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| author | priyanka | 2015-06-24 15:03:17 +0530 |
|---|---|---|
| committer | priyanka | 2015-06-24 15:03:17 +0530 |
| commit | b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b (patch) | |
| tree | ab291cffc65280e58ac82470ba63fbcca7805165 /2252 | |
| download | Scilab-TBC-Uploads-b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b.tar.gz Scilab-TBC-Uploads-b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b.tar.bz2 Scilab-TBC-Uploads-b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b.zip | |
initial commit / add all books
Diffstat (limited to '2252')
236 files changed, 4608 insertions, 0 deletions
diff --git a/2252/CH1/EX1.1/Ex1_1.sce b/2252/CH1/EX1.1/Ex1_1.sce new file mode 100755 index 000000000..341456e64 --- /dev/null +++ b/2252/CH1/EX1.1/Ex1_1.sce @@ -0,0 +1,7 @@ +
+//By KCL, I1 + I2=2.25
+I1=10/(2+8)
+I2=2.25-I1
+r=(10-5*I2)/I2
+mprintf("r=%d ohm, current in branch ABC=%d A and current in branch ADC=%f A", r, I1, I2)
+
diff --git a/2252/CH1/EX1.10/Ex1_10.sce b/2252/CH1/EX1.10/Ex1_10.sce new file mode 100755 index 000000000..f188ad745 --- /dev/null +++ b/2252/CH1/EX1.10/Ex1_10.sce @@ -0,0 +1,14 @@ +
+//refer Fig.1.22(a) in the textbook
+//resistance between A and B is removed
+//I1 be current in branch CD
+//applying KCL
+//100-I1 is the current in branch AF
+//I1-50 is the current in branch DE
+//70-I1 is the current in branch FE
+//applying KVL for mesh CDEFC, we get,
+I1=56
+V=.1*I1+.15*(I1-50) //thevenin's voltage
+r=(.1+.15)*(.1+.15)/(.25+.25) //thevenin's equivalent resistance
+I=V/(r+.05)
+mprintf("Current flowing in the branch AB of 0.05 ohm resistance is %f A", I)
diff --git a/2252/CH1/EX1.11/Ex1_11.sce b/2252/CH1/EX1.11/Ex1_11.sce new file mode 100755 index 000000000..f85950e2d --- /dev/null +++ b/2252/CH1/EX1.11/Ex1_11.sce @@ -0,0 +1,8 @@ +
+//by Norton's Theorem
+I=2*10//total current produced by current source
+r=2*2/(2+2)//resultant resistance of current source
+In=20*r/(r+1)//norton current
+Rn=1+r//norton resistance
+I=In*Rn/(Rn+8)
+mprintf("Current through the load resistance of 8 ohm=%f A from A to B", I)
diff --git a/2252/CH1/EX1.12/Ex1_12.sce b/2252/CH1/EX1.12/Ex1_12.sce new file mode 100755 index 000000000..065bae10d --- /dev/null +++ b/2252/CH1/EX1.12/Ex1_12.sce @@ -0,0 +1,17 @@ +
+//circuit has 4 nodes, viz, A, B, C and D
+//node D is taken as reference node
+//voltages at A, B and C be Va, Vb and Vc respectively
+//applying KCL
+//at node A, 7*Va-Vb-Vc=25
+//at node B, -4*Va+19*Vb-10*Vc=0
+//at node C, -4*Va-10*Vb+19*Vc=-40
+a=[7 -1 -1;-4 19 -10;-4 -10 19]
+b=[25;0;-40]
+v=inv(a)*b
+Va=v(1,1)
+Vb=v(2,1)
+Vc=v(3,1)
+I=(Va-Vc)/5
+mprintf("Current in 5 ohm AC branch=%f A from A to C", I)
+//error in textbook answer
diff --git a/2252/CH1/EX1.13/Ex1_13.sce b/2252/CH1/EX1.13/Ex1_13.sce new file mode 100755 index 000000000..4994e9580 --- /dev/null +++ b/2252/CH1/EX1.13/Ex1_13.sce @@ -0,0 +1,6 @@ +
+V=3*20/(2+3)//thevenin's voltage
+r=1+2*3/(2+3)//thevenin's equivalent resistance
+R=r
+Pmax=V^2/(4*r)
+mprintf("Max power transferred to the load is %f W when load resistance is %f ohm", Pmax, R)
diff --git a/2252/CH1/EX1.14/Ex1_14.sce b/2252/CH1/EX1.14/Ex1_14.sce new file mode 100755 index 000000000..fb3e10630 --- /dev/null +++ b/2252/CH1/EX1.14/Ex1_14.sce @@ -0,0 +1,16 @@ +
+//inner delta DEF is transformed to equivalent star connection having resistances Ra, Rb, Rc
+Ra=1.5*2.5/(1.5+2.5+1)
+Rb=1.5*1/(1.5+2.5+1)
+Rc=1*2.5/(1.5+2.5+1)
+//inner portion of obtained star network ABC is converted into equivalent delta with resistances R1, R2, R3
+R1=4+5.05+4*5.05/5
+R2=4+5+4*5/5.05
+R3=5+5.05+5*5.05/4
+//now the network reduces to the form in which the resistances across a branch are in parallel
+//let equivalent resistances be Rac, Rbc and Rab
+Rac=5*R1/(5+R1)
+Rbc=5*R2/(5+R2)
+Rab=5*R3/(5+R3)
+R=(Rac+Rbc)*Rab/(Rac+Rbc+Rab)
+mprintf("Equivalent resistance between A and B=%f ohm",R)
diff --git a/2252/CH1/EX1.16/Ex1_16.sce b/2252/CH1/EX1.16/Ex1_16.sce new file mode 100755 index 000000000..bb07e4d03 --- /dev/null +++ b/2252/CH1/EX1.16/Ex1_16.sce @@ -0,0 +1,41 @@ +
+//by Superposition Theorem
+//consider 2 V battery alone
+R1 =(3+1)*2/(3+1+2) //equivalent resistance of Raf, Rfg, Rab
+R2 =(1+R1)*12/(1+R1+12) //equivalent resistance of Rad, R1, Rde
+R=1+2+R2 //total resistance of the circuit
+I1=2/R
+I2=I1*12/(1+R1+12)
+I3=I2*4/(2+4) //current through 2 ohm
+//consider 4 V battery alone
+I4=34/71 //current through 2 ohm
+I=I3+I4
+mprintf("By Superposition Theorem, current through the 2 ohm resistance is %f A from A to B\n", I)
+//by Thevenin's Theorem
+//applying KCL
+//for mesh CDHIC, 15*i1+12*i2=2
+//for mesh DEGHD, 12*i1+17*i2=4
+a=[15 12;12 17]
+b=[2;4]
+i=inv(a)*b
+i1=i(1,1)
+i2=i(2,1)
+Vab=4-3*i2-i2
+R1=(1+2)*12/(1+2+12) //R1 is equivalent resistance of Rcd, Rci, Rdh
+R=(1+R1)*(3+1)/(1+R1+3+1) //thevenin's equivalent resistance
+I=Vab/(R+2)
+mprintf("By Thevenin Theorem, current through 2 ohm resistance is %f A from A to B\n", I)
+//by Maxwell Mesh Analysis
+//applying KVL
+//for mesh CDEHC, 15*I1-12*I2=2
+//for mesh DABED, -12*I1+15*I2+2*I3=0
+//for mesh AFGBA, 2*I2+6*I3=4
+a=[15 -12 0;-12 15 2;0 2 6]
+b=[2;0;4]
+i=inv(a)*b
+I1=i(1,1)
+I2=i(2,1)
+I3=i(3,1)
+mprintf("By Maxwell Mesh Analysis, current through 2 ohm resistance is %f A from A to B ", I2+I3)
+
+
diff --git a/2252/CH1/EX1.2/Ex1_2.sce b/2252/CH1/EX1.2/Ex1_2.sce new file mode 100755 index 000000000..4cd4e8245 --- /dev/null +++ b/2252/CH1/EX1.2/Ex1_2.sce @@ -0,0 +1,9 @@ +
+//i1, i2, i3 be the currents in the branches CD, EF and GH respectively
+//i1+i2+i3=1.5
+i2=(20-1.5*10)/15
+i3=(20-1.5*10)/15
+i1=1.5-i2-i3
+r=(20-1.5*10)/i1
+mprintf("r=%f ohm", r)
+
diff --git a/2252/CH1/EX1.3/Ex1_3.sce b/2252/CH1/EX1.3/Ex1_3.sce new file mode 100755 index 000000000..0b2762229 --- /dev/null +++ b/2252/CH1/EX1.3/Ex1_3.sce @@ -0,0 +1,14 @@ +
+//points A,E,F,G are at the same potential
+Rab=20
+Reb=50
+R1=Rab*Reb/(Rab+Reb) //equivalent resistance of Rab and Reb
+Rbc=25
+R2=R1+Rbc //equivalent resistance of R1 and Rbc
+Rfc=50
+R3=Rfc*R2/(Rfc+R2) //equivalent resistance of R2 and Rfc
+Rcd=30
+R4=R3+Rcd //equivalent resistance of R3 and Rcd
+R=R4*50/(50+R4) //equivalent resistance between A and D
+i=200/R //Ohm's Law
+mprintf("Current drawn by circuit=%f A", i)
diff --git a/2252/CH1/EX1.4/Ex1_4.sce b/2252/CH1/EX1.4/Ex1_4.sce new file mode 100755 index 000000000..7a4410a33 --- /dev/null +++ b/2252/CH1/EX1.4/Ex1_4.sce @@ -0,0 +1,16 @@ +
+//refer Fig. 1.10 in the textbook
+//applying KCL, I1+I2=20; -I2+I3=30
+//applying KVL
+//for mesh ABGHA, -0.1*I2+20*R1=108
+//for mesh BCFGB, 0.3*I2+20*R1-30*R2=0
+//for mesh CDEFC, 0.2*I2+30*R2=114
+a=[-0.1 20 0;0.3 20 -30;0.2 0 30]
+b=[108;0;114]
+x=inv(a)*b
+I2=x(1,1)
+R1=x(2,1)
+R2=x(3,1)
+I1=20-I2
+I3=30+I2
+mprintf("R1=%f ohm, R2=%f ohm, I1=%f A, I2=%f A, I3=%f A", R1, R2, I1, I2, I3)
diff --git a/2252/CH1/EX1.5/Ex1_5.sce b/2252/CH1/EX1.5/Ex1_5.sce new file mode 100755 index 000000000..5853d31ae --- /dev/null +++ b/2252/CH1/EX1.5/Ex1_5.sce @@ -0,0 +1,12 @@ +
+//refer Fig.1.11 in the textbook
+//applying KVL over loops ABEFA and BCDEB, I2=3.5*I1; -2*I1+7*I2=10
+a=[3.5 -1;-2 7]
+b=[0;10]
+i=inv(a)*b
+I1=i(1,1)
+I2=i(2,1)
+I=I2-I1
+mprintf("Current through 8 ohm resistance=%f A from E to B", I)
+
+
diff --git a/2252/CH1/EX1.6/Ex1_6.sce b/2252/CH1/EX1.6/Ex1_6.sce new file mode 100755 index 000000000..dbf1e85a1 --- /dev/null +++ b/2252/CH1/EX1.6/Ex1_6.sce @@ -0,0 +1,18 @@ +
+//refer Fig.1.12 in the textbook
+//Applying KVL
+//for mesh AHGBA, -23*i1+20*i2+3*i4=0
+//for mesh GFCBG, 20*i1-43*i2+20*i3+3*i4=0
+//for mesh FEDCF, 20*i2-43*i3+3*i4=0
+//for mesh ABCDJIA, 3*i1+3*i2+3*i3-9*i4+50=0
+a=[-23 20 0 3;20 -43 20 3;0 20 -43 3;3 3 3 -9]
+b=[0;0;0;-50]
+i=inv(a)*b
+i1=i(1,1)
+i2=i(2,1)
+i3=i(3,1)
+i4=i(4,1)
+V1=3*(i4-i1)
+V2=3*(i4-i2)
+V3=3*(i4-i3)
+mprintf("Voltage across branch AB=%f V, Voltage across branch BC=%f V, Voltage across branch CD=%f V", V1, V2, V3)
diff --git a/2252/CH1/EX1.7/Ex1_7.sce b/2252/CH1/EX1.7/Ex1_7.sce new file mode 100755 index 000000000..1226163b4 --- /dev/null +++ b/2252/CH1/EX1.7/Ex1_7.sce @@ -0,0 +1,13 @@ +
+//refer Fig.1.13 in the textbook
+//by applying KVL
+//for mesh ABCDA, 7.45*i1-3.25*i2=10
+//for mesh EFBAE, 8.55*i2-5.3*i3-3.25*i1=10
+//for mesh HGBFEAH, 11.3*i3-5.3*i2=80
+a=[7.45 -3.25 0;-3.25 8.55 -5.3;0 -5.3 11.3]
+b=[10;10;80]
+i=inv(a)*b
+i1=i(1,1)
+i2=i(2,1)
+i3=i(3,1)
+mprintf("Current in 6 ohm resistor=%f A, current in 3 ohm resistor=%f A", i3, i2-i1)
diff --git a/2252/CH1/EX1.8/Ex1_8.sce b/2252/CH1/EX1.8/Ex1_8.sce new file mode 100755 index 000000000..00bf20cd3 --- /dev/null +++ b/2252/CH1/EX1.8/Ex1_8.sce @@ -0,0 +1,13 @@ +
+//using Superposition Theorem
+//consider E1 alone
+E1=1.5
+R1=(1+1)*2/(1+1+2)+2 //total resistance
+I1=E1/R1 //current supplied
+i1=I1/2 //current in branch AB from B to A
+//consider E2 alone
+E2=1.1
+R2=(1+1)*2/(1+1+2)+1+1 //total resistance
+I2=E2/R2 //current supplied
+i2=I2/2 //current in branch AB from B to A
+mprintf("Current through 2 ohm resistor=%f A", i1+i2)
diff --git a/2252/CH1/EX1.9/Ex1_9.sce b/2252/CH1/EX1.9/Ex1_9.sce new file mode 100755 index 000000000..5dede4a0b --- /dev/null +++ b/2252/CH1/EX1.9/Ex1_9.sce @@ -0,0 +1,11 @@ +
+//refer Fig.1.20 in the textbook
+//applying KVL
+//for mesh BAEFB, 4*I1+2*I2=1.5
+//for mesh BACDB, 2*I1+4*I2=1.1
+a=[4 2;2 4]
+b=[1.5;1.1]
+i=inv(a)*b
+I1=i(1,1)
+I2=i(2,1)
+mprintf("Current through 2 ohm resistor=%f A from B to A", I1+I2)
diff --git a/2252/CH10/EX10.1/Ex10_1.sce b/2252/CH10/EX10.1/Ex10_1.sce new file mode 100755 index 000000000..31e74d321 --- /dev/null +++ b/2252/CH10/EX10.1/Ex10_1.sce @@ -0,0 +1,13 @@ +
+//calculating resistance of the shunt
+i=20D-3 //current throught the coil
+r=4 //resistance of coil
+V=i*r
+I=2 //total current to be measured
+Is=I-i //current through shunt
+R=V/Is //Ohm's law
+mprintf("Resistance of the shunt=%f ohm\n", R)
+//solving part (ii)
+V=30 //voltage to be measured
+R=V/i-r
+mprintf("Resistance to be connected in series with moving coil=%d ohm", R)
diff --git a/2252/CH10/EX10.2/Ex10_2.sce b/2252/CH10/EX10.2/Ex10_2.sce new file mode 100755 index 000000000..67ad7a382 --- /dev/null +++ b/2252/CH10/EX10.2/Ex10_2.sce @@ -0,0 +1,14 @@ +
+i=20D-3 //current throught the coil
+r=4 //resistance of coil
+V=30 //voltage to be measured
+R=(V-r*i)/i //resistance in series to read upto 30 V
+//to read upto 60 V
+V=60
+R1=V/i-r
+mprintf("Additional resistance needed to read upto 60 V=%d ohm\n", R1-R)
+//to read upto 90 V
+V=90
+R2=V/i-r
+mprintf("Additional resistance needed to read upto 90V=%d ohm",R2-R1)
+
diff --git a/2252/CH10/EX10.3/Ex10_3.sce b/2252/CH10/EX10.3/Ex10_3.sce new file mode 100755 index 000000000..46f9afa67 --- /dev/null +++ b/2252/CH10/EX10.3/Ex10_3.sce @@ -0,0 +1,16 @@ +
+i=20D-3 //current throught the coil
+r=4 //resistance of coil
+V=i*r
+//when total current to be measured=2 A
+Is=2-i //shunt current
+R1=V/Is
+mprintf("Resistance of shunt for 2A range=%f ohm\n",R1)
+//when total current to be measured=4 A
+Is=4-i //shunt current
+R2=V/Is
+mprintf("Resistance of shunt for 4A range=%f ohm\n", R2)
+//when total current to be measured=6 A
+Is=6-i //shunt current
+R3=V/Is
+mprintf("Resistance of shunt for 6A range=%f ohm",R3)
diff --git a/2252/CH10/EX10.4/Ex10_4.sce b/2252/CH10/EX10.4/Ex10_4.sce new file mode 100755 index 000000000..6e06fc842 --- /dev/null +++ b/2252/CH10/EX10.4/Ex10_4.sce @@ -0,0 +1,14 @@ +
+//calculating deflecting torque
+N=50 //no. of turns in coil
+B=.12 //flux density in Wb/m^2
+A=5D-4 //area of coil in m^2
+I=15D-3 //current through coil
+Td=N*B*A*I
+mprintf("Deflecting torque=%fD-6 N-m\n",Td*10^6)
+//calculating deflection of pointer
+C=18D-7 //constant for spring in N-m per degree
+Tc=Td //controlling torque
+theta=Tc/C
+mprintf("Deflection=%d degrees", theta)
+
diff --git a/2252/CH10/EX10.5/Ex10_5.sce b/2252/CH10/EX10.5/Ex10_5.sce new file mode 100755 index 000000000..e59027955 --- /dev/null +++ b/2252/CH10/EX10.5/Ex10_5.sce @@ -0,0 +1,12 @@ +
+N=80 //no. of turns in coil
+B=.5 //flux density
+A=15D-4 //area of coil
+Tc=2D-4 //controlling torque at full scale deflection
+Td=Tc //under final steady condition
+I=Td/(N*B*A)
+n=100 //no. of divisions
+v=2 //voltage measured per division
+V=n*v //at full scale deflection
+R=V/I
+mprintf("Series resistance=%f ohm",R)
diff --git a/2252/CH10/EX10.6/Ex10_6.sce b/2252/CH10/EX10.6/Ex10_6.sce new file mode 100755 index 000000000..e7f4dcdb6 --- /dev/null +++ b/2252/CH10/EX10.6/Ex10_6.sce @@ -0,0 +1,12 @@ +
+//calculating resistance of manganin shunt to extend range to 1 A
+R=10 //resistance of instrument coil
+I=10D-3 //current through coil
+V=I*R
+Is=1-I //shunt current
+r=V/Is
+mprintf("Resistance of manganin shunt to extend range to 1 A=%f ohm\n", r)
+//calculating value of series resistance to extend the range to 15 V
+v=15-V //voltage across series resistance
+Rs=v/I
+mprintf("Series resistance to be connected to extend range to 15 V=%d ohm", Rs)
diff --git a/2252/CH13/EX13.1/Ex13_1.sce b/2252/CH13/EX13.1/Ex13_1.sce new file mode 100755 index 000000000..6a42809c5 --- /dev/null +++ b/2252/CH13/EX13.1/Ex13_1.sce @@ -0,0 +1,18 @@ +
+//temp. rise at any time t is theta=theta_f-(theta_f-theta_1)*exp(-t/T)
+theta_1=0//initial temperature
+//theta =25 degree C when t=1 hr; theta =37.5 degree C when t=2 hr
+//on solving for T
+T=1/log(2)
+mprintf("Heating time constant=%f hr\n", T)
+//on solving for theta_f
+theta_f=25/(1-exp(-1/T))
+mprintf("Final steady full load temperature rise theta_f=%f degree C\n", theta_f)
+//Temp. fall at any time t is theta'=theta_f'+(theta_2-theta_f')*exp(-t/T')
+//As the transformer is disconnected now, theta_f'=0
+theta_2=theta_f
+theta_dash=40-30
+t=1.5
+T=t/log(theta_2/theta_dash)
+mprintf("Cooling time constant =%f hr", T)
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH13/EX13.2/Ex13_2.sce b/2252/CH13/EX13.2/Ex13_2.sce new file mode 100755 index 000000000..969a3f27d --- /dev/null +++ b/2252/CH13/EX13.2/Ex13_2.sce @@ -0,0 +1,14 @@ +
+//temp. rise of the motor at any time t is theta=theta_f-(theta_f-theta_1)*exp(-t/T)
+theta_f=50//final steady temp rise
+T=100//heating time constant in min
+t=20//full load working period in min
+//during cooling process, temp. decreases to theta_1=theta*exp(-t/T')
+t=40//stationary period in min
+T=140//cooling time constant in min
+//solving simultaneous equations
+a=[1 -exp(-20/100);-exp(-40/140) 1]
+b=[50-50*exp(-20/100);0]
+c=inv(a)*b
+theta=c(1,1)
+mprintf("Maximum temp attained=%f degree C", theta)
diff --git a/2252/CH14/EX14.1/Ex14_1.sce b/2252/CH14/EX14.1/Ex14_1.sce new file mode 100755 index 000000000..2293be978 --- /dev/null +++ b/2252/CH14/EX14.1/Ex14_1.sce @@ -0,0 +1,12 @@ +
+//calculating Bm
+Ep=400//induced emf in primary winding
+Np=350//no. of turns in primary
+Ai=55D-4//cross-sectional area
+f=50//frequency in Hz
+Bm=Ep/(4.44*f*Ai*Np)
+mprintf("Maximum value of flux density in the core=%f Tesla(Wb/m^2)\n",Bm)
+//calculating voltage induced in secondary winding
+Ns=1050
+Es=Ep*Ns/Np
+mprintf("Voltage induced in the secondary winding=%d V",round(Es))
diff --git a/2252/CH14/EX14.10/Ex14_10.sce b/2252/CH14/EX14.10/Ex14_10.sce new file mode 100755 index 000000000..b5b603c30 --- /dev/null +++ b/2252/CH14/EX14.10/Ex14_10.sce @@ -0,0 +1,10 @@ +
+e_max=.98//max efficiency
+Pout=.75*500*1000//output of transformer at max efficiency
+Wi=Pout*(1-e_max)/(2*e_max)
+Wcu1=Wi//copper losses at 3/4 full load
+Wcu=Wcu1/(.75)^2//copper losses at full load
+Is=500*1000/500//secondary current
+Vs=500//secondary voltage
+VR=(Wcu/(Vs*Is)*.8+sqrt(.1^2-(Wcu/(Vs*Is))^2)*.6)*100
+mprintf("Regulation at full load, 0.8 pf lagging=%f percent",VR)
diff --git a/2252/CH14/EX14.11/Ex14_11.sce b/2252/CH14/EX14.11/Ex14_11.sce new file mode 100755 index 000000000..eae8db70b --- /dev/null +++ b/2252/CH14/EX14.11/Ex14_11.sce @@ -0,0 +1,12 @@ +
+e1=.985//efficiency at full load, .8 pf lagging
+//.985=100D+3*.8/(100D+3*.8+Wi+Wcu)-->.985*Wi+.985*Wcu=1200
+e2=.99//efficiency at half load, unity pf
+//.99=((100D+3)/2)/((100D+3)/2+Wi+Wcu/4)-->.99*Wi+.2475*Wcu=500
+//solving for Wi and Wcu
+a=[.985 .985;.99 .2475]
+b=[1200;500]
+w=inv(a)*b
+Wi=w(1,1)
+Wcu=w(2,1)
+mprintf("Iron losses=%f W\nFull load copper losses=%f W",Wi,Wcu)
diff --git a/2252/CH14/EX14.12/Ex14_12.sce b/2252/CH14/EX14.12/Ex14_12.sce new file mode 100755 index 000000000..75f017e72 --- /dev/null +++ b/2252/CH14/EX14.12/Ex14_12.sce @@ -0,0 +1,16 @@ +
+//calculating regulation at full load, 0.8 pf lagging
+Pout1=.75*500D+3//output at max efficiency
+Wi=375D+3*(1-.97)/(2*.97)
+Wcu1=Wi//copper losses at 3/4th full load
+Wcu=(4/3)^2*Wcu1//copper losses at full load
+Is=500D+3/220
+Rs=Wcu/Is^2
+Vs=220//secondary voltage
+Zs=220*.1/Is
+Xs=sqrt(Zs^2-Rs^2)
+VR=(Is*Rs*.8+Is*Xs*.6)/Vs*100
+mprintf("Regulation at .8 pf lagging=%f percent\n",VR)
+//calculating regulation at full load, 0.8 pf leading
+VR=(Is*Rs*.8-Is*Xs*.6)/Vs*100
+mprintf("Regulation at .8 pf leading=%f percent\n",VR)
diff --git a/2252/CH14/EX14.13/Ex14_13.sce b/2252/CH14/EX14.13/Ex14_13.sce new file mode 100755 index 000000000..471d5c4f2 --- /dev/null +++ b/2252/CH14/EX14.13/Ex14_13.sce @@ -0,0 +1,20 @@ +
+e_max=.98//max efficiency of transformer
+P=15D+3//load at which max efficiency occurs at unity pf
+Wi=P*(1-e_max)/(2*e_max)
+Wcu=Wi
+//in the first interval
+P1=3D+3/0.6//load on the transformer
+Wcu1=Wcu*(P1/P)^2
+//in the second interval
+P2=10D+3/0.8//load on the transformer
+Wcu2=Wcu*(P2/P)^2
+//in the third interval
+P3=18D+3/0.9//load on the transformer
+Wcu3=Wcu*(P3/P)^2
+//load on the transformer during last interval=0-->copper losses=0, iron losses=0
+Wi=Wi*24//total iron losses
+Wcu=10*Wcu1+5*Wcu2+5*Wcu3//total copper losses
+Pout=(3*10+10*5+18*5)*10^3//total output
+e=Pout/(Pout+Wi+Wcu)*100
+mprintf("All day efficiency=%f percent",e)
diff --git a/2252/CH14/EX14.14/Ex14_14.sce b/2252/CH14/EX14.14/Ex14_14.sce new file mode 100755 index 000000000..b69f4e9ec --- /dev/null +++ b/2252/CH14/EX14.14/Ex14_14.sce @@ -0,0 +1,30 @@ +
+//for no load test
+V0=400//applied voltage
+I0=1//current
+W0=60//power consumed
+Iw=W0/V0
+R0=V0/Iw
+Im=sqrt(I0^2-Iw^2)
+Xm=V0/Im
+mprintf("No load parameters:\nR0=%f ohm,\nXm=%f ohm\n",R0,Xm)
+//for short circuit test
+Vsc=15//applied voltage
+Isc=12.5//current
+Wsc=50//power consumed
+Zp=Vsc/Isc
+Rp=Wsc/Isc^2
+Xp=sqrt(Zp^2-Rp^2)
+mprintf("Equivalent resistance and reactance referred to primary is %f ohm and %f ohm\n",Rp,Xp)
+//calculating regulation at full load, 0.8 pf lagging
+Vp=400
+Ip=5D+3/400
+VR=Ip*(Rp*.8+Xp*.6)/Vp*100
+mprintf("Voltage regulation=%f percent\n",VR)
+//calculating iron and copper losses
+Wi=W0
+Wcu=Wsc
+mprintf("Iron losses=%f W\nCopper losses at full load=%f W\n",Wi,Wcu)
+//calculating efficiency at full load and 0.8 pf lagging
+e=5D+3*.8/(5D+3*.8+Wi+Wcu)*100
+mprintf("Efficiency at full load and .8 pf lagging=%f percent",e)
diff --git a/2252/CH14/EX14.15/Ex14_15.sce b/2252/CH14/EX14.15/Ex14_15.sce new file mode 100755 index 000000000..f04e208a4 --- /dev/null +++ b/2252/CH14/EX14.15/Ex14_15.sce @@ -0,0 +1,10 @@ +
+W0=1300//power consumed in no load test
+Wsc=2400//power consumed in short circuit test performed at full load current
+Wi=W0
+Wcu=Wsc
+Pout=(8*200*.8+10*.5*200*1)*10^3//total output
+Wit=1300*24//total iron losses
+Wcut=2400*8+2400/4*10//total copper losses
+e=Pout/(Pout+Wit+Wcut)*100
+mprintf("All day efficiency=%f percent",e)
diff --git a/2252/CH14/EX14.16/Ex14_16.sce b/2252/CH14/EX14.16/Ex14_16.sce new file mode 100755 index 000000000..3120c0d39 --- /dev/null +++ b/2252/CH14/EX14.16/Ex14_16.sce @@ -0,0 +1,11 @@ +
+Woc=60//power consumed in OC test at 220 V
+//iron losses in transformer are proportional to square of applied voltage
+Wi=60*(200/220)^2//iron losses at normal voltage of 200 V
+Is=5D+3/400//full load current on HV side
+//for SC test
+Isc=10//current
+Wsc=120//power consumed
+Wcu=(Is/Isc)^2*Wsc//full load copper losses
+e=(5D+3*.8)/(5D+3*.8+Wi+Wcu)*100
+mprintf("Efficiency at full load=%f percent",e)
diff --git a/2252/CH14/EX14.17/Ex14_17.sce b/2252/CH14/EX14.17/Ex14_17.sce new file mode 100755 index 000000000..99b41db0e --- /dev/null +++ b/2252/CH14/EX14.17/Ex14_17.sce @@ -0,0 +1,28 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+
+j=%i
+I=pol2rect(300,-acosd(.8))//total load to be shared by transformers A and B at .8 pf lagging
+Za=.011+.042*j//impedance of transformer A
+Zb=.044+.072*j//impedance of transformer B
+
+//calculating load shared by transformer A
+Ia=Zb*I/(Za+Zb)
+[Ia theta]=rect2pol(Ia)
+mprintf("Load shared by transformer A=%f A, lagging by an angle of %f degrees\n",Ia,-theta)
+
+//calculating load shared by transformer B
+Ib=Za*I/(Za+Zb)
+[Ib theta]=rect2pol(Ib)
+mprintf("Load shared by transformer B=%f A, lagging by an angle of %f degrees",Ib,-theta)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH14/EX14.18/Ex14_18.sce b/2252/CH14/EX14.18/Ex14_18.sce new file mode 100755 index 000000000..3da54a415 --- /dev/null +++ b/2252/CH14/EX14.18/Ex14_18.sce @@ -0,0 +1,18 @@ +
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+
+j=%i
+Zl=8+6.2*j//load impedance
+//for transformer A
+Ea=6600//secondary induced emf
+Za=.3+3.2*j//equivalent impedance referred to secondary
+//for transformer B
+Eb=6400//secondary induced emf
+Zb=.2+1.2*j//equivalent impedance referred to secondary
+Ia=(Ea*Zb+(Ea-Eb)*Zl)/(Za*Zb+(Za+Zb)*Zl)
+Ib=(Eb*Za-(Ea-Eb)*Zl)/(Za*Zb+(Za+Zb)*Zl)
+mprintf("Current delivered by transformer A is %f A\nCurrent delivered by transformer B is %f A",mag(Ia),mag(Ib))
diff --git a/2252/CH14/EX14.2/Ex14_2.sce b/2252/CH14/EX14.2/Ex14_2.sce new file mode 100755 index 000000000..f43a852ed --- /dev/null +++ b/2252/CH14/EX14.2/Ex14_2.sce @@ -0,0 +1,12 @@ +
+//calculating no. of turns in secondary winding
+Es=500//no load voltage of low voltage winding
+phi=.06//flux
+f=50//frequency in Hz
+Ns=round(Es/(4.44*f*phi))
+mprintf("No. of turns in low voltage winding=%f\n",Ns)
+//calculating no. of turns in primary winding
+Np=Ns*6600/500
+mprintf("Np=%f(not possible)\n",Np)
+//Here, the no. of turns finally taken is 500 and not 502
+mprintf("No. of turns finally taken is 500 ,because the high voltage winding will be split up into a no. of coils")
diff --git a/2252/CH14/EX14.3/Ex14_3.sce b/2252/CH14/EX14.3/Ex14_3.sce new file mode 100755 index 000000000..4b57d8918 --- /dev/null +++ b/2252/CH14/EX14.3/Ex14_3.sce @@ -0,0 +1,13 @@ +
+Rp=.8
+Xp=3.2
+Rs=.009
+Xs=.03
+Rs_dash=(2200/220)^2*Rs
+mprintf("Equivalent resistance referred to primary=%f ohm\n",Rp+Rs_dash)
+Xs_dash=(2200/220)^2*Xs
+mprintf("Equivalent reactance referred to primary=%f ohm\n",Xp+Xs_dash)
+Rp_dash=(220/2200)^2*Rp
+mprintf("Equivalent resistance referred to secondary=%f ohm\n",Rp_dash+Rs)
+Xp_dash=(220/2200)^2*Xp
+mprintf("Equivalent reactance referred to secondary=%f ohm",Xp_dash+Xs)
diff --git a/2252/CH14/EX14.4/Ex14_4.sce b/2252/CH14/EX14.4/Ex14_4.sce new file mode 100755 index 000000000..40ed61bb7 --- /dev/null +++ b/2252/CH14/EX14.4/Ex14_4.sce @@ -0,0 +1,35 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+//calculating current in primary
+Is=10//at 0.8 pf lagging
+Ip_dash=Is*400/200//at 0.8 pf lagging
+Ip_dash=pol2rect(Ip_dash,-acosd(.8))
+Im=200/300//magnetizing current
+Iw=200/600//active component of no load current
+I0=Iw-Im*j//no load current
