summaryrefslogtreecommitdiff
path: root/1445/CH10
diff options
context:
space:
mode:
Diffstat (limited to '1445/CH10')
-rw-r--r--1445/CH10/EX10.10/ch10_ex_10.sce26
-rw-r--r--1445/CH10/EX10.11/ch10_ex_11.sce25
-rw-r--r--1445/CH10/EX10.12/ch10_ex_12.sce43
-rw-r--r--1445/CH10/EX10.13/ch10_ex_13.sce61
-rw-r--r--1445/CH10/EX10.14/ch10_ex_14.sce52
-rw-r--r--1445/CH10/EX10.15/ch10_ex_15.sce32
-rw-r--r--1445/CH10/EX10.16/ch10_ex_16.sce50
-rw-r--r--1445/CH10/EX10.2/ch10_ex_2.sce80
-rw-r--r--1445/CH10/EX10.3/ch10_ex_3.sce57
-rw-r--r--1445/CH10/EX10.4/ch10_ex_4.sce29
-rw-r--r--1445/CH10/EX10.5/ch10_ex_5.sce20
-rw-r--r--1445/CH10/EX10.6/ch10_ex_6.sce26
-rw-r--r--1445/CH10/EX10.7/ch10_ex_7.sce44
-rw-r--r--1445/CH10/EX10.8/ch10_ex_8.sce37
-rw-r--r--1445/CH10/EX10.9/ch10_ex_9.sce41
15 files changed, 623 insertions, 0 deletions
diff --git a/1445/CH10/EX10.10/ch10_ex_10.sce b/1445/CH10/EX10.10/ch10_ex_10.sce
new file mode 100644
index 000000000..ce8d85e4a
--- /dev/null
+++ b/1445/CH10/EX10.10/ch10_ex_10.sce
@@ -0,0 +1,26 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 10
+
+disp("CHAPTER 10");
+disp("EXAMPLE 10");
+
+//VARIABLE INITIALIZATION
+P=6; //number of poles
+f=60; //in Hertz
+p=48; //stator input in Watts
+N_r=1140; //in rpm
+cu_loss=1.4; //stator copper loss in Watts
+cr_loss=1.6; //stator core loss in Watts
+me_loss=1; //rotor mechanical loss in Watts
+
+//SOLUTION
+N_s=(120*f)/P;
+s=(N_s-N_r)/N_s;
+p_g=p-(cu_loss+cr_loss); //rotor input
+p_m=p_g*(1-s); //output mechanical power
+p_sh=p_m-me_loss; //shaft power
+eff=p_sh/p;
+disp(sprintf("The motor efficiency is %f %%",eff*100));
+
+//END
+
diff --git a/1445/CH10/EX10.11/ch10_ex_11.sce b/1445/CH10/EX10.11/ch10_ex_11.sce
new file mode 100644
index 000000000..2d2164770
--- /dev/null
+++ b/1445/CH10/EX10.11/ch10_ex_11.sce
@@ -0,0 +1,25 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 11
+
+disp("CHAPTER 10");
+disp("EXAMPLE 11");
+
+//VARIABLE INITIALIZATION
+P1=4; //number of poles
+s=5/100; //slip
+f=60; //in Hertz
+
+//SOLUTION
+
+//solution (a)
+N_s=(120*f)/P1;
+N_r=N_s*(1-s);
+N_r=round(N_r); //to round off the value
+disp(sprintf("(a) The speed of the motor is %d rpm",N_r));
+
+//solution (b)
+P2=6;
+N_s=(120*f)/P2;
+disp(sprintf("(b) The speed of the generator is %d rpm",N_s));
+
+//END
diff --git a/1445/CH10/EX10.12/ch10_ex_12.sce b/1445/CH10/EX10.12/ch10_ex_12.sce
new file mode 100644
index 000000000..c2ab1d370
--- /dev/null
+++ b/1445/CH10/EX10.12/ch10_ex_12.sce
@@ -0,0 +1,43 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 12
+
+disp("CHAPTER 10");
+disp("EXAMPLE 12");
+
+//VARIABLE INITIALIZATION
+v=440; //in Volts
+I=1200; //in Amperes
+eff=0.85; //full load efficiency
+pow_fact=0.8; //full load power factor
