Tst1=(1/Wms)*(3*Ipst**2*Rr_)    //starting torque
+
+//(iii) If motor is started using part winding method
+Rs_=2*Rs
+Xs_=2*Xs
+y=sqrt((Rs_+Rr_)**2+(Xs_+Xr_)**2)
+Ist2=(Vl*sqrt(3))/y      //starting line current 
+Ip=Ist2/sqrt(3)          //starting phase current
+Tst2=(1/Wms)*(3*Ip**2*Rr_)    //starting torque
+
+//(iv) motor is started using series reactors in line
+Rs_=Rs/3  ;  Rr_=Rr_/3
+Xs_=Xs/3  ;  Xr_=Xr_/3
+Il=2*Il        //line current at start
+x=(Vl/sqrt(3))**2/(Il**2)    //x=(Rs_+Rr_)**2+(Xs_+Xr_+Xe)**2
+y=x-(Rs_+Rr_)**2                  //y=(Xs_+Xr_+Xe)**2
+z=sqrt(y)                    //z=(Xs_+Xr_+Xe)
+Xe=z-Xs_-Xr_
+
+
+//Results
+
+mprintf("(i)Maximum value of line current during starting Ist:%d A",Ist)
+mprintf("\nRatio of starting torque to full load torque :%.3f",ratio1)
+mprintf("\nRatio of maximum torque to full load torque :%.2f\n",ratio2)
+mprintf("\n(ii)Transformation ratio aT:%.3f",aT)
+mprintf("\nStarting torque :%d N-m\n",Tst1)
+//Answer for the starting torque in the book is wrong due to accuracy
+
+mprintf("\n(iii)Maximum line current during starting :%d A",Ist2)
+mprintf("\nStarting torque :%d N-m\n",Tst2)
+//Answer for the starting torque in the book is wrong due to accuracy
+
+mprintf("\n(iv)Value of the reactor Xe:%.3f ohm",Xe)
diff --git a/3731/CH6/EX6.20/Ex6_20.sce b/3731/CH6/EX6.20/Ex6_20.sce
new file mode 100644
index 000000000..f9028a8ef
--- /dev/null
+++ b/3731/CH6/EX6.20/Ex6_20.sce
@@ -0,0 +1,55 @@
+//Chapter 6:Induction Motor Drives
+//Example 20
+clc;
+
+//Variable Initialization
+
+//Ratings of the single phase Induction motor 
+f=50           // frequency in HZ
+Vs=220         // supply voltage in V
+P=4            // number of poles
+N=1425         // rated speed in rpm
+
+//Parameters referred to the stator
+Xr_=6          // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=5          // resistance of the rotor windings in ohm
+Rs=2           // resistance of the stator windings in ohm
+Xm=60          // magnetizing reatance
+
+//Solution
+N1=1200      //when the motor is operating at the given speed in rpm
+Ns=120*f/P   // synchronous speed
+Wms=2*%pi*Ns/60
+s=(Ns-N)/Ns   //rated slip
+
+Zf=%i*(Xm)*(Rr_/s+%i*Xr_)/2/(Rr_/s+%i*(Xr_+Xm))
+Rf=real(Zf)
+Xf=imag(Zf)
+Zb=%i*(Xm)*(Rr_/(2-s)+%i*Xr_)/2/(Rr_/(2-s)+%i*(Xr_+Xm))
+Rb=real(Zb)
+Xb=imag(Zb)
+Zs=Rs+%i*Xs
+Z=Zs+Zf+Zb
+Is=(Vs)/Z
+T=(abs(Is))**2/Wms*(Rf-Rb)
+Tl=T
+K=Tl/N**2
+
+//Therefore for a speed of  of N1=1200 rpm we get 
+Tl=K*N1**2      //required load torque for the given speed N1
+s1=(Ns-N1)/Ns   // slip for the given speed N1
+
+Zf=%i*(Xm)*(Rr_/s1+%i*Xr_)/2/(Rr_/s1+%i*(Xm))
+Rf=real(Zf)
+Xf=imag(Zf)
+Zb=%i*(Xm)*(Rr_/(2-s1)+%i*Xr_)/2/(Rr_/(2-s1)+%i*(Xr_+Xm))
+Rb=real(Zb)
+Xb=imag(Zb)
+x=(Wms*Tl)/(Rf-Rb)    //since Tl=(abs(Is))**2/Wms*(Rf-Rb)   and x=Is**2