+Ip=Ip_dash+I0
+[Ip theta]=rect2pol(Ip)
+mprintf("Current in primary is %f A, lagging at an angle of %f degrees\n",Ip,-theta)
+//calculating terminal voltage
+Ip=pol2rect(Ip,-theta)
+Ep=Ip_dash*(.15+.37*j)
+Es_dash=200-Ep
+[Es_dash theta]=rect2pol(Es_dash)
+Es=Es_dash*400/200
+mprintf("Secondary terminal voltage=%f V, lagging at an angle of %f degrees",Es,-theta)
diff --git a/2252/CH14/EX14.5/Ex14_5.sce b/2252/CH14/EX14.5/Ex14_5.sce new file mode 100755 index 000000000..eeb014df0 --- /dev/null +++ b/2252/CH14/EX14.5/Ex14_5.sce @@ -0,0 +1,16 @@ + +//calculating voltage regulation at full load with 0.8 pf lagging
+Ip=2000/400//primary current at full load
+Rp=3
+Xp=4
+phi=acos(.8)
+Vp=400
+VR=Ip*(Rp*cos(phi)+Xp*sin(phi))/Vp*100
+mprintf("Voltage regulation at full load with 0.8 pf lagging=%f percent\n",VR)
+//calculating voltage regulation at full load with 0.8 pf leading
+VR=Ip*(Rp*cos(phi)-Xp*sin(phi))/Vp*100
+mprintf("Voltage regulation at full load with 0.8 pf leading=%f percent\n",VR)
+//calculating regulation at half load with 0.8 pf lagging
+Ip=Ip/2//half load primary current
+VR=Ip*(Rp*cos(phi)+Xp*sin(phi))/Vp*100
+mprintf("Voltage regulation at half load with 0.8 pf lagging=%f percent",VR)
diff --git a/2252/CH14/EX14.6/Ex14_6.sce b/2252/CH14/EX14.6/Ex14_6.sce new file mode 100755 index 000000000..2957a5c0d --- /dev/null +++ b/2252/CH14/EX14.6/Ex14_6.sce @@ -0,0 +1,8 @@ +
+//Is*Rs=.02*Vs,Is*Xs=.05*Vs
+//calculating regulation at .8 pf lagging
+VR=(.02*.8+.05*.6)*100
+mprintf("Voltage regulation at .8 pf lagging=%f percent\n",VR)
+//calculating regulation at .8 pf leading
+VR=(.02*.8-.05*.6)*100
+mprintf("Voltage regulation at 0.8 pf leading=%f percent",VR)
diff --git a/2252/CH14/EX14.7/Ex14_7.sce b/2252/CH14/EX14.7/Ex14_7.sce new file mode 100755 index 000000000..2451c0aac --- /dev/null +++ b/2252/CH14/EX14.7/Ex14_7.sce @@ -0,0 +1,24 @@ +
+Wcu_fl=425//copper losses at full load
+//calculating efficiency at full load, unity pf
+Pout=50*1000*1//output
+e=Pout/(Pout+350+425)*100
+mprintf("Efficiency at full load, unity pf=%f percent\n",e)
+//calculating efficiency at half load, unity pf
+Pout=Pout/2//output
+Wi=350//iron losses
+Wcu=Wcu_fl/2^2//copper losses
+e=Pout/(Pout+Wi+Wcu)*100
+mprintf("Efficiency at half load, unity pf=%f percent\n",e)
+//calculating efficiency at full load, 0.8 pf lagging
+Pout=(50D+3)*.8//output
+e=Pout/(Pout+Wi+Wcu_fl)*100
+mprintf("Efficiency at full load, .8 pf lagging=%f percent\n",e)
+//calculating maximum efficiency
+Wcu=Wi//copper losses
+x=sqrt(Wcu/Wcu_fl)//load at which maximum efficiency occurs
+mprintf("At %f percent of the full load, maximum efficiency will occur\n",x*100)
+Pout=(x*50D+3*1)
+e_max=Pout/(Pout+2*Wi)*100
+mprintf("Maximum efficiency=%f percent\nLoad at maximum efficiency=%f kVA",e_max,Pout/1000)
+
diff --git a/2252/CH14/EX14.8/Ex14_8.sce b/2252/CH14/EX14.8/Ex14_8.sce new file mode 100755 index 000000000..7ab99ca18 --- /dev/null +++ b/2252/CH14/EX14.8/Ex14_8.sce @@ -0,0 +1,33 @@ +
+Wi=1100//iron losses
+Wcu=400//copper losses at 50% load
+Is=100*1000/10000//secondary full load current
+//calculating efficiency at 25% load, unity pf
+Is1=Is/4//secondary current
+Wcu1=(25/50)^2*400//copper losses
+Pout=.25*100*1000//output
+e=Pout/(Pout+Wcu1+Wi)*100
+mprintf("Efficiency at 25 percent load, unity pf=%f percent\n",e)
+//calculating efficiency at 25% load, 0.8 pf
+e=(Pout*.8)/(Pout*.8+Wcu1+Wi)*100
+mprintf("Efficiency at 25 percent load, .8 pf=%f percent\n",e)
+//calculating efficiency at 50% load,unity pf
+Pout=.5*100*1000//output
+e=Pout/(Pout+Wi+Wcu)*100
+mprintf("Efficiency at 50 percent load, unity pf=%f percent\n",e)
+//calculating efficiency at 50% load, 0.8 pf
+e=Pout*.8/(Pout*.8+Wi+Wcu)*100
+mprintf("Efficiency at 50 percent load, 0.8 pf=%f percent\n",e)
+//calculating efficiency at full load, unity pf
+Pout=100*1000//output
+Wcu3=(10/5)^2*400//copper losses
+e=Pout/(Pout+Wcu3+Wi)*100
+mprintf("Efficiency at full load, unity pf=%f percent\n",e)
+//calculating efficiency at full load, .8 pf
+e=(Pout*.8)/(Pout*.8+Wcu3+Wi)*100
+mprintf("Efficiency at full load, 0.8 pf=%f percent\n",e)
+//calculating load for max efficiency at unity pf
+x=sqrt(Wi/Wcu3)
+mprintf("Load for max efficiency=%f kVA\nLoad for max efficiency will remain the same irrespective of power factor",x*Pout/1000)
+//error in the textbook answer for efficiency at 50 % load at unity pf as well as at .8 pf
+
diff --git a/2252/CH14/EX14.9/Ex14_9.sce b/2252/CH14/EX14.9/Ex14_9.sce new file mode 100755 index 000000000..f2a3a30f4 --- /dev/null +++ b/2252/CH14/EX14.9/Ex14_9.sce @@ -0,0 +1,16 @@ +
+e=.9//efficiency at full load
+Pout=500//output at full load
+//we get, .9=500/(500+Wi+Wcu)
+//efficiency at half load is also the same-->.9=(500/2)/(500/2+Wi+Wcu/4)
+//solving for Wi and Wcu at full load
+a=[.9 .9;.9 .225]
+b=[50;25]
+z=inv(a)*b
+Wi=z(1,1)
+Wcu=z(2,1)
+//calculating efficiency at 75% load
+Pout=.75*500//output
+Wcu1=.75^2*Wcu//copper losses
+e=Pout/(Pout+Wi+Wcu1)*100
+mprintf("Efficiency at 75 percent full load=%f percent",e)
diff --git a/2252/CH15/EX15.1/Ex15_1.sce b/2252/CH15/EX15.1/Ex15_1.sce new file mode 100755 index 000000000..ba388dde4 --- /dev/null +++ b/2252/CH15/EX15.1/Ex15_1.sce @@ -0,0 +1,19 @@ +
+
+P=50D+3 //power per phase
+Power_rating=3*P
+Vpp=2300 //primary phase voltage
+Vsp=230 //secondary phase voltage
+Vpl=sqrt(3)*Vpp //primary normal line voltage
+Vsl=Vsp //secondary normal line voltage
+mprintf("Rating of 3-phase transformer will be-\n3-phase, %d kVA, %d/%d V, star/delta connection\n",Power_rating/1D+3,round(Vpl),round(Vsl))
+Ipp=P/Vpp
+Ipl=Ipp
+Isp=P/Vsp
+Isl=sqrt(3)*Isp
+mprintf("Primary phase current=%f A\nPrimary line current=%f A\nSecondary phase current=%f A\nSecondary line current=%f A\n",Ipp,Ipl,Isp,Isl)
+//calculating voltage regulation
+Rp_dash=1.2 //equivalent resistance referred to primary
+Xp_dash=1.6 //equivalent reactance referred to primary
+VR=Ipp*(Rp_dash*.8+Xp_dash*.6)*100/Vpp
+mprintf("Voltage Regulation=%f percent", VR)
diff --git a/2252/CH15/EX15.2/Ex15_2.sce b/2252/CH15/EX15.2/Ex15_2.sce new file mode 100755 index 000000000..c08549323 --- /dev/null +++ b/2252/CH15/EX15.2/Ex15_2.sce @@ -0,0 +1,13 @@ +
+//calculating no. of turns per phase
+Vsp=440/sqrt(3) //secondary phase voltage
+Et=8 //emf per turn in volt
+Ts=round(Vsp/Et)
+Vpp=1100 //primary phase voltage
+Tp=Ts*Vpp/Vsp
+mprintf("No. of turns per phase on primary winding=%d\nNo. of turns per phase on secondary winding=%d\n", Tp, Ts)
+//calculating net cross-sectional area of core
+f=50 //frequency
+Bm=1.3 //flux density
+Ai=Et/(4.44*f*Bm)
+mprintf("Net cross-sectional area of core, Ai=%d cm^2", round(Ai*1D+4))
diff --git a/2252/CH15/EX15.3/Ex15_3.sce b/2252/CH15/EX15.3/Ex15_3.sce new file mode 100755 index 000000000..2612a0320 --- /dev/null +++ b/2252/CH15/EX15.3/Ex15_3.sce @@ -0,0 +1,14 @@ +
+//calculating currents in the main and teaser transformer
+P2=600D+3//output
+V2=110//applied voltage
+pf=.707//lagging power factor
+I2=P2/(pf*V2)
+I1t=1.15*I2*110/6600
+I1m=I2*110/6600
+mprintf("Currents in primary winding of main and teaser transformer is %f A and %f A respectively\n", I1m,I1t)
+//calculating line currents
+Ic=I1t
+Ib=sqrt(I1m^2+(I1t/2)^2)
+Ia=Ib
+mprintf("Line currents are %f A, %f A and %f A", Ia,Ib,Ic)
diff --git a/2252/CH15/EX15.4/Ex15_4.sce b/2252/CH15/EX15.4/Ex15_4.sce new file mode 100755 index 000000000..3277d88ec --- /dev/null +++ b/2252/CH15/EX15.4/Ex15_4.sce @@ -0,0 +1,14 @@ +
+function[r, theta]=rect2pol(x,y)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+Q=750//total load to be shared
+pf=.8//lagging power factor
+theta=-acosd(.8)
+Q=rect2pol(Q*cos(theta),Q*sin(theta))
+Zb=rect2pol(.35,3.3)//per phase impedance of transformer B
+Za=rect2pol(.2,1.8)//per phase impedance of transformer A
+Qa=Zb*Q/(Za+Zb)
+Qb=Za*Q/(Za+Zb)
+mprintf("Transformer A of 500 kVA rating shares a load of %f kVA whereas transformer B of 250 kVA rating shares a load of %f kVA", Qa,Qb)
diff --git a/2252/CH16/EX16.2/Ex16_2.sce b/2252/CH16/EX16.2/Ex16_2.sce new file mode 100755 index 000000000..355f23a54 --- /dev/null +++ b/2252/CH16/EX16.2/Ex16_2.sce @@ -0,0 +1,16 @@ +
+i=3//current in coil
+x=5D-2//length of air gap
+lambda=sqrt(i/(121*x^2))
+//calculating field energy W_f
+W_f=integrate("121*lambda^2*.05^2","lambda", 0, lambda)
+mprintf("Field energy stored=%f watt-sec\n", W_f)
+//calculating coenergy
+W_f_dash=integrate("i^.5/(11*.05)","i",0, i)
+mprintf("Co-energy=%f watt-sec\n", W_f_dash)
+//calculating mechanical force on moving part-keeping lambda constant
+function y=f(x)
+ y=121*x^2*lambda^3/3
+endfunction
+F_f=-1*derivative(f,x)
+mprintf("Mechanical force developed F_f=%d N-m", round(F_f))
diff --git a/2252/CH16/EX16.3/Ex16_3.sce b/2252/CH16/EX16.3/Ex16_3.sce new file mode 100755 index 000000000..c6a6b243b --- /dev/null +++ b/2252/CH16/EX16.3/Ex16_3.sce @@ -0,0 +1,12 @@ +
+mu_not=4D-7*%pi
+i=120/6 //current flowing in coil
+N=300 //no. of turns
+x=.005 //length of air gap
+Ag=36D-4 //cross-sectional area at gap
+//calculating stored field energy
+W_f=mu_not*N^2*Ag*i^2/(4*x)
+mprintf("Stored field energy=%f watt-sec\n", W_f)
+//calculating mechanical force developed
+F_f=mu_not*N^2*i^2*Ag/(4*x^2)
+mprintf("Mechanical force developed=%f N-m", F_f)
diff --git a/2252/CH17/EX17.1/Ex17_1.sce b/2252/CH17/EX17.1/Ex17_1.sce new file mode 100755 index 000000000..2f5ab61d0 --- /dev/null +++ b/2252/CH17/EX17.1/Ex17_1.sce @@ -0,0 +1,12 @@ +
+P=6//no. of poles
+a=P//no. of parallel circuits
+n=150//no. of slots
+c=8//no. of conductors per slot
+Z=n*c//total no. of conductors
+T=Z/2//no. of turns
+Lmt=250D-2//mean length of one turn
+S=10*2.5*1D-6//cross sectional area
+rho=2.1D-8//resistivity at 80 degree C
+R=(rho*Lmt*T)/(a^2*S)
+mprintf("Resistance=%f ohm\n",R)
diff --git a/2252/CH17/EX17.10/Ex17_10.sce b/2252/CH17/EX17.10/Ex17_10.sce new file mode 100755 index 000000000..ee5178e0a --- /dev/null +++ b/2252/CH17/EX17.10/Ex17_10.sce @@ -0,0 +1,16 @@ +
+V=250//terminal voltage
+Il=450//load current
+Rsh=50//shunt field resistance
+Ish=V/Rsh
+Ia=Ish+Il
+Ra=.05//armature resistance
+Eg=V+Ia*Ra
+P=4//no. of poles
+phi=.05//flux per pole in Wb
+n=120//no. of slots on armature
+c=4//conductors per slot
+Z=n*c//total no. of conductors
+A=P//no. of parallel paths
+N=60*Eg*A/(P*phi*Z)
+mprintf("Speed of rotation=%f rpm", round(N))
diff --git a/2252/CH17/EX17.11/Ex17_11.sce b/2252/CH17/EX17.11/Ex17_11.sce new file mode 100755 index 000000000..edbffe943 --- /dev/null +++ b/2252/CH17/EX17.11/Ex17_11.sce @@ -0,0 +1,18 @@ +
+//when the dc shunt machine works as a generator
+V=250//terminal voltage
+Il=80//load current
+Rsh=100//field resistance
+Ra=.12//armature resistance
+Ish=V/Rsh
+Ia=Il+Ish
+Eg=V+Ia*Ra
+
+//when the dc shunt machine works as a motor
+V=250//applied voltage to motor
+Il=80//line current drawn by the motor
+Ia=Il-Ish
+Eb=V-Ia*Ra
+//for a machine, P*phi*Z/(60*A) is a constant
+x=Eg/Eb
+mprintf("speed as generator/speed as motor=%f",x)
diff --git a/2252/CH17/EX17.12/Ex17_12.sce b/2252/CH17/EX17.12/Ex17_12.sce new file mode 100755 index 000000000..4606b11d9 --- /dev/null +++ b/2252/CH17/EX17.12/Ex17_12.sce @@ -0,0 +1,16 @@ +
+//calculating back emf
+V=120//applied voltage
+Il=200//line current
+Rsh=30//shunt field resistance
+Ra=.02//armature winding resistance
+Ish=V/Rsh
+Ia=Il-Ish
+Eb=V-Ia*Ra
+mprintf("Back emf=%f V\n",Eb)
+n=90//no. of slots on armature
+c=4//conductors per slot
+Z=n*c//total no. of conductors on armature
+phi=.04
+N=60*Eb/(phi*Z)
+mprintf("Speed at which motor will run when flux per pole is .04 Wb=%d rpm",round(N))
diff --git a/2252/CH17/EX17.13/Ex17_13.sce b/2252/CH17/EX17.13/Ex17_13.sce new file mode 100755 index 000000000..289a92bca --- /dev/null +++ b/2252/CH17/EX17.13/Ex17_13.sce @@ -0,0 +1,24 @@ +
+//calculating load current
+i=30//current drawn by each motor
+I=5*i//current drawn by 5 motors
+P=150*60//total lighting load
+V=110//applied voltage
+I1=P/V//current taken by lighting load
+I=I1+I
+mprintf("Total load current=%d A\n",round(I))
+//calculating terminal voltage
+V_dash=110//voltage at terminals of load
+R=.04//resistance of feeders
+Vd=I*R//voltage drop in feeders
+V=V_dash+Vd
+mprintf("Terminal voltage across the generator terminals=%f V\n",V)
+//calculating emf generated
+Rsh=55//resistance of shunt field
+Ish=V/Rsh
+Ia=I+Ish
+Ise=Ia
+Rse=.04//series field resistance
+Ra=.03//armature resistance
+Eg=V+Ia*(Ra+Rse)
+mprintf("Generated emf, Eg=%f V",Eg)
diff --git a/2252/CH17/EX17.14/Ex17_14.sce b/2252/CH17/EX17.14/Ex17_14.sce new file mode 100755 index 000000000..e93f7d9ea --- /dev/null +++ b/2252/CH17/EX17.14/Ex17_14.sce @@ -0,0 +1,19 @@ +
+//when the machine is working as generator
+V=240//terminal voltage across the load
+P=40D+3//load on generator
+Il=P/V//load current
+Rsh=60//resistance of shunt field
+Ish=V/Rsh
+Ia=Il+Ish
+Ra=.03//armature resistance
+e=2*1//voltage drop at brushes
+Eg=V+Ia*Ra+e
+N=450//speed as a generator at this load
+//let k=P*phi*Z/(60*A)
+k=Eg/N
+//when the machine is working as motor
+Ia=Il-Ish
+Eb=V-Ia*Ra-e
+N=Eb/k
+mprintf("Speed as a motor=%d rpm", round(N))
diff --git a/2252/CH17/EX17.2/Ex17_2.sce b/2252/CH17/EX17.2/Ex17_2.sce new file mode 100755 index 000000000..1f31d217d --- /dev/null +++ b/2252/CH17/EX17.2/Ex17_2.sce @@ -0,0 +1,10 @@ +
+P=4//no. of poles
+n=24//no. of slots
+c=2//conductors per slot
+Z=n*c//total no. of conductors
+p=Z/4//pole pitch
+Ybp=p+1//back pitch
+Yfp=p-1//front pitch
+Y=Ybp-Yfp
+mprintf("Resultant pitch=%f",Y)
diff --git a/2252/CH17/EX17.3/Ex17_3.sce b/2252/CH17/EX17.3/Ex17_3.sce new file mode 100755 index 000000000..dda2253cc --- /dev/null +++ b/2252/CH17/EX17.3/Ex17_3.sce @@ -0,0 +1,8 @@ +
+P=6//no. of poles
+A=P//no. of parallel paths
+phi=.018//flux per pole
+N=600//speed of rotation in rpm
+Z=840//total no. of conductors
+Eg=P*phi*N*Z/(60*A)
+mprintf("Emf generated=%f V\n",Eg)
diff --git a/2252/CH17/EX17.4/Ex17_4.sce b/2252/CH17/EX17.4/Ex17_4.sce new file mode 100755 index 000000000..c801749d2 --- /dev/null +++ b/2252/CH17/EX17.4/Ex17_4.sce @@ -0,0 +1,8 @@ +
+P=6//no. of poles
+A=2//no. of parallel paths
+Z=300//no. of conductors on armature
+N=1000//speed of rotation in rpm
+Eg=400//emf generated on open circuit
+phi=60*Eg*A/(P*N*Z)
+mprintf("Flux per pole=%f Wb\n", phi)
diff --git a/2252/CH17/EX17.5/Ex17_5.sce b/2252/CH17/EX17.5/Ex17_5.sce new file mode 100755 index 000000000..d1c3f734a --- /dev/null +++ b/2252/CH17/EX17.5/Ex17_5.sce @@ -0,0 +1,10 @@ +
+Eg=400//emf generated
+n=80//no. of slots on armature
+c=10//conductors per slot
+Z=n*c//total no. of conductors on armature
+N=1000//speed in rpm
+phi=60*Eg/(N*Z)
+Eg=220//desired value of generated voltage
+N=60*Eg/(phi*Z)
+mprintf("Speed of rotation to generate 220 V=%f rpm\n", round(N))
diff --git a/2252/CH17/EX17.6/Ex17_6.sce b/2252/CH17/EX17.6/Ex17_6.sce new file mode 100755 index 000000000..262a8164d --- /dev/null +++ b/2252/CH17/EX17.6/Ex17_6.sce @@ -0,0 +1,13 @@ +
+n=60//no. of slots on armature
+c=6//conductors per slot
+Z=n*c//total no. of conductors
+A=2//no. of parallel paths in armature winding
+N=750//speed of rotation
+P=4//no. of poles
+Eg=230//emf generated on open circuit
+phi=60*Eg*A/(P*N*Z)
+mprintf("Useful fux per pole=%f Wb\n",phi)
+Eg=115//emf to be generated at no load
+A=P*N*Z*phi/(60*Eg)//required no. of parallel paths in armature winding
+mprintf("As the machine has equal number of poles and parallel paths in armature winding, the armature will be lap connected to generate 115 V at the same speed")
diff --git a/2252/CH17/EX17.7/Ex17_7.sce b/2252/CH17/EX17.7/Ex17_7.sce new file mode 100755 index 000000000..eaac3e66e --- /dev/null +++ b/2252/CH17/EX17.7/Ex17_7.sce @@ -0,0 +1,17 @@ +
+//calculating terminal voltage
+P=10D+3//load supplied
+Vl=220//voltage at load terminals
+Il=P/Vl
+R=.1//resistance of feeders
+Vd=Il*R//voltage drop on feeders
+V=Vd+Vl
+mprintf("Terminal voltage across the armature terminals=%f V\n",V)
+//Calculating shunt field current
+Rsh=100//shunt resistance
+Ish=V/Rsh
+mprintf("Shunt field current=%f A\n",Ish)
+//Calculating generated emf
+Ra=.05//resistance of armature
+Eg=V+Il*Ra
+mprintf("Generated emf Eg=%f V",Eg)
diff --git a/2252/CH17/EX17.8/Ex17_8.sce b/2252/CH17/EX17.8/Ex17_8.sce new file mode 100755 index 000000000..30988730b --- /dev/null +++ b/2252/CH17/EX17.8/Ex17_8.sce @@ -0,0 +1,16 @@ +
+//calculating total armature current
+V=200//terminal voltage across armature
+Rsh=80//shunt field resistance
+Ish=V/Rsh//shunt field current
+Il=100//load current
+Ia=Il+Ish
+mprintf("Armature current=%f A\n",Ia)
+//calculating current per armature path
+A=4//no. of parallel paths
+mprintf("Current per armature path=%f A\n",Ia/A)
+//calculating emf generated
+Ra=.1//armature resistance
+e=2//brush contact drop
+Eg=V+Ia*Ra+e
+mprintf("Emf generated=%f V\n",Eg)
diff --git a/2252/CH17/EX17.9/Ex17_9.sce b/2252/CH17/EX17.9/Ex17_9.sce new file mode 100755 index 000000000..42e644dd4 --- /dev/null +++ b/2252/CH17/EX17.9/Ex17_9.sce @@ -0,0 +1,12 @@ +
+V=100//terminal voltage
+Il=200//load current
+Rse=.03//resistance of series field winding
+Ra=.04//resistance of armature winding
+Rsh=60//resistance of shunt
+Vd=Il*Rse//voltage drop in series field winding
+V_dash=V+Il*Rse//terminal voltage across armature
+Ish=V_dash/Rsh
+Ia=Il+Ish
+Eg=V+Il*Rse+Ia*Ra
+mprintf("Generated emf=%f V",Eg)
diff --git a/2252/CH18/EX18.1/Ex18_1.jpeg b/2252/CH18/EX18.1/Ex18_1.jpeg Binary files differnew file mode 100755 index 000000000..9ab33c091 --- /dev/null +++ b/2252/CH18/EX18.1/Ex18_1.jpeg diff --git a/2252/CH18/EX18.1/Ex18_1.sce b/2252/CH18/EX18.1/Ex18_1.sce new file mode 100755 index 000000000..8c3078f53 --- /dev/null +++ b/2252/CH18/EX18.1/Ex18_1.sce @@ -0,0 +1,17 @@ +
+i=linspace(0,1.6,9)
+V=[0 40 66 86 101 112 121 128 133]
+plot(i,V,rect=[0 0 1.6 133])
+xtitle("Magnetization curve for example 18.1","Field Current","Generated emf")
+
+//refer Fig. 18.4 in the textbook
+Rsh=94//resistance of shunt field winding
+//OA is the field resistance line for this resistance
+Voc=126//voltage corresponding to point A
+mprintf("Open circuit voltage when the field circuit resistance is 94 ohm=%d V\n",Voc)
+//D is point on OCC corresponding to 110 V. OD represents the field resistance line to generate this voltage
+R=70/.6//total resistance of shunt field circuit
+mprintf("Additional resistance in the shunt field circuit is %f ohm\n", R-Rsh)
+//line OE represents the critical resistance of shunt field
+Rc=40/.2
+mprintf("Critical resistance=%d ohm",Rc)
diff --git a/2252/CH18/EX18.2/Ex18_2.jpeg b/2252/CH18/EX18.2/Ex18_2.jpeg Binary files differnew file mode 100755 index 000000000..34b81de5d --- /dev/null +++ b/2252/CH18/EX18.2/Ex18_2.jpeg diff --git a/2252/CH18/EX18.2/Ex18_2.sce b/2252/CH18/EX18.2/Ex18_2.sce new file mode 100755 index 000000000..fbc373841 --- /dev/null +++ b/2252/CH18/EX18.2/Ex18_2.sce @@ -0,0 +1,30 @@ +
+i=linspace(0,3.5,8)
+V=[0 60 120 138 145 149 151 152]
+plot2d(i,V)
+xtitle("Magnetization curve for example 18.2","Field Current","Generated emf")
+
+//refer Fig. 18.5 in the textbook
+Rsh=60//shunt field resistance
+//line OA is field resistance line
+Voc=149//voltage corresponding to point A
+mprintf("Open circuit voltage=%d V\n",Voc)
+//resistance represented by OE is critical resistance
+Rc=120
+mprintf("Critical resistance of shunt field=%d ohm\n",Rc)
+//when the load has a resistance of 4 ohm
+R=4
+//load current I=V/4
+//Ish=V/60
+//Ia=I+Ish
+Eg=Voc
+Ra=.1//armature resistance
+//V=Eg-Ia*Ra
+V=Eg/(1+(1/R+1/Rsh)*Ra)
+mprintf("Terminal voltage, V=%f V\n",V)
+//when the terminal voltage is 100 V
+V=100//terminal voltage
+Ia=(Eg-V)/Ra
+Ish=V/Rsh
+I=Ia-Ish
+mprintf("Load current=%f A",I)
diff --git a/2252/CH18/EX18.3/Ex18_3.jpeg b/2252/CH18/EX18.3/Ex18_3.jpeg Binary files differnew file mode 100755 index 000000000..959079b88 --- /dev/null +++ b/2252/CH18/EX18.3/Ex18_3.jpeg diff --git a/2252/CH18/EX18.3/Ex18_3.sce b/2252/CH18/EX18.3/Ex18_3.sce new file mode 100755 index 000000000..bf8b49107 --- /dev/null +++ b/2252/CH18/EX18.3/Ex18_3.sce @@ -0,0 +1,22 @@ +
+i=linspace(0,2.5,6)
+V=[0 50 84 105 120 131]
+plot(i,V)
+xtitle("Magnetization curve for example 18.3","Field Current","Generated emf")
+
+//refer Fig.18.6 in the textbook
+//OE is the field resistance line of critical resistance
+Rc=100
+//solving (iii)
+Rsh=70//field resistance
+N=750//speed in rpm
+Nc=Rsh/Rc*N
+mprintf("When the field resistance is 70 ohm, critical speed=%d rpm\n",round(Nc))
+//solving (iv)
+Eg=100//open-circuit voltage
+Rsh=55//shunt field resistance
+//now, the operating point is M instead of A
+//LM/LN=N1/N
+//from the graph, LM/LN=100/115
+N1=100/115*N//desired speed
+mprintf("With shunt field resistance of 55 ohm, reduction in speed to make the open circuit voltage equal to 100 V=%d rpm",round(N-N1))
diff --git a/2252/CH18/EX18.4/Ex18_4.jpeg b/2252/CH18/EX18.4/Ex18_4.jpeg Binary files differnew file mode 100755 index 000000000..77da17518 --- /dev/null +++ b/2252/CH18/EX18.4/Ex18_4.jpeg diff --git a/2252/CH18/EX18.4/Ex18_4.sce b/2252/CH18/EX18.4/Ex18_4.sce new file mode 100755 index 000000000..12f47052d --- /dev/null +++ b/2252/CH18/EX18.4/Ex18_4.sce @@ -0,0 +1,19 @@ +
+//generated emf is directly proportional to speed
+//readings for OCC at 1000 rpm are
+Eg2=[10*(1000/800) 112*(1000/800) 198*(1000/800) 232*(1000/800) 252*(1000/800) 266*(1000/800)]
+i=linspace(0,5,6)
+plot2d(i,Eg2)
+xtitle("Magnetization curve for example 18.4","Field current","Generated emf")
+
+//refer Fig.18.7 in the textbook
+Rsh=70//resistance of field circuit
+//line OA is field resistance line
+V=330//voltage corresponding to point A
+mprintf("No load terminal voltage is %d V\n",V)
+//now, no load terminal voltage is 270 V
+V=270
+//the operating point is D
+//line OD is corresponding field resistance line
+R=V/2.4//resistance represented by line OD
+mprintf("Additional resistance required in the field circuit to reduce the voltage to 270 V=%f ohm\n",R-Rsh)
diff --git a/2252/CH18/EX18.5/Ex18_5.sce b/2252/CH18/EX18.5/Ex18_5.sce new file mode 100755 index 000000000..e78558b3b --- /dev/null +++ b/2252/CH18/EX18.5/Ex18_5.sce @@ -0,0 +1,21 @@ +
+//for generator A
+V1=240//initial terminal voltage
+V2=225//final terminal voltage
+Ia=120//armature current
+Ra=(V1-V2)/Ia//armature resistance
+//for generator B
+V1=230//initial terminal voltage
+V2=215//final terminal voltage
+Ib=100//armature current
+Rb=(V1-V2)/Ib//armature resistance
+I=200//total load current
+//I1+I2=I, V=240-I1*Ra, V=230-I2*Rb
+//solving for V, I1 and I2
+a=[1 1 0;Ra 0 1;0 Rb 1]
+b=[200;240;230]
+x=inv(a)*b
+I1=x(1,1)
+I2=x(2,1)
+V=x(3,1)
+mprintf("Bus-bar voltage=%f V,\nGenerator A supplies %f A,\nGenerator B supplies %f A", V,I1,I2)
diff --git a/2252/CH18/EX18.6/Ex18_6.sce b/2252/CH18/EX18.6/Ex18_6.sce new file mode 100755 index 000000000..acae7f29c --- /dev/null +++ b/2252/CH18/EX18.6/Ex18_6.sce @@ -0,0 +1,19 @@ +
+Ra=.03//armature resistance of each generator
+Rsh=60//field resistance of each generator
+I=4500//total load current
+//I1+I2=4500, Ish=V/60
+//Ia1=I1+V/60
+//Ia2=I2+V/60
+Ea1=500//induced emf in generator 1
+//500=V+Ia1*.03
+Ea2=510//induced emf in generator 2
+//510=V+Ia2*.03
+//solving for V,I1 and I2
+a=[1 1 0;.03 0 1+.03/60;0 .03 1+.03/60]
+b=[4500;500;510]
+x=inv(a)*b
+I1=x(1,1)
+I2=x(2,1)
+V=x(3,1)
