20 files changed, 363 insertions, 0 deletions
diff --git a/3811/CH7/EX7.1/Ex7_1.jpg b/3811/CH7/EX7.1/Ex7_1.jpg
new file mode 100644
index 000000000..19d9fe6e1
--- /dev/null
+++ b/3811/CH7/EX7.1/Ex7_1.jpg
diff --git a/3811/CH7/EX7.1/Ex7_1.sce b/3811/CH7/EX7.1/Ex7_1.sce
new file mode 100644
index 000000000..1f35287fb
--- /dev/null
+++ b/3811/CH7/EX7.1/Ex7_1.sce
@@ -0,0 +1,57 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.1
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=6;//number of poles
+f=60;//frequency in hertz
+Pout=30*746;//rated output voltage in volts
+R1=0.5;//stator resistance in ohm
+R2=0.5;//rotor resistance reffered to stator in ohm
+Protational=500;//rotational loss in watt
+Pcu=600;//core losses in watt
+c=0.05;//cost of energy
+t1=100;//time which the motor operates in a week
+Pd=Pout+Protational;//developed power in watt
+a=1;// the s^2 value from the equation s^2-s+0.039
+b=-1;//the s value from the equation s^2-s+0.039
+c=0.039;//the constant value from the equation s^2-s+0.039
+s1=(-(b)+sqrt((b)^2-(4*a*c)))/(2*a);
+s2=(-(b)-sqrt((b)^2-(4*a*c)))/(2*a);//roots to find the value of s from the equation s^2-s+0.03
+s=s2;//s1 is very large hence neglected thus slip=s2
+a1=120;//constant value in the formula
+ns=(a1*f)/p;//synchronous speed in rpm
+n=ns*(1-s);
+mprintf("\nThe speed of the motor is %d rpm",n)
+I2=sqrt((Pd*s)/(3*R2*(1-s)));//motor current in amps
+Pwinding=3*I2^(2)*(R1+R2);
+Pin=Pd+Pwinding+Pcu;
+eta=Pout/Pin;//efficiency of the motor
+eta=eta*100;//efficiency in percentage
+mprintf("\nThe efficiency of the motor without added resistance is %d percentage",eta)
+nnew=0.8*n;//speed after 20% reduction
+snew=(ns-nnew)/ns;
+rmsnew=nnew/60;//speed in rps
+omegadnew=(2*%pi*rmsnew);
+rps=n/60;//speed in rps
+omega=(2*%pi*rps);
+Pdnew=(Pd*omegadnew)/omega;
+Radd=R2*((snew-s)/s);//resistance added to reduce 20% of the speed
+mprintf("\nThe resistance added to reduce 20 percentage of the speed is %f ohm",Radd)
+I2new=sqrt((Pdnew*snew)/(3*(R2+Radd)*(1-snew)))
+Pwindingnew=3*I2^(2)*(R1+R2+Radd);
+Pinnew=Pdnew+Pwindingnew+Pcu;
+Poutnew=Pdnew-Protational;
+etanew=Poutnew/Pinnew;
+etanew=etanew*100;
+mprintf("\nThe efficiency of the motor with added resistance is %d percentage",etanew)
+Padd=3*I2^(2)*Radd;
+Padd=Padd*10^(-3);
+t=100*52;//total hours of operation in one year
+C=Padd*t*c;
+mprintf("\nThe annual cost of the operating motor is $%f",C)
+//The answer may vary due to roundoff error
+
diff --git a/3811/CH7/EX7.10/Ex7_10.jpg b/3811/CH7/EX7.10/Ex7_10.jpg
new file mode 100644
index 000000000..dfb908e92
--- /dev/null
+++ b/3811/CH7/EX7.10/Ex7_10.jpg
diff --git a/3811/CH7/EX7.10/Ex7_10.sce b/3811/CH7/EX7.10/Ex7_10.sce
new file mode 100644
index 000000000..529847e30
--- /dev/null
+++ b/3811/CH7/EX7.10/Ex7_10.sce
@@ -0,0 +1,23 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.10
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;                       //terminal voltage in volt
+p=6;                        //number of poles
+f=60;                      //frequency in hertz
