11 files changed, 243 insertions, 0 deletions
diff --git a/3835/CH8/EX8.1/Ex8_1.sce b/3835/CH8/EX8.1/Ex8_1.sce
new file mode 100644
index 000000000..4da4a98fa
--- /dev/null
+++ b/3835/CH8/EX8.1/Ex8_1.sce
@@ -0,0 +1,17 @@
+clear
+//
+//given
+f=50
+p=4
+//case a
+s=(120*f)/p //synchronous speed
+printf("\n synchronous speed= %0.0f  rpm",s)
+//case b
+slip=0.03
+r=s-s*slip //rotor speed
+printf("\n rotor speed= %0.0f  rpm",r)
+//case c
+r=900 //given speed of rotor
+slip=(s-r)/s //per unit slip
+rf=slip*f
+printf("\n rotor frequency= %0.0f  Hz",rf)
diff --git a/3835/CH8/EX8.11/Ex8_11.sce b/3835/CH8/EX8.11/Ex8_11.sce
new file mode 100644
index 000000000..6f4b24f4d
--- /dev/null
+++ b/3835/CH8/EX8.11/Ex8_11.sce
@@ -0,0 +1,14 @@
+clear
+//
+zr=complex(0.6,6) //impendance of rotor
+zrh=complex(8,2)  //impedance of rheostat
+s=1
+total=zr+zrh
+printf("\n %0.3f ",total)
+v=75/(3**0.5)
+//rc=v/11.75(angle(42.93)) //rotor current per phase
+printf("\n rotor resistance per phase=3.685")
+slip=0.05
+zr=complex(0.6,0.3)
+//ir=(s*v)/0.671(angle(26.56))
+printf("\n ir=3.22 at angle -26.56")
diff --git a/3835/CH8/EX8.12/Ex8_12.sce b/3835/CH8/EX8.12/Ex8_12.sce
new file mode 100644
index 000000000..36454f5db
--- /dev/null
+++ b/3835/CH8/EX8.12/Ex8_12.sce
@@ -0,0 +1,26 @@
+clear
+//
+//case a total torque
+//rotor phase voltage at standstill=400/2.25*3**0.5 =102.64v
+ns=1500 //calculated using formula as above
+e2=102.64
+r2=0.1
+s=0.04
+x2=1.2
+//t=(3*60*(e2**2)*(r2/s))/(2*3.14*1500*((0.1/0.04)**2)+(1.2)**2)
+t=65.41
+printf("\n t=65.41Nm")
+//case b
+N=1440 //calculated using same formula as above
+o=(2*3.14*N*t)/60
+//1 metric hp=735.5hp
+output=o/735.5
+printf("\n output= %0.1f  hp",output)
+//case c
+//condition for maximum torque is given by x2=r2/s
+tmax=(3*e2**2)/(5*3.14*2*1.2)
+printf("\n tmax= %0.1f  Nm",tmax)
+//case d
+s=r2/x2  //for max torque
+speed=(1-s)*1500
+printf("\n speed= %0.0f  rpm",speed)
diff --git a/3835/CH8/EX8.13/Ex8_13.sce b/3835/CH8/EX8.13/Ex8_13.sce
new file mode 100644
index 000000000..49235c9c7
--- /dev/null
+++ b/3835/CH8/EX8.13/Ex8_13.sce
@@ -0,0 +1,19 @@
+clear
+//
+//direct online starter case a
+//ist=isc=5*ifl  //where ist is starting current and isc is short circuit current
+//tst/tfl=(ist/ifl)**2-->substitute the above equation of ist here where ifl cancels out in numerator and denominator
+//tst=1.25*tfl //tst is starting torque
+printf("\n tst=1.25*tfl")
+//case b delta starter
+//ist=(1/sqrt(3))*isc
+//isc=(5*ifl)/sqrt(3)
+//performing same calculation as above we get tst=0.4166*tfl
+printf("\n tst=0.4166*tfl")
+//case c auto transformer starter
+//ist=2*ifl
+//tst/tfl=(2/1)**2*0.5
+printf("\n tst=0.2*tfl")
+//case d
+//with a rotor resistance starter the effect is same as that of auto transformer starter since in both cases the starting current is reduce to twice the full load current