+mprintf("Bus-bar voltage=%f V,\nLoad shared by generator 1=%f A,\nLoad shared by generator 2=%f A", V,I1,I2)
diff --git a/2252/CH18/EX18.7/Ex18_7.sce b/2252/CH18/EX18.7/Ex18_7.sce new file mode 100755 index 000000000..66d04f71e --- /dev/null +++ b/2252/CH18/EX18.7/Ex18_7.sce @@ -0,0 +1,28 @@ +
+//Let V be bus-bar voltage and I1, I2 be the currents supplied by generators 1 and 2 respectively
+Il=3000//total load current
+//I1+I2=Il
+//for generator 1
+Rsh1=30//field resistance
+Ra1=.05//armature resistance
+Eg1=400//induced emf
+//for generator 2
+Rsh2=25//field resistance
+Ra2=.03//armature resistance
+Eg2=380//induced emf
+//Ish1=V/Rsh1
+//Ish2=V/Rsh2
+//Ia1=I1+Ish1
+//Ia2=I2+Ish2
+//Eg1=V+Ia1*Ra1;Eg2=V+Ia2*Ra2
+//solving for I1,I2 and V
+a=[1 1 0;Ra1 0 1+Ra1/Rsh1;0 Ra2 1+Ra2/Rsh2]
+b=[Il;Eg1;Eg2]
+x=inv(a)*b
+I1=x(1,1)
+I2=x(2,1)
+V=x(3,1)
+P1=V*I1
+P2=V*I2
+mprintf("Output of generator 1=%f kW\nOutput of generator 2=%f kW", P1/1000,P2/1000)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH19/EX19.1/Ex19_1.sce b/2252/CH19/EX19.1/Ex19_1.sce new file mode 100755 index 000000000..3604fb04d --- /dev/null +++ b/2252/CH19/EX19.1/Ex19_1.sce @@ -0,0 +1,19 @@ +
+//calculating torque deveoped
+P=6//no. of poles
+A=6//no. of parallel circuits
+Ia=300//armature current
+n=500//no. of armature turns
+Z=2*500//total no. of conductors
+phi=75D-3//flux per pole
+Ta=.159*P*phi*Ia*Z/A
+mprintf("Torque developed=%f N-m\n",Ta)
+//calculating shaft torque
+T=2.5*Ta/100//torque lost in windage, friction and iron losses
+Tsh=Ta-T
+mprintf("Shaft torque=%f N-m\n",Tsh)
+//calculating shaft power
+N=400//speed in rpm
+Psh=2*%pi*N*Tsh/60
+mprintf("Shaft power=%f kW",Psh/1000)
+//answer vary from the textbook due to round off error
diff --git a/2252/CH19/EX19.10/Ex19_10.sce b/2252/CH19/EX19.10/Ex19_10.sce new file mode 100755 index 000000000..363416c44 --- /dev/null +++ b/2252/CH19/EX19.10/Ex19_10.sce @@ -0,0 +1,11 @@ +
+V=500//applied voltage
+N1=700//initial speed of motor
+Ia1=50//armature current
+Ra=.4//effective armature resistance
+Eb1=V-Ia1*Ra
+N2=600//reduced speeed of motor
+Ia2=Ia1//as torque and flux remains same
+//back emf is directly proportional to speed
+R=((V-Ia2*Ra)*N1-Eb1*N2)/(Ia2*N1)
+mprintf("Additional resistance in the armature circuit is %f ohm",R)
diff --git a/2252/CH19/EX19.11/Ex19_11.sce b/2252/CH19/EX19.11/Ex19_11.sce new file mode 100755 index 000000000..5575480c9 --- /dev/null +++ b/2252/CH19/EX19.11/Ex19_11.sce @@ -0,0 +1,20 @@ +
+R=.25+.05//total resistance of the armature circuit
+N1=500//normal speed
+V=250//applied voltage
+Ia1=100//armature current at normal speed
+Eb1=V-Ia1*R
+//solving part (i)
+R1=R+1//total resisitance in the armature circuit
+Ia2=50//armature current
+Eb2=V-Ia2*R1
+//back emf is directly proportional to speed
+N2=Eb2/Eb1*N1
+mprintf("For(i)\nSpeed=%d rpm\n",round(N2))
+//solving part (ii)
+Ia3=50//armature current
+Eb3=V-Ia3*R
+//Ish3=.6*Ish1-->phi3/phi1=.6
+//back emf is directly proportional to flux and speed
+N3=(Eb3/Eb1)*N1/.6
+mprintf("For(ii)\nSpeed=%d rpm", N3)
diff --git a/2252/CH19/EX19.12/Ex19_12.sce b/2252/CH19/EX19.12/Ex19_12.sce new file mode 100755 index 000000000..9829f1222 --- /dev/null +++ b/2252/CH19/EX19.12/Ex19_12.sce @@ -0,0 +1,23 @@ +
+//solving (i)
+Il=70//current drawn by the motor
+V=200//applied voltage
+Rsh=100//shunt field resistance
+Ish=V/Rsh//shunt field current
+Ia1=Il-Ish
+N1=500//initial speed
+Ra1=.2//armature resistance
+Eb1=200-Ia1*Ra1
+N2=350//reduced speed of motor
+Ia2=Ia1//armature current remains same
+//Eb2=200-68*(R+.2)
+//back emf is proportional to speed
+R=((V-Ia2*Ra1)*N1-Eb1*N2)/(Ia2*N1)
+mprintf("Additional resistance in the armature circuit=%f ohm\n",R)
+//solving (ii)
+Ra2=R+Ra1//armature resistance
+Ia3=35//armature current
+Eb3=V-Ia3*Ra2
+N3=N1*Eb3/Eb1
+mprintf("Speed=%d rpm",N3)
+//answer vary from the textbook due to round off error
diff --git a/2252/CH19/EX19.13/Ex19_13.sce b/2252/CH19/EX19.13/Ex19_13.sce new file mode 100755 index 000000000..e8416ea15 --- /dev/null +++ b/2252/CH19/EX19.13/Ex19_13.sce @@ -0,0 +1,14 @@ +
+V=250//voltage applied to the motor
+Eb1=V//Ra is negligible
+N1=500//speed in rpm
+Ia1=40//armature current
+R=25//additional resistance
+//as flux remains same, back emf is directly proportional to speed; and torque is directly proportional to armature current
+//Eb2=250-Ia2*25, N2=500-50*Ia2
+//also, torque varies as cube of speed
+//from these conditions, we get, Ia2^3-30*Ia2^2+325*Ia2-1000=0
+//solving this equation, we get
+Ia2=5
+N2=(Ia2/Ia1)^(1/3)*N1
+mprintf("Speed of the motor with 25 ohm resistor in the armature circuit=%d rpm",N2)
diff --git a/2252/CH19/EX19.2/Ex19_2.sce b/2252/CH19/EX19.2/Ex19_2.sce new file mode 100755 index 000000000..029497bb6 --- /dev/null +++ b/2252/CH19/EX19.2/Ex19_2.sce @@ -0,0 +1,28 @@ +
+//calculating torque developed by armature
+V=200//voltage applied across the motor
+Rsh=40//resistance of shunt field winding
+Ish=V/Rsh
+I=100//total current drawn by motor
+Ia=I-Ish
+Ra=.1//armature resistance
+Eb=V-Ia*Ra
+P=Eb*Ia//mechanical power developed
+N=750//speed in rpm
+Ta=60*P/(2*%pi*N)
+mprintf("Torque developed by armature=%f N-m\n",Ta)
+//calculating copper losses
+Wcu1=V*Ia-Eb*Ia//armature copper losses
+Wcu2=Ish^2*Rsh//field copper losses
+mprintf("Total copper losses=%f W\n",Wcu1+Wcu2)
+//calculating shaft power
+Wc=1500//friction and iron losses
+Pi=200*100//input to motor
+Psh=Pi-(Wc+Wcu1+Wcu2)
+mprintf("Shaft power=%f kW\n",Psh/1000)
+//calculating shaft torque
+Tsh=60*Psh/(2*%pi*N)
+mprintf("Shaft torque=%f N-m\n",Tsh)
+//calculating efficiency
+e=Psh/Pi*100
+mprintf("Efficiency=%f percent",e)
diff --git a/2252/CH19/EX19.3/Ex19_3.sce b/2252/CH19/EX19.3/Ex19_3.sce new file mode 100755 index 000000000..bf4c06282 --- /dev/null +++ b/2252/CH19/EX19.3/Ex19_3.sce @@ -0,0 +1,25 @@ +
+Po=60D+3//full load output of the motor
+e=0.905//efficiency of the motor
+Pin=Po/e
+V=400//applied voltage
+I=Pin/V//line current drawn by the motor
+Rsh=200//resistance of the shunt field winding
+Ish=V/Rsh
+Ia=I-Ish
+Ra=0.1//armature resistance
+Eb=V-Ia*Ra
+A=2//no. of parallel paths in armature winding
+P=4//no. of poles
+phi=45D-3//flux per pole
+Z=450//total number of conductors
+N=round(60*Eb*A/(P*phi*Z))
+mprintf("Full load speed=%d rpm\n",N)
+//calculating armature torque
+Ta=0.159*P*phi*Ia*Z/A
+mprintf("Torque developed by the armature of the DC motor=%f N-m\n",Ta)
+//calculating useful torque
+Psh=60D+3//shaft power
+Tsh=60*Psh/(2*%pi*N)
+mprintf("Useful torque=%f N-m",Tsh)
+//error in the textbook answer for useful torque
diff --git a/2252/CH19/EX19.4/Ex19_4.sce b/2252/CH19/EX19.4/Ex19_4.sce new file mode 100755 index 000000000..12d1aa463 --- /dev/null +++ b/2252/CH19/EX19.4/Ex19_4.sce @@ -0,0 +1,17 @@ +
+V=220//voltage applied to motor
+Rsh=157//shunt field resistance
+Ra=0.3//armature resistance
+Ish=V/Rsh
+I0=4.5//current drawn by the motor at no load
+Ia0=I0-Ish
+Eb0=V-Ia0*Ra
+//under loaded conditions,
+I=30//current drawn by motor
+Ia=I-Ish
+Eb=V-Ia*Ra
+//phi=.97*phi0
+//back emf is directly proportional to flux and speed
+N0=1000//speed at no load
+N=Eb*N0/(Eb0*.97)
+mprintf("Speed under loaded condition=%d rpm", round(N))
diff --git a/2252/CH19/EX19.5/Ex19_5.sce b/2252/CH19/EX19.5/Ex19_5.sce new file mode 100755 index 000000000..c49bfb308 --- /dev/null +++ b/2252/CH19/EX19.5/Ex19_5.sce @@ -0,0 +1,19 @@ +
+//calculating shaft power
+V=100//voltage applied to series motor
+Ra=.22//armature resistance
+Rse=.13//series field resistance
+Rm=Ra+Rse//total resistance
+Ia=45//current in armature circuit
+Eb=V-Ia*Rm
+Pm=Eb*Ia//mechanical power developed
+Wc=750//iron and friction losses
+Psh=Pm-Wc
+mprintf("Shaft power=%f kW\n",Psh/1000)
+//calculating torque developed
+N=750//speed in rpm
+Ta=60*Pm/(2*%pi*N)
+mprintf("Total torque=%f N-m\n",Ta)
+//calculating shaft torque
+Tsh=60*Psh/(2*%pi*N)
+mprintf("Shaft torque=%f N-m",Tsh)
diff --git a/2252/CH19/EX19.6/Ex19_6.sce b/2252/CH19/EX19.6/Ex19_6.sce new file mode 100755 index 000000000..e509de1c4 --- /dev/null +++ b/2252/CH19/EX19.6/Ex19_6.sce @@ -0,0 +1,29 @@ +
+//calculating speed
+P=4//no. of poles
+V=220//applied voltage
+Ia=46//current in armature circuit
+Ra=.25//field resistance
+Rse=.15//series field resistance
+Rm=Ra+Rse
+Eb=V-Ia*Rm
+A=2//no. of parallel circuits
+phi=20D-3//flux per pole
+Z=1200//total conductors on armature
+N=round(60*Eb*A/(P*phi*Z))
+mprintf("Speed, N=%d rpm\n", N)
+//calculating total torque
+Ta=.159*P*phi*Ia*Z/A
+mprintf("Total torque=%f N-m\n",Ta)
+//calculating shaft power
+Pm=Eb*Ia//mechanical power developed
+Wc=900//iron and friction losses
+Po=Pm-Wc
+mprintf("Shaft power=%f kW\n",Po/1000)
+//calculating shaft torque
+Tsh=60*Po/(2*%pi*N)
+mprintf("Shaft torque Tsh=%f N-m\n", Tsh)
+//calculating efficiency
+Pin=V*Ia//input to motor
+e=Po/Pin*100
+mprintf("Efficiency=%f percent",e)
diff --git a/2252/CH19/EX19.7/Ex19_7.sce b/2252/CH19/EX19.7/Ex19_7.sce new file mode 100755 index 000000000..3ab09f805 --- /dev/null +++ b/2252/CH19/EX19.7/Ex19_7.sce @@ -0,0 +1,27 @@ +
+//working as motor
+V1=110//applied voltage to motor
+Rsh=45//shunt field resistance
+Ish1=V1/Rsh//shunt field current
+Il=230
+Ia1=Il-Ish1
+Ra=.03//armature resistance
+Eb1=V1-Ia1*Ra
+N1=450//speed in rpm
+V2=210//changed value of applied voltage
+Ish2=V2/Rsh
+Il=85//current drawn by the motor from the main
+Ia2=Il-Ish2
+Eb2=V2-Ia2*Ra
+//back emf is directly proportional to shunt field current and speed
+N2=(Eb2/Eb1)*(Ish1/Ish2)*N1
+mprintf("Speed of the motor=%d rpm\n",N2)
+//working as generator
+V=200//terminal voltage across the load
+Ish3=V/Rsh
+Il=140//load current on the generator
+Ia3=Il+Ish3
+Eg=V+Ia3*Ra
+N3=(Eg/Eb1)*(Ish1/Ish3)*N1
+mprintf("Speed at which generator would have to run=%d rpm",N3)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH19/EX19.8/Ex19_8.sce b/2252/CH19/EX19.8/Ex19_8.sce new file mode 100755 index 000000000..142ba9a9e --- /dev/null +++ b/2252/CH19/EX19.8/Ex19_8.sce @@ -0,0 +1,12 @@ +
+V=230//voltage applied to motor
+N1=1000//initial speed
+Ia=35//armature current
+Ra=.3//resistance of armature circuit
+Eb1=V-Ia*Ra
+N1=1000//speed in rpm
+Ia=25//armature current in new situation
+N2=750//changed speed in rpm
+//back emf is directly proportional to speed
+R=((V-Ia*Ra)*N1-N2*Eb1)/(Ia*N1)
+mprintf("Additional resistance in armature circuit=%f ohm",R)
diff --git a/2252/CH19/EX19.9/Ex19_9.sce b/2252/CH19/EX19.9/Ex19_9.sce new file mode 100755 index 000000000..266cd5a22 --- /dev/null +++ b/2252/CH19/EX19.9/Ex19_9.sce @@ -0,0 +1,19 @@ +
+N1=600//initial speed of the motor in rpm
+Ia1=20//armature current
+V=200//applied voltage
+Ra=.4//armature resistance
+Eb1=V-Ia1*Ra
+Rf1=200//field resistance
+If1=200/200//field current
+N2=900//increased speed in rpm
+//If2=200/Rf
+//phi1/phi2=If1/If2=Rf/200
+//Ia2=Ia1*phi1/phi2=.1*Rf
+//Eb2=200-.04*Rf
+//back emf is directly proportional to flux and speed
+//we get a quadratic equation in Rf as .04*Rf^2-200*Rf+57600=0
+//solving for Rf
+Rf2=(200-sqrt(200^2-4*.04*57600))/(2*.04)
+mprintf("Additional resistance in the shunt field circuit=%f ohm",Rf2-Rf1)
+
diff --git a/2252/CH2/EX2.1/Ex2_1.sce b/2252/CH2/EX2.1/Ex2_1.sce new file mode 100755 index 000000000..bfb77d8a7 --- /dev/null +++ b/2252/CH2/EX2.1/Ex2_1.sce @@ -0,0 +1,12 @@ +
+epsilon=8.854D-12
+r=sqrt(.1^2+.1^2)//distance b/w A and C
+Fca=(2D-6)*(4D-6)/(4*%pi*epsilon*r^2)//from A to C
+Fcb=(4D-6)*(2D-6)/(4*%pi*epsilon*.1^2)//from C to B
+Fcd=(4D-6)*(4D-6)/(4*%pi*epsilon*.1^2)//from C to D
+//Fr has horizontal and vertical components as Frx and Fry respectively
+Frx=Fcd-Fca*cos(45*%pi/180)
+Fry=Fcb-Fca*sin(45*%pi/180)
+Fr=sqrt(Frx^2+Fry^2)
+mprintf("Resultant force acting on charge at C=%f N", Fr)
+//error in textbook answer
diff --git a/2252/CH2/EX2.2/Ex2_2.sce b/2252/CH2/EX2.2/Ex2_2.sce new file mode 100755 index 000000000..de311861b --- /dev/null +++ b/2252/CH2/EX2.2/Ex2_2.sce @@ -0,0 +1,12 @@ +
+epsilon=8.854D-12
+E1=(4D-8)/(4*%pi*epsilon*.05^2)//field intensity due to charge at A,direction is from D to A
+r=sqrt(2*.05^2)//distance b/w B and D
+E2=(4D-8)/(4*%pi*epsilon*r^2)//field intensity due to charge at B,direction is from B to D along diagonal BD
+E3=(8D-8)/(4*%pi*epsilon*.05^2)//field intensity due to charge at C,direction is from D to C
+//Er has horizontal and vertical components as Erx and Ery respectively
+Erx=E3-E2*cos(45*%pi/180)
+Ery=-E1+E2*sin(45*%pi/180)
+Er=sqrt(Erx^2+Ery^2)
+theta=atand(Ery/Erx)
+mprintf("Resultant intensity on charge at C=%f*10^4 N/C at angle %f degrees", Er/10^4,-theta)
diff --git a/2252/CH2/EX2.3/Ex2_3.sce b/2252/CH2/EX2.3/Ex2_3.sce new file mode 100755 index 000000000..bce226f86 --- /dev/null +++ b/2252/CH2/EX2.3/Ex2_3.sce @@ -0,0 +1,10 @@ +
+epsilon=8.854D-12
+AB=.05
+BC=.07
+AC=sqrt(.05^2+.07^2)
+V1=2D-10/(4*%pi*epsilon*.05)//potential at A due to charge at B
+V2=-8D-10/(4*%pi*epsilon*AC)//potential at A due to charge at C
+V3=4D-10/(4*%pi*epsilon*.07)//potential at A due to charge at D
+V=V1+V2+V3
+mprintf("Potential at A due to charges at B, C and D=%f V", V)
diff --git a/2252/CH2/EX2.4/Ex2_4.sce b/2252/CH2/EX2.4/Ex2_4.sce new file mode 100755 index 000000000..22988d1ca --- /dev/null +++ b/2252/CH2/EX2.4/Ex2_4.sce @@ -0,0 +1,21 @@ +
+C=30D-6
+R=500
+T=C*R
+mprintf("Time constant T=%f sec\n", T)
+//at t=0sec, voltage across capacitor is zero
+V=100//aplied voltage
+I=V/R//Ohm's Law
+mprintf("Initial current=%f A\n", I)
+t=.05
+Q=C*V
+q=Q*(1-exp(-t/T))
+mprintf("Charge on the capacitor after 0.05 sec is %f C\n", q)
+i1=I*exp(-t/T)
+mprintf("Charging current after 0.05 sec is %f A\n",i1)
+t=.015
+i2=I*exp(-t/T)
+mprintf("Charging current after 0.015 sec is %f A\n",i2)
+V=i1*R
+mprintf("Voltage across 500 ohm resistor after 0.05 sec is %f V", V)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH2/EX2.5/Ex2_5.sce b/2252/CH2/EX2.5/Ex2_5.sce new file mode 100755 index 000000000..aa52b7a98 --- /dev/null +++ b/2252/CH2/EX2.5/Ex2_5.sce @@ -0,0 +1,11 @@ +
+C=100D-6
+V=200
+Q=C*V
+Ct=100D-6+50D-6//total capacitance
+Vt=Q/Ct
+mprintf("P.D. across the combination =%f V\n", Vt)
+EE1=100D-6*V^2/2
+mprintf("Electrostatic energy before capacitors are connected in parallel=%f J\n", EE1)
+EE2=Ct*Vt^2/2
+mprintf("Electrostatic energy after capacitors are connected in parallel=%f J", EE2)
diff --git a/2252/CH2/EX2.6/Ex2_6.sce b/2252/CH2/EX2.6/Ex2_6.sce new file mode 100755 index 000000000..8b7f5df4c --- /dev/null +++ b/2252/CH2/EX2.6/Ex2_6.sce @@ -0,0 +1,15 @@ +
+C1=100D-6 //capacitance of first capacitor which is to be charged
+V=200 //voltage across C1
+Q=C1*V
+//Let Q1, Q2, Q3, Q4 be the charges on respective capacitors after connection
+Q2=4000D-6
+Q3=5000D-6
+Q4=6000D-6
+Q1=Q-(Q2+Q3+Q4)
+C2=C1*(Q2/Q1)
+C3=C1*(Q3/Q1)
+C4=C1*(Q4/Q1)
+mprintf("Three capacitors have capacitances %d microF, %d microF and %d microF\n", C2*10^6,C3*10^6,C4*10^6)
+Vt=Q1/C1
+mprintf("Voltage across the combination =%f V", Vt)
diff --git a/2252/CH20/EX20.1/Ex20_1.sce b/2252/CH20/EX20.1/Ex20_1.sce new file mode 100755 index 000000000..913e2cfa7 --- /dev/null +++ b/2252/CH20/EX20.1/Ex20_1.sce @@ -0,0 +1,8 @@ +
+E1=400//eddy current losses
+//for a machine, eddy current losses is directly proportional to Bmax^2 and f^2
+//Bmax is proportional to flux
+//f is proportional to speed
+//when speed and flux increased by 10%
+E2=1.1^2*1.1^2*E1 //Eddy current losses under changed condition
+mprintf("Increase in eddy current losses=%f W", E2-E1)
diff --git a/2252/CH20/EX20.2/Ex20_2.sce b/2252/CH20/EX20.2/Ex20_2.sce new file mode 100755 index 000000000..1d92950fe --- /dev/null +++ b/2252/CH20/EX20.2/Ex20_2.sce @@ -0,0 +1,15 @@ +
+N=1500//speed in rpm
+E1=300//hysteresis losses
+//E1=k1*N
+k1=E1/N
+E2=150//eddy current losses
+//E2=k2*N^2
+k2=E2/N^2
+E=E1+E2//total iron losses
+//when iron losses are reduced to half
+//k1*N1+k2*N1^2=.5*E
+//solving for N1
+N1=(-k1+sqrt(k1^2-4*k2*(-.5*E)))/(2*k2)
+mprintf("Total iron losses will be halved if speed is reduced to %d rpm", round(N1))
+
diff --git a/2252/CH20/EX20.3/Ex20_3.sce b/2252/CH20/EX20.3/Ex20_3.sce new file mode 100755 index 000000000..e082da154 --- /dev/null +++ b/2252/CH20/EX20.3/Ex20_3.sce @@ -0,0 +1,29 @@ +
+//calculating efficiency at full load
+Il=200 //current supplied
+Rsh=100 //shunt field resistance
+V=500 //terminal voltage
+Ish=V/Rsh
+Ia=Il+Ish
+Wcu=Ia^2*.1 //armature copper losses
+Wc=4000 //constant losses including field copper losses
+Wt=Wcu+Wc //total losses
+Po=V*Il //output power
+e=Po*100/(Po+Wt)
+mprintf("Efficiency at full load=%f percent\n", e)
+//Calculating efficiency at half load
+Il=200/2
+Ia=Il+Ish
+Wcu=Ia^2*.1
+Wt=Wc+Wcu
+Po=V*Il
+e=Po*100/(Po+Wt)
+mprintf("Efficiency at half load=%f percent\n", e)
+//Calculating efficiency at 1.5 times the full load
+Il=1.5*200
+Ia=Il+Ish
+Wcu=Ia^2*.1
+Wt=Wc+Wcu
+Po=V*Il
+e=Po*100/(Po+Wt)
+mprintf("Efficiency at 1.5 times the full load=%f percent", e)
diff --git a/2252/CH20/EX20.4/Ex20_4.sce b/2252/CH20/EX20.4/Ex20_4.sce new file mode 100755 index 000000000..86ad639cd --- /dev/null +++ b/2252/CH20/EX20.4/Ex20_4.sce @@ -0,0 +1,19 @@ +
+Po=10D+3 //output power of each motor at full load
+e=.85 //efficiency at full load
+Pi=Po/e
+W=Pi-Po //total losses at full load for each motor
+//calculating half load efficiency for motor A
+Wc=500 //constant losses
+Wcu1=(W-Wc)/2^2 //copper losses
+W1=Wc+Wcu1 //total losses
+P1=Po/2 //output
+e1=P1/(P1+W1)*100
+mprintf("Efficiency at half load for motor A=%f percent\n", e1)
+//calculating half load efficiency for motor B
+Wc=600 //constant losses
+Wcu2=(W-Wc)/2^2 //copper losses
+W2=Wc+Wcu2 //total losses
+P2=Po/2 //output
+e2=P2/(P2+W2)*100
+mprintf("Efficiency at half load for motor B=%f percent", e2)
diff --git a/2252/CH20/EX20.5/Ex20_5.sce b/2252/CH20/EX20.5/Ex20_5.sce new file mode 100755 index 000000000..28dc15940 --- /dev/null +++ b/2252/CH20/EX20.5/Ex20_5.sce @@ -0,0 +1,35 @@ +
+//calculating power required at the driving shaft at full load
+Po=30D+3 //output power of dc shunt generator
+Wi=1300 //mechanical and iron losses
+Rsh=125 //shunt field resistance
+V=250 //terminal voltage
+Ra=.13 //armature resistance
+Ish=V/Rsh
+Wcu=V*Ish //shunt field copper losses
+Wc=Wi+Wcu //constant losses of generator
+Il=Po/V
+Ia=Il+Ish
+Wcu=Ia^2*Ra //armature copper loss
+Wt=Wc+Wcu //total losses
+Pi=Po+Wt
+mprintf("Power required at the driving shaft at full load=%f kW\n", Pi/10^3)
+//calculating efficiency at full load
+e=Po/Pi*100
+mprintf("Efficiency at full load=%f percent\n", e)
+//calculating efficiency at half load
+Il=(Po/2)/V
+Ia=Il+Ish
+Wcu=Ia^2*Ra //copper losses
+Wt=Wc+Wcu //total losses
+e=(Po/2)/(Po/2+Wt)*100
+mprintf("Efficiency at half load=%f percent\n", e)
+//at maximum efficiency
+Wcu=Wc //copper losses
+Ia=sqrt(Wcu/Ra)
+Il=Ia-Ish
+mprintf("Power output at max efficiency=%f kW\n",Il*V/10^3)
+//calculating max efficiency
+e_max=Il*V/(Il*V+2*Wc)*100
+mprintf("Max efficiency=%f percent", e_max)
+//answer vary from the textbook due to round off error
diff --git a/2252/CH20/EX20.6/Ex20_6.sce b/2252/CH20/EX20.6/Ex20_6.sce new file mode 100755 index 000000000..b33c6f19e --- /dev/null +++ b/2252/CH20/EX20.6/Ex20_6.sce @@ -0,0 +1,27 @@ +
+V=500 //voltage applied to motor
+Ra=.2 //armature resistance
+Il0=4 //no load current taken by motor
+Ish=1 //shunt current
+Pi=V*Il0 //power input at no load
+Ia0=Il0-Ish
+Wcu=Ia0^2*Ra //armature copper losses at no load
+Wc=Pi-Wcu //constant losses
+//when input current=20 A
+Il=20
+Ia=Il-Ish
+Wcu=Ia^2*Ra //armature copper losses
+Wt=Wc+Wcu //total losses
+Pi=V*Il //power input to motor
+Po=Pi-Wt
+e=Po/Pi*100
+mprintf("When input current=20 A, output is %f W and efficiency of motor is %f percent\n",Po, e)
+//when input current =100 A
+Il=100
+Ia=Il-Ish
+Wcu=Ia^2*Ra //armature copper losses
+Wt=Wc+Wcu //total losses
+Pi=V*Il //power input to motor
+Po=Pi-Wt
+e=Po/Pi*100
+mprintf("When input current=100 A, output is %f W and efficiency of motor is %f percent\n", Po,e)
diff --git a/2252/CH20/EX20.7/Ex20_7.sce b/2252/CH20/EX20.7/Ex20_7.sce new file mode 100755 index 000000000..6c406cfd6 --- /dev/null +++ b/2252/CH20/EX20.7/Ex20_7.sce @@ -0,0 +1,32 @@ +
+//shunt generator was run as a shunt motor at no load
+I0=5 //current drawn
+Ish=1.5 //shunt field current
+Ia0=I0-Ish
+Ra=.15 //armature circuit resistance
+V=440 //terminal voltage
+Wcu=Ia0^2*Ra //armature copper loss
+Pi=V*I0 //power input
+Wc=Pi-Wcu //constant losses
+//calculating efficiency of shunt generator at full load
+Po=50D+3 //output of generator
+Il=Po/V //load current
+Ia=Il+Ish
+Wcu=Ia^2*Ra //copper losses
+Wt=Wc+Wcu //total losses
+e=Po/(Po+Wt)*100
+mprintf("Efficiency of shunt generator at full load=%f percent\n", e)
+//calculating efficiency at 3/4th load
+I1=3/4*Il //load current
+Ia=I1+Ish
+Wcu=Ia^2*Ra //copper losses
+Wt=Wc+Wcu //total losses
+e=(3/4*Po)/(3/4*Po+Wt)*100
+mprintf("Efficiency at 3/4th load=%f percent\n", e)
+//calculating efficiency at half load
+I2=.5*Il //load current
+Ia=I2+Ish
+Wcu=Ia^2*.15 //copper losses
+Wt=Wc+Wcu //total losses
+e=(.5*Po)/(.5*Po+Wt)*100
+mprintf("Efficiency at half load=%f percent", e)
diff --git a/2252/CH20/EX20.8/Ex20_8.sce b/2252/CH20/EX20.8/Ex20_8.sce new file mode 100755 index 000000000..ae02309b3 --- /dev/null +++ b/2252/CH20/EX20.8/Ex20_8.sce @@ -0,0 +1,20 @@ +
+I1=50 //input current from mains
+Po=100D+3 //output of generator on full load in W
+V=500 //terminal voltage
+I2=Po/V //load current of generator
+Rg=.1 //armature resistance of generator
+Rm=.1 //armature resistance of motor
+Pi=25D+3 //input power from mains
+Pr=(Pi-I2^2*Rg-(I1+I2)^2*Rm)/2 //iron and mechanical losses in each machine
+I3=4 //shunt field current of generator
+I4=3 //shunt field current of motor
+//calculating efficiency of generator
+Wt=Pr+V*I3+I2^2*Rg //total losses
+e=Po/(Po+Wt)*100
+mprintf("Efficiency of generator=%f percent\n", e)
+//calculating efficiency of motor
+Pi=V*(I1+I2+I4) //power input
+Wt=Pr+V*I4+(I1+I2)^2*Rm //total losses
+e=(Pi-Wt)/Pi*100
+mprintf("Efficiency of motor=%f percent", e)
diff --git a/2252/CH21/EX21.1/Ex21_1.sce b/2252/CH21/EX21.1/Ex21_1.sce new file mode 100755 index 000000000..68861da55 --- /dev/null +++ b/2252/CH21/EX21.1/Ex21_1.sce @@ -0,0 +1,24 @@ +
+//calculating speed
+f=50//frequency
+P=20//no. of poles
+N=120*f/P
+mprintf("Speed at which alternator must be run=%d rpm\n", N)
+//calculating the generated emf per phase
+x=180//total no. of slots
+y=x/P//slots per pole
+m=y/3//slots per pole per phase
+alpha=180/9//phase displacement between adjacent slots
+Kd=sin((m*alpha/2)*%pi/180)/(m*sin((alpha/2)*%pi/180))//distribution factor
+Kc=1//coil span factor
+Kw=Kd*Kc//winding factor
+Z=180*8//total no. of conductors
+a=Z/3//conductors per phase
+T=a/2//turns per phase
+phi=25D-3//flux per pole
+Eph=round(4.44*Kw*f*phi*T)
+mprintf("Generated emf per phase=%d V\n", Eph)
+//calculating line emf
+El=sqrt(3)*round(Eph)
+mprintf("Line emf=%d V", round(El))
+//answer vary from the textbook due to round off error
diff --git a/2252/CH21/EX21.10/Ex21_10.sce b/2252/CH21/EX21.10/Ex21_10.sce new file mode 100755 index 000000000..d8c061fbe --- /dev/null +++ b/2252/CH21/EX21.10/Ex21_10.sce @@ -0,0 +1,25 @@ +
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+//terminal voltage is taken as reference phasor and the rated quantities are taken as 1 p.u.