+Xl=3;                     //inductive reactance in ohm
+Rs=.2;                   //stator resistance in ohm
+X2=2;                   //rotor reactance in ohm
+R2=0.1;                //resistance reffered to the stator in ohm
+Xm=120;               //magnetizing reactance in the linear region in ohm
+Xm1=42;              //magnetizing reactance in the saturation region in ohm
+Td=100;            //constant load torque in Nm
+n=900;            //speed of the motor in rpm
+Is=21.6;
+rps=n/60;
+omega=(2*%pi*rps);
+f=(((3*Is^(2)*R2)/((2*%pi*Td)/f))+n)*(p/Xm);
+mprintf("\nThe frequency of the CSI to drive the machine at 900 rpm is %f Hz",f)
diff --git a/3811/CH7/EX7.2/Ex7_2.jpg b/3811/CH7/EX7.2/Ex7_2.jpg
new file mode 100644
index 000000000..d24de09e2
--- /dev/null
+++ b/3811/CH7/EX7.2/Ex7_2.jpg
diff --git a/3811/CH7/EX7.2/Ex7_2.sce b/3811/CH7/EX7.2/Ex7_2.sce
new file mode 100644
index 000000000..058a41a2c
--- /dev/null
+++ b/3811/CH7/EX7.2/Ex7_2.sce
@@ -0,0 +1,37 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.2
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=4;//number of poles
+f=60;//frequency in hertz
+Td=60;//constant torque load in Nm
+R1=0.4;
+R2=0.1;
+Xeq=4;
+N1=2;
+N2=1;
+n=1000;//speed of the motor in rpm
+a1=120;
+ns=(a1*f)/p;
+s=(ns-n)/ns;
+R21=R2*(N1/N2)^(2);
+theta=atand(Xeq/(R1+(R21/s)));
+a=0.05;
+b=8;
+c=-80.74;
+Vi11=(-b+sqrt(8^2-(4*a*c)))/(2*a);//obtained from the equation 0.05Vi^2+8Vi-80.74
+Vi12=(-b-sqrt(8^2-(4*a*c)))/(2*a);//obtained from the equation 0.05Vi^2+8Vi-80.74
+Vi1=Vi11;//because negative voltage is neglected
+Vi=(Vi1*N2)/N1;
+c1=122;//calculated constant values of the equation
+c2=1.85;//calculated constant values of the equation
+I2=(c1-Vi1)/c2;
+V1=sqrt(3)*Vi;//line to line injected voltage
+mprintf("\nThe magnitude of injected voltage is %f volt",V1)
+Pr=3*I2*Vi1*cosd(theta);
+mprintf("\nThe power delivered by the source of injected voltage is %f watt",Pr)
+//The answers vary due to round off error
diff --git a/3811/CH7/EX7.3/Ex7_3.jpg b/3811/CH7/EX7.3/Ex7_3.jpg
new file mode 100644
index 000000000..9abadd43b
--- /dev/null
+++ b/3811/CH7/EX7.3/Ex7_3.jpg
diff --git a/3811/CH7/EX7.3/Ex7_3.sce b/3811/CH7/EX7.3/Ex7_3.sce
new file mode 100644
index 000000000..2837d90bb
--- /dev/null
+++ b/3811/CH7/EX7.3/Ex7_3.sce
@@ -0,0 +1,35 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.3
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=4;//number of poles
+f=60;//frequency in hertz
+Tl=60;//load torque in Nm
+R1=0.4;
+R2=0.1;
+Xeq=4;
+N1=2;//obtained from the equation N1/N2=2 
+n=1000;//motor speed in rpm
+a=120;
+ns=(a*f)/p;
+rps=ns/60;
+omegas=(2*%pi*rps);
+mprintf("\na)Without injected voltage Vi=0v")
+Vs=V/sqrt(3);
+R21=R2*(N1^(2));
+I2st=Vs/sqrt((R1+R21)^(2)+Xeq^(2));//starting current in A
+I2st=ceil(I2st)//rounding off the starting current
+Tst=(3*I2st^(2)*R1)/omegas;//staring torque
+mprintf("\nThe starting current without injected voltage is %f A",I2st)
+mprintf("\nThe starting torque without injected voltage is %f Nm",Tst)
+mprintf("\nb)With injected voltage Vi=9.5v")
+Vi=9.5;//injected voltage in volt