+
+//SOLUTION
+
+//solution (a)
+I_fl1=I/5; //starting current at rated voltage is 5 times the rated full-load current
+p1=sqrt(3)*v*I_fl1*pow_fact*eff;
+disp(sprintf("(a) The maximum rating when the motor starts at full voltage is %f kW",p1/1000));
+
+//solution (b)
+I_fl2=I/((0.8^2)*5);
+p2=sqrt(3)*v*I_fl2*pow_fact*eff;
+disp(sprintf("(b) The maximum rating when the motor is used with an auto-transformer is %f kW",p2/1000));
+
+//solution (c)
+I_fl3=I/((0.578^2)*5);
+p3=sqrt(3)*v*I_fl3*pow_fact*eff;
+disp(sprintf("(c) The maximum rating when the motor is used with star-delta starter is %f kW",p3/1000));
+
+//The answers are slightly different due to precision of floating point numbers
+
+//END
+
+
+
+
+
+
+
+
+
+
+
diff --git a/1445/CH10/EX10.13/ch10_ex_13.sce b/1445/CH10/EX10.13/ch10_ex_13.sce
new file mode 100644
index 000000000..2450a5569
--- /dev/null
+++ b/1445/CH10/EX10.13/ch10_ex_13.sce
@@ -0,0 +1,61 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 13
+
+disp("CHAPTER 10");
+disp("EXAMPLE 13");
+
+//VARIABLE INITIALIZATION
+f=50; //in Hertz
+N_r=1440; //full-load speed in Hertz
+
+//SOLUTION
+
+//solution (a)
+function N=speed(pole);
+N=(120*f)/pole;
+endfunction;
+
+pole=2;
+N=speed(pole);
+if(N>N_r & N<2000)
+P=pole;
+N_s1=N;
+disp(sprintf("(a) The number of poles is %d",P));
+end;
+pole=4;
+N=speed(pole);
+if(N>N_r & N<2000)
+P=pole;
+N_s1=N;
+disp(sprintf("(a) The number of poles is %d",P));
+end;
+pole=6;
+N=speed(pole);
+if(N>N_r & N<2000)
+P=pole;
+N_s1=N;
+disp(sprintf("(a) The number of poles is %d",P));
+end;
+
+//solution (b)
+s=(N_s1-N_r)/N_s1;
+f_r=s*f;
+disp(sprintf("(b) The slip is %f %% and rotor frequency is %d Hz",s*100,f_r));
+
+//solution (c)
+w1=(2*%pi*N_s1)/60;
+disp(sprintf("(c(i)) The speed of stator field w.r.t. stator structure is %f rad/s",w1));
+N_s2=N_s1-N_r;
+w2=(2*%pi*N_s2)/60;
+disp(sprintf("(c(ii)) The speed of stator field w.r.t. rotor structure is %f rad/s",w2));
+
+//solution (d)
+factor=(2*%pi)/60; //converting factor from rpm to radian/second
+N_r1=(120*f_r)/P;
+disp(sprintf("(d(i)) The speed of rotor field w.r.t. rotor structure is %f rad/s",N_r1*factor));
+N_r2=N_r+N_r1;
+disp(sprintf("(d(ii)) The speed of rotor field w.r.t. stator structure is %f rad/s",N_r2*factor));
+N_r3=N_s1-N_r2;
+disp(sprintf("(d(iii)) The speed of rotor field w.r.t. stator structure is %d rad/s",N_r3));
+
+//END
diff --git a/1445/CH10/EX10.14/ch10_ex_14.sce b/1445/CH10/EX10.14/ch10_ex_14.sce
new file mode 100644
index 000000000..c9dddcdad
--- /dev/null
+++ b/1445/CH10/EX10.14/ch10_ex_14.sce
@@ -0,0 +1,52 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 14
+
+disp("CHAPTER 10");
+disp("EXAMPLE 14");
+
+//VARIABLE INITIALIZATION