+Vt=pol2rect(1,0)//terminal voltage
+pf=.8//lagging power factor
+phi=acosd(pf)
+Ia=pol2rect(1,-phi)//armature current
+Xd=.8*j
+Xq=.4*j
+//refer to Fig.21.24 in the textbook
+OB=Vt+Ia*Xq
+delta=14.47//power angle
+Id=Ia*sin((delta+phi)*%pi/180)
+Ef=mag(OB)+mag(Id)*mag(Xd-Xq)
+mprintf("Excitation voltage per phase is %f p.u.", Ef)
diff --git a/2252/CH21/EX21.2/Ex21_2.sce b/2252/CH21/EX21.2/Ex21_2.sce new file mode 100755 index 000000000..8083534d1 --- /dev/null +++ b/2252/CH21/EX21.2/Ex21_2.sce @@ -0,0 +1,18 @@ +
+funcprot(0)
+m=2//no. of slots per pole per phase
+x=m*3//no. of slots per pole
+alpha=180/x//phase displacement between adjacent slots in degrees
+Kd=sin((m*alpha/2)*%pi/180)/(m*sin((alpha/2)*%pi/180))//distribution factor
+beta=180-150//in degrees
+Kc=cos((beta/2)*%pi/180)//coil span factor
+Kw=Kd*Kc//winding factor
+P=10//no. of poles
+n=m*P//no. of slots per phase
+Zph=n*10//no. of conductors per phase
+Tph=100//no. of turns per phase
+N=600//speed of the alternator in rpm
+f=P*N/120//frequency
+phi=.05//useful flux per pole in Wb
+Eph=4.44*Kw*f*phi*Tph
+mprintf("Stator emf per phase at no load=%d V", round(Eph))
diff --git a/2252/CH21/EX21.3/Ex21_3.sce b/2252/CH21/EX21.3/Ex21_3.sce new file mode 100755 index 000000000..a570e3156 --- /dev/null +++ b/2252/CH21/EX21.3/Ex21_3.sce @@ -0,0 +1,25 @@ +
+funcprot(0)
+//calculating pitch factor
+beta=0//full pitch coil
+Kc=cos((beta/2)*%pi/180)
+mprintf("Pitch factor, Kc=%d\n", Kc)
+//calculating distribution factor
+m=4//no. of slots per pole per phase
+x=m*3//no. of slots per pole
+alpha=180/x//phase displacement between adjacent slots in degrees
+Kd=sin((m*alpha/2)*%pi/180)/(m*sin((alpha/2)*%pi/180))
+mprintf("Distribution factor of stator winding=%f\n", Kd)
+//calculating emf generated per phase
+Kw=Kd*Kc
+y=m*8//no. of slots per phase
+n=y*10//no. of conductors per phase
+Tph=160//no. of turns per phase
+f=50//frequency
+phi=.04//flux per pole
+Eph=round(4.44*f*Kw*Tph*phi)
+mprintf("Emf per phase at no load=%d V\n", Eph)
+//calculating line emf
+El=sqrt(3)*Eph
+mprintf("Line emf=%d V", round(El))
+//answer vary from the textbook due to round off error
diff --git a/2252/CH21/EX21.4/Ex21_4.sce b/2252/CH21/EX21.4/Ex21_4.sce new file mode 100755 index 000000000..6025b934d --- /dev/null +++ b/2252/CH21/EX21.4/Ex21_4.sce @@ -0,0 +1,22 @@ +
+funcprot(0)
+//calculating distribution factor of stator winding
+m=9//no. of slots per pole per phase
+x=m*3//no. of slots per pole
+alpha=180/x
+Kd=sin((m*alpha/2)*%pi/180)/(m*sin((alpha/2)*%pi/180))
+mprintf("Distribution factor of stator winding, Kd=%f\n",Kd)
+//calculating pitch factor of stator winding
+beta=2*20/3
+Kc=cos((beta/2)*%pi/180)
+mprintf("Pitch factor=%f\n", Kc)
+//calculating useful flux per pole
+Zph=9*2*4//no. of conductors per phase
+Tph=36//turns per phase of stator winding
+P=2//no. of poles
+N=3000//speed in rpm
+f=P*N/120
+V=3.3D+3//line voltage
+Eph=V/sqrt(3)
+phi=Eph/(4.44*f*Kd*Kc*Tph)
+mprintf("Useful flux per pole=%f Wb", phi)
diff --git a/2252/CH21/EX21.5/Ex21_5.sce b/2252/CH21/EX21.5/Ex21_5.sce new file mode 100755 index 000000000..341908d9b --- /dev/null +++ b/2252/CH21/EX21.5/Ex21_5.sce @@ -0,0 +1,17 @@ +
+funcprot(0)
+m=5//no. of slots per pole per phase
+x=m*3//no. of slots per pole
+alpha=180/x//in degrees
+Kd=sin((m*alpha/2)*%pi/180)/(m*sin((alpha/2)*%pi/180))//distribution factor
+beta=3*12//in degrees
+Kc=cos((beta/2)*%pi/180)//pitch factor of stator winding
+Tph=5*2*4/2//no. of turns per phase
+V=6D+3//line voltage
+Eph=V/sqrt(3)
+phi=.857//flux in Wb
+f=round(Eph/(4.44*Kd*Kc*Tph*phi))
+P=4//no. of poles
+N=120*f/P
+mprintf("Speed of rotation of alternator, N=%d rpm", round(N))
+//answer vary from the textbook due to round off error
diff --git a/2252/CH21/EX21.6/Ex21_6.sce b/2252/CH21/EX21.6/Ex21_6.sce new file mode 100755 index 000000000..014552ed4 --- /dev/null +++ b/2252/CH21/EX21.6/Ex21_6.sce @@ -0,0 +1,17 @@ +
+//calculating regulation at full load at unity pf
+V=3300//line voltage
+Vph=V/sqrt(3)
+P=500D+3//output
+Ia=P/(sqrt(3)*V)
+Ra=.4//resistance per phase
+Xs=3.8//reactance per phase
+pf=1//power factor
+Ef=[(Vph*1+Ia*Ra)^2+(Vph*0+Ia*Xs)^2]^.5//open circuit voltage per phase
+VR=(Ef-Vph)/Vph*100
+mprintf("Regulation at full load at unity pf=%f percent\n", VR)
+//calculating regulation at full load at .8 pf lagging
+Ef=[(Vph*.8+Ia*Ra)^2+(Vph*0.6+Ia*Xs)^2]^.5
+VR=(Ef-Vph)/Vph*100
+mprintf("Regulation full load at .8 pf lagging=%f percent\n", VR)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH21/EX21.7/Ex21_7.sce b/2252/CH21/EX21.7/Ex21_7.sce new file mode 100755 index 000000000..cfabb5ad1 --- /dev/null +++ b/2252/CH21/EX21.7/Ex21_7.sce @@ -0,0 +1,25 @@ +
+//calculating synchronous impedance
+Voc=90//open circuit voltage per phase
+Isc=15//short circuit current
+Zs=Voc/Isc
+mprintf("Synchronous impedance=%d ohm\n", Zs)
+//calculating synchronous reactance
+Ra=1//armature resistance per phase
+Xs=sqrt(Zs^2-Ra^2)
+mprintf("Synchronous reactance=%f ohm\n", Xs)
+//Solving part (iii)
+V=400//line voltage
+Vt=round(V/sqrt(3))//phase voltage at the terminals of load
+Ia=15//load current
+Ef=round([(Vt*.8+Ia*Ra)^2+(Vt*.6+Ia*Xs)^2]^.5)
+mprintf("Voltage rises from %d V to %d V, when the load is thrown off\n", Vt,Ef)
+//solving part (iv)
+//at 0.8 pf lagging
+VR=(Ef-Vt)/Vt*100
+mprintf("Regulation at .8 pf lagging=%f percent\n", VR)
+//at unity pf
+Ef=[(Vt*1+Ia*Ra)^2+(Vt*0+Ia*Xs)^2]^.5
+VR=(Ef-Vt)/Vt*100
+mprintf("Regulation at unity pf=%f percent", VR)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH21/EX21.8/Ex21_8.sce b/2252/CH21/EX21.8/Ex21_8.sce new file mode 100755 index 000000000..5e7450a9d --- /dev/null +++ b/2252/CH21/EX21.8/Ex21_8.sce @@ -0,0 +1,29 @@ +
+//refer Fig. 21.19 in the textbook
+AT=15D+3//PE represents the armature reaction ampere turns
+mprintf("Armature reaction ampere turns=%d\n", AT)
+Pout=15D+6//output of the alternator
+Vl=10.2D+3//line voltage
+Il=Pout/(sqrt(3)*Vl)
+Iph=Il
+Ia=Il
+//line DE represents the leakage reactance drop in terms of line values
+Es=1.3D+3
+Eph=Es/sqrt(3)
+Xl=Eph/Ia
+mprintf("Leakage reactance per phase, Xl=%f ohm\n", Xl)
+//calculating regulation for full load at .8 pf lagging
+Rt=.53//resistance of the stator winding between terminals
+Ra=Rt/2//resistance per phase
+Rd1=Ia*Ra//resistance drop in terms of phase value
+Rd2=sqrt(3)*Rd1//resistance drop in terms of line value
+//refer Fig.21.20(a) in the textbook
+Ifg=21.67D+3
+Ifs=1.67D+3
+Ifsc=18D+3
+//refer Fig.21.20(b) in the textbook
+Ifl=40.67D+3//total field ampere turns
+Ef=12.85D+3//no load voltage
+Vt=10.2D+3//full load rated voltage
+VR=(Ef-Vt)/Vt*100
+mprintf("Regulation at full load, 0.8 pf lagging=%d percent", round(VR))
diff --git a/2252/CH21/EX21.9/Ex21_9.sce b/2252/CH21/EX21.9/Ex21_9.sce new file mode 100755 index 000000000..671c25178 --- /dev/null +++ b/2252/CH21/EX21.9/Ex21_9.sce @@ -0,0 +1,26 @@ +
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+Vt=1100/sqrt(3)//terminal voltage,taken as reference phasor
+Vt=pol2rect(Vt,0)
+Ia=1200*1000/(3*Vt)//armature current
+pf=.8//lagging power factor
+phi=acosd(pf)
+Ia=pol2rect(Ia,-phi)
+Xq=1.2*j
+Xd=1.8*j
+//refer Fig.21.24 in the textbook, phasor OB in the direction of Ef is given as
+OB=Vt+Ia*Xq
+delta=29//power angle
+Id=Ia*sin((delta+phi)*%pi/180)
+Ef=mag(OB)+mag(Id)*mag(Xd-Xq)
+mprintf("Excitation voltage Ef=%d V", round(Ef))
diff --git a/2252/CH22/EX22.1/Ex22_1.sce b/2252/CH22/EX22.1/Ex22_1.sce new file mode 100755 index 000000000..18f97f492 --- /dev/null +++ b/2252/CH22/EX22.1/Ex22_1.sce @@ -0,0 +1,22 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+Va=400/sqrt(3)//per phase applied voltage
+Ef=Va//per phase excitation voltage
+delta=4*2//equivalent electrical degrees by which the rotor is retarted
+Xs=2//per phase synchronous reactance
+Vt=pol2rect(Va,0)
+Ef=pol2rect(Ef,-8)
+Xs=pol2rect(2,90)
+Ia=(Vt-Ef)/Xs
+[Ia theta]=rect2pol(Ia)
+mprintf("Armature current drawn by the motor is %f A, lagging the applied voltage by %f degrees", Ia, -theta)
diff --git a/2252/CH22/EX22.2/Ex22_2.sce b/2252/CH22/EX22.2/Ex22_2.sce new file mode 100755 index 000000000..b1d64a704 --- /dev/null +++ b/2252/CH22/EX22.2/Ex22_2.sce @@ -0,0 +1,23 @@ +
+//calculating armature current
+Pout=7.46D+3//output power
+Wc=500//iron amd mechanical losses
+P=Pout+Wc//total mechanical power developed
+Pm=P/3
+Va=440/sqrt(3)//applied voltage per phase
+pf=.75//lagging power factor
+Ra=.5//effective resistance per phase
+//Pm=Va*Ia*pf-Ia^2*Ra
+//solving this quadratic equation
+Ia=(Va*pf-sqrt((Va*pf)^2-4*Ra*Pm))/(2*Ra)
+mprintf("Armature current=%f A\n", Ia)
+//calculating total power supplied
+Pin=Va*Ia*pf
+Pi=3*Pin//total input to stator
+Pe=650//excitation loss
+Pt=Pi+Pe
+mprintf("Total power supplied=%f W\n", Pt)
+//calculating efficiency
+e=Pout/Pt*100
+mprintf("Efficiency=%f percent", e)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH22/EX22.3/Ex22_3.sce b/2252/CH22/EX22.3/Ex22_3.sce new file mode 100755 index 000000000..017443bf8 --- /dev/null +++ b/2252/CH22/EX22.3/Ex22_3.sce @@ -0,0 +1,37 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+f=50
+P=4
+Ns=120*f/P
+//calculating excitation voltage and power angle
+Va=400/sqrt(3)
+Va=pol2rect(Va,0)
+pf=1//power factor
+Pin=3000//input to motor
+Ia=Pin/(3*mag(Va))
+Xs=8
+Ef=mag(Va)-%i*Ia*Xs
+[Ef theta]=rect2pol(Ef)
+mprintf("Excitation voltage Ef=%f V, power angle=%f degrees\n", Ef,-theta)
+//calculating torque developed
+omega_s=2*%pi*Ns/60
+T=3*mag(Va)*Ef/(Xs*omega_s)*sin(-theta*%pi/180)
+mprintf("Mechanical torque developed T=%f N-m\n",T)
+//calculating max torque developed
+Tmax=3*mag(Va)*Ef/(Xs*omega_s)
+mprintf("Max torque developed or pull out torque=%f N-m",Tmax)
diff --git a/2252/CH22/EX22.4/Ex22_4.sce b/2252/CH22/EX22.4/Ex22_4.sce new file mode 100755 index 000000000..a754c5b97 --- /dev/null +++ b/2252/CH22/EX22.4/Ex22_4.sce @@ -0,0 +1,38 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+//calculating per phase current drawn from the supply
+Pout=100*746//output power
+Va=500/sqrt(3)//per phase applied voltage
+Zs=.06+j*.6//synchronous impedance per phase
+e=.89//efficiency of motor at full load
+Pin=Pout/e//input to the motor
+pf=.8//leading power factor
+Ia=Pin/(3*Va*pf)
+theta=acosd(.8)
+mprintf("Current drawn from the supply is %f A leading the applied voltage by %f degrees\n", Ia, theta)
+//calculating excitation voltage per phase
+Va=pol2rect(Va,0)
+Ia=pol2rect(Ia,theta)
+Ef=Va-Ia*Zs
+[Ef delta]=rect2pol(Ef)
+mprintf("Excitation voltage per phase is %f V\nPower angle=%f degrees\n", mag(Ef),-delta)
+//calculating mechanical power developed Pm
+Ra=.06//stator winding resistance per phase
+Pm=Pin-3*mag(Ia)^2*Ra
+mprintf("Mechanical power developed=%f W\n", Pm)
diff --git a/2252/CH22/EX22.5/Ex22_5.sce b/2252/CH22/EX22.5/Ex22_5.sce new file mode 100755 index 000000000..282350b05 --- /dev/null +++ b/2252/CH22/EX22.5/Ex22_5.sce @@ -0,0 +1,26 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+
+j=%i
+Pout=10D+3//output of the motor at full load
+e=.85//efficiency at full load
+Pin=Pout/e//input at full load
+Zs=.4+j*3//synchronous impedance per phase
+Va=400/sqrt(3)//per phase applied voltage
+pf=.8//leading power factor
+Ia=Pin/(3*Va*pf)
+Ia=pol2rect(Ia,acosd(pf))
+Ef=Va-Ia*Zs
+[Ef delta]=rect2pol(Ef)
+mprintf("Motor must be excited to a voltage of %f V per phase and the angle of retard is %f degrees\n", Ef,-delta)
+
diff --git a/2252/CH22/EX22.6/Ex22_6.sce b/2252/CH22/EX22.6/Ex22_6.sce new file mode 100755 index 000000000..415ff3eef --- /dev/null +++ b/2252/CH22/EX22.6/Ex22_6.sce @@ -0,0 +1,18 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+
+
+j=%i
+Va=400/sqrt(3)//applied voltage per phase
+Zs=.5+j*4//synchronous impedance per phase
+pf=1//power factor
+Ia=15
+Ef=Va-Ia*Zs
+[Ef delta]=rect2pol(Ef)
+mprintf("Excitation voltage is %f V and power angle is equal to %d degrees", Ef,-delta)
+
diff --git a/2252/CH22/EX22.7/Ex22_7.sce b/2252/CH22/EX22.7/Ex22_7.sce new file mode 100755 index 000000000..2b231af99 --- /dev/null +++ b/2252/CH22/EX22.7/Ex22_7.sce @@ -0,0 +1,39 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+
+j=%i
+//applied voltage per phase is taken as the reference phasor
+Va=1//applied voltage per phase in p.u.
+pf=.8//lagging power factor
+theta=acosd(pf)
+Ia=pol2rect(1,-theta)//armature current per phase
+Xq=.4*j
+Xd=.8*j
+OC=Va-Ia*Xq
+[OC alpha]=rect2pol(OC)
+delta=-alpha//power angle
+Id=Ia*sin((theta-delta)*%pi/180)
+Ef=OC-mag(Id)*mag(Xd-Xq)//armature resistance is neglected
+mprintf("Excitation voltage per phase is %f p.u. lagging the applied voltage by %f degrees\n",Ef,delta)
+//calculating power due to excitation
+Pf=Va*Ef*sin(delta*%pi/180)/mag(Xd)
+mprintf("Per phase power developed due to field excitation is %f p.u.\n",Pf)
+//calculating power due to saliency
+Pr=Va^2*mag((Xd-Xq)/(2*Xd*Xq))*sin(2*delta*%pi/180)
+mprintf("Per phase power developed due to saliency of the motor is %f p.u.\n",Pr)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH22/EX22.8/Ex22_8.sce b/2252/CH22/EX22.8/Ex22_8.sce new file mode 100755 index 000000000..ec6c32ee4 --- /dev/null +++ b/2252/CH22/EX22.8/Ex22_8.sce @@ -0,0 +1,35 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+j=%i
+//calculating new power angle
+Va=400/sqrt(3)//applied voltage per phase
+Pin=8.5D+3/3//power input per phase
+pf=.8//lagging power factor
+Ia=Pin/(Va*pf)//armature current per phase
+theta=acosd(pf)
+Ia=pol2rect(Ia,-theta)
+Zs=4*j
+Ef=Va-Ia*Zs
+[Ef theta]=rect2pol(Ef)
+delta=-theta
+//the excitation voltage is increased by 50%
+Ef_dash=1.5*Ef
+//as the power developed remains same
+delta_dash=asind(Ef*sin(delta*%pi/180)/Ef_dash)
+mprintf("The new power angle is %f degrees\n",delta_dash)
+//calculating new armature current and power factor
+Ef_dash=pol2rect(Ef_dash,-delta_dash)
+Ia_dash=(Va-Ef_dash)/Zs
+[Ia_dash theta]=rect2pol(Ia_dash)
+mprintf("The armature current drawn from the supply is %f A and is now leading the applied voltage by %f degrees with power factor=%f(leading)\n",Ia_dash,theta,cos(theta*%pi/180))
+//answers vary from the textbook due to round off error
diff --git a/2252/CH23/EX23.1/Ex23_1.sce b/2252/CH23/EX23.1/Ex23_1.sce new file mode 100755 index 000000000..c1482c934 --- /dev/null +++ b/2252/CH23/EX23.1/Ex23_1.sce @@ -0,0 +1,15 @@ +
+
+//calculating full load speed of induction motor
+P1=8//no. of poles of alternator
+N=750//speed at which alternator runs
+f=P1*N/120//frequency of alternator
+P2=6//no. of poles of induction motor
+Ns=120*f/P2//synchronous speed
+s=.03//full load slip
+Nr=Ns*(1-s)
+mprintf("Full load speed of induction motor=%d rpm\n", round(Nr))
+//calculating frequency of rotor emf
+fr=s*f
+mprintf("Frequency of rotor emf=%f Hz", fr)
+
diff --git a/2252/CH23/EX23.10/Ex23_10.sce b/2252/CH23/EX23.10/Ex23_10.sce new file mode 100755 index 000000000..cfd472399 --- /dev/null +++ b/2252/CH23/EX23.10/Ex23_10.sce @@ -0,0 +1,13 @@ +
+f=50//frequency
+P=6//no. of poles
+Ns=120*f/P//synchronous speed in rpm
+Nr=950//speed at which the motor is running in rpm
+s=(Ns-Nr)/Ns//slip
+Pm=3.73D+3//mechanical power developed by the motor
+//iron losses in the rotor are neglected
+Prcu=s*Pm/(1-s)//rotor copper loss
+P1=Pm+Prcu//rotor input
+P=.25D+3//stator losses
+P2=P1+P
+mprintf("Stator input to the 3-phase induction motor=%f kW\n",P2/1000)
diff --git a/2252/CH23/EX23.11/Ex23_11.sce b/2252/CH23/EX23.11/Ex23_11.sce new file mode 100755 index 000000000..44787744a --- /dev/null +++ b/2252/CH23/EX23.11/Ex23_11.sce @@ -0,0 +1,22 @@ +
+//calculating rotor copper losses
+s=.04//slip of the motor
+Pout=14.92D+3//output of the motor
+Pfw=200//friction and windage losses
+Prcu=s*(Pout+Pfw)/(1-s)
+mprintf("Rotor copper losses=%d W\n",round(Prcu))
+//calculating efficiency at full load
+P=Pout+Pfw+Prcu+1620//stator input
+e=Pout/P*100
+mprintf("Efficiency at full load=%f percent\n",e)
+//calculating line current
+pf=.86//power factor of load
+Vl=500//line voltage
+Il=P/(sqrt(3)*Vl*pf)
+mprintf("Line current=%f A\n",Il)
+//calculating no of complete cycles of the rotor electromotive force per minute
+f=50//supply frequency
+f_r=s*f//frequency of rotor emf
+n=f_r*60
+mprintf("No of complete cycles of the rotor electromotive force per minute=%d\n",n)
+//answer vary from the textbook due to round off error, also there is an error in value of stator input given in textbook
diff --git a/2252/CH23/EX23.12/Ex23_12.sce b/2252/CH23/EX23.12/Ex23_12.sce new file mode 100755 index 000000000..be5e01c4f --- /dev/null +++ b/2252/CH23/EX23.12/Ex23_12.sce @@ -0,0 +1,24 @@ +
+//calculating slip
+n=100//no. of complete alternations per minute of rotor emf
+f_r=n/60//rotor frequency in Hz
+f=50//supply frequency in Hz
+s=f_r/f
+mprintf("Slip of the motor=%f percent\n",s*100)
+//calculating rotor speed
+P=6//no. of poles
+Ns=120*f/P//synchronous speed
+Nr=(1-s)*Ns
+mprintf("Rotor speed=%d rpm\n",round(Nr))
+//calculating rotor copper losses per phase
+P1=75D+3//rotor input
+Prcu=P1*s
+mprintf("Rotor copper losses per phase=%f W\n",Prcu/3)
+//calculating mechanical power developed
+Pm=P1-Prcu
+mprintf("Mechanical power developed=%f kW\n",Pm/1000)
+//calculating rotor resistance per phase
+Ir=60//rotor current
+Rr=Prcu/(3*Ir^2)
+mprintf("Rotor resistance per phase=%f ohm",Rr)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH23/EX23.13/Ex23_13.sce b/2252/CH23/EX23.13/Ex23_13.sce new file mode 100755 index 000000000..85a00b6af --- /dev/null +++ b/2252/CH23/EX23.13/Ex23_13.sce @@ -0,0 +1,24 @@ +
+
+//calculating ratio of maximum to full load torque
+Nr=970//speed at full load torque in rpm
+Ns=50*120/6//synchronous speed in rpm
+s=(Ns-Nr)/Ns//slip at full load
+R2=.02//rotor resistance per phase
+X2=.3//rotor reactance per phase at standstill
+alpha=R2/X2
+//Full load torque Tf=k1*Kt
+k1=s*alpha/(s^2+alpha^2)
+//maximum torque Tmax=Kt/2
+x=1/(2*k1)
+mprintf("Ratio of maximum to full load torque=%f\n",x)
+//calculating speed at maximum torque
+s_m=R2/X2//slip at maximum torque
+Nm=(1-s_m)*Ns
+mprintf("Speed at maximum torque=%d rpm\n",round(Nm))
+//calculating ratio of starting torque to full load torque
+s=1//slip at starting
+//starting torque Tst=k2*Kt
+k2=s*alpha/(s^2+alpha^2)
+y=k2/k1
+mprintf("Ratio of starting torque to full load torque=%f\n",y)
diff --git a/2252/CH23/EX23.14/Ex23_14.sce b/2252/CH23/EX23.14/Ex23_14.sce new file mode 100755 index 000000000..1eb3cb4aa --- /dev/null +++ b/2252/CH23/EX23.14/Ex23_14.sce @@ -0,0 +1,44 @@ +
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+Vl=220//line voltage
+Vph=Vl/sqrt(3)//stator phase voltage
+n=.65//ratio of no. of rotor winding turns to no. of stator winding turns
+E2=n*Vph//phase voltage induced in the rotor winding at standstill
+R2=.1//rotor resistance per phase
+X2=.8//standstill reactance per phase
+//at 5 % slip
+s=5/100
+X=s*X2//reactance per phase
+Z2=R2+X*j//rotor impedance
+e2=s*E2//rotor phase voltage
+I2=e2/mag(Z2)
+mprintf("Rotor current at 5 percent slip=%f A\n",I2)
+//calculating rotor input
+Prcu=3*I2^2*R2//total rotor copper losses
+Pg=Prcu/s
+mprintf("Rotor input=%f W\n",Pg)
+//calculating total torque at 5% slip
+Pm=Pg-3*I2^2*R2//mechanical power developed by the rotor
+Ns=120*50/4//synchronous speed
+Nr=Ns*(1-s)//speed of the rotor
+T=60*Pm/(2*%pi*round(Nr))
+mprintf("Total torque developed by the rotor at 5 percent slip=%f N-m\nTotal mechanical power at 5 percent slip=%f kW\n",T,Pm/1000)
+//calculating rotor current at maximum torque
+s_m=R2/X2//slip for maximum torque
+I2m=s_m*E2/sqrt(R2^2+(s_m*X2)^2)
+mprintf("Rotor current at maximum torque=%d A\n",round(I2m))
+//calculating rotor input corresponding to maximum torque
+Sm=3*round(I2m)^2*R2//total rotor copper losses
+Pg=Sm/s_m
+mprintf("Rotor input corresponding to maximum torque=%f W\n",Pg)
+//calculating maximum torque
+Pm=Pg-Sm
+Nm=Ns*(1-s_m)
+T=60*Pm/(2*%pi*round(Nm))
+mprintf("Maximum torque=%f N-m\nSpeed at maximum torque=%d rpm\nMaximum mechanical power=%f kW",T,Nm,Pm/1000)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH23/EX23.15/Ex23_15.sce b/2252/CH23/EX23.15/Ex23_15.sce new file mode 100755 index 000000000..fce72b704 --- /dev/null +++ b/2252/CH23/EX23.15/Ex23_15.sce @@ -0,0 +1,17 @@ +
+Ns=120*50/4//synchronous speed
+R2=.03//rotor resistance
+X2=.15//rotor reactance
+alpha=R2/X2
+s_m=alpha//slip at maximum torque
+Nr=(1-s_m)*Ns//speed at maximum torque
+//alpha=(.03+r)/.15
+//Tst=Kt*alpha/(1+alpha^2)
+//Tmax=Kt/2
+//Tst/Tmax=3/4-->3*alpha^2-8*alpha+3=0
+//solving for alpha
+alpha=(8-sqrt(8^2-4*3*3))/(2*3)
+r=.15*alpha-.03
+mprintf("If a resistance of %f ohm is added in the circuit, the required starting torque will be achieved",r)
+
+
diff --git a/2252/CH23/EX23.16/Ex23_16.sce b/2252/CH23/EX23.16/Ex23_16.sce new file mode 100755 index 000000000..588fddc7f --- /dev/null +++ b/2252/CH23/EX23.16/Ex23_16.sce @@ -0,0 +1,16 @@ +
+R2=1.1//rotor resistance per phase
+//at 60 Hz supply
+f=60//frequency of supply
+P=6//no. of poles
+Ns1=120*f/P//synchronous speed
+Nr=1000//speed of rotor
+s_m1=(Ns1-Nr)/Ns1//slip at maximum torque
+X2=R2/s_m1
+L2=X2/(2*%pi*60)
+//at 50 Hz supply
+X2=2*%pi*50*L2
+s_m2=R2/X2//slip at maximum torque
+Ns2=120*50/6//synchronous speed
+Nr2=(1-s_m2)*Ns2
+mprintf("Rotor speed at maximum torque=%d rpm",round(Nr2))
diff --git a/2252/CH23/EX23.17/Ex23_17.sce b/2252/CH23/EX23.17/Ex23_17.sce new file mode 100755 index 000000000..60f980197 --- /dev/null +++ b/2252/CH23/EX23.17/Ex23_17.sce @@ -0,0 +1,38 @@ +
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta)
+ y=r*sin(theta)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+
+j=%i
+R1=.15//per phase stator winding resistance
+//block rotor test
+Vb=133/sqrt(3)//per phase voltage
+Ib=100//per phase current
+Wb=8085/3//per phase power
+Zb=Vb/Ib//per phase impedance
+Rb=Wb/Ib^2//per phase resistance
+Xb=sqrt(Zb^2-Rb^2)//per phase reactance
+R2_dash=Rb-R1//per phase rotor resistance referred to stator
+X2_dash=Xb/2//per phase rotor reactance referred to stator
+X1=X2_dash//per phase stator leakage reactance
