diff options
Diffstat (limited to '3760/CH3')
27 files changed, 603 insertions, 0 deletions
diff --git a/3760/CH3/EX3.10/Ex3_10.sce b/3760/CH3/EX3.10/Ex3_10.sce new file mode 100644 index 000000000..9d1e3c533 --- /dev/null +++ b/3760/CH3/EX3.10/Ex3_10.sce @@ -0,0 +1,30 @@ +clc;
+disp('case a');
+f1=2/3; // fraction of slot wound
+p1=f1*180; // phase spread , 2/3 of the slots are wound
+kd1=sin((p1/2)*(%pi/180))/((p1/2)*(%pi/180)); // distribution factor
+p2=180; // phase spread , All the slots are wound
+f2=1; // fraction of slot wound
+kd2=sin((p2/2)*(%pi/180))/((p2/2)*(%pi/180)); // distribution factor
+// output is directly proportional to the product of fraction of slots wound and distribution factor
+ro=(f2*kd2)/(f1*kd1); // It is assumed that frequency ,flux per pole and the conductor cross section is same
+printf('Ratio of outputs is %f \n',ro);
+rc=f2/f1;
+printf('ratio of copper required is %f\n',rc);
+disp('case b');
+p3=60; // for 3-phase winding ,phase spread is 60 degrees
+kd3=sin((p3/2)*(%pi/180))/((p3/2)*(%pi/180)); // distribution factor
+// since all the slots are wound for both 1-phase and 3-phase, fraction of the slots wound is 1
+f3=1; // fraction of the slots wound
+ro=kd3/kd2;
+printf('Ratio of outputs is %f \n',ro);
+rc=f2/f3;
+printf('ratio of copper required is %f\n',rc);
+disp('case c');
+f4=1; // fraction of the slots wound
+p4=90; // for 2-phase winding ,phase spread is 90 degrees
+kd4=sin((p4/2)*(%pi/180))/((p4/2)*(%pi/180)); // distribution factor
+ro=kd3/kd4;
+printf('Ratio of outputs is %f \n',ro);
+rc=f3/f4;
+printf('ratio of copper required is %f\n',rc);
diff --git a/3760/CH3/EX3.11/Ex3_11.sce b/3760/CH3/EX3.11/Ex3_11.sce new file mode 100644 index 000000000..4b1729239 --- /dev/null +++ b/3760/CH3/EX3.11/Ex3_11.sce @@ -0,0 +1,47 @@ +clc;
+d=0.28; // air gap diameter
+l=0.23; // core length of alternator
+spp=4; // slots per pole per phase
+b1=0.87; // amplitude of flux density in fundamental harmonic in Tesla
+b3=0.24; // amplitude of flux density in third harmonic in Tesla
+b5=0.14; // amplitude of flux density in fifth harmonic in Tesla
+p=6; // number of poles in alternator
+np=3; // number of phases
+c=8; // number of conductor per slot
+f=50; // frequency of supply
+f1=(2*d*l*b1)/p; // flux for fundamental harmonic
+f3=(2*d*l*b3)/(p*3); // flux for third harmonic
+f5=(2*d*l*b5)/(p*5); // flux for fifth harmonic
+ap=180/(spp*np); // slot angular pitch
+kd1=sin(((spp*ap)/2)*(%pi/180))/(spp*sin((ap/2)*(%pi/180))); // distribution factor for fundamental harmonic
+kd3=sin(((3*spp*ap)/2)*(%pi/180))/(spp*sin(((3*ap)/2)*(%pi/180))); // distribution factor for third harmonic
+kd5=sin(((5*spp*ap)/2)*(%pi/180))/(spp*sin(((5*ap)/2)*(%pi/180))); // distribution factor for fifth harmonic
+// coil is short pitched by one slot, therefore
+e=180/(spp*np); // chording angle
+cs1=cos((e/2)*(%pi/180)); // coil span factor for fundamental harmonic
+cs3=cos(((3*e)/2)*(%pi/180)); // coil span factor for third harmonic
+cs5=cos(((5*e)/2)*(%pi/180)); // coil span factor for fifth harmonic
+kw1=cs1*kd1; // winding factor for fundamental harmonic
+kw3=cs3*kd3; // winding factor for third harmonic
+kw5=cs5*kd5; // winding factor for fifth harmonic
+ts=spp*np*p; // total number of slots
+tt=(ts*c)/2; // total number of turns
+nph=tt/np; // series turn per phase
+ep1=sqrt(2)*%pi*f*kw1*nph*f1; // emf per phase for fundamental harmonics
+ep3=(ep1*kw3*3*f3)/(kw1*f1); // emf per phase for third harmonics
+ep5=(ep1*kw5*5*f5)/(kw1*f1); // emf per phase for fifth harmonics
+disp('case a(1): star connected alternator');
+ep=sqrt(ep1^2+ep3^2+ep5^2);
+printf('Resultant EMF per phase is %f V\n',ep);