+Is=sqrt(x)
+Z=Zs+Zf+Zb
+V=Is*abs(Z)
+
+//Result
+mprintf("Hence the motor terminal voltage at the speed of%d rpm is :%.1f V",N1,V)
diff --git a/3731/CH6/EX6.3/Ex6_3.sce b/3731/CH6/EX6.3/Ex6_3.sce
new file mode 100644
index 000000000..c7b9ab538
--- /dev/null
+++ b/3731/CH6/EX6.3/Ex6_3.sce
@@ -0,0 +1,66 @@
+//Chapter 6:Induction Motor Drives
+//Example 3
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor
+f=50           // frequency in HZ
+Vl=400         // line voltage in V
+P=6            // number of poles
+
+//Parameters referred to the stator
+Xr_=2         // rotor winding reactance in ohm
+Xs=Xr_        // stator winding reactance in ohm
+Rr_=1         // resistance of the rotor windings in ohm
+Rs=Rr_        // resistance of the stator windings in ohm
+
+//Solution
+Ns=120*f/P     //synchronous speed in rpm
+Wms=2*%pi*Ns/60        
+
+//(i)
+Sm=-Rr_/sqrt(Rs**2+(Xs+Xr_)**2)   //slip at maximum torque
+x=sqrt((Rs+Rr_/Sm)**2+(Xs+Xr_)**2)
+Ir_=(Vl/sqrt(3))/x        //current at maximum torque 
+Tmax=(1/Wms)*3*Ir_**2*Rr_/Sm   //maximum torque
+N=(1-Sm)*Ns                    //range of speed
+
+//(ii)an overhauling torque of 100Nm
+Tl=100   //overhauling torque in Nm
+// Tl=(3/Wms)*(Vl**2*Rr_/s)/y
+// where y=(Rs+Rr_/s)**2+(Xs+Xr_)**2
+a=(1/Wms)*(Vl**2*Rr_)/(-Tl)    //a=s*(Rs+Rr_/s)**2+(Xs+Xr_)**2
+a = 17
+b = 17.3
+c = 1
+
+//Discriminant
+d = (b**2) - (4*a*c)
+
+// find two solutions
+s1 = (-b-sqrt(d))/(2*a)
+s2 = (-b+sqrt(d))/(2*a)
+
+N2=(1-s2)*Ns           //motor speed and we neglect s1 
+
+//slight difference in the answer due to accuracy
+
+//(iii)when a capacitive reactance of 2 ohm is inserted in each phase stator
+Xc=2      //reactance of the capacitor in ohms
+Sm=-Rr_/sqrt(Rs**2+(Xs+Xr_-Xc)**2)   //slip at maximum torque 
+x=sqrt((Rs+Rr_/Sm)**2+(Xs+Xr_-Xc)**2)
+Ir_=(Vl/sqrt(3))/x        //current at maximum torque 
+Tmax_=(1/Wms)*3*Ir_**2*Rr_/Sm   //maximum overhauling torque with capacitor
+ratio=Tmax_/Tmax
+
+
+//Results
+mprintf("(i)Maximum overhauling torque that the motor can hold is:%.1f N-m",abs(Tmax))
+mprintf("      \nRange of speed is from %d to %d rpm\n",Ns,abs(N))
+mprintf("\n(ii)Now s*(1+1/s)**2+16s=%d",a)
+mprintf("\n    Or 17s**s+17.3s+1=0")
+mprintf("\nThe solutions for s are %.3f and %.3f\n",s1,s2)
+mprintf("\nTherefore Motor speed is:%d rpm\n",N2)
+//Note :There is a slight difference in the answer due to the decimal place"
+mprintf("\n(iii) Ratio of maximum torque with capacitor and to maximum torque without capacitor is:%.2f",ratio)
diff --git a/3731/CH6/EX6.4/Ex6_4.sce b/3731/CH6/EX6.4/Ex6_4.sce
new file mode 100644
index 000000000..7ec27cbb1
--- /dev/null
+++ b/3731/CH6/EX6.4/Ex6_4.sce
@@ -0,0 +1,53 @@
+//Chapter 6:Induction Motor Drives
+//Example 4
+clc;
+
+//Variable Initialization
+
+//Ratings of the motor are same as that in Ex-6.3