+//no load test
+Vo=400/sqrt(3)//per phase voltage
+Io=20//per phase current
+Wo=2080/3//per phase power
+pf=Wo/(Vo*Io)//power factor
+phi0=acos(pf)
+Iw=Io*cos(phi0)
+Im=-Io*sin(phi0)*j
+Io=pol2rect(Io,-phi0)
+Z1=R1+X1*j
+Ro=(Vo-Io*Z1)/Iw
+Xm=(Vo-Io*Z1)/Im
+mprintf("Equivalent circuit parameters are\nR1=%f ohm;\nX1=%f ohm;\nR2_dash=%f ohm;\nX2_dash=%f ohm;\nRo=%f ohm;\nXm=%f ohm",R1,X1,R2_dash,X2_dash,mag(Ro),mag(Xm))
+
diff --git a/2252/CH23/EX23.18/Ex23_18.sce b/2252/CH23/EX23.18/Ex23_18.sce new file mode 100755 index 000000000..5923dd9b2 --- /dev/null +++ b/2252/CH23/EX23.18/Ex23_18.sce @@ -0,0 +1,26 @@ +
+//refer Fig. 23.25 in the textbook
+k1=40//current scale
+Vph=400/sqrt(3)//voltage per phase
+P=k1*Vph//power per phase
+k2=3*P//power scale
+//calculating full load stator current
+P=33.6D+3//output of motor
+P1=P/k2//ouput of motor to scale
+//P is the corresponding operating point
+OP=1.55
+I1=OP*k1
+phi1=28.5
+mprintf("Full load stator current=%f A with %f power factor lagging\n",I1,cos(phi1*%pi/180))
+//calculating efficiency at full load
+PL=2.35
+PX=2.75
+e=PL/PX*100
+mprintf("Efficiency at full load=%f percent\n",e)
+//calculating max power output
+NPm=2.6
+mprintf("Maximum output power=%f kW\n",NPm*k2*10^-3)
+//calculting max torque developed
+MTm=3.12
+mprintf("Maximum torque developed by the motor=%f kW",MTm*k2*10^-3)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH23/EX23.19/Ex23_19.sce b/2252/CH23/EX23.19/Ex23_19.sce new file mode 100755 index 000000000..1db9fe321 --- /dev/null +++ b/2252/CH23/EX23.19/Ex23_19.sce @@ -0,0 +1,19 @@ +
+//at short circuit
+Vsc=100//applied voltage
+Isc=15//line value of current
+Iph=Isc/sqrt(3)//phase value of current
+//calculating starting current drawn by the motor
+V=400//line voltage
+Vph=V/sqrt(3)//phase voltage
+I=Iph*Vph/Vsc//phase value of starting current
+Il=I
+mprintf("Starting current drawn by the motor=%d A\n",Il)
+//calculating ratio of starting to full load current
+Pout=5D+3//output
+e=.84//full load efficiency
+pf=.82//power factor
+I=Pout/(sqrt(3)*V*pf*e)//full load current
+r=Il/I
+mprintf("Ratio of starting to full load current=%f",r)
+
diff --git a/2252/CH23/EX23.2/Ex23_2.sce b/2252/CH23/EX23.2/Ex23_2.sce new file mode 100755 index 000000000..2e6fa1d45 --- /dev/null +++ b/2252/CH23/EX23.2/Ex23_2.sce @@ -0,0 +1,27 @@ +
+//calculating no. of poles
+Ns=1200//synchronous speed of rotating magnetic field
+f=60//frequency of the supply to the stator
+P=120*f/Ns
+mprintf("No. of poles=%d\n", P)
+//calculating slip at full load
+Nr=1140//full load speed
+s=(Ns-Nr)/Ns
+mprintf("Percentage slip at full load=%f percent\n",s*100)
+//calculating frequency of rotor voltage
+fr=s*f
+mprintf("Frequency of rotor voltage=%d Hz\n",fr)
+//calculating speed of rotor field w.r.t. rotor
+N1=120*fr/P//speed
+mprintf("Speed of rotor field w.r.t. rotor=%d rpm\n",N1)
+//calculating speed of rotor field w.r.t. stator
+N2=1140//speed of the rotor w.r.t. stator
+mprintf("Speed of the rotor field w.r.t. stator=%d rpm\nSpeed of the rotor field w.r.t. stator field=%d rpm\n", N2+N1,N1+N2-Ns)
+s=.1
+N1=(1-s)*Ns
+mprintf("Speed of the rotor at 10 percent slip=%d rpm\nRotor frequency at 10 percent slip=%d Hz\n",N1,s*f)
+Eph=230//applied voltage per phase
+E1ph=Eph//induced emf per phase in the stator winding
+E2ph=E1ph*.5//rotor induced emf at standstill
+E2ph_dash=s*E2ph
+mprintf("Rotor induced emf at standstill=%f V\nRotor induced emf at 10 percent slip=%f V",E2ph,E2ph_dash)
diff --git a/2252/CH23/EX23.20/Ex23_20.sce b/2252/CH23/EX23.20/Ex23_20.sce new file mode 100755 index 000000000..c6224e7e5 --- /dev/null +++ b/2252/CH23/EX23.20/Ex23_20.sce @@ -0,0 +1,18 @@ +
+V=400//phase voltage applied to motor
+//when started directly on line
+Iph=25//phase current
+Il=sqrt(3)*Iph
+mprintf("Line current drawn by the motor when started directly on line=%f A\n",Il)
+//when started with auto-transformer starter with a tapping percent of 60 percent
+Vl=.6*V//line voltage
+Vph=Vl//phase voltage
+Iph=25//phase current
+Ist=Iph*Vph/V
+Il=sqrt(3)*Ist
+mprintf("When started with auto-transformer starter with a tapping of 60 percent\nPhase starting current =%f A\nLine starting current=%f A\n",Ist,Il)
+//when started with star-delta starter
+Vph=V/sqrt(3)//phase voltage
+I=Iph*Vph/V
+Il=I
+mprintf("When started with star-delta starter\nPhase starting current =%f A\nLine starting current=%f A",I,Il)
diff --git a/2252/CH23/EX23.3/Ex23_3.sce b/2252/CH23/EX23.3/Ex23_3.sce new file mode 100755 index 000000000..589ed39c0 --- /dev/null +++ b/2252/CH23/EX23.3/Ex23_3.sce @@ -0,0 +1,26 @@ +
+//calculating synchronous speed
+f=50//frequency
+P=4//no. of poles
+Ns=120*f/P
+mprintf("Synchronous speed=%f rpm\n",Ns)
+//calculating speed of rotating air gap field
+mprintf("Rotating field in air gap rotates at synchronous speed,hence its speed=%f rpm\n",Ns)
+//calculating speed of induction motor
+s=.04//slip
+Nr=(1-s)*Ns
+mprintf("Speed of induction motor=%f rpm\n",Nr)
+//calculating slip in rpm
+mprintf("Slip of the motor in rpm=%f rpm\n",s*Ns)
+mprintf("The rotor field rotates at synchronous speed w.r.t. stator, hence relative speed=%f rpm\n",Ns)
+mprintf("Both rotor and stator field rotate at synchronous speed,relative to the stator, hence, speed of rotor field w.r.t. stator field=0 rpm\n")
+mprintf("Speed of the rotor field w.r.t. rotor=%f rpm\n",s*Ns)
+//calculating frequency of rotor induced emf
+fr=s*f
+mprintf("Frequency of rotor induced emf=%f Hz\n",fr)
+//calculating rotor induced emf per phase
+k=.6//turns ratio
+E1ph=400/sqrt(3)//induced emf in stator winding
+E2ph=E1ph*k//rotor induced emf per phase at the instant of starting
+E2ph_dash=s*E2ph
+mprintf("Rotor induced emf per phase under loaded condition=%f V",E2ph_dash)
diff --git a/2252/CH23/EX23.4/Ex23_4.sce b/2252/CH23/EX23.4/Ex23_4.sce new file mode 100755 index 000000000..de0464c7f --- /dev/null +++ b/2252/CH23/EX23.4/Ex23_4.sce @@ -0,0 +1,18 @@ +
+R2=.5//rotor resistance per phase
+//at standstill
+E=40//induced emf
+E2=E/sqrt(3)//induced emf per phase
+X2=3//rotor reactance per phase
+R=4//additional resistance per phase in the rotor circuit
+Rt=R2+R//total resistance per phase in the rotor circuit
+Z2=sqrt(Rt^2+X2^2)//rotor impedance per phase
+I2=E2/Z2
+mprintf("Rotor current per phase at standstill=%f A\n", I2)
+//calculating rotor current per phase at 5% slip
+s=.05//slip
+X2=s*X2
+Z2=sqrt(R2^2+X2^2)
+E2=s*E2//induced emf per phase
+I2=E2/Z2
+mprintf("Rotor current per phase at 5 percent slip=%f A",I2)
diff --git a/2252/CH23/EX23.5/Ex23_5.sce b/2252/CH23/EX23.5/Ex23_5.sce new file mode 100755 index 000000000..25f8dde56 --- /dev/null +++ b/2252/CH23/EX23.5/Ex23_5.sce @@ -0,0 +1,27 @@ +
+//calculating rotor starting current per phase on normal voltage with slip ring short-circuited
+V=400//voltage applied to the stator winding
+V1=V/sqrt(3)//phase voltage
+k=2.5//transformation ratio
+R2=.02//rotor resistance per phase
+//at standstill
+s=1//slip
+E2=V1/k//induced phase voltage in the rotor winding
+X2=2*%pi*50*.6D-3//rotor reactance per phase
+Z2=sqrt(R2^2+X2^2)
+I2=E2/Z2
+mprintf("Rotor starting current per phase on normal voltage with slip ring short-circuited=%f A\n",I2)
+//calculating rotor power factor at starting
+pf=R2/Z2
+mprintf("Rotor power factor at starting=%f\n",pf)
+//calculating rotor current per phase at 3 % slip
+s=.03//slip
+E2=s*E2
+X2=s*X2
+Z2=sqrt(R2^2+X2^2)
+I2=E2/Z2
+mprintf("Rotor current per phase at 3 percent slip=%f A\n",I2)
+//calculating rotor power factor at 3% slip
+pf=R2/Z2
+mprintf("Rotor power factor at 3 percent slip=%f",pf)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH23/EX23.6/Ex23_6.sce b/2252/CH23/EX23.6/Ex23_6.sce new file mode 100755 index 000000000..7f6e6c72f --- /dev/null +++ b/2252/CH23/EX23.6/Ex23_6.sce @@ -0,0 +1,45 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+R2_dash=.16
+s=.03
+X2=.4
+Z2_dash=R2_dash/s+X2*j//effective rotor impedance referred to stator
+R0=200
+Xm=20*j
+Z=1/(1/R0+1/Xm+1/Z2_dash)//equivalent impedance
+Z1=.15+.4*j//stator impedance
+Zin=Z1+Z//total input impedance
+V=400//applied voltage
+//calculating stator current
+V1=V/sqrt(3)//per phase stator voltage
+I1=V1/Zin
+[I1 theta1]=rect2pol(I1)
+mprintf("Stator current=%f A at %f power factor lagging\n",I1,cos(theta1*%pi/180))
+//calculating rotor current
+I1=V1/Zin
+E1=V1-I1*Z1
+Iw=E1/R0//per phase core loss component of no load current
+Im=E1/Xm//per phase magnetising current
+I0=Iw+Im//no load current
+I2_dash=I1-I0
+[I2_dash theta2]=rect2pol(I2_dash)
+mprintf("Per phase rotor current=%f A lagging by %f degrees\n",I2_dash,-theta2)
+//calculating mechanical output power
+P=I2_dash^2*R2_dash*(1-s)/s//mechanical power output per phase
+Pout=3*P
+mprintf("Total mechanical power output=%f kW\n",Pout/1000)
+//calculating input power drawn by the motor
+Pin=3*V1*mag(I1)*cos(theta1*%pi/180)
+mprintf("Total input power drawn by the motor=%f kW\n",Pin/1000)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH23/EX23.7/Ex23_7.sce b/2252/CH23/EX23.7/Ex23_7.sce new file mode 100755 index 000000000..c9c73c3ab --- /dev/null +++ b/2252/CH23/EX23.7/Ex23_7.sce @@ -0,0 +1,45 @@ +
+
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+R2_dash=.16
+s=3/100//slip
+Rl=R2_dash*(1-s)/s//load resistance
+Z1=.15+.4*j//stator impedance
+Z2_dash=.16+.4*j//equivalent rotor impedance
+Z=Rl+Z1+Z2_dash//total impedance per phase
+Vph=400/sqrt(3)//applied voltage per phase
+I2_dash=Vph/Z
+R0=200
+Xm=20
+Iw=Vph/R0
+Im=Vph/Xm
+I0=Iw-Im*j
+I1=I0+I2_dash
+[I1 theta]=rect2pol(I1)
+pf=cos(theta*%pi/180)
+p=mag(I2_dash)^2*Rl//output power per phase
+Pout=3*p
+Pin=3*Vph*I1*pf
+mprintf("By using approximate equivalent circuit, the values of different parameters are as under\nPer phase stator current=%f A\nPer phase rotor current=%f A\nOperating power factor=%f\nInput power=%f kW\nMechanical output power=%f kW\n",I1,I2_dash,pf,Pin/10^3,Pout/10^3)
+//refer Fig. 23.16 in the textbook
+Z2_dash=5.3+j*0.4
+Z=(j*Xm)*Z2_dash/(j*Xm+Z2_dash)//equivalent impedance
+Zin=Z1+Z//total input impedance
+I1=Vph/Zin
+I2_dash=I1*j*Xm/(j*Xm+Z2_dash)
+[I1 theta]=rect2pol(I1)
+pf=cos(theta*%pi/180)
+Pout=3*(mag(I2_dash))^2*R2_dash*(1-s)/s
+Pin=3*Vph*I1*pf
+mprintf("By solving the problem using the circuit in Fig. 23.16 in the book, the values of different parameters are as under\nPer phase stator current=%f A\nPer phase rotor current=%f A\nOperating power factor=%f\nInput power=%f kW\nMechanical output power=%f kW\n",mag(I1),I2_dash,pf,Pin/10^3,Pout/10^3)
diff --git a/2252/CH23/EX23.8/Ex23_8.sce b/2252/CH23/EX23.8/Ex23_8.sce new file mode 100755 index 000000000..2773846d9 --- /dev/null +++ b/2252/CH23/EX23.8/Ex23_8.sce @@ -0,0 +1,8 @@ +
+Pin=60D+3//power input
+p=1D+3//stator losses
+Pg=Pin-p//air gap power
+s=3/100//slip
+Pm=Pg*(1-s)
+Prcu=s*Pg
+mprintf("Mechanical power developed by the motor=%f kW with rotor copper losses of %f kW",Pm/1000,Prcu/1000)
diff --git a/2252/CH23/EX23.9/Ex23_9.sce b/2252/CH23/EX23.9/Ex23_9.sce new file mode 100755 index 000000000..86224ef06 --- /dev/null +++ b/2252/CH23/EX23.9/Ex23_9.sce @@ -0,0 +1,16 @@ +
+Po=50D+3//power output
+e=90/100//efficiency
+Pin=Po/e//power input
+P=Pin-Po//total losses
+//P=Pscu+Psi+Prcu+Pfw
+//Pscu=Prcu=Psi, Pfw=Psi/3
+Psi=P/(1+1+1+1/3)
+Pscu=Psi//stator copper loss
+Prcu=Psi
+mprintf("Rotor copper loss=%d W\n",round(Prcu))
+Pg=Pin-2*Pscu
+mprintf("Air gap power=%d W\n",round(Pg))
+s=Prcu/Pg
+mprintf("Slip=%f p.u.", s)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH24/EX24.1/Ex24_1.sce b/2252/CH24/EX24.1/Ex24_1.sce new file mode 100755 index 000000000..e7b062f74 --- /dev/null +++ b/2252/CH24/EX24.1/Ex24_1.sce @@ -0,0 +1,19 @@ +
+f=50//frequency in Hz
+P=4//no. of poles
+Ns=120*f/P//synchronous speed
+Nr=1420
+//calculating forward slip
+s=(Ns-Nr)/Ns
+mprintf("Forward slip=%f p.u.\n",s)
+//calculating backward slip
+s1=2-s
+mprintf("Backward slip s_b=%f p.u.\n",s1)
+//calculating effective rotor resistance in forward branch
+R2_dash=4.5
+Rf=R2_dash/(2*s)
+mprintf("Effective rotor resistance in forward branch=%f ohm\n", Rf)
+//calculating effective rotor resistance in backward branch
+Rb=R2_dash/(2*(2-s))
+mprintf("Effective rotor resistance in backward branch=%f ohm", Rb)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH24/EX24.2/Ex24_2.sce b/2252/CH24/EX24.2/Ex24_2.sce new file mode 100755 index 000000000..2a71d4091 --- /dev/null +++ b/2252/CH24/EX24.2/Ex24_2.sce @@ -0,0 +1,52 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+f=50//frequency
+P=4//no. of poles
+Ns=120*f/P//synchronous speed
+Nr=1420
+s=(Ns-Nr)/Ns
+Xm=70
+R2_dash=3.75
+X2_dash=1.75
+Zf=(Xm*%i/2)*(R2_dash/(2*s)+%i*X2_dash/2)/(R2_dash/(2*s)+%i*(Xm+X2_dash)/2)//forward impedance
+Zb=(%i*Xm/2)*(R2_dash/(2*(2-s))+%i*X2_dash/2)/(R2_dash/(2*(2-s))+%i*(Xm+X2_dash)/2)//backward impedance
+Z1=2.5+%i*1.5
+Zin=Z1+Zf+Zb//input impedance
+//calculating input current
+V1=pol2rect(230,0)
+I1=V1/Zin
+[I1 theta]=rect2pol(I1)
+mprintf("Input current drawn by the motor is %f A, lagging the applied voltage by %f degrees\n", I1,-theta)
+//calculating input power
+Pin=mag(V1)*I1*cos(theta*%pi/180)
+mprintf("Power input=%f W\n", Pin)
+//calculating mechanical power developed
+Pgf=I1^2*real(Zf)
+Pgb=I1^2*real(Zb)
+Pm=(Pgf-Pgb)*(1-s)
+mprintf("Mechanical power developed=%f W\n", Pm)
+//calculating resultant torque developed
+omega_s=2*%pi*Ns/60
+T=(Pgf-Pgb)/omega_s
+mprintf("Resultant torque developed=%f N-m\n",T)
+//calculating efficiency
+Prot=35+60
+Pout=Pm-Prot
+e=Pout/Pin*100
+mprintf("Efficiency=%f percent", e)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH24/EX24.3/Ex24_3.sce b/2252/CH24/EX24.3/Ex24_3.sce new file mode 100755 index 000000000..a50b2d2db --- /dev/null +++ b/2252/CH24/EX24.3/Ex24_3.sce @@ -0,0 +1,43 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atan(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta)
+ y=r*sin(theta)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+f=50//frequency
+P=4//no. of poles
+Ns=120*f/P//synchronous speed
+Nr=1425
+s=(Ns-Nr)/Ns//slip
+R2_dash=7.5
+X2_dash=4.5
+Xm=150
+Zf=(Xm*%i/2)*(R2_dash/(2*s)+%i*X2_dash/2)/(R2_dash/(2*s)+%i*(Xm+X2_dash)/2)//forward impedance
+Zb=(%i*Xm/2)*(R2_dash/(2*(2-s))+%i*X2_dash/2)/(R2_dash/(2*(2-s))+%i*(Xm+X2_dash)/2)//backward impedance
+Z1=2.5+4.5*%i
+Zin=Z1+Zf+Zb//input impedance
+//calculating input current
+V1=pol2rect(230,0)
+I1=V1/Zin
+[I1 theta]=rect2pol(I1)
+mprintf("Input current drawn by the motor is %f A at %f pf lagging\n", I1,cos(theta))
+//calculating air gap power
+Pgf=I1^2*real(Zf)//air gap power due to forward field
+Pgb=I1^2*real(Zb)//air gap power due to backward field
+Pg=Pgf+Pgb
+mprintf("Air gap power=%f W\n",Pg)
+//calculating rotor copper losses
+Prc=s*Pgf+(2-s)*Pgb
+mprintf("Rotor copper losses=%f W",Prc)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH24/EX24.4/Ex24_4.sce b/2252/CH24/EX24.4/Ex24_4.sce new file mode 100755 index 000000000..4e8ac436b --- /dev/null +++ b/2252/CH24/EX24.4/Ex24_4.sce @@ -0,0 +1,21 @@ +
+//under block rotor condition
+Vb=82.5
+Ib=9.3
+Zb=Vb/Ib
+P=500//power consumed
+Rb=P/Ib^2
+Xb=sqrt(Zb^2-Rb^2)
+R1=2.5//main resistance winding
+R2_dash=Rb-R1//rotor resistance referred to stator
+X1=Xb/2
+X2_dash=X1//rotor reactance referred to stator
+//under no load
+I0=6.4
+V0=230
+Z0=V0/I0
+P0=220//power consumed
+R0=P0/I0^2
+X0=sqrt(Z0^2-R0^2)
+Xm=2*X0-3/2*Xb
+mprintf("Equivalent circuit parameters of the motor are:\nR1=%f ohm,\nX1=%f ohm,\nXm=%f ohm,\nR2_dash=%f ohm,\nX2_dash=%f ohm\n", R1,X1,Xm,R2_dash,X2_dash)
diff --git a/2252/CH24/EX24.5/Ex24_5.sce b/2252/CH24/EX24.5/Ex24_5.sce new file mode 100755 index 000000000..160df9d31 --- /dev/null +++ b/2252/CH24/EX24.5/Ex24_5.sce @@ -0,0 +1,62 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+f=50//frequency
+P=4//no. of poles
+Ns=120*f/P//synchronous speed
+Nr=1420//motor speed
+s=(Ns-Nr)/Ns
+R1=2.5
+X1=3.365
+Xm=60.945
+R2_dash=3.28
+X2_dash=3.365
+Zf=(Xm*%i/2)*(R2_dash/(2*s)+%i*X2_dash/2)/(R2_dash/(2*s)+%i*(Xm+X2_dash)/2)//forward impedance
+Zb=(%i*Xm/2)*(R2_dash/(2*(2-s))+%i*X2_dash/2)/(R2_dash/(2*(2-s))+%i*(Xm+X2_dash)/2)//backward impedance
+Z1=R1+%i*X1
+Zin=Z1+Zf+Zb//input impedance
+//calculating input current and power factor
+V1=pol2rect(230,0)
+I1=V1/Zin
+[I1 theta]=rect2pol(I1)
+mprintf("Input current drawn by the motor is %f A lagging the applied voltage by an angle of %f degrees, that is at %f pf lagging\n", I1,-theta,cos(theta*%pi/180))
+//calculating input power
+Pin=mag(V1)*I1*cos(theta*%pi/180)
+mprintf("Power input=%f W\n", Pin)
+//calculating torque developed
+Pgf=I1^2*real(Zf)
+Pgb=I1^2*real(Zb)
+omega_s=2*%pi*Ns/60
+T=(Pgf-Pgb)/omega_s
+mprintf("Resultant torque developed=%f N-m\n",T)
+//calculating output power
+Pm=(Pgf-Pgb)*(1-s)//mechanical power developed
+W0=220//power consumed under no load
+I0=6.4//no load current
+Prot=W0-I0^2*(R1+R2_dash/4)//rotational losses
+Pout=Pm-Prot
+mprintf("Output power developed=%f W\n", Pout)
+//calculating efficiency
+e=Pout/Pin*100
+mprintf("Efficiency=%f percent\n", e)
+//calculating air gap power
+Pg=Pgf+Pgb
+mprintf("Air gap power=%f W\n",Pg)
+//calculating rotor copper losses
+Prc=s*Pgf+(2-s)*Pgb
+mprintf("Rotor copper losses=%f W",Prc)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH3/EX3.2/Ex3_2.sce b/2252/CH3/EX3.2/Ex3_2.sce new file mode 100755 index 000000000..1a20e0d62 --- /dev/null +++ b/2252/CH3/EX3.2/Ex3_2.sce @@ -0,0 +1,7 @@ +
+mu_not=4D-7*%pi
+N=150 //no. of turns of coil
+I=4 //current carried by coil
+l=.3 //length of solenoid in mtrs
+Bc=mu_not*N*I/l
+mprintf("Flux density at centre =%f*10^-3 Wb/m^2", Bc*10^3)
diff --git a/2252/CH3/EX3.3/Ex3_3.sce b/2252/CH3/EX3.3/Ex3_3.sce new file mode 100755 index 000000000..dc0297c6b --- /dev/null +++ b/2252/CH3/EX3.3/Ex3_3.sce @@ -0,0 +1,11 @@ +
+mu_not=4D-7*%pi
+//calculating flux density at centre of coil B=mu_not*I/(2*R)
+I=50
+R=4D-2
+B=mu_not*I/(2*R)
+mprintf("Flux density at centre of coil=%f*10^-6 Wb/m^2(Tesla)\n", B*10^6)
+//calculating flux density perpendicular to plane of coil at a distance of 10 cm from it
+z=10D-2
+B=mu_not*I*R^2/(2*(R^2+z^2)^1.5)
+mprintf("Flux density perpendicular to plane of coil at a distance of 10 cm from it=%f*10^-6 Wb/m^2(Tesla)", B*10^6)
diff --git a/2252/CH3/EX3.4/Ex3_4.sce b/2252/CH3/EX3.4/Ex3_4.sce new file mode 100755 index 000000000..e1cf9bf01 --- /dev/null +++ b/2252/CH3/EX3.4/Ex3_4.sce @@ -0,0 +1,8 @@ +
+
+mu_not=4D-7*%pi
+I1=30//current in wire A
+I2=30//current in wire B
+R=10D-2//distance b/w 2 wires
+F=mu_not*I1*I2/(2*%pi*R)
+mprintf("Force per metre length is %d*10^-4 N/m in both cases (i)and (ii). However in case(i), it is attractive and in case(ii), it is repulsive", F*10^4)
diff --git a/2252/CH3/EX3.5/Ex3_5.sce b/2252/CH3/EX3.5/Ex3_5.sce new file mode 100755 index 000000000..da1ec43b5 --- /dev/null +++ b/2252/CH3/EX3.5/Ex3_5.sce @@ -0,0 +1,7 @@ +
+B=.06//flux density
+I=40D-3//current in coil
+l=4D-2//length of coil side
+F=B*I*l
+N=50//no. of turns
+mprintf("Force acting on each coil side=%f*10^-3 N",F*N*10^3)
diff --git a/2252/CH4/EX4.1/Ex4_1.sce b/2252/CH4/EX4.1/Ex4_1.sce new file mode 100755 index 000000000..d2792b9a1 --- /dev/null +++ b/2252/CH4/EX4.1/Ex4_1.sce @@ -0,0 +1,25 @@ +
+
+mu_not=4D-7*%pi
+a=(3D-2)^2//cross-sectional area
+La=(20-1.5-1.5)*1D-2//length of flux path in part A
+mu_r=1000//relative permeability for part A
+Sa=La/(mu_not*mu_r*a)
+mprintf("Reluctance of part A=%f*10^4AT/Wb\n",Sa/10^4)
+Lb=(17+8.5+8.5)*1D-2//length of flux path in part B
+mu_r=1200//relative permeability for part B
+Sb=Lb/(mu_not*mu_r*a)
+mprintf("Reluctance of part B=%f*10^4AT/Wb\n",Sb/10^4)
+Lg=(2+2)*1D-3//length of flux path in air gap
+Sg=Lg/(mu_not*a)
+mprintf("Reluctance of 2 air gaps=%f*10^4 AT/Wb\n",Sg/10^4)
+S=Sa+Sb+Sg
+mprintf("Total reluctance of magnetic circuit=%f*10^4 AT/Wb\n", S/10^4)
+N=1000//no. of turns on each coil
+I=1//current in coil
+mmf=2*N*I
+mprintf("mmf=%d AT\n", mmf)
+flux=mmf/S
+mprintf("Flux in magnetic circuit=%f*10^-4 Wb\n",flux*10^4)
+flux_density=flux/a
+mprintf("Flux density=%f Tesla", flux_density)
diff --git a/2252/CH4/EX4.10/Ex4_10.sce b/2252/CH4/EX4.10/Ex4_10.sce new file mode 100755 index 000000000..1a9b446cd --- /dev/null +++ b/2252/CH4/EX4.10/Ex4_10.sce @@ -0,0 +1,19 @@ +
+mu_not=4D-7*%pi
+flux=.018
+//consider part A
+a=205D-4 //cross sectional area
+Ba=flux/a
+H=760 //corresponding to Ba as obtained from Fig. 4.2 in the textbook
+l=(38-.25)*1D-2 //length of mean flux path in iron portion of part A
+ATi=H*l
+ATg=.796*Ba*2.5D-3*10^6
+ATa=ATi+ATg
+//consider part B
+a=255D-4
+Bb=flux/a
+H=670 //corresponding to Bb as obtained from Fig. 4.2 in the textbook
+l=.25 //length of mean flux path in iron portion of part B
+ATb=H*l
+AT=round(ATa)+round(ATb)
+mprintf("Total ampere turns required for complete magnetic circuit=%d", AT)
diff --git a/2252/CH4/EX4.11/Ex4_11.jpeg b/2252/CH4/EX4.11/Ex4_11.jpeg Binary files differnew file mode 100755 index 000000000..4ae0281c5 --- /dev/null +++ b/2252/CH4/EX4.11/Ex4_11.jpeg diff --git a/2252/CH4/EX4.11/Ex4_11.sce b/2252/CH4/EX4.11/Ex4_11.sce new file mode 100755 index 000000000..2b5b20d93 --- /dev/null +++ b/2252/CH4/EX4.11/Ex4_11.sce @@ -0,0 +1,21 @@ +
+mu_not=4D-7*%pi
+b=[.5 1 1.2 1.4]
+mu_r=[2500 2000 1500 1000]
+plot2d(b,mu_r,rect=[0,0,1.5,3000])
+xtitle("B-mu_r curve for example 4.11", "B(Wb/m^2)", "mu_r")
+
+phi=.38D-3 //flux in ring
+A=3D-4 //cross-sectional area
+B=phi/A
+mu_r=1300 //correspondng to B from B-mu_r curve plotted
+H=B/(mu_not*mu_r) //ampere turns per metre of flux path length
+l=%pi*58D-2 //length of mean flux path
+AT_iron=H*l
+mprintf("Total ampere turns required by iron ring=%d\n", round(AT_iron))
+//after saw cut of 1 mm width has been made
+l=l-.1D-2 //length of mean flux path in iron portion of ring
+ATi=H*l
+ATg=.796*B*1D-3*1D+6
+AT=round(ATi)+round(ATg)
+mprintf("Extra ampere turns required =%d", round(AT)-round(AT_iron))
diff --git a/2252/CH4/EX4.12/Ex4_12.sce b/2252/CH4/EX4.12/Ex4_12.sce new file mode 100755 index 000000000..705bbe522 --- /dev/null +++ b/2252/CH4/EX4.12/Ex4_12.sce @@ -0,0 +1,19 @@ +