+// third frequency line emf doesnot appear in line voltage
+el=sqrt(3)*sqrt(ep1^2+ep5^2);
+printf('Resultant line voltage is %f V\n',el);
+disp('case a(2): Delta connected alternator');
+// third frequency line emf doesnot appear in line and phase voltage as they are short circuited by closed delta
+ep=sqrt(ep1^2+ep5^2);
+printf('Resultant EMF per phase(also line voltage) is %f V\n',ep);
+disp('case b: delta connected alternator ');
+rpp=10; // reactance per phase
+// emf to due first and third harmonic cancels each other but third harmonic gives rise to circulating current
+I=(3*ep3)/(3*np*rpp);
+printf('Circulating current is %f A',I);
diff --git a/3760/CH3/EX3.12/Ex3_12.sce b/3760/CH3/EX3.12/Ex3_12.sce new file mode 100644 index 000000000..c69386c56 --- /dev/null +++ b/3760/CH3/EX3.12/Ex3_12.sce @@ -0,0 +1,19 @@ +clc;
+spp=3; // slots per pole per phase
+np=3; // number of phases
+cs=8; // coil span
+fp=0.20; // fraction of third harmonic in flux density wave in air gap
+sp=spp*np; // slots per pole
+v=180/sp; // slot angular pitch
+kd1=sin(((spp*v)/2)*(%pi/180))/(spp*sin((v/2)*(%pi/180))); // distribution factor
+// for a coil span of 8 slots the coil is short pitched by one slot
+e=v; // chording angle
+kp1=cos((e/2)*(%pi/180)); // coil span factor
+kw1=kp1*kd1; // winding factor
+kd3=sin(((3*spp*v)/2)*(%pi/180))/(spp*sin(((v*3)/2)*(%pi/180))); // distribution factor for third harmonic
+kp3=cos(((3*e)/2)*(%pi/180)); // coil span factor for third harmonic
+kw3=kd3*kp3; // winding factor for third harmonic
+er=(kw3/kw1)*fp; // ratio of third harmonic emf to fundamental emf
+ep=sqrt(1+er^2); // ratio of net emf to fundamental emf
+pi=((ep-1)/1)*100;
+printf('Percentage increase in per phase rms emf is %f percent',pi);
diff --git a/3760/CH3/EX3.13/Ex3_13.sce b/3760/CH3/EX3.13/Ex3_13.sce new file mode 100644 index 000000000..86c0bf447 --- /dev/null +++ b/3760/CH3/EX3.13/Ex3_13.sce @@ -0,0 +1,29 @@ +clc;
+p=6; // number of poles in alternator
+s=42; // number of slots in alternator
+f=0.012; // flux per pole
+t=8; // number of turns in full pitch coil
+F=50; // frequency of alternator
+disp('case a');
+np=2; // number of phases
+spp=42/(p*np); // slots per pole per phase
+// spp is not an integer, the 2-phase winding is a fractional slot winding, therefore Sk is given by
+Sk=spp*2;
+v=90; // phase spread for 2-phase winding
+kd=sind(v/2)/(Sk*sind(v/(2*Sk))); // distribution factor
+kw=kd; // winding factor as kp=1
+nph=(s*t)/np; // per phase series turn
+eph=sqrt(2)*F*%pi*kw*nph*f;
+el=sqrt(2)*eph;
+printf('Phase emf is %f V\n',eph);
+printf('Line emf is %f V\n ',el);
+disp('case b');
+np=3; // number of phases
+v=60; // phase spraed for 3-phase winding
+kd=sind(v/2)/(Sk*sind(v/(2*Sk))); // distribution factor
+kw=kd; // winding factor as kp=1
+nph=(s*t)/np; // per phase series turn
+eph=sqrt(2)*F*%pi*kw*nph*f;
+el=sqrt(3)*eph;
+printf('Phase emf is %f V\n',eph);
+printf('Line emf is %f V\n ',el);
diff --git a/3760/CH3/EX3.14/Ex3_14.sce b/3760/CH3/EX3.14/Ex3_14.sce new file mode 100644 index 000000000..0755c00db --- /dev/null +++ b/3760/CH3/EX3.14/Ex3_14.sce @@ -0,0 +1,30 @@ +clc;
+s=81; // number of slots
+p=6; // number of poles
+np=3; // number of phases
+cs=13; // coil span in terms of slot pitches
+v=60; // phase spread for three phase winding
+f3=0.4; // ratio of third harmonic flux to first harmonic flux
+f5=0.25; // ratio of fifth harmonic flux to first harmonic flux
+spp=s/(p*np); // // spp is not an integer, the 2-phase winding is a fractional slot winding, therefore Sk is given by
+Sk=spp*2;
+ap=(p*180)/s;
+Cs=cs*ap; // coil span
+e=180-Cs; // chording angle
+kd1=sind(v/2)/(Sk*sind(v/(2*Sk))); // distribution factor for fundamental harmonic