+I2st1=(Vs-Vi)/sqrt((R1+R21)^(2)+Xeq^(2));//starting current with injected resistance in A
+thetar=atand(Xeq/(R1+R21));
+Tst1=(3/omegas)*((I2st1^2*R1)+(I2st*Vi)*cosd(thetar));
+mprintf("\nThe starting current with injected voltage is %f A",I2st1)
+mprintf("\nThe starting torque with injected voltage is %f Nm",Tst1)
diff --git a/3811/CH7/EX7.4/Ex7_4.jpg b/3811/CH7/EX7.4/Ex7_4.jpg
new file mode 100644
index 000000000..463dc9c04
--- /dev/null
+++ b/3811/CH7/EX7.4/Ex7_4.jpg
diff --git a/3811/CH7/EX7.4/Ex7_4.sce b/3811/CH7/EX7.4/Ex7_4.sce
new file mode 100644
index 000000000..161dcd5fe
--- /dev/null
+++ b/3811/CH7/EX7.4/Ex7_4.sce
@@ -0,0 +1,49 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.4
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=6;//number of poles
+f=60;//frequency in hertz
+Tout=300;//constant load torque in Nm
+N1=1;
+N2=1;
+Prot=1e3;//rotational power in watt
+alpha=120;//trigerring angle in degree
+mprintf("\nTo find speed of the motor:")
+a=120;//constant value
+ns=(a*f)/p;
+n=ns*(1+((N1/N2)*cosd(alpha)));
+mprintf("\nThe speed of the motor is %f rpm",n)
+s=(ns-n)/ns;
+mprintf("\nTo compute current in DC link:")
+rps=n/60;//speed in rps
+omega=(2*%pi*rps);
+Pout=Tout*omega;
+Pd=Pout+Prot;
+K=(3*sqrt(2))/%pi;
+I=(Pd/(1-s))/(K*V);
+mprintf("\nThe current in DC link is %f A",I)
+mprintf("\nTo compute rotor rms current:")
+itr=sqrt(2/3);//solved integration value
+I2=itr*I;
+mprintf("\nThe rotor rms current is %f A",I2)
+mprintf("\nTo compute stator rms current:")
+I1=(N1/N2)*I2
+mprintf("\nThe stator rms current is %f A",I1)
+mprintf("\nTo compute power returned to the source:")
+Pr=Pd;
+Pr=Pr*10^(-3);
+mprintf("\nThe power returned to the source is %f watt",Pr)
+mprintf("\nTo compute the losses when additional resistance is added:")
+Td=Pd/omega;
+rpss=ns/60;//speed in rps
+omegas=(2*%pi*rpss);
+Radd=(V^2*s)/(Td*omegas);//additional resistance added in ohm
+I2=sqrt(((s/(1-s))*(Pd/3))/Radd);//rotor current
+Padd=3*I2^2*Radd;//additional power loss
+Padd=Padd*10^(-3);
+mprintf("\nThe power losses when additional resistance added is %f watt",Padd)
diff --git a/3811/CH7/EX7.5/Ex7_5.jpg b/3811/CH7/EX7.5/Ex7_5.jpg
new file mode 100644
index 000000000..04219237f
--- /dev/null
+++ b/3811/CH7/EX7.5/Ex7_5.jpg
diff --git a/3811/CH7/EX7.5/Ex7_5.sce b/3811/CH7/EX7.5/Ex7_5.sce
new file mode 100644
index 000000000..860fc8c16
--- /dev/null
+++ b/3811/CH7/EX7.5/Ex7_5.sce
@@ -0,0 +1,25 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.5
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=6;//number of poles
+Pout=30*746;//output power interms of watt
+f=60;//frequency in hertz
+R1=0.5;//stator resistance in ohm
+R2=0.5;//rotor resistance reffered to stator in ohm
+ns=1200;//synchronus speed in rpm
+rps=ns/60;
+omegas=(2*%pi*rps);//angular synchronous speed
+Td=120;//load torque constant
+s=(Td*omegas*R2)/V^2;
+n=ns*(1-s);//the speed at full voltage in rpm
+n=ceil(n)
+Vnew=0.8*V;//when voltage is reduced by 20%
+snew=(V^2*s)/Vnew^2;//new slip after the reduction of 20% of the rated voltage
+nnew=ns*(1-snew);//new speed of the motor in rpm