+//two parallel magnetic circuits have equal reluctances
+phi_cc=1.2D-3 //flux in central core
+phi_ol=phi_cc/2 //flux in each outer limb
+//calculating AT for central core
+a=9D-4 //cross-sectional area
+B_cc=phi_cc/a
+H=1600 //corresponding to B_cc from Fig 4.2 in the textbook
+l=.15 //length of mean flux path
+AT_cc=H*l
+//calculating AT for outer limbs
+a=5D-4 //cross-sectional area
+B_ol=phi_ol/a
+H=1200 //corresponding to B_ol from Fig 4.2 in the textbook
+l=.35 //length of mean flux path
+AT_ol=H*l
+AT=AT_cc+AT_ol
+N=400
+mprintf("Current required in the coil=%f A", AT/N)
diff --git a/2252/CH4/EX4.13/Ex4_13.sce b/2252/CH4/EX4.13/Ex4_13.sce new file mode 100755 index 000000000..8189c4f00 --- /dev/null +++ b/2252/CH4/EX4.13/Ex4_13.sce @@ -0,0 +1,20 @@ +
+mu_not=4D-7*%pi
+phi_cc=1.2D-3 //flux in central core
+phi_ol=phi_cc/2 //flux in each outer limb
+//consider central core
+a=9D-4 //cross-sectional area
+B_cc=phi_cc/a //flux density
+H=1600 //corresponding to B_cc from Fig 4.2 in the textbook
+l=(15-.2)*1D-2 //length of mean flux path of cast steel
+AT_cc=H*l
+ATg=.796*B_cc*2D-3*10^6
+//consider outer limb
+a=5D-2//cross-sectional area
+B_ol=phi_ol/a
+H=1200 //corresponding to B_ol from Fig 4.2 in the textbook
+l=.35 //length of mean flux path
+AT_ol=H*l
+AT=AT_cc+ATg+AT_ol
+N=400
+mprintf("Exciting current in the coil=%f A",AT/N)
diff --git a/2252/CH4/EX4.2/Ex4_2.sce b/2252/CH4/EX4.2/Ex4_2.sce new file mode 100755 index 000000000..8de55cc78 --- /dev/null +++ b/2252/CH4/EX4.2/Ex4_2.sce @@ -0,0 +1,12 @@ +
+
+Bg=.7//flux density in air gap
+Lg=3D-3//length of air gap
+ATg=.796*Bg*Lg*1D+6
+Bs=Bg//flux density in iron path
+H=660//ampere turns corresponding to Bs from B-H curve(Fig.4.2) of textbook
+Li=40D-2//length of flux path in iron portion
+ATs=H*Li
+AT=round(ATg)+round(ATs)
+mprintf("Total ampere turns to be provided on the electromagnet=%d AT", AT)
+//answer vary from the textbook due to round off error
diff --git a/2252/CH4/EX4.3/Ex4_3.sce b/2252/CH4/EX4.3/Ex4_3.sce new file mode 100755 index 000000000..e38a9e835 --- /dev/null +++ b/2252/CH4/EX4.3/Ex4_3.sce @@ -0,0 +1,21 @@ +
+mu_not=4D-7*%pi
+N=700 //no. of turns on steel ring
+I=2 //current carried by the winding on the ring
+AT=N*I
+mprintf("mmf produced=%d AT\n",AT)
+ATi=.35*AT //iron portion takes 35% of total mmf
+ATg=AT-ATi
+l=1.5D-3 //length of flux path in air gap
+B=mu_not*ATg/l
+mprintf("Flux density=%f Wb/m^2\n", B)
+d=3D-2 //diameter of circular section of ring
+A=%pi*d^2/4 //cross-sectional area of ring
+flux=B*A
+mprintf("Magnetic flux=%f milliWb\n", flux*10^3)
+S=AT/flux //Ohm's law for magnetic circuits
+mprintf("Reluctance=%f*10^6 AT/Wb\n", S/10^6)
+l=%pi*25D-2 //length of mean flux path in steel ring
+H=ATi/l
+mu_r=B/(H*mu_not)
+mprintf("Rel. permeability of steel ring=%d", round(mu_r))
diff --git a/2252/CH4/EX4.4/Ex4_4.sce b/2252/CH4/EX4.4/Ex4_4.sce new file mode 100755 index 000000000..5d0b80866 --- /dev/null +++ b/2252/CH4/EX4.4/Ex4_4.sce @@ -0,0 +1,23 @@ +
+phi=.26D-3//flux
+d=2D-2//diameter of circular cross-section of ring
+A=%pi*d^2/4
+B=phi/A
+H=740//ampere turns per length of flux path corresponding to B as obtained from B-H curve of cast steel
+L=90D-2//length of mean flux path in the cast steel ring
+AT=H*L
+N=800//no. of turns of the coil wound on the ring
+I=AT/N
+mprintf("Current in the coil=%f A\n",I)
+Lg=2D-3//length of air gap
+Li=L-Lg//length of mean flux path in ring
+mu=B/H
+Bg=AT/(Li/mu+.796*Lg*1D+6)
+flux=Bg*A
+mprintf("Magnetic flux produced=%f*10^-4 Wb\n",flux*1D+4)
+//calculating value of current which will produce the same flux as in (i)
+ATi=H*Li
+ATg=.796*B*Lg*1D+6
+AT=ATi+ATg
+I=AT/N
+mprintf("Current in the coil which will give the same flux as in (i)=%f A",I)
diff --git a/2252/CH4/EX4.5/Ex4_5.sce b/2252/CH4/EX4.5/Ex4_5.sce new file mode 100755 index 000000000..5665bb504 --- /dev/null +++ b/2252/CH4/EX4.5/Ex4_5.sce @@ -0,0 +1,11 @@ +
+mu_not=4D-7*%pi
+N=400 //number of turns on the coil wound on iron ring
+I=1.2 //current through the coil
+AT=N*I
+l=1 //mean flux path in ring in mtrs
+H=AT/l
+B=1.15 //flux Density
+mu_r=B/(H*mu_not)
+mprintf("Rel permeability of iron ring mu_r=%d", round(mu_r))
+//error in textbook answer
diff --git a/2252/CH4/EX4.6/Ex4_6.sce b/2252/CH4/EX4.6/Ex4_6.sce new file mode 100755 index 000000000..e06f77392 --- /dev/null +++ b/2252/CH4/EX4.6/Ex4_6.sce @@ -0,0 +1,20 @@ +
+mu_not=4D-7*%pi
+Li=50d-2//length of flux path in iron
+mu_r=1300//relative permeability
+a=12D-4//cross sectional area
+Si=Li/(mu_not*mu_r*a)
+mprintf("Reluctance of iron part of magnetic circuit=%f*10^3 AT/Wb\n",Si/10^3)
+Lg=.4D-2//length of flux path in air gap
+Sg=Lg/(mu_not*a)
+mprintf("Reluctance of air gap of magnetic circuit=%f*10^3 AT/Wb\n",Sg/10^3)
+S=Si+Sg
+mprintf("Total reluctance of magnetic circuit=%f*10^3 AT/Wb\n",S/10^3)
+N=400+400 //total no. of turns
+I=1 //current through each coil
+mmf=N*I
+flux=mmf/S
+mprintf("Total flux=%f milliWb\n", flux*10^3)
+B=flux/a
+mprintf("Flux density in air gap=%f Wb/m^2", B)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH4/EX4.7/Ex4_7.sce b/2252/CH4/EX4.7/Ex4_7.sce new file mode 100755 index 000000000..b50442e04 --- /dev/null +++ b/2252/CH4/EX4.7/Ex4_7.sce @@ -0,0 +1,11 @@ +
+mu_not=4D-7*%pi
+N=300//no. of turns in coil
+I=.7//current through coil
+AT=N*I
+L=60D-2//length of ring
+Lg=2D-3//length of air gap
+Li=L-Lg//length of flux path in ring
+mu_r=300//rel permeability of iron
+B=AT/(Li/(mu_not*mu_r)+.796*Lg*1D+6)
+mprintf("Flux density=%f Wb/m^2", B)
diff --git a/2252/CH4/EX4.8/Ex4_8.jpeg b/2252/CH4/EX4.8/Ex4_8.jpeg Binary files differnew file mode 100755 index 000000000..0e919daa8 --- /dev/null +++ b/2252/CH4/EX4.8/Ex4_8.jpeg diff --git a/2252/CH4/EX4.8/Ex4_8.sce b/2252/CH4/EX4.8/Ex4_8.sce new file mode 100755 index 000000000..99298b25f --- /dev/null +++ b/2252/CH4/EX4.8/Ex4_8.sce @@ -0,0 +1,18 @@ +
+mu_not=4D-7*%pi
+phi=.0006//flux
+A=5.5D-4//cross-sectional area of ring
+B=phi/A
+h=[0 200 400 500 600 800 1000]
+b=[0 .4 .8 1 1.09 1.17 1.19]
+plot2d(h,b)
+xtitle("B-H curve for example 4.8", "H(ampere turns per metre)", "B(Wb/m^2)")
+H=600//corresponding to B from B-H curve
+L=270D-2//length of ring
+Lg=4.5D-3//length of air gap
+Li=L-Lg//length of flux path in iron portion of ring
+ATi=H*Li
+ATg=.796*B*Lg*1D+6
+AT=round(ATi)+round(ATg)
+mprintf("Total ampere turns=%d", AT)
+//error in textbook answer
diff --git a/2252/CH4/EX4.9/Ex4_9.sce b/2252/CH4/EX4.9/Ex4_9.sce new file mode 100755 index 000000000..ce7e09760 --- /dev/null +++ b/2252/CH4/EX4.9/Ex4_9.sce @@ -0,0 +1,18 @@ +
+mu_not=4D-7*%pi
+flux=1.1D-3
+A=4*4*1D-4//cross-sectional area
+B=flux/A
+mu_r=2000//rel permeability
+H=B/(mu_not*mu_r)
+//calculating ampere turns required for potion C
+l=.25//length of mean flux path
+ATc=H*l
+//calculating ampere turns required for potion D
+l=.3//length of mean flux path
+ATd=H*l
+//calculating ampere turns required for air gap
+ATg=.796*B*.002*10^6
+AT=round(ATc)+round(ATd)+round(2*ATg)
+mprintf("Total ampere turns required=%d", AT)
+//answer vary from the textbook due to round off error
diff --git a/2252/CH5/EX5.1/Ex5_1.sce b/2252/CH5/EX5.1/Ex5_1.sce new file mode 100755 index 000000000..a920c649a --- /dev/null +++ b/2252/CH5/EX5.1/Ex5_1.sce @@ -0,0 +1,6 @@ +
+N=1000//no. of turns in the coil
+dphi=-2*900D-6//change in flux in Wb
+dt=.2//time in sec in which change takes place
+emf=-N*dphi/dt
+mprintf("Average emf induced in the coil=%d V",round(emf))
diff --git a/2252/CH5/EX5.10/Ex5_10.sce b/2252/CH5/EX5.10/Ex5_10.sce new file mode 100755 index 000000000..b5e0e51c8 --- /dev/null +++ b/2252/CH5/EX5.10/Ex5_10.sce @@ -0,0 +1,13 @@ +
+mu_not=4D-7*%pi
+N=800//no. of turns for each solenoid
+l=90D-2//length of each solenoid
+Ax=%pi*(3D-2)^2/4//cross-sectional area of solenoid X
+Ay=%pi*(6D-2)^2/4//cross-sectional area of solenoid Y
+M=N*N*mu_not*Ax/l
+mprintf("Mutual inductance of arrangement=%f mH\n",1000*M)
+//calculating coupling co-efficient
+Lx=N*mu_not*N*Ax/l
+Ly=N*mu_not*N*Ay/l
+k=M/sqrt(Lx*Ly)
+mprintf("Coupling co-efficient=%f",k)
diff --git a/2252/CH5/EX5.11/Ex5_11.sce b/2252/CH5/EX5.11/Ex5_11.sce new file mode 100755 index 000000000..ab8daa6c5 --- /dev/null +++ b/2252/CH5/EX5.11/Ex5_11.sce @@ -0,0 +1,13 @@ +
+mu_not=4D-7*%pi
+Nb=500//no. of turns in coil B
+l=120D-2//mean length of flux path in iron circuit
+Na=50//no. of turns in coil A
+mu_r=2000//relative permeability of iron
+A=80*10^-4//cross-sectional area
+M=Nb*mu_not*mu_r*Na*A/(l)
+mprintf("Mutual inductance M=%f H\n",M)
+di=12
+dt=.015
+e=-M*di/dt
+mprintf("Emf induced in coil B=%f V",e)
diff --git a/2252/CH5/EX5.12/Ex5_12.sce b/2252/CH5/EX5.12/Ex5_12.sce new file mode 100755 index 000000000..fdeb41482 --- /dev/null +++ b/2252/CH5/EX5.12/Ex5_12.sce @@ -0,0 +1,13 @@ +
+V=110//applied voltage
+L=.5//inductance of coil
+r=V/L
+mprintf("Rate of change of current=%d A/s\n",r)
+R=8//resistance of coil
+I=V/R
+mprintf("Final steady current=%f A\n",I)
+T=L/R
+mprintf("Time constant=%f sec\n",T)
+//solving part(iv)
+t=-log(.5)*T
+mprintf("Time taken for the current to rise to half its final value=%f sec",t)
diff --git a/2252/CH5/EX5.13/Ex5_13.sce b/2252/CH5/EX5.13/Ex5_13.sce new file mode 100755 index 000000000..1a09ad2ed --- /dev/null +++ b/2252/CH5/EX5.13/Ex5_13.sce @@ -0,0 +1,17 @@ +
+//calculating time it will take current to reach .8 of its final steady value
+L=5//inductance of winding
+R=50//resistance of winding
+T=L/R
+V=110//applied voltage
+I=V/R//final steady current
+i=.8*I
+t=-T*log(1-i/I)
+mprintf("Current grows to .8 times its final steady value, %f sec after the switch is closed\n",t)
+//calculating time it will take for the current to reach .9 of its final steady value
+i=.9*I
+t=-T*log(1-i/I)
+mprintf("Time taken for the current to grow to .9 time its final steady value is %f sec\n",t)
+//calculating average emf induced
+e=-L*(-2.2/.05)
+mprintf("emf induced=%d V\n",round(e))
diff --git a/2252/CH5/EX5.14/Ex5_14.sce b/2252/CH5/EX5.14/Ex5_14.sce new file mode 100755 index 000000000..5654b0af1 --- /dev/null +++ b/2252/CH5/EX5.14/Ex5_14.sce @@ -0,0 +1,11 @@ +
+//calculating inductance and resistance of the relay
+T=.004//time constant which is time taken for the current to rise to .632 of its final steady value
+I=.35/.632//final steady value
+V=200//applied voltage
+R=V/I
+L=T*R
+mprintf("Resistance of relay circuit=%f ohm\nInductance of relay circuit=%f H\n",R,L)
+//calculating initial rate of rise of current
+r=V/L
+mprintf("Initial rate of rise of current=%f A/s",r)
diff --git a/2252/CH5/EX5.15/Ex5_15.sce b/2252/CH5/EX5.15/Ex5_15.sce new file mode 100755 index 000000000..ccb33a886 --- /dev/null +++ b/2252/CH5/EX5.15/Ex5_15.sce @@ -0,0 +1,9 @@ +
+R=.5+40+15//total resistance
+L=1//total inductance
+T=L/R
+V=12//emf of battery
+I=V/R//final steady current in the circuit
+i=.04//current at time t after closing the circuit
+t=-T*log(1-i/I)
+mprintf("The relay will begin to operate %f sec after the relay circuit is closed\n",t)
diff --git a/2252/CH5/EX5.16/Ex5_16.sce b/2252/CH5/EX5.16/Ex5_16.sce new file mode 100755 index 000000000..c847dcbc8 --- /dev/null +++ b/2252/CH5/EX5.16/Ex5_16.sce @@ -0,0 +1,14 @@ +
+mu_not=4*%pi*1D-7
+//calculating inductance
+N=4000//number of turns
+I=2//current flowing in the solenoid
+d=8D-2//diameter of solenoid
+As=%pi/4*d^2
+l=80D-2//length of solenoid in mtrs
+phi=mu_not*N*I*As/l
+L=N*phi/I
+mprintf("Inductance=%f H\n",L)
+//calculating energy stored in the magnetic field
+E=L*I^2/2
+mprintf("Energy stored in the magnetic field=%f J",E)
diff --git a/2252/CH5/EX5.17/Ex5_17.sce b/2252/CH5/EX5.17/Ex5_17.sce new file mode 100755 index 000000000..e11e2d046 --- /dev/null +++ b/2252/CH5/EX5.17/Ex5_17.sce @@ -0,0 +1,34 @@ +
+mu_not=4D-7*%pi
+//calculating exciting current
+B=1.2//flux density
+mu_r=500//rel permeability for iron
+H=B/(mu_not*mu_r)
+D=10D-2//mean diameter
+l=%pi*D//length of flux path in the ring
+AT=H*l
+N=300//number of turns on the ring
+I=AT/N
+mprintf("Exciting current=%d A\n",round(I))
+//calculating inductance
+As=8D-4//cross-sectional area
+phi=B*As
+L=N*phi/I
+mprintf("Inductance=%f H\n",L)
+//calculating energy stored
+E=L*I^2/2
+mprintf("Energy stored=%f J\n",E)
+//consider the case in which an air gap of 2 mm in the ring is made
+li=l-2D-3//length of flux path in iron portion
+lg=2D-3//length of air gap
+ATi=H*li//ampere turns for iron portion
+ATg=.796*B*lg*10^6//ampere turns for air gap
+AT=ATi+ATg
+I=AT/N
+mprintf("When there is an air gap of 2mm in the ring\nExciting current=%f A\n",I)
+L=N*phi/I
+mprintf("Inductance=%f mH\n",L*1000)
+E=L*I^2/2
+mprintf("Energy stored=%f J\n",E)
+
+
diff --git a/2252/CH5/EX5.18/Ex5_18.sce b/2252/CH5/EX5.18/Ex5_18.sce new file mode 100755 index 000000000..ace78dfb5 --- /dev/null +++ b/2252/CH5/EX5.18/Ex5_18.sce @@ -0,0 +1,21 @@ +
+mu_not=4D-7*%pi
+//calculating pull on the armature
+mu_r=300//rel permeability of iron
+AT=2000//total ampere turns
+li=50D-2//length of iron path
+lg=1.5D-3//length of air gap
+B=AT/(li/(mu_not*mu_r)+.796*lg*10^6)
+A=3D-4//area of each pole shoe
+x=B^2*A/(2*mu_not)//pull on the armature at each pole
+p=2*x
+mprintf("Total pull due to both the poles=%f N\n",p)
+//considering the gap closes to .2 mm
+lg=.2*1D-3
+B=AT/(li/(mu_not*mu_r)+.796*lg*10^6)
+x=B^2*A/(2*mu_not)
+p=2*x
+mprintf("When the gap closes to .2 mm, total force needed due to both the poles, to pull the armature away=%f N",p)
+//answer vary from the textbook due to round off error
+
+
diff --git a/2252/CH5/EX5.2/Ex5_2.sce b/2252/CH5/EX5.2/Ex5_2.sce new file mode 100755 index 000000000..40cee7bf2 --- /dev/null +++ b/2252/CH5/EX5.2/Ex5_2.sce @@ -0,0 +1,10 @@ +
+l=80D-2//length of conductor
+B=1.2//flux density of uniform magnetic field
+v=30//velocity of conductor in m/s
+//when the direction of motion is perpendicular to field
+e=B*l*v
+mprintf("emf induced in the conductor when the direction of motion is perpendicular to field=%f V\n",e)
+//when the direction of motion is inclined 45 degrees to field
+e=B*l*v*sin(%pi/4)
+mprintf("emf induced in the coil when the direction of motion is inclined 45 degrees to field=%f V",e)
diff --git a/2252/CH5/EX5.3/Ex5_3.sce b/2252/CH5/EX5.3/Ex5_3.sce new file mode 100755 index 000000000..6c6fe8c88 --- /dev/null +++ b/2252/CH5/EX5.3/Ex5_3.sce @@ -0,0 +1,9 @@ +
+N=120//no. of turns in coil
+dphi=(.3-.8)*1D-3//change in flux due to motion of conductor
+dt=.08//time taken for change in flux
+e=-N*dphi/dt
+mprintf("Induced emf in the coil=%f V\n",e)
+R=200//resistance offered by the coil
+I=e/R
+mprintf("Induced current=%f mA",I*1000)
diff --git a/2252/CH5/EX5.4/Ex5_4.sce b/2252/CH5/EX5.4/Ex5_4.sce new file mode 100755 index 000000000..f8a0efaec --- /dev/null +++ b/2252/CH5/EX5.4/Ex5_4.sce @@ -0,0 +1,19 @@ +
+mu_not=4D-7*%pi
+N=3500//no. of turns on iron rod
+I=.6//current through coil
+AT=N*I
+B=.45//flux density in Wb/m^2
+l=25D-2//length of mean magnetic flux path
+H=AT/l
+mu_r=B/(H*mu_not)
+mprintf("Relative permeability of metal=%f\n",mu_r)
+A=%pi*2.5D-2^2/4//cross sectional area of ring
+phi=B*A
+L=N*phi/I
+mprintf("Self inductance of coil=%f H\n",L)
+//solving part(iii)
+dphi=.08*phi-phi//change in flux
+dt=.0015//time taken for change
+e=-N*dphi/dt
+mprintf("emf induced in the coil when value of flux falls to 8 percent its valiue in 0.0015 sec=%f V",e)
diff --git a/2252/CH5/EX5.5/Ex5_5.sce b/2252/CH5/EX5.5/Ex5_5.sce new file mode 100755 index 000000000..7e0a3aeb7 --- /dev/null +++ b/2252/CH5/EX5.5/Ex5_5.sce @@ -0,0 +1,20 @@ +
+mu_not=4D-7*%pi
+H=3500//ampere turns per metre of flux path length
+l=%pi*40D-2//length of mean flux path in ring
+AT=H*l
+N=440//no. of turns on coil
+I=AT/N//exciting current
+mprintf("Exciting current=%d A\n",round(I))
+B=.9//flux density
+A=15D-4//cross-sectional area of ring
+phi=B*A
+L=N*phi/I
+mprintf("Self-inductance of coil=%f H\n",L)
+//solving part(iii)
+l=(l-1/10^2)//length of mean flux path in steel ring
+ATi=H*l//ampere turns required for iron portion
+ATg=.796*B*1D-2*1D+6//ampere turns for air gap
+AT=ATi+ATg
+I=AT/N
+mprintf("When an air gap 1 cm long is cut in the ring, exciting current I=%f A and self inductance of coil=%f H\n",I,N*phi/I)
diff --git a/2252/CH5/EX5.6/Ex5_6.sce b/2252/CH5/EX5.6/Ex5_6.sce new file mode 100755 index 000000000..e175fff9b --- /dev/null +++ b/2252/CH5/EX5.6/Ex5_6.sce @@ -0,0 +1,11 @@ +
+N=800//no. of turns
+dI=10-5//change in current
+dB=1.2-.8//corresponding change in flux density
+A=15D-4//cross sectional area
+L=A*N*dB/dI
+mprintf("Self inductance of coil,L=%f H\n",L)
+di=5-10//change in current
+dt=.04//time taken for change
+e=-L*di/dt
+mprintf("Induced emf when the current falls uniformly from 10 A to 5 A in 0.04 sec=%d V",round(e))
diff --git a/2252/CH5/EX5.7/Ex5_7.sce b/2252/CH5/EX5.7/Ex5_7.sce new file mode 100755 index 000000000..ffea3f37a --- /dev/null +++ b/2252/CH5/EX5.7/Ex5_7.sce @@ -0,0 +1,12 @@ +
+mu_not=4D-7*%pi
+N=1200//no. of turns in the coil on solenoid
+l=80D-2//length of solenoid
+A=%pi/4*(5D-2)^2//cross-sectional area
+L=N*(mu_not*N*A/l)
+mprintf("Self inductance=%f mH\n",L*1000)
+//calculating induced emf
+di=-5-5
+dt=.03
+e=-L*di/dt
+mprintf("Induced emf=%f V",e)
diff --git a/2252/CH5/EX5.8/Ex5_8.sce b/2252/CH5/EX5.8/Ex5_8.sce new file mode 100755 index 000000000..6b70fe7b3 --- /dev/null +++ b/2252/CH5/EX5.8/Ex5_8.sce @@ -0,0 +1,15 @@ +
+N=1500//no. of turns in coil A
+phi=.04D-3//flux linking coil A in Wb
+I=4//current in coil
+La=N*phi/I
+mprintf("Self inductance of coil A=%f mH. As the coils are identical, coil B will also have the same self-inductance.Hence, self-inductance of coil B=%f mH\n",La*1000,La*1000)
+k=.7
+M=N*k*phi/I
+mprintf("Mutual inductance of arrangement=%f mH\n",M*1000)
+di=-8
+dt=.02
+e=-M*di/dt
+mprintf("Emf induced in the coil B due to a change of current in coil A=%f V\n",e)
+
+
diff --git a/2252/CH5/EX5.9/Ex5_9.sce b/2252/CH5/EX5.9/Ex5_9.sce new file mode 100755 index 000000000..a5825f315 --- /dev/null +++ b/2252/CH5/EX5.9/Ex5_9.sce @@ -0,0 +1,9 @@ +
+mu_not=4D-7*%pi
+Ns=400//no. of turns on search coil
+N=1000//no. of turns of wire on solenoid
+M=mu_not*Ns*N*25D-4/80D-2
+mprintf("Mutual inductance of arrangement=%f mH\n",M*1000)
+//di/dt=200
+e=-M*200
+mprintf("emf induced in search coil=%f V",e)
diff --git a/2252/CH6/EX6.1/Ex6_1.jpeg b/2252/CH6/EX6.1/Ex6_1.jpeg Binary files differnew file mode 100755 index 000000000..4b24cd48e --- /dev/null +++ b/2252/CH6/EX6.1/Ex6_1.jpeg diff --git a/2252/CH6/EX6.1/Ex6_1.sce b/2252/CH6/EX6.1/Ex6_1.sce new file mode 100755 index 000000000..ec52e74ab --- /dev/null +++ b/2252/CH6/EX6.1/Ex6_1.sce @@ -0,0 +1,14 @@ +
+//plotting graph for i1
+theta=linspace(0,2*%pi,100)
+i1=50*sin(theta)+50*sin(theta-%pi/4)
+plot(theta,i1)
+//plotting graph for i2
+theta=linspace(0,2*%pi,100)
+i2=50*cos(theta)+50*cos(theta+%pi/4)
+plot(theta,i2,"o")
+//plotting graph for i3
+i3=50*cos(theta)-20*sin(theta)
+plot(theta,i3,"-*")
+xtitle("Graphs of i1(-),i2(oo) and i3(-*)","theta","current")
+//round off error while plotting graphs
diff --git a/2252/CH6/EX6.10/Ex6_10.jpeg b/2252/CH6/EX6.10/Ex6_10.jpeg Binary files differnew file mode 100755 index 000000000..f42a7ddbe --- /dev/null +++ b/2252/CH6/EX6.10/Ex6_10.jpeg diff --git a/2252/CH6/EX6.10/Ex6_10.sce b/2252/CH6/EX6.10/Ex6_10.sce new file mode 100755 index 000000000..f0f56bd39 --- /dev/null +++ b/2252/CH6/EX6.10/Ex6_10.sce @@ -0,0 +1,13 @@ +
+//the graph is drawn considering R=%pi
+R=%pi
+theta=linspace(-%pi,%pi,100)
+V=sqrt(R^2-theta^2)
+plot2d(theta,V)
+xtitle("Wave shape for example 6.10","theta","Voltage")
+theta=linspace(%pi,3*%pi,100)
+V=-sqrt(R^2-(theta-2*%pi)^2)
+plot2d(theta,V)
+
+Vrms=sqrt(integrate('(R^2-x^2)/(2*R)','x',-R,R))
+mprintf("RMS value of such a wave shape will be %f of its maximum voltage",Vrms/R)
diff --git a/2252/CH6/EX6.11/Ex6_11.sce b/2252/CH6/EX6.11/Ex6_11.sce new file mode 100755 index 000000000..e799a075b --- /dev/null +++ b/2252/CH6/EX6.11/Ex6_11.sce @@ -0,0 +1,16 @@ +
+//consider part (i)
+phi=%pi/12
+mprintf("For part (i)\nVoltage leads the current wave by %d degrees\n",round(phi*180/%pi))
+f=377.16/(2*%pi)
+mprintf("Frequency of the wave shape=%d Hz\n",f)
+//consider part (ii)
+phi=%pi/3
+mprintf("For part (ii)\nVoltage leads the current by %d degrees\n",round(phi*180/%pi))
+mprintf("Frequency of the wave shape=omega/(2*pi)\n")
+//consider part (iii)
+phi=0-(-%pi/2)
+mprintf("For part (iii)\nVoltage leads the current wave by %d degrees\n",round(phi*180/%pi))
+mprintf("Frequency of the wave shape=omega/pi\n")
+//consider part (iv)
+mprintf("For part (iv)\nCurrent wave lags the voltage by an angle=alpha+atan(x/R) and the frequency of this wave shape is omega/(2*pi)")
diff --git a/2252/CH6/EX6.13/Ex6_13.sce b/2252/CH6/EX6.13/Ex6_13.sce new file mode 100755 index 000000000..91df96886 --- /dev/null +++ b/2252/CH6/EX6.13/Ex6_13.sce @@ -0,0 +1,23 @@ +
+V=230//applied voltage
+L=60D-3//inductance of coil
+f=50 //frequency of supply
+Xl=2*%pi*f*L
+I=230/Xl
+//if frequency is reduced to 20 Hz
+Xl=2*%pi*20*L
+I1=V/Xl
+mprintf("Current through the coil if frequency is reduced to 20 Hz=%f A\n",I1)
+//if frequency is increased to 60 Hz
+Xl=2*%pi*60*L
+I2=V/Xl
+mprintf("Current through the coil if frequency is increased to 60 Hz=%f A\n",I2)
+//if frequency is increased to 100 Hz
+Xl=2*%pi*100*L
+I3=V/Xl
+mprintf("Current through the coil if frequency is increased to 100 Hz=%f A\n",I3)
+
+
+
+
+
diff --git a/2252/CH6/EX6.14/Ex6_14.sce b/2252/CH6/EX6.14/Ex6_14.sce new file mode 100755 index 000000000..ab057bb0b --- /dev/null +++ b/2252/CH6/EX6.14/Ex6_14.sce @@ -0,0 +1,12 @@ +
+//calculating reactance of capacitor
+C=100D-6
+Xc=1/(2*%pi*50*C)
+mprintf("Capacitive reactance,Xc=%f ohm\n",Xc)
+//calculating RMS value of current
+V=200
+Irms=V/Xc
+mprintf("RMS value of current=%f A\n",Irms)
+//calculating max current
+Imax=Irms*sqrt(2)
+mprintf("Maximum current=%f A",Imax)