+kp1=cosd(e/2); // coil span factor
+kd3=sind((3*v)/2)/(Sk*sind((3*v)/(2*Sk))); // distribution factor for third harmonic
+kp3=cosd((3*e)/2); // coil span factor for third harmonic
+kd5=sind((5*v)/2)/(Sk*sind((5*v)/(2*Sk))); // distribution factor for fifth harmonic
+kp5=cosd((5*e)/2); // coil span factor for fifth harmonic
+kw1=kd1*kp1; // winding factor for fundamental harmonics
+kw3=kd3*kp3; // winding factor for third harmonic
+kw5=kd5*kp5; // winding factor for fifth harmonic
+ep3=(kw3*f3)/kw1;
+printf('rms value of third harmonic emf is %f times the fundamental harmonic emf\n',ep3);
+ep5=(kw5*f5)/kw1;
+printf('rms value of fifth harmonic emf is %f times the fundamental harmonic emf\n',ep5);
+ep=sqrt(1+ep3^2+ep5^2); // resultant phase emf
+el=sqrt(3)*sqrt(1+ep5^2); // resultant line emf
+r=el/ep;
+printf('Ratio of resultant line emf to resultant phase emf is %f',r);
diff --git a/3760/CH3/EX3.15/Ex3_15.sce b/3760/CH3/EX3.15/Ex3_15.sce new file mode 100644 index 000000000..56ea082a9 --- /dev/null +++ b/3760/CH3/EX3.15/Ex3_15.sce @@ -0,0 +1,11 @@ +clc;
+B=1; // peak flux density in Tesla
+l=0.8; // length of armature conductor
+v=20; // velocity of coil
+// for 0< theta <30 coil aa' is moving in zero B-wave, emf for this range is zero
+// for 30< theta < 60 coil side a is cutting through B-wave and coil side a' is cutting zero B-wave, therefore
+e1=B*l*v; // emf at given position of coil
+// for 60< theta < 150 both coil sides are cutting through B-wave
+e2=2*B*l*v; // net emf at given position of coil
+rms=sqrt((1/%pi)*(((e1^2*%pi*2)/6)+((e2^2*%pi)/2)));
+printf('RMS value of generated emf in one single turn coil is %f V',rms);
diff --git a/3760/CH3/EX3.16/Ex3_16.sce b/3760/CH3/EX3.16/Ex3_16.sce new file mode 100644 index 000000000..035a5678e --- /dev/null +++ b/3760/CH3/EX3.16/Ex3_16.sce @@ -0,0 +1,15 @@ +clc;
+f=50; // frequency of alternator
+B=1; // peak flux density
+t=360; // total turns
+v=60; // phase spread
+pi=0.6; // pole pitch
+l=0.8; // stator length
+cs=180; // coil span in electrical degrees
+nph=t/3; // series turn per phase
+Bp=(4*B*cosd(v/2))/%pi; // fundamental value of peak flux density
+F=(2*l*pi*Bp)/%pi; // Fundamental air-gap flux per pole
+kd=sind(v/2)/((v/2)*(%pi/180)); // distribution factor
+kw=kd; // winding factor , as kp=1
+eph=sqrt(2)*%pi*f*F*kw*nph;
+printf('RMS value of fundamental emf per phase is %f V',eph);
diff --git a/3760/CH3/EX3.18/Ex3_18.sce b/3760/CH3/EX3.18/Ex3_18.sce new file mode 100644 index 000000000..fd107806a --- /dev/null +++ b/3760/CH3/EX3.18/Ex3_18.sce @@ -0,0 +1,22 @@ +clc;
+p=6; // number of poles
+s=54; // number of slots
+n=1000; // speed of alternator in rpm
+t=80; // number of turn in coils A and B
+f=0.015; // flux per pole
+F=50; // given frequency of alternator
+// Coil A is over pitched by one slot and coil B is short pitched by one slot
+pp=s/p; // pole pitch
+sap=(p*180)/s; // slot angular pitch
+e1=(%pi*F*f*t)/sqrt(2); // EMF generated in one coil side of coil A or B
+// same EMF is generated in col side 11 but with a phase of (180+sap) degrees. Resultant of emf in coil side 1 and 11 is given by
+Ea=2*e1*cosd(sap/2); // net emf in coil side 1
+Eb=Ea; // net emf in coil side 2
+//Ea and Eb are in phase with each other from phasor diagram (fig. 3.26)
+disp('case a');
+en=Ea+Eb;
+printf('Resultant e.m.f when coils A and B are connected in series aiding is %f V\n',en);
+disp('case b');
+en=Ea-Eb;
+printf('Resultant e.m.f when coils A and B are connected in series opposing is %f V\n',en);
+
diff --git a/3760/CH3/EX3.19/Ex3_19.sce b/3760/CH3/EX3.19/Ex3_19.sce new file mode 100644 index 000000000..6814446d3 --- /dev/null +++ b/3760/CH3/EX3.19/Ex3_19.sce @@ -0,0 +1,14 @@ +clc;