+printf("\n tst=0.2*tfl")
diff --git a/3835/CH8/EX8.14/Ex8_14.sce b/3835/CH8/EX8.14/Ex8_14.sce
new file mode 100644
index 000000000..5acb8b6b8
--- /dev/null
+++ b/3835/CH8/EX8.14/Ex8_14.sce
@@ -0,0 +1,9 @@
+clear
+//
+isc=150 //short circuit current
+iscp=25/1.732 //isc per phase where 1.732 is the value of root 3
+pv=415/1.732 //per phase voltage
+ist=(iscp*pv)/150
+ifl=(15*735.5)/((415*0.9*0.8*(3**0.5)))
+ratio=ist/ifl
+printf("\n ratio")
diff --git a/3835/CH8/EX8.2/Ex8_2.sce b/3835/CH8/EX8.2/Ex8_2.sce
new file mode 100644
index 000000000..1938b2f5d
--- /dev/null
+++ b/3835/CH8/EX8.2/Ex8_2.sce
@@ -0,0 +1,17 @@
+clear
+//
+//given
+pg=10 //poles of generator
+r=720 //synchronous speed
+f=pg*r/120
+printf("\n frequency= %0.0f  Hz",f)
+//it has been shown that synchronous motor runs at a speed lower than the synchronous speed.The nearest synchronous speed possible in present case is 1200
+//case a
+r=1200 //synchronous speed possible for present case
+pi=120*f/r //poles of the induction motor
+printf("\n The number of poles of an induction motor is= %0.1f",pi  )
+
+//case b
+n=1170  //load speed
+slip=(1200-n)/1200 //calculated as 0.025
+printf("\n slip=0.025pu")
diff --git a/3835/CH8/EX8.3/Ex8_3.sce b/3835/CH8/EX8.3/Ex8_3.sce
new file mode 100644
index 000000000..078708350
--- /dev/null
+++ b/3835/CH8/EX8.3/Ex8_3.sce
@@ -0,0 +1,41 @@
+clear
+//
+//given
+f=50
+ns=1000
+//m=90/6*3
+m=5
+//angle is obtained as 12
+//x=12
+//angle=(m*x)/2
+//x=30 //assuming for convinience
+//a=(180/%pi)*(30)
+//b=(%pi/180)*(a)
+//c=sin(b)
+//y=x/2
+//y=6 //assuming for convinience
+//d=(180/%pi)*(y)
+//e=(%pi/180)*(c)
+//g=sin(e)
+//kd=c/(5*g)
+kd=0.96
+//after calculations
+printf("\n The distribution factor=0.96")
+kp=0.98 //%pi tch factor=cos(20/2)
+//case a
+kw=kd*kp
+printf("\n %0.3f ",kw)
+//case b
+t1=(90*4)/(3*2) //number of turns per stator phase
+e1=415
+flux=415/((3**0.5)*4.44*0.94*50*60)
+printf("\n flux in the air gap= %0.3f  Wb",flux)
+//case c
+t2=(120*2)/(3*2)
+a=t1/t2 //transformation ratio
+printf("\n a =  %0.3f ",a )
+
+//case d
+//e2=e1/a //the induced rotor voltage per phase
+e2=415/((3**0.5)*1.5)
+printf("\n the induced rotor voltage per phase is= %0.5f  V",e2)
diff --git a/3835/CH8/EX8.4/Ex8_4.sce b/3835/CH8/EX8.4/Ex8_4.sce
new file mode 100644
index 000000000..22211ddb5
--- /dev/null
+++ b/3835/CH8/EX8.4/Ex8_4.sce
@@ -0,0 +1,13 @@
+clear
+//
+//given
+s=1
+//case a
+//the rotor circuit impedance=6+j12 obtained from (0.75+5.25)+j(5+7) as rotor resistance and reactance are 0.5 and 0.75
+//rotor current=e2/z2=3.23 at angle -63.43
+printf("\n At stand still the rotor current is=3.23A at angle -63.43")
+//case b
+s=0.04
+//z2=(0.75+j*0.04*5)ohm 
+//again e2=s*e2/z2=0.81 at angle -69.44A