+f=50           // frequency in HZ
+Vl=400         //line voltage in V
+P=6            // number of poles
+
+//Parameters referred to the stator
+Xr_=2         // rotor winding reactance in ohm
+Xs=Xr_        // stator winding reactance in ohm
+Rr_=1         // resistance of the rotor windings in ohm
+Rs=Rr_        // resistance of the stator windings in ohm
+N=950         //full load speed in rpm
+SR=2.3        //stator to rotor turns ratio
+
+//Solution
+Ns=120*f/P     //synchronous speed in rpm
+Wms=2*%pi*Ns/60        
+s=(Ns-N)/Ns     //full load slip
+x=sqrt((Rs+Rr_/s)**2+(Xs+Xr_)**2)
+Irf_=(Vl/sqrt(3))/x         //full load current
+Tf=(1/Wms)*3*Irf_**2*Rr_/s       //full load  torque
+
+//(i)initial braking current and torque
+S=2-s     //during plugging at 950rpm
+y=sqrt((Rs+Rr_/S)**2+(Xs+Xr_)**2)
+Ir_=(Vl/sqrt(3))/y         //initial braking current
+ratio1=Ir_/Irf_
+T=(1/Wms)*3*Ir_**2*Rr_/S       //initial braking  torque
+ratio2=T/Tf
+
+//(ii)when an external resistance is connected such 
+//that maximum braking current is 1.5 times the full load current
+Ir_=1.5*Irf_
+x=(Vl/sqrt(3))/Ir_    //x=sqrt((Rs+(Rr_+Re_)/S)**2+(Xs+Xr_)**2)
+y=x**2                     //y=(Rs+(Rr_+Re_)/S)**2+(Xs+Xr_)**2
+z=y-(Xs+Xr_)**2            //z=(Rs+(Rr_+Re_)/S)**2
+a=sqrt(z)             //a=(Rs+(Rr_+Re_)/S)
+b=(a-Rs)*S                 //b=(Rr_+Re_)
+Re_=b-Rs
+Re=Re_/SR**2
+T=(1/Wms)*3*Ir_**2*(Rr_+Re_)/S       //initial braking  torque
+ratio=T/Tf
+
+
+//Results
+mprintf("(i)Ratio of initial braking current to full load current is:%.1f",ratio1)
+mprintf("\nRatio of initial braking torque to full load torque is:%.2f\n",ratio2)
+mprintf("\n(ii)Ratio of initial braking torque to full load torque when the resistance is added is:%.3f",ratio)
diff --git a/3731/CH6/EX6.5/Ex6_5.sce b/3731/CH6/EX6.5/Ex6_5.sce
new file mode 100644
index 000000000..72969a347
--- /dev/null
+++ b/3731/CH6/EX6.5/Ex6_5.sce
@@ -0,0 +1,57 @@
+//Chapter 6:Induction Motor Drives
+//Example 4
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor
+f=50           // frequency in HZ
+Vl=440         // line voltage in V
+P=6            // number of poles
+Vp=Vl/sqrt(3)  //phase voltage in V
+
+//Parameters referred to the stator
+Xr_=1.2       // rotor winding reactance in ohm
+Xs=Xr_        // stator winding reactance in ohm
+Rr_=0.4       // resistance of the rotor windings in ohm
+Rs=0.5        // resistance of the stator windings in ohm
+Xm=50         // no load reactance in ohms
+N=950         // full load speed in rpm
+Sm=2          // slip at maximum torque
+
+//Solution
+Rr_=Sm*sqrt(Rs**2+(Xs+Xr_)**2)    //Since Sm=Rr_/sqrt(Rs**2+(Xs+Xr_)**2)
+Ns=120*f/P      //synchronous speed in rpm
+Wms=2*%pi*Ns/60        
+s=(Ns-N)/Ns            //slip at 950 rpm
+
+x=%i*Xm*(Rr_/s+%i*Xr_)
+y=Rr_/s+%i*(Xr_+Xm)