+np=3; // number of phases
+p=2; // number of poles
+spp=5; // slots per pole per phase
+n=4; // number of turns in coil
+i=20; // per phase current
+v=(spp*180)/(spp*np); // phase spread
+imax=sqrt(2)*i; // maximum value of current
+mmf=spp*n*imax; // resultant amplitude of mmf
+kd=sind(v/2)/((v/2)*(%pi/180)); // distribution factor
+fp=(4*mmf*kd)/%pi; // peak value of fundamental component
+fr=(4*3*spp*n*i)/%pi^2; // rms value of fundamental component
+printf('Maximum value of the peak of fundamental m.m.f wave is %f AT/pole\n',fp);
+printf('RMS value of the peak of fundamental m.m.f wave is %f AT/pole\n',fr);
diff --git a/3760/CH3/EX3.2/Ex3_2.sce b/3760/CH3/EX3.2/Ex3_2.sce new file mode 100644 index 000000000..2de444f82 --- /dev/null +++ b/3760/CH3/EX3.2/Ex3_2.sce @@ -0,0 +1,25 @@ +clc;
+n=24; // Number of armature conductor
+v=2; // average voltage per conductor
+i=5; // current carrying capacity of each conductor
+disp('case a');
+a=2; // number of parallel path
+sc=n/a; // series connected conductor in each path
+Ea=sc*v; // output voltage
+Ia=i*a; // output current
+p=Ea*Ia; // power rating
+printf('Generator rating is %f W\n',p);
+disp('case b');
+a=4; // number of parallel path
+sc=n/a; // series connected conductor in each path
+Ea=sc*v; // output voltage
+Ia=i*a; // output current
+p=Ea*Ia; // power rating
+printf('Generator rating is %f W\n',p);
+disp('case c');
+a=6; // number of parallel path
+sc=n/a; // series connected conductor in each path
+Ea=sc*v; // output voltage
+Ia=i*a; // output current
+p=Ea*Ia; // power rating
+printf('Generator rating is %f W\n',p);
diff --git a/3760/CH3/EX3.20/Ex3_20.sce b/3760/CH3/EX3.20/Ex3_20.sce new file mode 100644 index 000000000..522ef1775 --- /dev/null +++ b/3760/CH3/EX3.20/Ex3_20.sce @@ -0,0 +1,17 @@ +clc;
+p=2; // number of pole
+i=24; // phase current
+t=300; // full pitched turns
+v=60; // phase spread
+np=3; // number of phases
+nph=t/np; // series turn per phase
+j=(nph*sqrt(2)*i*180)/(v*%pi); // peak value of uniform current density
+disp('case a');
+A=(j*v*%pi)/(2*180); // peak amplitude of trapezoidal m.m.f wave
+printf('Peak amplitude of trapezoidal m.m.f wave is %f ATs/pole\n',A);
+disp('case b');
+kd=sind(v/2)/((v/2)*(%pi/180)); // distribution factor
+fp=(4*kd*A)/%pi;
+printf('Peak value of fundamental mmf wave is %f AT/pole\n',fp);
+fr=(4*3*A)/(%pi^2*sqrt(2));
+printf('RMS value of fundamental mmf wave is %f AT/pole\n',fr);
diff --git a/3760/CH3/EX3.3/Ex3_3.sce b/3760/CH3/EX3.3/Ex3_3.sce new file mode 100644 index 000000000..75b386d92 --- /dev/null +++ b/3760/CH3/EX3.3/Ex3_3.sce @@ -0,0 +1,22 @@ +clc;
+p=4; // number of poles
+s=60; // number of slots
+c=8; // number of conductors per slot
+f=20*10^-3; // flux per pole
+nr=1500; // relative speed in rpm between field flux and armature winding
+disp('case a');
+// winding is lap connected
+a=p; // for lap connected winding , number of parallel path=number of pole
+z=s*c; // total number of conductors
+n=nr/60; // speed in rps
+E=(f*z*n*p)/a;
+printf('Generated EMF is %f V\n',E);
+disp('case b');
+kw=0.96; // winding factor
+nt=z/2; // Total number of turns
+nph=nt/3; // number of series turns per phase
+fg=(p*n)/2; // generated EMF frequency
+E=sqrt(2)*%pi*fg*nph*kw*f;
+printf('Generated EMF per phase is %f V\n',E);
+e=round(sqrt(3)*E);
+printf('Generated EMF between line terminal is %f V\n',e);
diff --git a/3760/CH3/EX3.30/Ex3_30.sce b/3760/CH3/EX3.30/Ex3_30.sce new file mode 100644 index 000000000..04c1b63de --- /dev/null +++ b/3760/CH3/EX3.30/Ex3_30.sce @@ -0,0 +1,7 @@ +clc;
+p=6; // number of poles in induction motor
+f=50; // frequency of motor