+p=10*1000; //in Watts
+I_nl=8; //no load line current in Amperes
+p_ni=660; //input power at no load in Watts
+I_fl=18; //full load current in Amperes
+p_fi=11.20*1000; //input power at full load in Watts
+r=1.2; //stator resistance per phase in Ohms
+loss=420; //friction and winding loss in Watts
+
+//SOLUTION
+
+//solution (a)
+I1=I_nl/sqrt(3);
+i_sq_r1=(I1^2)*r*3; //stator (I^2*R) loss at no load
+s_loss=p_ni-loss-i_sq_r1;
+disp(sprintf("(a) The stator core loss is %f W",s_loss));
+
+//solution (b)
+I2=I_fl/sqrt(3);
+i_sq_r2=(I2^2)*r*3;
+p_g=p_fi-s_loss-i_sq_r2;
+r_loss=p_g-p;
+disp(sprintf("(b) The total rotor loss at full load is %f W",r_loss));
+
+//solution (c)
+o_loss=r_loss-loss;
+disp(sprintf("(c) The total rotor ohmic loss at full load is %f W",o_loss));
+
+//solution (d)
+s_fl=o_loss/p_g; //full load slip
+N_s=1500;
+N_r=N_s*(1-s_fl);
+disp(sprintf("(d) The full load speed is %f rpm",N_r));
+
+//solution (e)
+w=(2*%pi*N_s)/60;
+T_e=p_g/w;
+disp(sprintf("(e) The internal torque is %f N-m",T_e));
+T_sh=p/(w*(1-s_fl));
+disp(sprintf(" The shaft torque is %f N-m",T_sh));
+eff=p/p_fi;
+disp(sprintf(" The motor efficiency is %f %%",eff*100));
+
+//The answers may be slightly different due to precision of floating point numbers
+
+//END
diff --git a/1445/CH10/EX10.15/ch10_ex_15.sce b/1445/CH10/EX10.15/ch10_ex_15.sce
new file mode 100644
index 000000000..8797d77be
--- /dev/null
+++ b/1445/CH10/EX10.15/ch10_ex_15.sce
@@ -0,0 +1,32 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 15
+
+disp("CHAPTER 10");
+disp("EXAMPLE 15");
+
+//VARIABLE INITIALIZATION
+P=4; //number of poles
+f_s=50; //in Hertz
+f_l=20; //in Hertz
+
+//SOLUTION
+
+//solution (a)
+N1=(120*f_s)/P; //speed of rotor field w.r.t. stator structure
+N2=(120*f_l)/P; //speed of rotor field w.r.t. rotor structure
+N_r1=N1-N2;
+N_r2=N1+N2;
+disp("(a) The prime mover should should drive the rotor at two speeds-");
+disp(sprintf("At %d rpm in the direction of stator field",N_r1));
+disp(sprintf("At %d rpm against the direction of stator field",N_r2));
+
+//solution (b)
+s1=(N1-N_r1)/N1;
+s2=(N1-N_r2)/N1;
+ratio=s1/s2; //all other parameters in the expressions of the two voltages are equal
+disp(sprintf("(b) The ratio of the two voltages at the two speeds is %d",ratio));
+
+//solution (c)
+disp("(c) The poles sequence of -3Φ rotor voltage do not remain the same");
+
+//END
diff --git a/1445/CH10/EX10.16/ch10_ex_16.sce b/1445/CH10/EX10.16/ch10_ex_16.sce
new file mode 100644
index 000000000..f2fd39150
--- /dev/null
+++ b/1445/CH10/EX10.16/ch10_ex_16.sce
@@ -0,0 +1,50 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 16
+
+disp("CHAPTER 10");
+disp("EXAMPLE 16");
+
+//VARIABLE INITIALIZATION
+ratio1=1.5; //ratio of T_est and T_efl