+Zp=Rs+%i*Xs+x/y
+Ip=Vp/sqrt(3)/Zp    
+//The value of Ip is wrong which leads to other wrong answers
+
+Irp_=Ip*(%i*Xm)/(Rr_/s+%i*(Xr_+Xm))
+Tp=(1/Wms)*3*abs(Irp_)**2*Rr_/s
+x=%i*Xm*(Rr_/(2-s)+%i*Xr_)
+y=Rr_/(2-s)+%i*(Xr_+Xm)
+Zn=Rs+%i*Xs+x/y
+In=Vp/sqrt(3)/Zn
+Irn_=In*(%i*Xm)/(Rr_/(2-s)+%i*(Xr_+Xm))
+Tn=-(1/Wms)*3*abs(Irn_)**2*Rr_/(2-s)    
+//The value of In is wrong
+
+T=Tp-Tn
+I=abs(Ip)+abs(In)
+Rr_=0.4    // from the parameters of the motor referred to the stator
+x=sqrt((Rs+Rr_/s)**2+(Xs+Xr_)**2)
+If=(Vl/sqrt(3))/x       //full load current
+Tf=(1/Wms)*3*If**2*Rr_/s     //full load  torque
+
+ratio1=I/If
+ratio2=abs(T)/Tf
+
+//Results
+mprintf("Ratio of braking current to full load current is:%.3f",ratio1)
+mprintf("\nRatio of braking torque to full load torque is:%.3f",ratio2)
+//Answer provided in the book is wrong
diff --git a/3731/CH6/EX6.6/Ex6_6.sce b/3731/CH6/EX6.6/Ex6_6.sce
new file mode 100644
index 000000000..9e1487acd
--- /dev/null
+++ b/3731/CH6/EX6.6/Ex6_6.sce
@@ -0,0 +1,91 @@
+
+//Chapter 6:Induction Motor Drives
+//Example 6
+clc;
+
+//Variable Initialization
+
+//Ratings of the star connected Induction motor which operates under dynamic braking
+f=50           // frequency in HZ
+P=6            // number of poles
+
+//Parameters referred to the stator
+Xr_=3.01       // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=4.575      // resistance of the rotor windings in ohm
+Rs=1.9         // resistance of the stator windings in ohm
+J=0.1          // moment of inertia of the motor load system in kg-m2
+Id=12          // given DC current
+
+N=1500         //given asynchronous speed
+//magnetization chacrateristic at the given asynchronous speed
+Im=[0.13,0.37,0.6,0.9,1.2,1.7,2.24,2.9,3.9,4.9,6,8,9,9.5]       //magnetization current
+E=[12.8,32,53.8,80,106,142,173,200,227,246,260,280,288,292]     //back emf
+
+//Solution
+Ns=120*f/P      //synchronous speed in rpm
+torque=[]
+speed=[]
+temp=[]
+Is=sqrt(2/3)*Id   //value of stator current for two lead connection
+Wms=2*%pi*N/60
+for i=2:14
+x=(Is**2-Im(i)**2)/(1+2*Xr_*Im(i)/E(i))   //x=Ir_**2
+Ir_=sqrt(x)       //required rotor current
+y=(E(i)/Ir_)**2-Xr_**2
+S=Rr_/sqrt(y)        //required slip
+N=S*Ns                    //required speed
+T=(3/Wms)*(Ir_)**2*Rr_/S  //required torque
+speed($+1)=N
+torque($+1)=T
+temp($+1)=T
+end
+mprintf("Hence the magnetization curve is")
+disp(speed,"Speed:in rpm")
+for i=1:13
+torque(i)=-1*torque(i)
+end
+disp(torque,"Braking torque :in N-m")
+
+//Results
+
+//Plot of of torque vs speed
+subplot(2,1,1)
+plot(torque,speed)
+xlabel('Torque, N-m') 
+ylabel('Speed, rpm')
+title('Torque vs Speed')
+xgrid(2)
+
+//Plot of Wm vs J/T
+inertia_over_torque=[]
+for i=3:13
+J_T=1000*J/temp(i)
+inertia_over_torque($+1)=J_T
+end
+disp(inertia_over_torque,"J/t :") 