+d=1.2; // stator bore diameter
+// in one revolution peripheral distance of Pi*diameter is transversed
+v=(2*f*%pi*d)/p;
+printf('Linear velocity of travelling mmf wave is %f m/sec',v);
diff --git a/3760/CH3/EX3.32/Ex3_32.sce b/3760/CH3/EX3.32/Ex3_32.sce new file mode 100644 index 000000000..b73327fe2 --- /dev/null +++ b/3760/CH3/EX3.32/Ex3_32.sce @@ -0,0 +1,26 @@ +clc;
+p=2; // number of poles
+f=50; // frequency of machine
+D=1.6; // diameter of cylindrical rotor
+l=1.8; // length of cylindrical rotor
+g=0.012; // air gap length
+rm=4000; // peak value of rotor mmf
+rs=6000; // peak value of stator mmf
+ph=140; // phase difference between stator mmf and rotor mmf
+uo=4*%pi*10^-7; // free space permeability0
+disp('a');
+rp=sqrt(rm^2+rs^2+2*rm*rs*cosd(ph));
+printf('Resultant peak gap mmf is %f AT/pole\n',rp);
+disp('b');
+Bp=(uo*rp)/g;
+printf('Peak gap flux density is %f T\n',Bp);
+disp('c');
+ge=(uo*%pi*D*l*rp^2)/(4*g);
+printf('Total gap energy is %f Joules\n',ge);
+disp('d');
+T=(p*uo*%pi*D*l*rs*rm*sind(ph))/(4*g);
+printf('Electromagnetic torque is %f Nm\n',T);
+disp('e');
+wm=(4*%pi*f)/2; // synchronous speed
+P=(T*wm)/1000
+printf('Electromagnetic power is %f KW',P);
diff --git a/3760/CH3/EX3.33/Ex3_33.sce b/3760/CH3/EX3.33/Ex3_33.sce new file mode 100644 index 000000000..3b8035b69 --- /dev/null +++ b/3760/CH3/EX3.33/Ex3_33.sce @@ -0,0 +1,21 @@ +clc;
+d=0.8; // diameter of rotor machine
+l=0.5; // length of rotor machine
+g=0.005; // air gap length
+as=10000; // peak current density for stator
+ar=6000; // peak current density for rotor
+t=60; // torque angle
+disp('case a');
+p=2; // number of pole
+uo=4*%pi*10^-7; // free space permeability
+Fs=(as*d)/p; // peak stator mmf per pole
+Fr=(ar*d)/p; // peak rotor mmf per pole
+Te=(p*uo*%pi*d*l*Fs*Fr*sind(t))/(4*g);
+printf('Torque for given number of poles is %f Nm\n',Te);
+disp('case b');
+p=6; // number of pole
+uo=4*%pi*10^-7; // free space permeability
+Fs=(as*d)/p; // peak stator mmf per pole
+Fr=(ar*d)/p; // peak rotor mmf per pole
+Te=(p*uo*%pi*d*l*Fs*Fr*sind(t))/(4*g);
+printf('Torque for given number of poles is %f Nm\n',Te);
diff --git a/3760/CH3/EX3.35/Ex3_35.sce b/3760/CH3/EX3.35/Ex3_35.sce new file mode 100644 index 000000000..f295338c2 --- /dev/null +++ b/3760/CH3/EX3.35/Ex3_35.sce @@ -0,0 +1,34 @@ +clc;
+p=4; // number of poles
+np=3; // number of phases
+f=50; // frequency of alternator
+sap=8; // slot angular pitch
+c=12; // number of concentric coils in field winding
+tf=6; // turns per field coil
+ta=28; // series armature turn per phase
+ar=0.6; // armature radius
+la=4; // armature length
+g=0.06; // gap length
+w=0.96; // winding factor for armature winding
+fc=1000; // field current
+disp('case a');
+kd=sind((np*sap)/2)/(np*sind(sap/2)); // distribution factor
+kp=1; // coil span factor
+kf=kd*kp; // winding factor for field winding
+nf=tf*c; // number of field turn
+F=(4*kf*nf*fc)/(%pi*p);
+printf('Peak value of fundamental mmf produced by field winding is %f AT/pole\n',F);
+disp('case b');
+uo=4*%pi*10^-7; // free space permeability
+B=(uo*F)/g;
+printf('Peak value of fundamental flux density wave is %f T\n',B);
+disp('case c');
+v=(4*B*la*ar)/p;
+printf('Fundamental value of air gap flux per pole is %f W\n',v);
+disp('case d');
+eph=sqrt(2)*%pi*f*v*ta*w;
+printf('EMF per phase is %f V\n',eph);
+el=sqrt(3)*round(eph);
+printf('Line EMF is %f V',el);
+
+
diff --git a/3760/CH3/EX3.36/Ex3_36.sce b/3760/CH3/EX3.36/Ex3_36.sce new file mode 100644 index 000000000..29f3dfd5d --- /dev/null +++ b/3760/CH3/EX3.36/Ex3_36.sce @@ -0,0 +1,40 @@ +clc;
+np=3; // number of phases
+p=6; // number of poles
+f=50; // frequency of alternator