+ratio2=2.5; //ratio of T_em and T_efl
+
+//SOLUTION
+s=1;
+
+//solution (a)
+//directly solving the quadratic equation
+a=1;
+b=-3.333;
+c=1;
+D=(b)^2-(4*a*c); //discriminant
+sm1=(-b+sqrt(D))/(2*a);
+sm2=(-b-sqrt(D))/(2*a);
+if(sm1<=0 & sm2<=0) then
+disp("The value of the slip at maximum torque is not valid");
+else if(sm1>0 & sm1<1)
+disp(sprintf("The slip at maximum torque is %f",sm1));
+else if(sm2>0 & sm2<1)
+disp(sprintf("The slip at maximum torque is %f",sm2));
+end;
+
+//solution (b)
+//directly solving the quadratic equation
+a=1;
+b=-1.665;
+c=0.111;
+D=(b)^2-(4*a*c);
+ans1=(-b+sqrt(D))/(2*a);
+ans2=(-b-sqrt(D))/(2*a);
+if(ans1>0 & ans1<1)
+disp(sprintf("The full load slip is %f",ans1));
+sfl=ans1;
+else if(ans2>0 & ans2<1)
+disp(sprintf("The full load slip is %f",ans2));
+sfl=ans2;
+end;
+
+//solution (c)
+I=sqrt(ratio1/sfl);
+disp(sprintf("The rotor current at the starting in terms of full load current is %f A",I));
+
+//END
diff --git a/1445/CH10/EX10.2/ch10_ex_2.sce b/1445/CH10/EX10.2/ch10_ex_2.sce
new file mode 100644
index 000000000..220675f0f
--- /dev/null
+++ b/1445/CH10/EX10.2/ch10_ex_2.sce
@@ -0,0 +1,80 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 2
+
+disp("CHAPTER 10");
+disp("EXAMPLE 2");
+
+//VARIABLE INITIALIZATION
+P=6; //number of poles
+f1=60; //frequency in Hertz
+N_r1=1140; //in rpm
+
+//SOLUTION
+N_s=(120*f1)/P;
+s1=(N_s-N_r1)/N_s; //slip at full load
+
+//solution (a)
+N_r2=0;
+s2=(N_s-N_r2)/N_s;
+disp(sprintf("(a) At standstill, the slip is %f %%",s2*100));
+if(s2>1)
+disp("Since the slip is greater than 100%, the motor operates as brake");
+end;
+if(s2<0)
+disp("Since the slip is negative, the motor operates as generator");
+end;
+f2=s2*f1;
+disp(sprintf("And the frequency is %d Hz",f2));
+if(f2<0)
+disp("Since frequency is negative, phase sequence of voltage induced in rotor winding is reversed");
+end;
+
+//solution (b)
+N_r3=500;
+s3=(N_s-N_r3)/N_s;
+disp(sprintf("(b) At %d rpm, the slip is %f %%",N_r3,s3*100));
+if(s3>1)
+disp("Since the slip is greater than 100%, the motor operates as brake");
+end;
+if(s3<0)
+disp("Since the slip is negative, the motor operates as generator");
+end;
+f3=s3*f1;
+disp(sprintf("And the frequency is %d Hz",f3));
+if(f3<0)
+disp("Since frequency is negative, phase sequence of voltage induced in rotor winding is reversed");
+end;
+
+//solution (c)
+N_r4=500;
+s4=(N_s+N_r4)/N_s; //as motor runs in opposite direction
+disp(sprintf("(c) At %d rpm, the slip is %f %%",N_r4,s4*100));
+if(s4>1)
+disp("Since the slip is greater than 100%, the motor operates as brake");
+end;
+if(s4<0)
+disp("Since the slip is negative, the motor operates as generator");
+end;
+f4=s4*f1;