+
+Wm=[1,4,8,12,16,20,25,55,95,125,160]  
+//the values of Wm are taken for the angular frequency with maximum value of Wms=50*pi rad/s
+subplot(2,1,2)
+plot(Wm,inertia_over_torque)
+xlabel('$Angular speed \omega_m$') 
+ylabel(' J/T,1*10e-2')
+title('$J/T   vs   \omega_m$')
+xgrid(2)
+x=[6.5,6.5]
+y=[2,4.5]
+plot(x,y,'blue')
+str=["${A}$"]
+str1=["${B}$"]
+str2=["${C}$"]
+str3=["${D}$"]
+str4=["${E}$"]
+xstring(6,2,str)
+xstring(6,4.5,str1)
+xstring(80,3.4,str2)
+xstring(156,8.3,str3)
+xstring(156,2,str4)
+
+mprintf("Hence from the plot the area ABCDEA between the curve and the speed axis for speed change ")
+mprintf("for synchronous to 0.02 times synchrnous speed is the stopping time which is equal to: 9.36 sec")
diff --git a/3731/CH6/EX6.7/Ex6_7.sce b/3731/CH6/EX6.7/Ex6_7.sce
new file mode 100644
index 000000000..234242390
--- /dev/null
+++ b/3731/CH6/EX6.7/Ex6_7.sce
@@ -0,0 +1,50 @@
+//Chapter 6:Induction Motor Drives
+//Example 7
+clc;
+
+//Variable Initialization
+
+//Ratings of the Star connected Induction motor
+f=50           // frequency in HZ
+Vl=2200        // line voltage in V
+P=6            // number of poles
+
+//Parameters referred to the stator
+Xr_=0.5        // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=0.12       // resistance of the rotor windings in ohm
+Rs=0.075       // resistance of the stator windings in ohm
+J=100          // combine inertia of motor and load in kg-m2
+
+//Solution
+
+//(i) During starting of the motor
+Sm=Rr_/sqrt(Rs**2+(Xs+Xr_)**2)   //slip at maximum torque
+Wms=4*%pi*f/P                     //angular frequency
+x=Rs+sqrt(Rs**2+(Xs+Xr_)**2)
+Tmax=(3/2/Wms)*(Vl/sqrt(3))**2/x  //maximum torque
+tm=J*Wms/Tmax                          //mechanical time constant of the motor
+ts=tm*(1/4/Sm+1.5*Sm)                  //time taken during starting
+Es=1/2*J*Wms**2*(1+Rs/Rr_)             //energy disspated during starting
+
+//(ii) When the motor is stopped by plugging method
+tb=tm*(0.345*Sm+0.75/Sm)        //time required to stop by plugging
+Eb=3/2*J*Wms**2*(1+Rs/Rr_)      //energy disspated during braking 
+
+//(iii)Required resistance to be inserted during plugging
+tb1=1.027*tm       //minimum value of stopping time during braking
+x=1.47*(Xs+Xr_)    //x=Rr_+Re
+Re=x-Rr_           //Re is the required external resistance to be connected
+Ee=3/2*J*Wms**2*(Re/(Re+Rr_))      //energy disspated in the external resistor
+Eb1=Eb-Ee                           //total energy disspated during braking 
+
+
+//Results
+
+mprintf("(i)Time taken during starting is ts:%.4f s",ts)
+mprintf("   \nEnergy dissipated during starting is Es:%d kilo-watt-sec",Es/1000)
+mprintf("\n\n(ii)Time taken to stop by plugging is tb:%.2f s",tb)
+mprintf("    \nEnergy dissipated during braking is Eb:%d kilo-watt-sec",Eb/1000)