diff --git a/2252/CH6/EX6.2/Ex6_2.sce b/2252/CH6/EX6.2/Ex6_2.sce new file mode 100755 index 000000000..8a19c6e55 --- /dev/null +++ b/2252/CH6/EX6.2/Ex6_2.sce @@ -0,0 +1,17 @@ +
+
+//i=Imax*sin(2*%pi*f*t)
+Imax=100//max value of current
+f=25//frequency in Hz
+//calculating time after which current becomes 20 A
+i=20
+t=asin(i/Imax)/(2*%pi*f)
+mprintf("Time after which current becomes 20 A=%f sec\n",t)
+//calculating time after which current becomes 50 A
+i=50
+t=asin(i/Imax)/(2*%pi*f)
+mprintf("Time after which current becomes 50 A=%f sec\n",t)
+//calculating time after which current becomes 100 A
+i=100
+t=asin(i/Imax)/(2*%pi*f)
+mprintf("Time after which current becomes 100 A=%f sec\n",t)
diff --git a/2252/CH6/EX6.3/Ex6_3.sce b/2252/CH6/EX6.3/Ex6_3.sce new file mode 100755 index 000000000..1dff2465e --- /dev/null +++ b/2252/CH6/EX6.3/Ex6_3.sce @@ -0,0 +1,12 @@ +
+//calculating instantaneous voltage at .005 sec after the wave passes through zero in positive direction
+f=50//frequency
+Emax=350//max value of voltage
+t=.005
+e1=Emax*sin(2*%pi*f*t)
+mprintf("Voltage at .005 sec after the wave passes through zero in positive direction=%d V\n",e1)
+//calculating instantaneous voltage at .008 sec after the wave passes through zero in negative direction
+t=.008
+e2=-Emax*sin(2*%pi*f*t)
+mprintf("Voltage at .008 sec after the wave passes through zero in negative direction=%f V",e2)
+
diff --git a/2252/CH6/EX6.4/Ex6_4.sce b/2252/CH6/EX6.4/Ex6_4.sce new file mode 100755 index 000000000..9b1d85eb5 --- /dev/null +++ b/2252/CH6/EX6.4/Ex6_4.sce @@ -0,0 +1,15 @@ +
+//e=100*sin(100*%pi*t)
+//calculating rate of change of voltage at t=.0025 sec
+t=.0025
+r1=10000*%pi*cos(100*%pi*t)
+mprintf("Rate of change of voltage at .0025 sec=%f V/sec\n",r1)
+//calculating rate of change of voltage at t=.005 sec
+t=.005
+r2=10000*%pi*cos(100*%pi*t)
+mprintf("Rate of change of voltage at .005 sec=%d V/sec\n",r2)
+//calculating rate of change of voltage at t=.01 sec
+t=.01
+r3=10000*%pi*cos(100*%pi*t)
+mprintf("Rate of change of voltage at .01 sec=%f V/sec\n",r3)
+//error in textbook answer in first and last case
diff --git a/2252/CH6/EX6.5/Ex6_5.sce b/2252/CH6/EX6.5/Ex6_5.sce new file mode 100755 index 000000000..89fde7293 --- /dev/null +++ b/2252/CH6/EX6.5/Ex6_5.sce @@ -0,0 +1,16 @@ +
+
+//calculating greatest rate of change of current
+//i=50*sin(100*%pi*t)
+mprintf("Greatest rate of change of current=%f A/sec\n",50*100*%pi)
+//calculating average value of current
+f=50//frequency of the wave
+T=1/f
+Imean=1/.01*integrate("50*sin(100*%pi*t)","t",0,T/2)
+mprintf("Average value of the given current=%f A\n",Imean)
+Irms=sqrt(integrate("(50*sin(theta))^2","theta",0,2*%pi)/(2*%pi))
+mprintf("RMS value of current=%f A\n",Irms)
+//calculating time interval between a maximum value and next zero value
+t=(%pi/2)/(100*%pi)
+mprintf("Time interval between a maximum value and the next zero value is %f sec to %f sec",t,2*t)
+//value of greatest rate of change of current is given wrong in the textbook due to approximation
diff --git a/2252/CH6/EX6.6/Ex6_6.jpeg b/2252/CH6/EX6.6/Ex6_6.jpeg Binary files differnew file mode 100755 index 000000000..f01531de8 --- /dev/null +++ b/2252/CH6/EX6.6/Ex6_6.jpeg diff --git a/2252/CH6/EX6.6/Ex6_6.sce b/2252/CH6/EX6.6/Ex6_6.sce new file mode 100755 index 000000000..f6d351b2e --- /dev/null +++ b/2252/CH6/EX6.6/Ex6_6.sce @@ -0,0 +1,77 @@ +
+i=linspace(0,0,2)
+t=linspace(0,1,2)
+plot2d(t,i)
+for j=0:3
+ i=linspace(40+20*j,40+20*j,2)
+ t=linspace(j+1,j+2,2)
+ plot2d(t,i)
+ if j==0 then
+ t=linspace(j+1,j+1,2)
+ i=linspace(0,40,2)
+ plot2d(t,i)
+ else
+ t=linspace(j+1,j+1,2)
+ i=linspace(40+20*(j-1),40+20*j,2)
+ plot2d(t,i)
+ end
+end
+for j=1:3
+ i=linspace(100-20*j,100-20*j,2)
+ t=linspace(j+4,j+5,2)
+ plot2d(t,i)
+ i=linspace(100-20*(j-1),100-20*j,2)
+ t=linspace(j+4,j+4,2)
+ plot2d(t,i)
+end
+i=linspace(40,0,2)
+t=linspace(8,8,2)
+plot2d(t,i)
+i=linspace(0,0,2)
+t=linspace(8,9,2)
+plot2d(t,i)
+for j=0:3
+ i=linspace(-(40+20*j),-(40+20*j),2)
+ t=linspace(j+9,j+10,2)
+ plot2d(t,i)
+ if j==0 then
+ t=linspace(j+9,j+9,2)
+ i=linspace(0,-40,2)
+ plot2d(t,i)
+ else
+ t=linspace(j+9,j+9,2)
+ i=linspace(-40-20*(j-1),-40-20*j,2)
+ plot2d(t,i)
+end
+end
+for j=1:3
+ i=linspace(-(100-20*j),-(100-20*j),2)
+ t=linspace(j+12,j+13,2)
+ plot2d(t,i)
+ i=linspace(-100+20*(j-1),-100+20*j,2)
+ t=linspace(j+12,j+12,2)
+ plot2d(t,i)
+end
+i=linspace(0,-40,2)
+t=linspace(16,16,2)
+plot2d(t,i)
+xtitle("Periodic current wave for example 6.6","time in seconds","current")
+
+//calculating average value for this wave shape
+Iavg=(0+40+60+80+100+80+60+40)/8
+mprintf("Average value of current of given wave shape=%f A\n",Iavg)
+//calculating RMS value for the given wave shape
+Irms=sqrt((0^2+40^2+60^2+80^2+100^2+80^2+60^2+40^2)/8)
+mprintf("RMS value of current of given wave shape=%f A\n",Irms)
+//calculating form factor
+x=Irms/Iavg
+mprintf("Form factor of given wave form=%f\n",x)
+//calculating peak factor
+Imax=100//maximum value of current wave
+y=Imax/Irms
+mprintf("Peak factor of given wave=%f\n",y)
+//calculating average and RMS value of current considering the wave to be sinusoidal having peak value of 100 A
+Iavg=integrate('100/%pi*sin(theta)','theta',0,%pi)
+mprintf("Average value of sine wave=%f A\n",Iavg)
+Irms=sqrt(integrate('(100*sin(theta))^2/%pi','theta',0,%pi))
+mprintf("RMS value of sine wave=%f A",Irms)
diff --git a/2252/CH6/EX6.7/Ex6_7.jpeg b/2252/CH6/EX6.7/Ex6_7.jpeg Binary files differnew file mode 100755 index 000000000..88232775e --- /dev/null +++ b/2252/CH6/EX6.7/Ex6_7.jpeg diff --git a/2252/CH6/EX6.7/Ex6_7.sce b/2252/CH6/EX6.7/Ex6_7.sce new file mode 100755 index 000000000..95d8b768f --- /dev/null +++ b/2252/CH6/EX6.7/Ex6_7.sce @@ -0,0 +1,12 @@ +
+theta=linspace(0,2*%pi,100)
+i=10+10*sin(theta)//expression for the resultant wave
+plot2d(theta,i)
+xtitle("Wave shape for example 6.7","theta","current")
+
+//calculating average value of the resultant wave
+Iavg=integrate('10+10*sin(theta)','theta',0,2*%pi)/(2*%pi)
+mprintf("Average value of the resultant current wave=%d A\n",Iavg)
+//calculating RMS value of current of the resultant wave
+Irms=sqrt(integrate('(10+10*sin(theta))^2','theta',0,2*%pi)/(2*%pi))
+mprintf("RMS value of the resultant current wave=%f A",Irms)
diff --git a/2252/CH6/EX6.8/Ex6_8.sce b/2252/CH6/EX6.8/Ex6_8.sce new file mode 100755 index 000000000..8a8cd3ddd --- /dev/null +++ b/2252/CH6/EX6.8/Ex6_8.sce @@ -0,0 +1,68 @@ +
+theta=linspace(0,2*%pi,100)
+i=50*sin(theta)
+xset('window',0)
+plot2d(theta,i)
+xtitle("Current wave shape for example 6.8-->(a)","theta","current")
+
+xset('window',1)
+theta=linspace(0,%pi,100)
+i=50*sin(theta)
+plot2d(theta,i)
+theta=linspace(%pi,2*%pi,100)
+i=-50*sin(theta)
+plot2d(theta,i)
+xtitle("Current wave shape for example 6.8-->(b)","theta","current")
+
+xset('window',2)
+theta=linspace(0,0,2)
+i=linspace(0,50,2)
+plot2d(theta,i)
+theta=linspace(0,%pi,2)
+i=linspace(50,50,2)
+plot2d(theta,i)
+theta=linspace(%pi,%pi,2)
+i=linspace(50,-50,2)
+plot2d(theta,i)
+theta=linspace(%pi,2*%pi,2)
+i=linspace(-50,-50,2)
+plot2d(theta,i)
+i=linspace(-50,0,2)
+theta=linspace(2*%pi,2*%pi,2)
+plot2d(theta,i)
+xtitle("Current wave shape for example 6.8-->(c)","theta","current")
+
+xset('window',3)
+theta=linspace(0,%pi/2,2)
+i=linspace(0,50,2)
+plot2d(theta,i)
+theta=linspace(%pi/2,%pi,2)
+i=linspace(50,0,2)
+plot2d(theta,i)
+theta=linspace(%pi,3*%pi/2,2)
+i=linspace(0,-50,2)
+plot2d(theta,i)
+theta=linspace(3*%pi/2,2*%pi,2)
+i=linspace(-50,0,2)
+plot2d(theta,i)
+xtitle("Current wave shape for example 6.8-->(d)","theta","current")
+
+//consider wave shape (a)
+mprintf("For wave shape (a)\nAs the negative and positive parts of the wave are equal, reading of moving coil ammeter is zero\n")
+Irms=sqrt(integrate('(50*sin(theta))^2','theta',0,2*%pi)/(2*%pi))
+mprintf("Reading of moving iron ammeter=%f A\n",Irms)
+
+//consider wave shape (b)
+Iavg=integrate('50*sin(theta)','theta',0,%pi)/%pi
+mprintf("For wave shape (b)\nReading on the moving coil ammeter=%f A\n",Iavg)
+Irms=sqrt(integrate('(50*sin(theta))^2','theta',0,2*%pi)/(2*%pi))
+mprintf("Reading on moving iron ammeter=%f A\n",Irms)
+
+//consider case (c)
+mprintf("For wave shape (c)\nAverage value over one complete period is clearly zero. Thus reading on moving coil ammeter is zero. As the value of current remains constant at 50 A during various intervals, RMS value will be 50 A only. Hence, reading on moving iron ammeter=50 A\n")
+
+//consider case(d)
+Iavg=(0+10+20+30+40+50++40+30+20+10+0+(-10)+(-20)+(-30)+(-40)+(-50)+(-40)+(-30)+(-20)+(-10)+0)/20
+mprintf("For wave shape (d)\nReading on moving coil ammeter=%d\n",Iavg)
+Irms=sqrt((0^2+10^2+20^2+30^2+40^2+50^2+40^2+30^2+20^2+10^2+0^2+(-10)^2+(-20)^2+(-30)^2+(-40)^2+(-50)^2+(-40)^2+(-30)^2+(-20)^2+(-10)^2+0^2)/20)
+mprintf("Reading on moving iron ammeter=%f A\n",Irms)
diff --git a/2252/CH6/EX6.9/Ex6_9.sce b/2252/CH6/EX6.9/Ex6_9.sce new file mode 100755 index 000000000..bf3f1b42a --- /dev/null +++ b/2252/CH6/EX6.9/Ex6_9.sce @@ -0,0 +1,11 @@ +
+//let us assume V=1 V, T=1 sec
+//e=V*t/T
+V=1
+T=1
+Erms=sqrt(integrate("(V*t/T)^2","t",0, T)/T)
+mprintf("RMS value of voltage is %f times maximum voltage\n",Erms/V)
+Emean=integrate("V*t/T","t",0,T)/T
+k=Erms/Emean
+mprintf("Form factor of this wave=%f",k)
+
diff --git a/2252/CH7/EX7.1/Ex7_1.sce b/2252/CH7/EX7.1/Ex7_1.sce new file mode 100755 index 000000000..3a626c6ea --- /dev/null +++ b/2252/CH7/EX7.1/Ex7_1.sce @@ -0,0 +1,14 @@ +
+//calculating current flowing in the circuit
+L=0.1//inductance
+f=50//frequency
+Xl=2*%pi*f*L
+R=15//total resistance in the circuit
+Z=sqrt(R^2+Xl^2)
+V=230//voltage applied to series circuit
+I=V/Z
+mprintf("Current flowing in the circuit=%f A\n",I)
+//calculating power factor
+pf=R/Z
+mprintf("Power factor of the circuit is %f(lagging)\nVoltage across reactor=%f V\nVoltage across resistor=%f V",pf,I*Xl,I*R)
+
diff --git a/2252/CH7/EX7.10/Ex7_10.sce b/2252/CH7/EX7.10/Ex7_10.sce new file mode 100755 index 000000000..5d359443a --- /dev/null +++ b/2252/CH7/EX7.10/Ex7_10.sce @@ -0,0 +1,10 @@ +
+//rating of bulb is 100 W,110 V
+P=100
+V=110
+I=P/V//normal current of bulb
+//voltage across bulb should be 110 V
+Vc=sqrt(230^2-V^2)//voltage across the capacitance
+Xc=Vc/I
+C=1/(100*%pi*Xc)
+mprintf("Capacitance of %f microF must be connected in series with the bulb",C*1D+6)
diff --git a/2252/CH7/EX7.11/Ex7_11.sce b/2252/CH7/EX7.11/Ex7_11.sce new file mode 100755 index 000000000..9d695a364 --- /dev/null +++ b/2252/CH7/EX7.11/Ex7_11.sce @@ -0,0 +1,7 @@ +
+C=35D-6//capacitance
+f=50//frequency
+Xc=1/(2*%pi*f*C)
+Z=2*Xc//voltage applied across the capacitance is equal to half of total voltage applied
+R=sqrt(Z^2-Xc^2)
+mprintf("Resistance of variable resistor, R=%f ohm",R)
diff --git a/2252/CH7/EX7.12/Ex7_12.sce b/2252/CH7/EX7.12/Ex7_12.sce new file mode 100755 index 000000000..b4ac5109d --- /dev/null +++ b/2252/CH7/EX7.12/Ex7_12.sce @@ -0,0 +1,25 @@ +
+//calculating current drawn
+V=230//voltage applied
+R=15+10//total resistance of the circuit
+L=.04+.1//total inductance
+Xl=2*%pi*50*L
+C=100D-6//capacitance
+Xc=1/(2*%pi*50*C)
+X=Xl-Xc
+Z=sqrt(R^2+X^2)
+I=V/Z
+mprintf("Current drawn=%f A\n",I)
+//calculating voltages V1 and V2
+Z1=sqrt(15^2+(2*%pi*50*.04)^2)
+V1=I*Z1
+phi1=atand(2*%pi*50*.04/15)
+mprintf("V1=%f V and leads the current by %f degrees\n",V1,round(phi1))
+Z2=sqrt(10^2+(2*%pi*50*.1-1/(2*%pi*50*100D-6))^2)
+V2=I*Z2
+phi2=acosd(10/Z2)
+mprintf("V2=%f V and lags the current by %f degrees\n",V2,phi2)
+//calculating power factor of overall circuit
+pf=R/Z
+mprintf("Power factor of overall circuit=%f lagging",pf)
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH7/EX7.13/Ex7_13.sce b/2252/CH7/EX7.13/Ex7_13.sce new file mode 100755 index 000000000..30d282dbe --- /dev/null +++ b/2252/CH7/EX7.13/Ex7_13.sce @@ -0,0 +1,26 @@ +
+//solving part(i)
+Rb=5//resistance of coil B
+Xb=2*%pi*50*.02//inductive reactance of coil B
+Zb=sqrt(Rb^2+Xb^2)
+phi_b=atand(Xb/Rb)//phase difference of Vb with current as reference phasor
+phi_a=90*%pi/180-phi_b*%pi/180//Va and Vb are in quadrature
+//Xc/R=tan(phi_a)
+//Vb=2*Va-->R^2+Xc^2=Zb^2/4
+//on solving for R and Xc
+R=sqrt((Zb^2/4)/(1+tan(phi_a)^2))
+Xc=tan(phi_a)*R
+C=1/(2*%pi*50*Xc)
+mprintf("R=%f ohm\nC=%f microF\n",R,C*1D+6)
+//solving part(ii)
+Rt=5+R//total resistance of circuit
+Xt=Xb-Xc//resultant reactance of circuit
+Zt=sqrt(Rt^2+Xt^2)
+V=220//applied voltage
+I=V/Zt
+mprintf("Current drawn by the circuit=%f A\n",I)
+//solving part(iii)
+//as the reactance is positive, circuit is inductive
+pf=Rt/Zt//lagging
+mprintf("Power factor of the circuit=%f(lagging)\n",pf)
+//the answers vary from the textbook due to round off error
diff --git a/2252/CH7/EX7.14/Ex7_14.sce b/2252/CH7/EX7.14/Ex7_14.sce new file mode 100755 index 000000000..52d115364 --- /dev/null +++ b/2252/CH7/EX7.14/Ex7_14.sce @@ -0,0 +1,28 @@ +
+//calculating frequency of applied voltage
+C=25.5D-6//capacitance
+I=.4//current through circuit
+V=50//voltage across capacitor
+Xc=V/I
+f=1/(2*%pi*C*Xc)
+mprintf("Frequency=%d Hz\n",round(f))
+//calculating parameters of choke coil
+V=35//voltage across choke coil
+Z=V/I//impedance of choke coil
+//r^2+(100*%pi*L)^2=Z^2
+R=20/.4
+Vac=45//voltage across ac portion of circuit
+Zac=Vac/I//impedance of ac portion
+//(R+r)^2+(100*%pi*L)^2=Zac^2
+//solving for r and L
+r=(Zac^2-Z^2-R^2)/(2*R)
+L=sqrt(Z^2-r^2)/(100*%pi)
+Xl=2*%pi*50*L
+mprintf("Parameters of choke coil:\nResistance=%f ohm\nInductance=%f H\nInductive reactance=%f ohm\n",r,L,Xl)
+//calculating applied voltage
+Z=sqrt((R+r)^2+(Xl-Xc)^2)
+V=I*Z
+mprintf("Voltage applied to the circuit=%f V\n",V)
+//calculating losses in choke coil
+W=I^2*r
+mprintf("Losses in choke coil=%d W\n",round(W))
diff --git a/2252/CH7/EX7.15/Ex7_15.sce b/2252/CH7/EX7.15/Ex7_15.sce new file mode 100755 index 000000000..143938678 --- /dev/null +++ b/2252/CH7/EX7.15/Ex7_15.sce @@ -0,0 +1,23 @@ +
+//calculating capacitance to give resonance
+Xl=2*%pi*50*.4
+Xc=Xl
+C=1/(2*%pi*50*Xc)
+mprintf("Capacitance=%f microF\n",C*1D+6)
+//calculating current
+R=5
+Z=R
+V=110
+I=V/Z
+mprintf("current drawn=%f A\n",I)
+//calculating voltage across inductance
+Xl=2*%pi*50*.4
+Vl=I*Xl
+mprintf("Voltage across inductance=%f V\n",Vl)
+//calculating voltage across capacitance
+Xc=Xl
+Vc=I*Xc
+mprintf("Voltage across capacitance=%f V\n",Vc)
+//calculating Q-factor
+Q_factor=Vl/V
+mprintf("Q-factor of the circuit=%f",Q_factor)
diff --git a/2252/CH7/EX7.2/Ex7_2.sce b/2252/CH7/EX7.2/Ex7_2.sce new file mode 100755 index 000000000..1a917a6f9 --- /dev/null +++ b/2252/CH7/EX7.2/Ex7_2.sce @@ -0,0 +1,11 @@ +
+V1=200//voltage applied to non-inductive load
+I1=20//current flowing through the load
+R=V1/I1
+V=230//applied voltage to series connection of R and L
+I=I1
+Z=V/I
+Xl=sqrt(Z^2-R^2)
+L=Xl/(2*%pi*50)
+phi=atand(Xl/R)
+mprintf("Inductance of the reactor=%f H, phase angle between applied voltage and the current is %f degrees",L,phi)
diff --git a/2252/CH7/EX7.3/Ex7_3.sce b/2252/CH7/EX7.3/Ex7_3.sce new file mode 100755 index 000000000..bf97b140e --- /dev/null +++ b/2252/CH7/EX7.3/Ex7_3.sce @@ -0,0 +1,25 @@ +
+//calculating resistance, reactance and impedance of choke coil
+I=7.5//current flowing through the circuit
+V1=110//voltage across non-inductive resistor
+R=V1/I
+V2=180//voltage across choke coil
+Z=V2/I
+Zt=230/I//impedance of whole circuit
+r=(Zt^2-R^2-Z^2)/(2*R)
+Xl=sqrt(Z^2-r^2)
+mprintf("Reactance of coil=%f ohm\nResistance of coil=%f ohm\nImpedance of coil=%f ohm\n",Xl,r,Z)
+//calculating total resistance and impedance of the circuit
+Rt=r+R
+Zt=sqrt(Rt^2+Xl^2)
+mprintf("Total resistance of circuit=%f ohm\nTotal impedance of circuit=%f ohm\n",Rt,Zt)
+//calculating power absorbed by the coil
+P1=I^2*r
+mprintf("Power absorbed by the coil=%f W\n",P1)
+//calculating power drawn by circuit
+P2=I^2*(r+R)
+mprintf("Power drawn by the circuit=%f W\n",P2)
+//calculating power factor of whole circuit
+pf=Rt/Zt
+mprintf("Power factor of the whole circuit=%f lagging",pf)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH7/EX7.4/Ex7_4.sce b/2252/CH7/EX7.4/Ex7_4.sce new file mode 100755 index 000000000..5ef975f0a --- /dev/null +++ b/2252/CH7/EX7.4/Ex7_4.sce @@ -0,0 +1,17 @@ +
+//calculating current drawn at 50 Hz
+V=220//voltage applied to choke coil
+f=50//frequency of supply
+I1=12//current taken by choke coil
+R1=0//resistance of coil is negligible
+Xl=V/I1
+I2=16.5//current taken by the resistor
+R=V/I2
+Z=sqrt(R^2+Xl^2)
+I=V/Z
+mprintf("Current taken by the circuit at 50 Hz=%f A\n",I)
+//calculating current drawn at 30 Hz
+Xl_dash=30/50*Xl
+Z_dash=sqrt(Xl_dash^2+R^2)
+I=V/Z_dash
+mprintf("Current drawn by the circuit at 30 Hz=%f A\n",I)
diff --git a/2252/CH7/EX7.5/Ex7_5.sce b/2252/CH7/EX7.5/Ex7_5.sce new file mode 100755 index 000000000..98834677a --- /dev/null +++ b/2252/CH7/EX7.5/Ex7_5.sce @@ -0,0 +1,13 @@ +
+//let resistance and inductance of the coil be R and L respectively
+V=220//voltage applied to coil
+f=50//frequency of supply
+I=60//current indicated by ammeter
+Z1=V/I
+//when the frequency is increased to 100 Hz
+I=40//current indicated by ammeter
+Z2=V/I
+//on solving for L
+L=sqrt((Z2^2-Z1^2)/3)/(100*%pi)
+R=sqrt(Z1^2-(100*%pi*L)^2)
+mprintf("Resistance of coil=%f ohm\nInductance of coil=%f H",R,L)
diff --git a/2252/CH7/EX7.6/Ex7_6.sce b/2252/CH7/EX7.6/Ex7_6.sce new file mode 100755 index 000000000..3ece3a104 --- /dev/null +++ b/2252/CH7/EX7.6/Ex7_6.sce @@ -0,0 +1,38 @@ +
+//calculating parameters of each coil
+I=3//current through the circuit
+//for coil A
+Ra=12/3//resistance
+Va=15//voltage drop
+Za=Va/I
+Xa=sqrt(Za^2-Ra^2)
+//for coil B
+Rb=6/3//resistance
+Vb=9//voltage drop
+Zb=Vb/I
+Xb=sqrt(Zb^2-Rb^2)
+//for coil C
+Rc=9/3//resistance
+Vc=12//voltage drop
+Zc=Vc/I
+Xc=sqrt(Zc^2-Rc^2)
+mprintf("Parameters of\nCoilA: Ra=%f ohm, Xa=%f ohm\nCoil B: Rb=%f ohm, Xb=%f ohm\nCoil C: Rc=%f ohm, Xc=%f ohm\n",Ra,Xa,Rb,Xb,Rc,Xc)
+//calculating power factor of each coil
+pf_a=Ra/Za
+pf_b=Rb/Zb
+pf_c=Rc/Zc
+mprintf("power factor of the coils are\npf_a=%f(lagging)\npf_b=%f(lagging)\npf_c=%f(lagging)\n",pf_a,pf_b,pf_c)
+//calculating power dissipated for each coil
+Pa=I^2*Ra
+Pb=I^2*Rb
+Pc=I^2*Rc
+mprintf("Power dissipated in these coils:\nPa=%f W\nPb=%f W\nPc=%f W\n",Pa,Pb,Pc)
+//calculating power factor of whole circuit
+Rt=Ra+Rb+Rc
+Xt=Xa+Xb+Xc
+Zt=sqrt(Rt^2+Xt^2)
+pf=Rt/Zt
+mprintf("Power factor of the whole circuit=%f lagging\n",pf)
+//calculating voltage applied across the whole circuit
+V=I*Zt
+mprintf("Voltage applied across the whole circuit=%f V",V)
diff --git a/2252/CH7/EX7.7/Ex7_7.sce b/2252/CH7/EX7.7/Ex7_7.sce new file mode 100755 index 000000000..7fa398ef9 --- /dev/null +++ b/2252/CH7/EX7.7/Ex7_7.sce @@ -0,0 +1,20 @@ +
+//r1 be the variable resistance
+X=10//total inductive reactance of circuit
+V=200//rms value of applied voltage
+//RMS value of current I=200/sqrt((2+r1)^2+10^2)
+//power consumed is P=I^2*r1
+//For max power, dP/dr=0
+//on solving
+r1=sqrt(104)
+mprintf("Value of variable resistor at the instant of max power consumed in it is %f ohm\n",r1)
+//solving part(ii), let r2 be the variable resistance-I=200/sqrt((200+r2)^2+10^2),P=I^2*(2+r2)
+//for max power, dP/dr=0
+//on solving
+r2=10-2
+mprintf("Value of variable resistor=%d ohm for the condition of max power consumed by the circuit\n",round(r2))
+I1=200/sqrt((2+r1)^2+10^2)
+I2=200/sqrt((2+r2)^2+10^2)
+pf1=(2+r1)/sqrt((2+r1)^2+10^2)
+pf2=(2+r2)/sqrt((2+r2)^2+10^2)
+mprintf("Current in case(i)=%f A at %f pf lagging\nCurrent in case(ii)=%f A at %f pf lagging\n",I1,pf1,I2,pf2)
diff --git a/2252/CH7/EX7.8/Ex7_8.sce b/2252/CH7/EX7.8/Ex7_8.sce new file mode 100755 index 000000000..baed86f02 --- /dev/null +++ b/2252/CH7/EX7.8/Ex7_8.sce @@ -0,0 +1,23 @@ +
+//both the coils draw lagging currents, hence both are inductive
+//for coil A
+Va=10//voltage applied
+Ia=2//current drawn
+Za=Va/Ia
+pf=.8//power factor
+Ra=pf*Za
+Xa=sqrt(Za^2-Ra^2)
+//for coil B
+Vb=5//voltage applied
+Ib=2//current drawn
+Zb=Vb/Ib
+pf=.7//power factor
+Rb=pf*Zb
+Xb=sqrt(Zb^2-Rb^2)
+
+Rt=Ra+Rb//total resistance of circuit
+Xt=Xa+Xb//total reactance of circuit
+Z=sqrt(Rt^2+Xt^2)
+V=Ia*Z
+pf=Rt/Z
+mprintf("Voltage to be applied to the circuit of coils A and B in series=%f V and pf=%f lagging",V,pf)
diff --git a/2252/CH7/EX7.9/Ex7_9.sce b/2252/CH7/EX7.9/Ex7_9.sce new file mode 100755 index 000000000..161f705fd --- /dev/null +++ b/2252/CH7/EX7.9/Ex7_9.sce @@ -0,0 +1,24 @@ +
+//calculating capacitance
+Xc=4//capacitive reactance
+f=50
+omega=2*%pi*f
+C=1/(omega*Xc)
+mprintf("Capacitance C=%f microF\n",C*1D+6)
+//calculating impedance
+R=5//resistance of circuit
+Z=sqrt(R^2+Xc^2)
+mprintf("Impedance of circuit=%f ohm\n",Z)
+//calculating current taken by circuit
+V=200
+I=V/Z
+mprintf("Current drawn by circuit=%f A\n",I)
+//calculating voltage drop across the resistance
+Vr=I*R
+mprintf("Voltage drop across the resistance=%f V\n",Vr)
+//calculating voltage drop across the reactance
+Vc=I*Xc
+mprintf("Voltage drop across the reactance=%f V\n",Vc)
+//calculating power factor
+pf=R/Z
+mprintf("Power factor of the circuit=%f leading",pf)
diff --git a/2252/CH8/EX8.1/Ex8_1.sce b/2252/CH8/EX8.1/Ex8_1.sce new file mode 100755 index 000000000..b23c308bf --- /dev/null +++ b/2252/CH8/EX8.1/Ex8_1.sce @@ -0,0 +1,40 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+//calculating current in each branch and its angle of lag or lead
+V=230
+f=50
+//for branch A
+Ra=10//resistance
+L=.04//inductance
+Xl=2*%pi*f*L//inductive reactance
+Za=sqrt(Ra^2+Xl^2)//impedance
+Ia=V/Za
+phi_a=atand(Xl/Ra)
+//for branch B
+R=25//resistance
+Zb=R//impedance
+Ib=V/Zb
+phi_b=0
+mprintf("Current in branch A, Ia=%f A lagging the applied voltage by %f degrees\nCurrent in branch B, Ib=%f A in phase with applied voltage\n",Ia, phi_a,Ib)
+//calculating current drawn by the circuit
+Ia=pol2rect(Ia,phi_a)
+Ib=pol2rect(Ib,0)
+I=Ia+Ib
+mprintf("Total current drawn by the circuit=%f A\n", mag(I))
+phi=atand(imag(I)/real(I))
+mprintf("Phase angle of combination=%f degrees and power factor =%f lagging",phi,cos(phi*%pi/180))