+disp(sprintf("And the frequency is %d Hz",f4));
+if(f4<0)
+disp("Since frequency is negative, phase sequence of voltage induced in rotor winding is reversed");
+end;
+
+//solution (d)
+N_r5=2000;
+s5=(N_s-N_r5)/N_s;
+disp(sprintf("(d) At %d rpm, the slip is %f %%",N_r5,s5*100));
+if(s5>1)
+disp("Since the slip is greater than 100%, the motor operates as brake");
+end;
+if(s5<0)
+disp("Since the slip is negative, the motor operates as generator");
+end;
+f5=s5*f1;
+disp(sprintf("And the frequency is %d Hz",f5));
+if(f5<0)
+disp("Since frequency is negative, phase sequence of voltage induced in rotor winding is reversed");
+end;
+
+//END
diff --git a/1445/CH10/EX10.3/ch10_ex_3.sce b/1445/CH10/EX10.3/ch10_ex_3.sce
new file mode 100644
index 000000000..11806edbe
--- /dev/null
+++ b/1445/CH10/EX10.3/ch10_ex_3.sce
@@ -0,0 +1,57 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 3
+
+disp("CHAPTER 10");
+disp("EXAMPLE 3");
+
+//VARIABLE INITIALIZATION
+N_r=1140; //full load speed in rpm
+f=60; //in Hz
+
+//SOLUTION
+
+//solution (i)
+P=(120*f)/N_r;
+P=round(P);
+disp(sprintf("(i) The number of poles is %d",P));
+
+//solution (ii)
+N_s=(120*f)/P;
+s=(N_s-N_r)/N_s;
+disp(sprintf("(ii) The slip at full load is %d %%",s*100));
+
+//solution (iii)
+f_r=s*f;
+disp(sprintf("(iii) The frequency of the rotor voltge is %d Hz",f_r));
+
+//solution (iv)
+N1=(120*f_r)/P; //speed of rotor field w.r.t stator
+N1=round(N1);
+disp(sprintf("(iv) The speed of rotor field w.r.t rotor is %d rpm",N1));
+
+//solution (v)
+N2=N_r+N1; //speed of stator field w.r.t stator field
+N3=N_s-N2; //speed of rotor field w.r.t stator field
+disp(sprintf("(v) The speed of rotor field w.r.t stator field is %d rpm",N3));
+disp("Hence, the rotor field is stationary w.r.t stator field");
+
+//solution (vi)
+ratio=10/100; //10% slip
+N_r=N_s*(1-ratio);
+N_r=round(N_r);
+disp(sprintf("(vi) The speed of rotor at 10%% slip is %d rpm",N_r));
+s1=(N_s-N_r)/N_s;
+fr=s1*f;
+disp(sprintf(" The rotor frequency at this speed is %f Hz",fr));
+
+//solution (vii)
+v=230;
+ratio1=1/0.5;
+E_rotor=v*(1/ratio1);
+E_rotor_dash=ratio*E_rotor;
+disp(sprintf("(vii) The rotor induced emf is %f V",E_rotor_dash));
+
+//END
+
+
+
diff --git a/1445/CH10/EX10.4/ch10_ex_4.sce b/1445/CH10/EX10.4/ch10_ex_4.sce
new file mode 100644
index 000000000..e81b21b5b
--- /dev/null
+++ b/1445/CH10/EX10.4/ch10_ex_4.sce
@@ -0,0 +1,29 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 4
+
+disp("CHAPTER 10");
+disp("EXAMPLE 4");
+
+//VARIABLE INITIALIZATION
+r2=0.2; //in Ohms
+X2=2; //in Ohms
+
+//SOLUTION
+s_m=r2/X2;
+
+//solution (a)
+s=1;
+ratio1=2/((s/s_m)+(s_m/s)); //ratio of T_starting and T_max
+ratio2=2*ratio1; //ratio of T_starting and T_full-load (T_max=2*T_full-load)