+mprintf("\n\n(iii)Minimum Time taken to stop by plugging is tb:%.2f s",tb1)
+mprintf("     \nRequired external resistance to be connected is Re:%.2f ohm",Re)
+mprintf("     \nTotal Energy dissipated during braking is Eb:%.2f kilo-watt-sec",Eb1/1000)
diff --git a/3731/CH6/EX6.8/Ex6_8.sce b/3731/CH6/EX6.8/Ex6_8.sce
new file mode 100644
index 000000000..0499ed6ab
--- /dev/null
+++ b/3731/CH6/EX6.8/Ex6_8.sce
@@ -0,0 +1,69 @@
+//Chapter 6:Induction Motor Drives
+//Example 8
+clc;
+
+//Variable Initialization
+
+//Ratings of the delta connected Induction motor
+f=50           // frequency in HZ
+Vl=400         // line voltage in V
+P=4            // number of poles
+Pm=2.8*1000    // rated mechanical power developed in W
+N=1370         // rated speed in rpm
+
+//Parameters referred to the stator
+Xr_=5          // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=5          // resistance of the rotor windings in ohm
+Rs=2           // resistance of the stator windings in ohm
+Xm=80          // no load reactance in ohm
+
+//Solution
+Ns=120*f/P                    //synchronous speed in rpm
+Wms=2*%pi*Ns/60           //synchronous speed in rad/s
+s=(Ns-N)/Ns                   //full load slip
+x=(Rs+Rr_/s)**2+(Xs+Xr_)**2   //total impedance
+T=(3/Wms)*(Vl**2*Rr_/s)/x     //full load torque
+Tl=T
+K=Tl/(1-s)**2                 //since Tl=K*(1-s)**2
+
+//(i) When the motor is running at 1200 rpm
+N1=1200            //speed in rpm
+s1=(Ns-N1)/Ns      //slip at the given speed N1
+Tl=K*(1-s1)**2     //torque at the given speed N1
+
+y=(Rs+Rr_/s1)**2+(Xs+Xr_)**2   //total impedance
+a=Tl*(Wms/3)*y*(s1/Rr_)        //Since T=(3/Wms)*(Vl**2*Rr_/s)/x      and a=V**2
+V=sqrt(a)                 //required voltage at the given speed N1
+Ir_=V/((Rs+Rr_/s1)+%i*(Xs+Xr_))//rotor current
+Im=V/(%i*Xm)                   //magnetizing current
+Is=Ir_+Im                      //total current
+Il=abs(Is)*sqrt(3)        //line current
+
+//(ii)When the terminal voltage is 300 V
+V1=300  //terminal voltage in V
+x=(Rs+Rr_)**2+(Xs+Xr_)**2   
+T=(3/Wms)*(V1**2*Rr_)/x
+
+//Now we have to solve for the value of slip 's' from the given equation 104s**4- 188s**3 + 89s**2 - 179s + 25=0"
+coeff = [104,-188,89,-179,25]    //coeffcient of the polynomial equation 
+s=[]
+s=roots(coeff)                //roots of the polynomial equation
+
+T=K*(1-real(s(4)))**2     //torque at the given terminal voltage of 300 V
+N=Ns*(1-real(s(4)))       //speed at the given terminal voltage of 300 V
+Ir_=V1/((Rs+Rr_/real(s(4)))+%i*(Xs+Xr_))//rotor current
+Im=V1/(%i*Xm)                   //magnetizing current
+Is=Ir_+Im                       //total current
+Il1=abs(Is)*sqrt(3)        //line current
+
+
+//Results
+mprintf("(i)Required torque is Tl:%.1f N-m",Tl)
+mprintf("\nRequired motor terminal voltage is V: %.1f V",V)