+e=415; // open circuit emf;
+s=36; // number of slots in armature
+t=4; // number of turns per coil
+g=0.18; // air gap diameter
+l=0.4; // core length
+G=0.002; // gap length
+T=42; // number of turns in field winding
+kf=0.96; // winding factor
+uo=4*%pi*10^-7; // free space permeability
+disp('case a');
+nph=(s*t)/np; // series turn per phase
+spp=s/(p*np); // slots per pole per phase
+v=180/p; // slot angular pitch
+kd=sind((spp*v)/2)/(spp*sind(v/2)); // distribution factor
+Flu=e/(sqrt(2)*sqrt(3)*%pi*f*nph*kd); // flux per pole
+B=(p*Flu*2)/(4*l*g);
+printf('Peak value of fundamental flux density wave is %f T\n',B);
+disp('case b');
+Fl=(G*B)/uo; // peak fundamental field mmf wave
+printf('Peak value of fundamental mmf wave is %f AT/pole\n',Fl);
+If=(%pi*Fl*p)/(4*kf*T);
+printf('DC field current is %f A\n',If);
+disp('case c');
+Te=114; // given torque
+Ta=146; // torque angle
+Fm=floor((Te*4*G)/(p*uo*%pi*g*l*Fl*sind(Ta)));
+printf('Peak value of fundamental armature mmf is %f AT/pole\n',Fm);
+Fr=sqrt(Fl^2+Fm^2+2*Fl*Fm*cosd(Ta));
+printf('Resultant mmf per pole is %f AT/pole\n',Fr);
+disp('case d')
+ia=(Fm*2*%pi*p)/(12*kd*nph*sqrt(2));
+printf('RMS value of armature current is %f A\n',ia);
+ns=1000; // speed in rpm
+wm=(2*%pi*ns)/60; // angular speed in rps
+pf=(Te*wm)/(sqrt(3)*e*ia);
+printf('Power factor is %f lagging',pf);
diff --git a/3760/CH3/EX3.37/Ex3_37.sce b/3760/CH3/EX3.37/Ex3_37.sce new file mode 100644 index 000000000..2dfb9ff79 --- /dev/null +++ b/3760/CH3/EX3.37/Ex3_37.sce @@ -0,0 +1,6 @@ +clc;
+n1=0.95; // efficiency of transformer 1
+lo=((1/n1)-1); // fraction of output lost
+d=2; // Linear dimension of transformer B is two times the Linear dimension of transformer A
+nb=(1/(1+((1*lo)/d)))*100;
+printf('Full load efficiency of transformer B is %f percent',nb);
diff --git a/3760/CH3/EX3.39/Ex3_39.sce b/3760/CH3/EX3.39/Ex3_39.sce new file mode 100644 index 000000000..01cbed2b9 --- /dev/null +++ b/3760/CH3/EX3.39/Ex3_39.sce @@ -0,0 +1,18 @@ +clc;
+t0=0; // accelerating period
+t1=30; // decelerating period
+l1=2000; // maximum load during accelerating period
+lf=600; // maximum load during decelerating period
+l=1000; // load during full load
+tf=60; // full load duration
+td=10; // decelerating duration
+tde=20; // decting period
+sa=l1/t1; // slope during accelerating
+sd=lf/td; // slope during decelerating
+e1=integrate('(sa*t)^2','t',t0,t1); // term 1 for finding motor rating
+e2=l^2*tf; // term 2 for finding motor rating
+e3=integrate('(sd*t)^2','t',t0,td); // term 3 for finding motor rating
+T=t1+tf+td+tde; // total duration
+R=sqrt((1/120)*(e1+e2+e3));
+printf('KW rating of motor is %f KW',R);
+disp('Choose a motor of rating above the calculated rating');
diff --git a/3760/CH3/EX3.4/Ex3_4.sce b/3760/CH3/EX3.4/Ex3_4.sce new file mode 100644 index 000000000..438dae1c9 --- /dev/null +++ b/3760/CH3/EX3.4/Ex3_4.sce @@ -0,0 +1,25 @@ +clc;
+p1=4; // number of poles in slip ring induction motor
+p2=6; // number of poles in synchronous motor
+f=50; // frequency of supply
+ns=(120*f)/p2; // synchronous motor speed
+ni=(120*f)/p1; // induction motor speed
+disp('case a(1)');
+// when synchronous motor is driven in direction opposite to the rotating field produced the induction motor stator
+nr=ns+ni; // relative speed
+F=(p1*nr)/120;
+printf('Frequency of EMF at rotor slip ring terminals is %f Hz\n',F);
+disp('case a(2)');
+// when synchronous motor is driven in direction of the rotating field produced the induction motor stator
+nr=ni-ns; // relative speed
+F=(p1*nr)/120;
+printf('Frequency of EMF at rotor slip ring terminals is %f Hz\n',F);
+disp('case b');
+fn=150; // frequency of rotor terminal voltage required