+disp(sprintf("(a) If the motor is started by direct-on-line starter, the ratio of starting torque to full load torque is %f",ratio2));
+
+//solution (b)
+ratio3=(1/3)*ratio2; //In star-delta starter, T_starting=(1/3)*T_starting_of_DOL
+disp(sprintf("(b) If the motor is started by star-delta starter, the ratio of starting torque to full load torque is %f",ratio3));
+
+//solution (c)
+ratio4=0.7*2*ratio2; //due to 70% tapping
+disp(sprintf("(c) If the motor is started by auto-transformer, the ratio of starting torque to full load torque is %f",ratio4));
+
+//END
+
diff --git a/1445/CH10/EX10.5/ch10_ex_5.sce b/1445/CH10/EX10.5/ch10_ex_5.sce
new file mode 100644
index 000000000..f7a59dae9
--- /dev/null
+++ b/1445/CH10/EX10.5/ch10_ex_5.sce
@@ -0,0 +1,20 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 5
+
+disp("CHAPTER 10");
+disp("EXAMPLE 5");
+
+//VARIABLE INITIALIZATION
+P1=12; //number of poles of alternator
+N_s1=500; //synchronous speed of alternator in rpm
+P2=8; //number of poles of motor
+s=0.03; //slip of the motor
+
+//SOLUTION
+f=(N_s1*P1)/120;
+N_s2=(120*f)/P2;
+N_r=N_s2*(1-s);
+N_r=round(N_r); //to round off the value
+disp(sprintf("The speed of the motor is %d rpm",N_r));
+
+//END
diff --git a/1445/CH10/EX10.6/ch10_ex_6.sce b/1445/CH10/EX10.6/ch10_ex_6.sce
new file mode 100644
index 000000000..d32ab7468
--- /dev/null
+++ b/1445/CH10/EX10.6/ch10_ex_6.sce
@@ -0,0 +1,26 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 6
+
+disp("CHAPTER 10");
+disp("EXAMPLE 6");
+
+//VARIABLE INITIALIZATION
+P=4; //number of poles
+f_r=2; //rotor frequency in Hertz
+f_s=50; //stator frequency in Hertz
+v=400; //in Volts
+ratio=1/0.5; //stator to rotor turn ratio
+
+//SOLUTION
+s=f_r/f_s;
+N_s=(120*f_s)/P;
+N_r=N_s*(1-s);
+N_r=round(N_r);
+disp(sprintf("The speed of the motor is %d rpm",N_r));
+E_s=v/sqrt(3);
+E_r=E_s*(1/ratio);
+E_r_dash=s*E_r;
+disp(sprintf("The rotor induced emf above 2 Hz is %f V",E_r_dash));
+
+//END
+
diff --git a/1445/CH10/EX10.7/ch10_ex_7.sce b/1445/CH10/EX10.7/ch10_ex_7.sce
new file mode 100644
index 000000000..0199f014c
--- /dev/null
+++ b/1445/CH10/EX10.7/ch10_ex_7.sce
@@ -0,0 +1,44 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 7
+
+disp("CHAPTER 10");
+disp("EXAMPLE 7");
+
+//VARIABLE INITIALIZATION
+P=4; //number of poles
+f=50; //in Hz
+r2=0.1; //rotor resistance in Ohms
+X2=2; //standstill reactance in Ohms
+E1=100; //induced emf between slip ring in Volts
+N_r=1460; //full load speed in rpm
+
+//SOLUTION
+
+//solution (i)
+N_s=(120*f)/P;
+s_fl=(N_s-N_r)/N_s;
+disp(sprintf("(i) The slip at full load is %f %%",s_fl*100));
+s_m=r2/X2;
+disp(sprintf("The slip at which maximum torque occurs is %f %%",s_m*100));
+
+//solution (ii)