+nnew=ceil(nnew)
+mprintf("The speed of the motor after the reduction of the rated voltage is %d rpm",nnew)
diff --git a/3811/CH7/EX7.6/Ex7_6.jpg b/3811/CH7/EX7.6/Ex7_6.jpg
new file mode 100644
index 000000000..c2da97297
--- /dev/null
+++ b/3811/CH7/EX7.6/Ex7_6.jpg
diff --git a/3811/CH7/EX7.6/Ex7_6.sce b/3811/CH7/EX7.6/Ex7_6.sce
new file mode 100644
index 000000000..99185d778
--- /dev/null
+++ b/3811/CH7/EX7.6/Ex7_6.sce
@@ -0,0 +1,44 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.6
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=2;//number of poles
+f=60;//frequency in hertz
+Xeq=4;//inductive reactance in ohm
+R1=0.2;//stator resistance in ohm
+R2=0.3;//rotor resistance reffered to stator in ohm
+Td=60;//driving constant load torque in Nm
+n=3500;//speed of the motor in rpm
+a=120;//constant value
+ns=(a*f)/p;//synchronous speed in rpm
+mprintf("\nTo compute the maximum frequency of the supply voltage:")
+Tmax=Td;
+rpss=ns/60;
+omegas=(2*%pi*rpss);
+fmax=sqrt((V^2*f^2)/(Tmax*2*omegas*4));
+mprintf("\nThe maximum frequency of the supply voltage is %f Hz",fmax)
+mprintf("\nTo calculate the motor current at f and fmax:")
+s=(ns-n)/ns;//slip at 60Hz
+Vs=V/sqrt(3);
+I2=Vs/sqrt((R1+(R2/s))^2+Xeq^2);
+mprintf("\nThe motor current at 60 Hz is %f A",I2)
+Xeqmax=(fmax/f)*Xeq;
+smax=R2/sqrt(R1^2+Xeqmax^2);
+nmax=((a*fmax)/p)*(1-smax);
+I2max=Vs/sqrt((R1+(R2/smax))^2+Xeqmax^2);
+mprintf("\nThe motor current at 67.7Hz is %f A",I2max)
+mprintf("\nTo calculate the power delivered to the load at f and fmax:")
+rps=n/60;
+omega=(2*%pi*rps);
+Pd=Td*omega;//developed power at 60Hz
+Pd=Pd*10^(-3);//developed power in kilowatt
+mprintf("\nThe power delivered to the load at 60Hz is %f Kw",Pd)
+rpsmax=nmax/60;
+omegamax=(2*%pi*rpsmax);
+Pdmax=Td*omegamax;//developed power at 67.7Hz
+Pdmax=Pdmax*10^(-3);//developed power in kilowatt
+mprintf("\nThe power delivered to the load at 67.7Hz is %f Kw",Pdmax)
diff --git a/3811/CH7/EX7.7/Ex7_7.jpg b/3811/CH7/EX7.7/Ex7_7.jpg
new file mode 100644
index 000000000..e5c1c41c3
--- /dev/null
+++ b/3811/CH7/EX7.7/Ex7_7.jpg
diff --git a/3811/CH7/EX7.7/Ex7_7.sce b/3811/CH7/EX7.7/Ex7_7.sce
new file mode 100644
index 000000000..7f08ac482
--- /dev/null
+++ b/3811/CH7/EX7.7/Ex7_7.sce
@@ -0,0 +1,27 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.7
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=2;//number of poles
+fst=60;//frequency in hertz
+f=50;//decreased frequency in Hz
+Xeq=4;//inductive reactance in ohm
+R1=0.2;//stator resistance in ohm
+R2=0.3;//rotor resistance reffered to stator in ohm
+Td=60;//driving constant load torque in Nm
+n=3500;//speed of the motor in rpm
+ns=(120*f)/p;//synchronous speed in rpm
+Vs=V/sqrt(3);
+rps=ns/60;
+omegas=(2*%pi*rps);
+s=(Td*omegas*R2)/V^2;
+n=ns*(1-s);//the new motor speed at 50Hz in rpm
+mprintf("\nThe new motor speed at 50Hz is %f rpm",n)
+I2st=Vs/sqrt((R1+R2)^(2)+Xeq^(2));//starting current in A
+Xeqnew=(f/fst)*Xeq;//inductive reactance at 50Hz
+I2stnew=Vs/sqrt((R1+R2)^(2)+Xeqnew^(2));//starting current at 50Hz in A