+mprintf("\nRequired line current is Il:%.2f A",Il)
+mprintf("\n(ii)The roots of the polynomial equation are s1:%.3f s2:%.3f s3:%.3f s4:%.3f",real(s(1)),real(s(2)),real(s(3)),real(s(4)))
+mprintf("\nHence Only s4: %.3f is valid",real(s(4)))
+mprintf("\nRequired torque is Tl:%.2f N-m",T)
+mprintf("\nRequired speed is N:%.1f rpm",N)
+mprintf("\nRequired line current is Il:%.2f A",Il1)
diff --git a/3731/CH6/EX6.9/Ex6_9.sce b/3731/CH6/EX6.9/Ex6_9.sce
new file mode 100644
index 000000000..c478d4446
--- /dev/null
+++ b/3731/CH6/EX6.9/Ex6_9.sce
@@ -0,0 +1,70 @@
+//Chapter 6:Induction Motor Drives
+//Example 9
+clc;
+clf();
+//Variable Initialization
+
+//Ratings of the star connected squirrel Induction motor
+f=50           // frequency in HZ
+Vl=400         // line voltage in V
+P=4            // number of poles
+N=1370         // rated speed
+
+//Frequency variation is from 10 Hz to 50 Hz
+fmin=10     
+fmax=50
+
+//Parameters referred to the stator
+Xr_=3.5        // rotor winding reactance in ohm
+Xs=Xr_         // stator winding reactance in ohm
+Rr_=3          // resistance of the rotor windings in ohm
+Rs=2           // resistance of the stator windings in ohm
+
+//Solution
+Ns=120*f/P     //synchronous speed
+N1=Ns-N        //increase in speed from no load to full torque rpm
+Wms=2*%pi*Ns/60
+s=(Ns-N)/Ns    //full load slip
+
+//(i)to obtain the plot between the breakdown torque and the frequency
+K=0.1
+k=[]
+frequency=[]
+torque=[]
+for i=0:8
+K=K+0.1
+f1=K*f
+x=Rs/K+sqrt((Rs/K)**2+(Xs+Xr_)**2)
+Tmax=(3/2/Wms)*(Vl/sqrt(3))**2/x
+k($+1)=K
+frequency($+1)=f1
+torque($+1)=Tmax
+end
+disp(k,"K:")
+disp(frequency,"f:in Hz")
+disp(torque,"Tmax:in N-m")
+
+//Plotting the values of Tmax vs f 
+plot(frequency,torque)
+xgrid(2)
+xlabel('f,Hz')
+ylabel('Tmax,N-m')
+title('Torque  vs frequency characteristic')
+
+//(ii) to obtain the starting torque and current at rated frequency and voltage
+x=(Rs+Rr_)**2+(Xs+Xr_)**2
+Tst=(3/Wms)*(Vl/sqrt(3))**2*Rr_/x     //starting torque at 50 Hz frequency
+Ist=(Vl/sqrt(3))/sqrt(x)         //starting current at 50 Hz frequency
+
+K=fmin/fmax     //minimum is available at 10 Hz
+y=((Rs+Rr_)/K)**2+(Xs+Xr_)**2
+Tst_=(3/Wms)*(Vl/sqrt(3))**2*Rr_/K/y     //starting torque at 10 Hz frequency
+Ist_=(Vl/sqrt(3))/sqrt(y)           //starting current at 10 Hz frequency
+
+ratio1=Tst_/Tst    //ratio of starting torque to the rated starting torque
+ratio2=Ist_/Ist    //ratio of starting current to the rated starting current
+
+//Results
+mprintf("\n(i)Hence from the plot we can see that for a constant (V/f) ratio breakdown torque decreases with frequency")
+mprintf("\n(ii)Hence the required ratio of starting torque to the rated starting torque is :%.3f",ratio1)
+mprintf("\nHence the required ratio of starting current to the rated starting current is :%.2f",ratio2)