+// let new number of pole be pn then relative speed is nr=ns+(120*50)/pn;
+pn=((fn*120)-(120*f))/ns;
+printf('Number of poles that the induction motor must have is %f \n',pn);
+disp('case c');
+pi=8; // number of poles in induction motor
+ps=(120*f*pi)/((fn*120)-(120*f));
+printf('Number of synchronous motor poles required is %f',ps);
diff --git a/3760/CH3/EX3.40/Ex3_40.sce b/3760/CH3/EX3.40/Ex3_40.sce new file mode 100644 index 000000000..32f2f8b04 --- /dev/null +++ b/3760/CH3/EX3.40/Ex3_40.sce @@ -0,0 +1,20 @@ +clc;
+T=80; // total duration
+t1=5-0; // duration of first increasing loading period
+t2=36-5; // duration of second increasing loading period
+t3=39-36; // duration of first decreasing loading period
+t4=55-39; // duration of second decreasing loading period
+t5=80-55; // duration of uniform loading
+l1=150; // initial load
+l2=1000; // load at 5th sec
+l3=1400; // load at 36th sec
+l4=300; // load at 39th sec
+l5=150; // load during uniform loading
+T1=(t1/3)*(l1^2+l2^2+l1*l2); // term 1 for evaluating rms power
+T2=(t2/3)*(l2^2+l3^2+l2*l3); // term 2 for evaluating rms power
+T3=(t3/3)*(l3^2+l4^2+l3*l4); // term 3 for evaluating rms power
+T4=(t4/3)*(l4^2+l5^2+l4*l5); // term 4 for evaluating rms power
+T5=t5*l5^2; // term 5 for evaluating rms power
+R=sqrt((1/T)*(T1+T2+T3+T4+T5));
+printf('As per the load time graph rating is %f KW',R);
+disp('Choose a motor of rating above the calculated rating');
diff --git a/3760/CH3/EX3.41/Ex3_41.sce b/3760/CH3/EX3.41/Ex3_41.sce new file mode 100644 index 000000000..98b2ed0b7 --- /dev/null +++ b/3760/CH3/EX3.41/Ex3_41.sce @@ -0,0 +1,21 @@ +clc;
+p=200; // rated KVA of transformer
+n=0.98; // efficiency
+t1=20; // temperature after one hour of operation
+t2=34; // temperature after two hour of operation
+r=1/3; // ratio of full load core losses to ohmic loss
+disp('case a');
+t=[(t2/t1)-1];
+th=-1/log(t); // heating time constant in hours
+theta=t1/(1-exp(-1/th));
+printf('Final steady temperature rise of the transformer on rated load is %f degree celsius\n',theta);
+disp('case b');
+f=1.2; //with increased heat dissipation ,ratio of new loss to old loss
+Pn=sqrt((f*(1+r))-r)*p;
+printf('New KVA rating of transformer is %f KVA\n',Pn);
+// for a temperature rise of 78 degree
+t3=78;
+f=(t3/theta)*f; // ratio of new loss to old loss
+Pn=sqrt((f*(1+r))-r)*p;
+printf('New KVA rating of transformer is %f KVA\n',Pn);
+
diff --git a/3760/CH3/EX3.42/Ex3_42.sce b/3760/CH3/EX3.42/Ex3_42.sce new file mode 100644 index 000000000..35e15d311 --- /dev/null +++ b/3760/CH3/EX3.42/Ex3_42.sce @@ -0,0 +1,14 @@ +clc;
+p=100; // KW rating of transformer
+al=1; // ratio of core loss to ohmic loss
+th=3; // heating time constant in hours
+h=1; // duration in hour for which KVA rating has to be determined
+disp('case a');
+// constant losses are equal to variable losses
+pn=p*sqrt(((1+al)/(1-exp(-h/th)))-al);
+printf('One hour rating is %f KW\n',pn);
+disp('case b');
+// consatant losses are neglected
+al=0; // ratio of core loss to ohmic loss
+pn=p*sqrt(((1+al)/(1-exp(-h/th)))-al);
+printf('One hour rating is %f KW\n',pn);
diff --git a/3760/CH3/EX3.43/Ex3_43.sce b/3760/CH3/EX3.43/Ex3_43.sce new file mode 100644 index 000000000..1755e5c53 --- /dev/null +++ b/3760/CH3/EX3.43/Ex3_43.sce @@ -0,0 +1,5 @@ +clc;
+t=1/2; //ratio of continuous rating to one hour rating
+p=2; // ratio of new KVA rating to old KVA rating
+al=2*(p*t);
+printf('Ratio of core loss to ohmic loss is %f ',al);
diff --git a/3760/CH3/EX3.5/Ex3_5.sce b/3760/CH3/EX3.5/Ex3_5.sce new file mode 100644 index 000000000..5d835efab --- /dev/null +++ b/3760/CH3/EX3.5/Ex3_5.sce @@ -0,0 +1,37 @@ +clc;
+p=4; // number of pole