diff --git a/2252/CH8/EX8.10/Ex8_10.sce b/2252/CH8/EX8.10/Ex8_10.sce new file mode 100755 index 000000000..f4e72beb1 --- /dev/null +++ b/2252/CH8/EX8.10/Ex8_10.sce @@ -0,0 +1,48 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+//calculating impedance of overall circuit
+Za=2+0*j//impedance of branch A
+Zb=3+4*j//impedance of branch B
+Zab=Za*Zb/(Za+Zb)//equivalent impedances of branches A and B
+Zc=2-2*j
+Z1=Zab*Zc/(Zab+Zc)//equivalent impedance of parallel circuit
+Zd=1+1*j//impedance of branch D
+Z=Z1+Zd
+[Z theta]=rect2pol(Z)
+mprintf("Total impedance of overall circuit=%f ohm at angle %f degrees\n", Z,theta)
+//calculating current taken by overall circuit
+V=110//voltage applied to the overall circuit
+I=V/Z
+mprintf("Current taken by the overall circuit=%f A\n", I)
+//Calculating power consumed in each branch and total power consumed
+Id=I//current in the series branch
+Rd=1//resistance of branch D
+Pd=I^2*Rd//power consumed by branch D
+Ia=I*mag(Z1)/mag(Za)//current in branch A
+Ib=I*mag(Z1)/mag(Zb)//current in branch B
+Ic=I*mag(Z1)/mag(Zc)//current in branch C
+Ra=2
+Pa=Ia^2*Ra
+Rb=3
+Pb=Ib^2*Rb
+Rc=2
+Pc=Ic^2*Rc
+P=Pa+Pb+Pc+Pd
+mprintf("Power consumed by branch A=%f W,\nPower consumed by branch B=%f W,\nPower consumed by branch C=%f W,\nPower consumed by branch D=%f W,\nTotal power consumed=%f W",Pa,Pb,Pc,Pd,P)
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH8/EX8.11/Ex8_11.sce b/2252/CH8/EX8.11/Ex8_11.sce new file mode 100755 index 000000000..84e1df88b --- /dev/null +++ b/2252/CH8/EX8.11/Ex8_11.sce @@ -0,0 +1,33 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+//using Maxwell's mesh analysis
+//refer Fig.8.14 in the textbook
+//considering mesh FDCEF, (18+8*j)*I1-(10+8*j)*I2=24
+//considering mesh ABCDA, (10+8*j)*I1-(14+10*j)*I2=0
+a=[18+8*j -(10+8*j);10+8*j -(14+10*j)]
+b=[24;0]
+x=inv(a)*b
+I1=x(1,1)
+I2=x(2,1)
+[I2 theta]=rect2pol(I2)
+mprintf("By Maxwell Mesh Analysis, current in branch AB of the circuit shown is %f A, lagging the applied voltage by %f degrees\n",I2, -theta)
+//using thevenin's theorem
+//refer Fig.8.14(a),(b) and (c)
+Zth=8*(10+8*j)/(8+10+8*j)+(-4*j)//thevenin's impedance
+//for calculating the equivalent Thevenin's voltage Vth, I1 be the current flowing in the branch CD
+I1=24/(8+10+8*j)
+Vth=I1*(10+8*j)//equivalent thevenin's voltage
+I=Vth/((4+6*j+Zth))
+[I theta]=rect2pol(I)
+mprintf("By Thevenin Theorem, current in the branch AB is %f A lagging the voltage by %f degrees\n",I,-theta)
diff --git a/2252/CH8/EX8.12/Ex8_12.sce b/2252/CH8/EX8.12/Ex8_12.sce new file mode 100755 index 000000000..b95c37a56 --- /dev/null +++ b/2252/CH8/EX8.12/Ex8_12.sce @@ -0,0 +1,29 @@ +
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+V=200
+//calculating supply frequency
+L=.1//inductance of branch A
+//Xa=2*%pi*f*.1
+Ra=10//resistance of branch A
+C=150D-6//capacitance of branch B
+//Xb=1/(2*%pi*f*150D-6)
+Rb=0//resistance of branch B
+//Zb=-Xb*j
+//total current I=Ia+Ib, total current is in phase with voltage-->j component of I=0
+//on solving for f,
+f=sqrt((V*2*%pi*L)*(1/(2*%pi*C))/V-Ra^2)/(2*%pi*L)
+mprintf("Frequency of the supply which is also the resonant frequency, f=%f Hz\n", f)
+Xa=2*%pi*f*.1
+Za=Ra+Xa*j
+Ia=V/Za
+Xb=1/(2*%pi*f*150D-6)
+Zb=-Xb*j
+Ib=V/Zb
+I=Ia+Ib
+mprintf("Total current drawn by the circuit=%f A", mag(I))
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH8/EX8.13/Ex8_13.sce b/2252/CH8/EX8.13/Ex8_13.sce new file mode 100755 index 000000000..cb2856476 --- /dev/null +++ b/2252/CH8/EX8.13/Ex8_13.sce @@ -0,0 +1,31 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+//calculating branch currents
+Z1=15+12*j//impedance of branch 1
+I1=200/Z1
+phi1=atand(12/15)
+Z2=25-17*j//impedance of branch 2
+I2=200/Z2
+phi2=atand(17/25)
+mprintf("I1=%f A at angle of %f degrees\nI2=%f A at angle of %f degrees\n",mag(I1),phi1,mag(I2),phi2)
+//calculating total current
+I=I1+I2
+[I phi]=rect2pol(I)
+mprintf("Total current drawn by the circuit I=%f A, angle of lag=%f degrees and power factor=%f lagging\n",I,-phi,cos(phi*%pi/180))
+//power factor is to be raised to unity-a capacitor has to be connected in parallel
+//at unity power factor, imaginary part of I must be zero
+Xc=-200/imag(I1+I2)
+f=40
+C=1/(2*%pi*f*Xc)
+mprintf("If power factor is to be raised to unity-a capacitor of %f microF has to be connected in parallel to given circuit", C*1D+6)
diff --git a/2252/CH8/EX8.2/Ex8_2.sce b/2252/CH8/EX8.2/Ex8_2.sce new file mode 100755 index 000000000..d20d9c86c --- /dev/null +++ b/2252/CH8/EX8.2/Ex8_2.sce @@ -0,0 +1,38 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+//solving part (i)
+Xa=2*%pi*50*.1//inductive reactance of branch A
+Za=sqrt(50^2+Xa^2)
+Ia=230/Za
+phi_a=atand(Xa/50)//angle of lag of Ia w.r.t. applied voltage
+Ia=pol2rect(Ia,-phi_a)
+Xb=1/(2*%pi*50*100D-6)//capacitive reactance of branch B
+Zb=sqrt(45^2+Xb^2)
+Ib=230/Zb
+phi_b=atand(Xb/45)//angle of lead of Ib w.r.t. applied voltage
+Ib=pol2rect(Ib,phi_b)
+I=Ia+Ib
+mprintf("Current drawn by the circuit=%f A\n", mag(I))
+//calculating power factor
+phi=atan(imag(I)/real(I))//phase angle of the circuit
+pf=cos(phi)
+mprintf("Power factor of the circuit=%f(leading)\n",pf)
+//calculating power taken by the parallel circuit
+P=230*mag(I)*pf
+mprintf("Power taken by the parallel circuit=%d W", round(P))
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH8/EX8.3/Ex8_3.sce b/2252/CH8/EX8.3/Ex8_3.sce new file mode 100755 index 000000000..f55997510 --- /dev/null +++ b/2252/CH8/EX8.3/Ex8_3.sce @@ -0,0 +1,44 @@ +
+
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+//calculating current in coil A
+Xa=2*%pi*50*.02//inductive reactance of coil A
+Za=sqrt(12^2+Xa^2)
+Ia=200/Za
+phi_a=atand(Xa/12)//angle of lag of Ia w.r.t. applied voltage
+mprintf("Ia=%f A, lagging the applied voltage by %f degrees\n", Ia, phi_a)
+//calculating current in coil B
+Xb=2*%pi*50*.03//inductive reactance of coil B
+Zb=sqrt(6^2+Xb^2)
+Ib=200/Zb
+phi_b=atand(Xb/6)//angle of lag of Ib w.r.t. applied voltage
+mprintf("Ib=%f A, lagging the applied voltage by %f degrees\n", Ib, phi_b)
+//calculating total current in the circuit
+Ia=pol2rect(Ia,-phi_a)
+Ib=pol2rect(Ib,-phi_b)
+I=Ia+Ib
+mprintf("Total current drawn by circuit=%f A lagging the applied voltage by %f degrees\n", mag(I),-atand(imag(I)/real(I)))
+//calculating total current when additional circuit is added
+Xc=1/(2*%pi*50*120D-6)//capacitive reactance
+Zc=sqrt(15^2+Xc^2)
+Ic=200/Zc
+phi_c=atand(Xc/15)//angle of lag of Ic w.r.t. applied voltage
+Ic=pol2rect(Ic,phi_c)
+I=Ia+Ib+Ic
+phi=atand(imag(I)/real(I))
+mprintf("For the new circuit, total current drawn=%f A lagging the applied voltage by %f degrees, i.e. pf=%f(lagging)", mag(I),-phi,cos(phi*%pi/180))
diff --git a/2252/CH8/EX8.4/Ex8_4.sce b/2252/CH8/EX8.4/Ex8_4.sce new file mode 100755 index 000000000..8f48fa02f --- /dev/null +++ b/2252/CH8/EX8.4/Ex8_4.sce @@ -0,0 +1,47 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+//for coil A
+Ia=5//current taken
+Va=110//voltage applied
+Pa=300//power dissipated
+Ra=Pa/Ia^2
+Za=Va/Ia
+Xa=sqrt(Za^2-Ra^2)
+//for coil B
+Ib=5//current taken
+Vb=110//voltage applied
+Pb=400//power dissipated
+Rb=Pb/Ib^2
+Zb=Vb/Ib
+Xb=sqrt(Zb^2-Rb^2)
+//calculating current drawn and power factor when coils conected in series
+R=Ra+Rb
+Xl=Xa+Xb
+Z=sqrt(R^2+Xl^2)//impedance of series circuit
+I=Va/Z
+pf=R/Z
+mprintf("Current in the series circuit=%f A at pf=%f lagging\n", I,pf)
+//calculating current drawn and power factor when coils conected in parallel
+Ia=pol2rect(Ia,-acosd(Ra/Za))
+Ib=pol2rect(Ib,-acosd(Rb/Zb))
+I=Ia+Ib
+phi=atan(imag(I)/real(I))
+mprintf("Total current drawn by the parallel circuit=%f A at pf=%f(lagging)", mag(I),cos(phi))
+
+
+
diff --git a/2252/CH8/EX8.5/Ex8_5.sce b/2252/CH8/EX8.5/Ex8_5.sce new file mode 100755 index 000000000..a4933df80 --- /dev/null +++ b/2252/CH8/EX8.5/Ex8_5.sce @@ -0,0 +1,36 @@ +
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+//solving part (i)
+//for coil 1
+Z1=5+2*%pi*50*.03*j//impedance
+Y1=1/Z1
+G1=real(Y1)
+B1=imag(Y1)
+mprintf("For coil 1,\nConductance=%f mho\nSuspectance=%f mho\nAdmittance=%f mho\n", G1,-B1,mag(Y1))
+//for coil 2
+Z2=3+2*%pi*50*.04*j//impedance
+Y2=1/Z2
+G2=real(Y2)
+B2=imag(Y2)
+mprintf("For coil 2,\nConductance=%f mho\nSuspectance=%f mho\nAdmittance=%f mho\n", G2,-B2,mag(Y2))
+//solving part(ii)
+Y=Y1+Y2//total admittance
+I=200*Y
+phi=atan(imag(I)/real(I))
+pf=cos(phi)
+mprintf("Total current drawn by the circuit=%f A at pf of %f(lagging)\n",mag(I),pf)
+//calculating power
+P=200*mag(I)*pf
+mprintf("Power absorbed by the circuit=%f W\n",P)
+//solving part(iv)
+Z=1/Y
+R=real(Z)
+Xl=imag(Z)
+L=Xl/(2*%pi*50)
+mprintf("R=%f ohm, L=%f H of single coil which will take the same current and power as taken by the original circuit",R,L)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH8/EX8.6/Ex8_6.sce b/2252/CH8/EX8.6/Ex8_6.sce new file mode 100755 index 000000000..486ff171a --- /dev/null +++ b/2252/CH8/EX8.6/Ex8_6.sce @@ -0,0 +1,27 @@ +
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+//voltage V is taken as reference phasor
+Z1=5+10*j//impedance of inductive branch
+Z2=10-15*j//impedance of capacitive branch
+I=20//total current
+V=I/mag(1/Z1+1/Z2)
+mprintf("Applied voltage=%f V\n",V)
+//calculating power factor of total current
+I1=V/Z1
+I2=V/Z2
+I=I1+I2
+phi=atan(imag(I)/real(I))//angle of lag
+pf=cos(phi)
+mprintf("Power factor of the total circuit=%f(lagging)\n",pf)
+//calculating power taken by each branch
+R1=5//resistance of branch 1
+P1=mag(I1)^2*R1
+R2=10//resistance of branch 2
+P2=mag(I2)^2*R2
+mprintf("Power taken by inductive branch=%f W\nPower taken by capacitive branch=%f W", P1,P2)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH8/EX8.7/Ex8_7.sce b/2252/CH8/EX8.7/Ex8_7.sce new file mode 100755 index 000000000..77e86860a --- /dev/null +++ b/2252/CH8/EX8.7/Ex8_7.sce @@ -0,0 +1,33 @@ +
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+//for coil A
+Va=10//voltage applied
+Ia=2//current taken
+pf=.8//lagging power factor
+Ia=pol2rect(Ia,-acosd(pf))
+Za=Va/Ia//impedance
+//for coil B
+Vb=5//voltage applied
+Ib=2//current taken
+pf=.7//lagging power factor
+Ib=pol2rect(2,-acosd(pf))
+Zb=Vb/Ib//impedance
+//calculating voltage required to produce a current of 2 A with A and B in series
+I=2
+Z=Za+Zb//impedance of series circuit
+V=I*mag(Z)
+mprintf("Voltage required to produce a current of 2 A with A and B in series=%f V\n", V)
+//calculating voltage required to produce a current of 2 A with A and B in parallel
+Z=Za*Zb/(Za+Zb)//impedance of parallel circuit
+V=I*mag(Z)
+mprintf("Voltage required to produce a current of 2 A with A and B in parallel=%f V\n", V)
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH8/EX8.8/Ex8_8.sce b/2252/CH8/EX8.8/Ex8_8.sce new file mode 100755 index 000000000..8e2ee65eb --- /dev/null +++ b/2252/CH8/EX8.8/Ex8_8.sce @@ -0,0 +1,15 @@ +
+//calculating value of unknown capacitance
+V=110//applied voltage
+R=30//resistance of resistive circuit
+Ir=V/R//Ohm's Law
+I=5//total current drawn
+Xc=V/sqrt(I^2-Ir^2)
+f=50//frequency of supply
+C=1/(2*%pi*f*Xc)
+mprintf("Capacitance=%f microF\n",C*10^6)
+//calculating unknown frequency
+I=4//total current drawn
+f=sqrt(I^2-Ir^2)/(V*2*%pi*C)
+mprintf("To decrease the total current to 4 A, the frequency of the supply should be adjusted to %f Hz",f)
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH8/EX8.9/Ex8_9.sce b/2252/CH8/EX8.9/Ex8_9.sce new file mode 100755 index 000000000..b3664b036 --- /dev/null +++ b/2252/CH8/EX8.9/Ex8_9.sce @@ -0,0 +1,26 @@ +
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+
+j=%i
+R1=12//resistance of series circuit
+X1=2*%pi*50*.025//inductive reactance of the series circuit
+Z1=R1+X1*j
+pf1=R1/mag(Z1)//power factor of the series circuit(lagging)
+//the impedances and power factor of the parallel circuit are to be same as that of series circuit
+//on solving, we get, R*Xl/sqrt(R^2+Xl^2)=mag(Z1); Xl/(sqrt(R^2+Xl^2))=pf1
+R=mag(Z1)/pf1
+//solving for Xl
+Xl=pf1*R/sqrt(1-pf1^2)
+L=Xl/(2*%pi*50)
+mprintf("Resistance=%f ohm; Inductance=%f H\n",R,L)
+//calculating current in each case
+V=230//applied voltage
+I1=V/mag(Z1)
+mprintf("Current in series circuit=%f A\n",I1)
+I2=V/mag(Z1)
+mprintf("Current drawn by parallel circuit=%f A",I2)
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH9/EX9.1/Ex9_1.sce b/2252/CH9/EX9.1/Ex9_1.sce new file mode 100755 index 000000000..6f76c11a1 --- /dev/null +++ b/2252/CH9/EX9.1/Ex9_1.sce @@ -0,0 +1,26 @@ +
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+
+j=%i
+//considering coils to be star connected
+Vl=400//line voltage
+Vph=Vl/sqrt(3)
+Rph=15//resistance of load
+Xl=2*%pi*50*.03//inductive reactance of each coil
+Zph=Rph+Xl*j
+Iph=Vph/mag(Zph)
+Il=Iph
+pf=Rph/mag(Zph)//power factor
+P=sqrt(3)*Vl*Il*pf
+mprintf("In star connected circuit,\nPhase current=%f A,\nLine current=%f A,\nPower absorbed=%f kW\n", Iph, Il,P/10^3)
+//considering coils to be delta connected
+Vph=Vl
+Iph=Vph/mag(Zph)
+Il=sqrt(3)*Iph
+P=sqrt(3)*Vl*Il*pf
+mprintf("In delta connected circuit,\nPhase current=%f A,\nLine current=%f A,\nPower absorbed=%f kW\n", Iph, Il,P/10^3)
+//answers vary from the textbook due to round off error
diff --git a/2252/CH9/EX9.10/Ex9_10.sce b/2252/CH9/EX9.10/Ex9_10.sce new file mode 100755 index 000000000..d9e02295f --- /dev/null +++ b/2252/CH9/EX9.10/Ex9_10.sce @@ -0,0 +1,20 @@ +
+//calculating phase voltage
+Vl=440//line voltage
+Vph=Vl/sqrt(3)//star connected circuit
+mprintf("Phase voltage=%f V\n", Vph)
+Iph=20//phase current
+Zph=Vph/Iph//impedance of load per phase
+//calculating load parameters-current in each phase lags behind its voltage by 40 degrees
+//on solving for R
+R=Zph/sqrt(1+(tan(40*%pi/180))^2)
+X=R*tan(40*%pi/180)
+mprintf("Load parameters are\nR=%f ohm\nX=%f ohm\n",R,X)
+//calculating total power
+P=3*Vph*Iph*cos(40*%pi/180)
+mprintf("Total power consumed=%f kW\n",P*10^-3)
+//calculating W1 and W2-->W1+W2=P, W1-W2=P*tan(phi)/sqrt(3)
+a=[1 1;1 -1]
+b=[P;P*tan(40*%pi/180)/sqrt(3)]
+w=inv(a)*b
+mprintf("W1=%f kW,\nW2=%f kW", w(1,1)/1000, w(2,1)/1000)
diff --git a/2252/CH9/EX9.11/Ex9_11.sce b/2252/CH9/EX9.11/Ex9_11.sce new file mode 100755 index 000000000..94e27e8fc --- /dev/null +++ b/2252/CH9/EX9.11/Ex9_11.sce @@ -0,0 +1,15 @@ +
+Pout=37.3D+3//power output
+e=.88//efficiency
+Pin=Pout/e//input power
+pf=.82//power factor
+phi=acosd(pf)
+//calculating W1 and W2-->W1+W2=Pin, W1-W2=Pin*tan(phi)/sqrt(3)
+a=[1 1;1 -1]
+b=[Pin;Pin*tan(phi*%pi/180)/sqrt(3)]
+w=inv(a)*b
+mprintf("Readings of two wattmeters are:\nW1=%f kW,\nW2=%f kW\n", w(1,1)/1000, w(2,1)/1000)
+Vl=440//line voltage
+Il=Pin/(sqrt(3)*Vl*pf)
+mprintf("Full load line current=%f A", Il)
+
diff --git a/2252/CH9/EX9.12/Ex9_12.sce b/2252/CH9/EX9.12/Ex9_12.sce new file mode 100755 index 000000000..dde16cc34 --- /dev/null +++ b/2252/CH9/EX9.12/Ex9_12.sce @@ -0,0 +1,27 @@ +
+//considering star connected circuit
+Rph=20//resistance of coil
+Xph=15//reactance of coil
+Vl=400//line voltage
+Vph=Vl/sqrt(3)//phase voltage
+Zph=sqrt(Rph^2+Xph^2)//impedance per phase
+Iph=Vph/Zph//phase current
+Il=Iph//line current
+pf=Rph/Zph//power factor
+phi=acosd(pf)
+Pin=sqrt(3)*Vl*Il*pf//input power
+//calculating W1 and W2-->W1+W2=Pin, W1-W2=Pin*tan(phi)/sqrt(3)
+a=[1 1;1 -1]
+b=[Pin;Pin*tan(phi*%pi/180)/sqrt(3)]
+w=inv(a)*b
+mprintf("Readings of two wattmeters in case of star connection are\nW1=%f W,\nW2=%f W\n", w(1,1), w(2,1))
+//considering delta connected circuit
+Iph=Vl/Zph//phase current
+Il=sqrt(3)*Iph//line current
+Pin=sqrt(3)*Vl*Il*pf//input power
+//calculating W1 and W2-->W1+W2=Pin, W1-W2=Pin*tan(phi)/sqrt(3)
+a=[1 1;1 -1]
+b=[Pin;Pin*tan(phi*%pi/180)/sqrt(3)]
+w=inv(a)*b
+mprintf("Readings of two wattmeters in case of delta connection are\nW1=%f W,\nW2=%f W", w(1,1), w(2,1))
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH9/EX9.2/Ex9_2.sce b/2252/CH9/EX9.2/Ex9_2.sce new file mode 100755 index 000000000..ceb9158ab --- /dev/null +++ b/2252/CH9/EX9.2/Ex9_2.sce @@ -0,0 +1,18 @@ +
+//calculating phase current
+Vl=440//line voltage
+Vph=Vl
+Pout=200D+3//output
+e=.91//efficiency
+Pin=Pout/e//input
+pf=.86//power factor
+Iph=Pin/(3*Vph*pf)
+mprintf("Current drawn by each motor phase=%f A\n", Iph)
+//calculating line current
+Il=sqrt(3)*Iph
+mprintf("Line current=%f A\n", Il)
+//calculating active and reactive components of phase current
+phi=acos(pf)
+Iact=Iph*pf
+Ireact=Iph*sin(phi)
+mprintf("Active component of phase current=%f A\nReactive component of phase current=%f A",Iact,Ireact)
diff --git a/2252/CH9/EX9.3/Ex9_3.sce b/2252/CH9/EX9.3/Ex9_3.sce new file mode 100755 index 000000000..34a7e72d7 --- /dev/null +++ b/2252/CH9/EX9.3/Ex9_3.sce @@ -0,0 +1,23 @@ +
+Vl=400//line voltage across alternator and motor
+Vph=Vl//as the motor is delta connected
+Pout=112D+3//output of motor
+e=.88//efficiency of motor
+Pin=Pout/e//input to motor
+pf=.86
+phi=acos(pf)
+Il=Pin/(sqrt(3)*Vl*pf)
+Iph=Il/sqrt(3)
+mprintf("Current in each motor phase, Iph=%f A\n", Iph)
+//alternator is star connected
+mprintf("Current in each alternator phase=%f A\n",Il)
+//calculating active and reactive components of current in each phase of motor
+Iact=Iph*pf
+Ireact=Iph*sin(phi)
+mprintf("Active component of current in each phase of motor=%f A\nReactive component of current in each phase of motor=%f A\n", Iact,Ireact)
+//phase angle between the phase voltage and phase current will be the same for both motor and alternator if we neglect line impedance
+Iph=Il
+Iact=Iph*pf
+Ireact=Iph*sin(phi)
+mprintf("Active component of current in each phase of alternator=%f A\nReactive component of current in each phase of alternator=%f A\n", Iact,Ireact)
+//The answers vary from the textbook due to round off error
diff --git a/2252/CH9/EX9.4/Ex9_4.sce b/2252/CH9/EX9.4/Ex9_4.sce new file mode 100755 index 000000000..9198ec85b --- /dev/null +++ b/2252/CH9/EX9.4/Ex9_4.sce @@ -0,0 +1,25 @@ +
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+
+//calculating current in each line
+Vl=400//line voltage
+Vph=Vl/sqrt(3)//phase voltage
+Ir=8D+3/Vph
+Iy=6D+3/Vph
+Ib=4D+3/Vph
+mprintf("Current in R-phase,Ir=%f A\nCurrent in Y-phase,Iy=%f A\nCurrent in B-phase,Ib=%f A\n",Ir,Iy,Ib)
+//Loads on three phases are resistive
+Ir=pol2rect(Ir,0)
+Iy=pol2rect(Iy,-120)
+Ib=pol2rect(Ib,-240)
+In=Ir+Iy+Ib
+mprintf("Current in the neutral=%f A", mag(In))
diff --git a/2252/CH9/EX9.5/Ex9_5.sce b/2252/CH9/EX9.5/Ex9_5.sce new file mode 100755 index 000000000..cca135052 --- /dev/null +++ b/2252/CH9/EX9.5/Ex9_5.sce @@ -0,0 +1,10 @@ + +Pout=30D+3//output
+e=.86//efficiency
+Pin=Pout/e//input
+Vl=440//line voltage
+pf=.83//power factor
+Il=Pin/(sqrt(3)*Vl*pf)
+mprintf("Line current=%f A\n", Il)
+Iph=Il/sqrt(3)//motor is delta connected
+mprintf("Phase current=%f A", Iph)
diff --git a/2252/CH9/EX9.6/Ex9_6.sce b/2252/CH9/EX9.6/Ex9_6.sce new file mode 100755 index 000000000..87df8bfd4 --- /dev/null +++ b/2252/CH9/EX9.6/Ex9_6.sce @@ -0,0 +1,48 @@ +
+function[r,theta]=rect2pol(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+ theta=atand(y/x)
+endfunction
+function[z]=pol2rect(r,theta)
+ x=r*cos(theta*%pi/180)
+ y=r*sin(theta*%pi/180)
+ z=x+y*%i
+endfunction
+function[r]=mag(A)
+ x=real(A)
+ y=imag(A)
+ r=sqrt(x^2+y^2)
+endfunction
+j=%i
+//calculating phase currents-let the sequence be RYB
+Vl=440//line voltage
+Vph=Vl//delta connected load
+Zph1=150//impedance of the phase between A and B(resistive)
+I1=Vph/Zph1
+mprintf("I1=%f A at 0 degrees w.r.t. Vry\n", I1)
+Zph2=30+50*j//impedance of the phase between B and C
+I2=Vph/mag(Zph2)
+//as the load is inductive, current will lag the voltage Vyb by phi2
+phi2=atand(50/30)
+mprintf("I2=%f A at -%f degrees w.r.t. Vyb\n", I2,phi2)
+C=20D-6
+f=50
+Xc=-(1/(2*%pi*f*C))*j
+I3=Vph/mag(Xc)
+//as the load is capacitive, current will lead the voltage Vbr by 90 degrees
+mprintf("I3=%f A at 90 degrees w.r.t. Vbr\n", I3)
+
+//calculating line currents-
+Vry=pol2rect(440,0)
+Vyb=pol2rect(440,-120)
+Vbr=pol2rect(440,-240)
+I1=Vry/Zph1
+I2=Vyb/Zph2
+I3=Vbr/Xc
+//using KCL
+Ir=I1-I3
+Iy=I2-I1
+Ib=I3-I2
+mprintf("Current in line R, Ir=%f A,\nCurrent in line Y, Iy=%f A,\nCurrent in line B, Ib=%f A,\n", mag(Ir),mag(Iy),mag(Ib))
diff --git a/2252/CH9/EX9.7/Ex9_7.sce b/2252/CH9/EX9.7/Ex9_7.sce new file mode 100755 index 000000000..b24cfadd5 --- /dev/null +++ b/2252/CH9/EX9.7/Ex9_7.sce @@ -0,0 +1,14 @@ +
+Vl=1100//line voltage
+Vph=Vl/sqrt(3)//star connected load
+Il=80//current through load
+Iph=Il
+Zph=Vph/Iph
+P=100D+3//power drawn by load
+pf=P/(sqrt(3)*Vl*Il)//power factor
+Rph=Zph*pf
+Xc=sqrt(Zph^2-Rph^2)
+f=50
+C=1/(2*%pi*f*Xc)
+mprintf("Capacitance per phase=%f microF", C*10^6)
+//Answer vary from the textbook due to round off error
diff --git a/2252/CH9/EX9.8/Ex9_8.sce b/2252/CH9/EX9.8/Ex9_8.sce new file mode 100755 index 000000000..bd65498ba --- /dev/null +++ b/2252/CH9/EX9.8/Ex9_8.sce @@ -0,0 +1,7 @@ +
+W1=15D+3//reading of first wattmeter
+W2=-1.5D+3//reading of second wattmeter
+W=W1+W2//total power fed to the load
+mprintf("Total power fed to the load=%f kW\n",W/10^3)
+phi=atand(sqrt(3)*(W1-W2)/W)
+mprintf("Power factor angle, phi=%f degrees\nPower factor of load=%f", phi, cos(phi*%pi/180))
diff --git a/2252/CH9/EX9.9/Ex9_9.sce b/2252/CH9/EX9.9/Ex9_9.sce new file mode 100755 index 000000000..540b3445f --- /dev/null +++ b/2252/CH9/EX9.9/Ex9_9.sce @@ -0,0 +1,16 @@ +
+W1=115D+3
+W2=50D+3
+//calculating input to motor
+W=W1+W2
+mprintf("Power input to the motor=%f kW\n", W/1000)
+//calculating power factor
+phi=atand(sqrt(3)*(W1-W2)/(W1+W2))
+mprintf("Power factor angle, phi=%f degrees\nPower factor of load=%f A\n", phi, cos(phi*%pi/180))
+//calculating line current
+Il=W/(sqrt(3)*440*cos(phi*%pi/180))
+mprintf("Line current drawn by the motor=%f A\n",Il)
+//calculating efficiency
+Pout=150D+3//output of motor
+e=Pout/W*100
+mprintf("Efficiency of the induction motor=%f percent",e )
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