+mprintf("\nThe starting current at 50Hz is %f A",I2stnew)
diff --git a/3811/CH7/EX7.8/Ex7_8.jpg b/3811/CH7/EX7.8/Ex7_8.jpg
new file mode 100644
index 000000000..51bc4807c
--- /dev/null
+++ b/3811/CH7/EX7.8/Ex7_8.jpg
diff --git a/3811/CH7/EX7.8/Ex7_8.sce b/3811/CH7/EX7.8/Ex7_8.sce
new file mode 100644
index 000000000..9f50eccee
--- /dev/null
+++ b/3811/CH7/EX7.8/Ex7_8.sce
@@ -0,0 +1,36 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.8
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=2;//number of poles
+f=60;//frequency in hertz
+fd=50;//decreased frequency in Hz
+Xeq=4;//inductive reactance in ohm
+R1=0.2;//stator resistance in ohm
+R2=0.3;//rotor resistance reffered to stator in ohm
+Td=60;//driving constant load torque in Nm
+n=3500;//speed of the motor in rpm
+VFR=V/f;//voltage frequency ratio
+Vnew=fd*VFR;
+a=120;//constant value
+ns=(a*fd)/p;//synchronous speed in rpm
+Vs=V/sqrt(3);
+rps=n/60;
+omegas=(2*%pi*rps);
+s=(Td*omegas*R2)/Vnew^2;
+n=ns*(1-s);//the new motor speed at 50Hz in rpm
+rpss=ns/60;
+omega=(2*%pi*rpss)/60;
+mprintf("\nTo compute the starting current at 60Hz,480v:")
+I2st=Vs/sqrt((R1+R2)^(2)+Xeq^(2));//starting current in A
+mprintf("\nThe starting current at 60Hz,480v is %f A",I2st)
+mprintf("\nTo compute the starting current at 50Hz,400v:")
+Vsnew=Vnew/sqrt(3);
+Xeqnew=(fd/f)*Xeq;//inductive reactance at 50Hz
+I2stnew=Vsnew/sqrt((R1+R2)^(2)+Xeqnew^(2));//starting current at 50Hz in A
+mprintf("\nThe starting current at 50Hz,400v is %f A",I2stnew)
+mprintf("\nThe starting current is almost unchanged due to the v/f control")
diff --git a/3811/CH7/EX7.9/Ex7_9.jpg b/3811/CH7/EX7.9/Ex7_9.jpg
new file mode 100644
index 000000000..bdd6b7839
--- /dev/null
+++ b/3811/CH7/EX7.9/Ex7_9.jpg
diff --git a/3811/CH7/EX7.9/Ex7_9.sce b/3811/CH7/EX7.9/Ex7_9.sce
new file mode 100644
index 000000000..52652c7e3
--- /dev/null
+++ b/3811/CH7/EX7.9/Ex7_9.sce
@@ -0,0 +1,30 @@
+//Book Name: Fundamentals of electrical drives by Mohamad A. El- Sharkawi
+//chapter 7
+//example 7.9
+//edition 1
+//publisher and place:Nelson Engineering
+clc;
+clear;
+V=480;//terminal voltage in volt
+p=6;//number of poles
+f=60;//frequency in hertz
+Xl=3;//inductive reactance in ohm
+Rs=.2;//stator resistance in ohm
+X2=2;//rotor reactance in ohm
+R2=0.1;//resistance reffered to the stator in ohm
+Xm=120;//magnetizing reactance in the linear region in ohm
+Xm1=42;//magnetizing reactance in the saturation region in ohm
+Td=100;//constant load torque in Nm
+n=900;//speed of the motor in rpm
+ns=(120*f)/p;//synchronous speed of the machine in rpm
+s=(ns-n)/ns;//slip of the machine
+//If the machine is in the linear region
+rps=ns/60;
+omegas=(2*%pi*rps);
+Is=sqrt(((Td*s*omegas)*((R2/s)^2+(X2+Xm)^2))/(3*Xm^2*R2));
+costheta=0.7;//assumed power factor value
+I1rated=(Td*omegas)/(sqrt(3)*V*costheta);
+mprintf("\nThe input current if the machine is in the linear region is %f A",I1rated)
+//if the machine is in saturation region
+Is1=sqrt(((Td*s*omegas)*((R2/s)^2+(X2+Xm1)^2))/(3*Xm^2*R2));
+mprintf("\nThe input current if the machine is in the saturation region is %f A",Is1)