+f=50; // frequency of supply
+ns=420; // stator turns
+nr=240; // rotor turns
+F=30*10^-3; // flux per pole
+kw=0.96; // winding factor for both stator and rotor
+nsph=ns/3; // stator turn per phase
+nrph=nr/3; // rotor turn per phase
+es=sqrt(2)*%pi*f*kw*nsph*F; // stator turn per phase
+disp('case a');
+// rotor is stationary
+s=1; // at standstill slip=1
+er=sqrt(2)*%pi*f*kw*nrph*F;
+printf('frequency of EMF in stator is %f Hz\n',f);
+printf('frequency of EMF in rotor is %f Hz\n',f);
+printf('Per phase stator EMF is %f V\n',es);
+printf('Per phase rotor EMF is %f V\n',er);
+disp('case b');
+sr=1440; // speed of rotor in rpm in direction of rotating flux
+Ns=(120*f)/p; // speed of rotating flux
+s=(Ns-sr)/Ns; // slip
+fr=s*f; // frequency of EMF in rotor
+er=sqrt(2)*%pi*fr*kw*nrph*F;
+printf('frequency of EMF in stator is %f Hz\n',f);
+printf('frequency of EMF in rotor is %f Hz\n',fr);
+printf('Per phase stator EMF is %f V\n',es);
+printf('Per phase rotor EMF is %f V\n',er);
+disp('case c');
+sr=1440; // speed of rotor in rpm opposite to the direction of rotating flux
+s=(Ns+sr)/Ns; // slip
+fr=s*f; // frequency of EMF in rotor
+er=sqrt(2)*%pi*fr*kw*nrph*F;
+printf('frequency of EMF in stator is %f Hz\n',f);
+printf('frequency of EMF in rotor is %f Hz\n',fr);
+printf('Per phase stator EMF is %f V\n',es);
+printf('Per phase rotor EMF is %f V\n',er);
diff --git a/3760/CH3/EX3.6/Ex3_6.sce b/3760/CH3/EX3.6/Ex3_6.sce new file mode 100644 index 000000000..db8332e66 --- /dev/null +++ b/3760/CH3/EX3.6/Ex3_6.sce @@ -0,0 +1,25 @@ +clc;
+disp('case a');
+s=54; // number of slots in stator,3 phase
+p=6; // number of poles
+spp=s/(3*p); // slots per pole per phase
+v=(p*180)/s; // slot angular pitch
+k1=sin(((spp*v)/2)*(%pi/180))/(spp*sin((v/2)*(%pi/180))); // fundamental harmonics
+k3=sin(((3*spp*v)/2)*(%pi/180))/(spp*sin(((3*v)/2)*(%pi/180))); // third harmonic
+k5=sin(((5*spp*v)/2)*(%pi/180))/(spp*sin(((5*v)/2)*(%pi/180))); // fifth harmonic
+printf('First harmonic component is %f\n',k1);
+printf('Third harmonic component is %f\n',k3);
+printf('Fifth harmonic component is %f\n',k5);
+disp('case b');
+s=48; // number of slots in stator,3 phase
+p=6; // number of poles
+spp=s/(3*p); // slots per pole per phase
+sk=spp*3;
+v=(p*180)/s; // slot angular pitch
+ps=spp*v; // phase spread
+k1=sin(((ps)/2)*(%pi/180))/(sk*sin(((ps)/(sk*2))*(%pi/180))); // fundamental harmonics
+k3=sin(((3*ps)/2)*(%pi/180))/(sk*sin(((3*ps)/(sk*2))*(%pi/180))); // third harmonic
+k5=sin(((5*ps)/2)*(%pi/180))/(sk*sin(((5*ps)/(sk*2))*(%pi/180))); // fifth harmonic
+printf('First harmonic component is %f\n',k1);
+printf('Third harmonic component is %f\n',k3);
+printf('Fifth harmonic component is %f\n',k5);
diff --git a/3760/CH3/EX3.8/Ex3_8.sce b/3760/CH3/EX3.8/Ex3_8.sce new file mode 100644 index 000000000..5a126aa39 --- /dev/null +++ b/3760/CH3/EX3.8/Ex3_8.sce @@ -0,0 +1,23 @@ +clc;
+disp('case a');
+cs=160*(%pi/180); // coil span in radian
+ps=120*(%pi/180); // phase spread
+kd=sin(ps)/(ps/2); // distribution factor for uniformly distributed winding
+e=180-(cs*(180/%pi)); // chording angle
+kp=cos((e/2)*(%pi/180)); // Coil span factor
+wf=kd*kp; // winding factor
+disp('Distribution factor is');
+disp(kd);
+disp('Winding factor is');
+disp(wf);
+disp('case b');
+s=9; // number of slots per pole
+sa=180/s; // slot angular pitch
+// for a phase spread of 120 , 6*20=120, 6 adjacent slots must belong to the same phase, therefore
+p=6; // poles belonging to same phase
+kd=sin(ps/2)/(p*sin(ps/(2*6)));
+wf=kd*kp;
+disp('Distribution factor is');
+disp(kd);
+disp('Winding factor is');
+disp(wf);
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