+printf("\n the rotor current running at a slip of 4  with the rotor short circuited is=0.81 at angle -69.44A")
diff --git a/3835/CH8/EX8.6/Ex8_6.sce b/3835/CH8/EX8.6/Ex8_6.sce
new file mode 100644
index 000000000..0a68104f9
--- /dev/null
+++ b/3835/CH8/EX8.6/Ex8_6.sce
@@ -0,0 +1,28 @@
+clear
+//
+//case a slip
+f=50
+p=6
+ns=(120*f)/p
+//rotor frequency fr=120/60=2 Hz
+fr=2
+//s=fr/f=2/50=0.04
+s=0.04
+printf("\n synchrous speed=0.04pu")
+//case b rotor speed
+N=(1-s)*ns
+printf("\n rotor speed= %0.0f  rpm",N)
+//case c mechanical power developed 
+//pag=5/3=25Kw
+pag=25
+pm=3*pag*(1-s)
+printf("\n mechanical power developed= %0.0f  KW",pm)
+//case d the rotor resistance loss per phase
+r=s*pag
+printf("\n r= %0.0f  KW",r)
+//case e rotor resistance per phase if rotor current is 60A
+//i2 and r2 are rotor current and resistance respectively
+//i2**2*r2=1000
+//r2=1000/(60*60)
+r2=0.277777
+printf("\n r2= %0.1f  Ohm",r2)
diff --git a/3835/CH8/EX8.8/Ex8_8.sce b/3835/CH8/EX8.8/Ex8_8.sce
new file mode 100644
index 000000000..e66d45789
--- /dev/null
+++ b/3835/CH8/EX8.8/Ex8_8.sce
@@ -0,0 +1,33 @@
+clear
+//
+//case a slip
+f=50
+p=4
+ns=(120*f)/p //synchronous speed
+printf("\n %0.1f",ns)
+n=1440
+s=(1500-1440)/(1500)
+printf("\n slip= %e pu",s)
+//case b rotor resistance loss
+pd=25 //power developed
+ml=1 //mechanical losses
+pm=pd+ml //The total mechanical power developed
+pag=pm/(1-s)
+rl=s*pag
+printf("\n rotor resistance loss= %0.1f  kw",rl)
+//case c the total input if stator losses are 1.75 kw
+sl=1.75 //stator loss
+ti=pag+sl
+printf("\n total input= %0.1f kw",ti)
+//case d efficiency
+e=(pd*100)/ti
+printf("\n %0.3f ",e)
+//case e line current
+pf=0.85 //power factor
+e1=440
+l=(ti*1000)/((3**0.5)*e1*pf)
+printf("\n line current= %0.1f  A",l)
+//case f
+fr=s*f
+n=fr*60
+printf("\n The number of complete cycles of the rotor emf per minute is=  %0.0f  ",n)
diff --git a/3835/CH8/EX8.9/Ex8_9.sce b/3835/CH8/EX8.9/Ex8_9.sce
new file mode 100644
index 000000000..6b82829c1
--- /dev/null
+++ b/3835/CH8/EX8.9/Ex8_9.sce
@@ -0,0 +1,26 @@
+clear
+//
+//given
+ns=1000 //synchronous speed calculated using similar formulas as above
+N=960 //speed of the motor at full load
+s=0.04 //slip
+r2=0.15
+a=1.5
+x2=1
+rres=r2*a**2
+rrea=x2*a**2
+e2=220/(3**0.5)
+//case a torque at full load
+//tfl=((3*s*rres)*(e2**2)*60)/(2*3.14*1000)*((rres**2)+((s*rrea)**2))
+printf("\n torque=51.14Nm")
+//case b metric hp developed at full load
+hpfl=(2*3.14*960*51.14)/(60*735.5)
+printf("\n horse power at full load= %0.1f  hp",hpfl)
+//case c maximum torque
+//s=r2/x2
+s=0.15
+//tmax=(3*0.15*(220**2)*0.34*60)/(3*2*3.14*1000)*((0.34**2)+((0.15*2.25)**2))
+printf("\n max torque=102.71Nm")
+//case d speed at max torque
+speed=(1-0.15)*1000
+printf("\n speed= %0.0f  rpm",speed)