+E2=E1/sqrt(3);
+disp(sprintf("(ii) The emf induced in rotor per phase is %f V",E2));
+
+//solution (iii)
+X2_dash=s_fl*X2;
+disp(sprintf("(iii) The rotor reactance per phase is %f Ω",X2_dash));
+
+//solution (iv)
+z=sqrt((r2^2)+(X2_dash)^2);
+I2=(s_fl*E2)/z;
+disp(sprintf("(iv) The rotor current is %f A",I2));
+
+//solution (v)
+pow_fact_r=r2/z;
+disp(sprintf("(v) The rotor power factor is %f (lagging)",pow_fact_r));
+
+//END
+
+
+
diff --git a/1445/CH10/EX10.8/ch10_ex_8.sce b/1445/CH10/EX10.8/ch10_ex_8.sce
new file mode 100644
index 000000000..1ab32dcaa
--- /dev/null
+++ b/1445/CH10/EX10.8/ch10_ex_8.sce
@@ -0,0 +1,37 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 8
+
+disp("CHAPTER 10");
+disp("EXAMPLE 8");
+
+//VARIABLE INITIALIZATION
+N_s=1200; //in rpm
+p_in=80; //in kW
+loss=5; //copper and iron losses in kW
+f_loss=2; //friction and windage loss in kW
+N=1152; //in rpm
+
+//SOLUTION
+
+//solution (a)
+p_rotor=p_in-loss;
+disp(sprintf("(a) The active power transmitted to rotor is %d kW",p_rotor));
+
+//solution (b)
+s=(N_s-N)/N_s;
+cu_loss=s*p_rotor;
+disp(sprintf("(b) The rotor copper loss is %d kW",cu_loss));
+
+//solution (c)
+p_m=(1-s)*p_rotor;
+disp(sprintf("(c) The mechanical power developed is %d kW",p_m));
+
+//solution (d)
+p_shaft=p_m-f_loss; //output power
+disp(sprintf("(d) The mechanical power developed to load is %d kW",p_shaft));
+
+//solution (e)
+eff=p_shaft/p_in;
+disp(sprintf("(e) The efficiency of the motor is %f %%",eff*100));
+
+//END
diff --git a/1445/CH10/EX10.9/ch10_ex_9.sce b/1445/CH10/EX10.9/ch10_ex_9.sce
new file mode 100644
index 000000000..83153991b
--- /dev/null
+++ b/1445/CH10/EX10.9/ch10_ex_9.sce
@@ -0,0 +1,41 @@
+//CHAPTER 10- THREE-PHASE INDUCTION MACHINES
+//Example 9
+
+disp("CHAPTER 10");
+disp("EXAMPLE 9");
+
+//VARIABLE INITIALIZATION
+p=150*1000; //in Watts
+v=3000; //in Volts
+f=50; //in Hertz
+P=6; //number of poles
+ratio=3.6; //ratio of stator turn to rotor turn
+r2=0.1; //rotor resistance in Ohms
+L=3.61/1000; //leakage inductance per phase in Henry
+
+//SOLUTION
+
+//solution (a)
+X2=2*%pi*f*L;
+E1=v/sqrt(3);
+E2=E1*(1/ratio);
+z1=sqrt((r2^2)+(X2^2));
+I2=E2/z1; //rotor current
+I_s=I2/ratio; //stator current
+N_s=(120*f)/P;
+w=(2*%pi*N_s)/60;
+T_s1=(3*E2^2*r2)/(w*z1^2);
+disp(sprintf("(a) The starting current is %f A and torque is %f N-m",I_s,T_s1));
+
+//solution (b)
+I_s1=30;
+I_r=ratio*I_s1;
+r=sqrt(((E2/I_r)^2)-(X2^2));
+r_ext=r-r2;
+z2=sqrt((r_ext^2)+(X2^2));
+T_s2=(3*E2^2*r)/(w*z2^2);
+disp(sprintf("(b) The external resistance is %f Ω and torque is %f N-m",r_ext,T_s2));
+
+//There answers are different due to precision of floating point numbers
+
+//END
generated by cgit (git 2.34.1) at 2024-12-19 13:10:49 +0000