{
"metadata": {
"name": "",
"signature": "sha256:3ac2c23233482dc3087073e89bf82acd0d43f65ffc269ad874ae8200d4170ec2"
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter6-Three phase Circuits"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex8-pg6.14"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.8 :(pg 6.14)\n",
"VL=440.;\n",
"import math\n",
"P=50*10**3;\n",
"IL=90.;\n",
"Iph=IL/math.sqrt(3);\n",
"pf=(P/(math.sqrt(3)*VL*IL));\n",
"S=math.sqrt(3)*VL*IL;\n",
"print(\"\\nVL=440 V \\nP=50kW \\nIL=90 A\");\n",
"print\"%s %.2f %s\"%(\"\\nVL=Vph=\",VL,\" V\");##For delta-connected load\n",
"print\"%s %.2f %s\"%(\"\\nIph=IL/sqrt(3)=\",Iph,\" A\");\n",
"print(\"\\nP=sqrt(3)*VL*IL*cos(phi)\");\n",
"print\"%s %.2f %s\"%(\"\\ncos(phi)=\",pf,\" (lagging)\");\n",
"print\"%s %.2f %s\"%(\"\\nS=sqrt(3)*VL*IL =\",S,\" VA\");"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"VL=440 V \n",
"P=50kW \n",
"IL=90 A\n",
"\n",
"VL=Vph= 440.00 V\n",
"\n",
"Iph=IL/sqrt(3)= 51.96 A\n",
"\n",
"P=sqrt(3)*VL*IL*cos(phi)\n",
"\n",
"cos(phi)= 0.73 (lagging)\n",
"\n",
"S=sqrt(3)*VL*IL = 68589.21 VA\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex9-pg6.15"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.9 :(pg 6.15)\n",
"IL=15.;\n",
"import math\n",
"P=11.*10**3;\n",
"S=15.*10**3;\n",
"VL=S/(math.sqrt(3.)*IL);\n",
"Vph=VL/math.sqrt(3.);\n",
"x=(P/S)*57.3;\n",
"phi=math.acos(P/S);\n",
"Q=math.sqrt(3.)*VL*IL*math.sin(phi/57.3);\n",
"Iph=IL;\n",
"Zph=Vph/Iph;\n",
"R=Zph*math.cos(phi/57.3);\n",
"XL=Zph*math.sin(phi/57.3);\n",
"Vph1=VL;\n",
"Iph1=(Vph1/Zph);\n",
"IL1=math.sqrt(3.)*Iph1;\n",
"P1=math.sqrt(3.)*VL*IL1*math.cos(phi/57.3);\n",
"Q1=math.sqrt(3.)*VL*IL1*math.sin(phi/57.3);\n",
"print(\"\\nIL=15 A \\nP=11kW \\nS=15kVA \");\n",
"##For a star-connected load\n",
"print\"%s %.2f %s\"%(\"\\nS=sqrt(3)*VL*IL \\nVL=\",Vph,\" V\");\n",
"print\"%s %.2f %s\"%(\"\\ncos(phi)=P/S =\",x,\"\");\n",
"print\"%s %.3f %s\"%(\"\\nphi=\",phi,\" degrees\"); \n",
"print\"%s %.2f %s\"%(\"\\nQ=sqrt(3).VL.IL.sin(phi) = \",Q,\" VAR\");\n",
"print\"%s %.2f %s\"%(\"\\nIph=IL = \",IL,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nZph=Vph/Iph = \",Zph,\" Ohm\");\n",
"print\"%s %.2f %s\"%(\"\\nR= Zph*cos(phi) =\",R,\" Ohm\");\n",
"print\"%s %.2f %s\"%(\"\\nXL=Zph*sin(phi)= \",XL,\" Ohm\");\n",
"##If these coils are connected in Delta \n",
"print\"%s %.2f %s\"%(\"\\nCph =VL =\",VL,\" V\");\n",
"print\"%s %.2f %s\"%(\"\\nZph= \",Zph,\" Ohm\");\n",
"print\"%s %.2f %s\"%(\"\\nIph=Vph/Zph =\",Iph1,\" A \");\n",
"print\"%s %.2f %s\"%(\"\\nIL=sqrt(3)*Iph =\",IL1,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nP=sqrt(3)*VL*IL*cos(phi) =\",P1,\" W\");\n",
"print\"%s %.2f %s\"%(\"\\nQ=sqrt(3)*VL*IL*sin(phi) =\",Q1,\" VAR\");\n",
"\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"IL=15 A \n",
"P=11kW \n",
"S=15kVA \n",
"\n",
"S=sqrt(3)*VL*IL \n",
"VL= 333.33 V\n",
"\n",
"cos(phi)=P/S = 42.02 \n",
"\n",
"phi= 0.748 degrees\n",
"\n",
"Q=sqrt(3).VL.IL.sin(phi) = 195.70 VAR\n",
"\n",
"Iph=IL = 15.00 A\n",
"\n",
"Zph=Vph/Iph = 22.22 Ohm\n",
"\n",
"R= Zph*cos(phi) = 22.22 Ohm\n",
"\n",
"XL=Zph*sin(phi)= 0.29 Ohm\n",
"\n",
"Cph =VL = 577.35 V\n",
"\n",
"Zph= 22.22 Ohm\n",
"\n",
"Iph=Vph/Zph = 25.98 A \n",
"\n",
"IL=sqrt(3)*Iph = 45.00 A\n",
"\n",
"P=sqrt(3)*VL*IL*cos(phi) = 44996.17 W\n",
"\n",
"Q=sqrt(3)*VL*IL*sin(phi) = 587.09 VAR\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex10-pg6.15"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.10 :(pg 6.16)\n",
"P=1500.*10**3;\n",
"import math\n",
"pf=0.85;\n",
"VL=2.2*10**3;\n",
"phi=math.acos(pf)*57.3;\n",
"IL=P/(math.sqrt(3.)*VL*pf);\n",
"Iph=IL/math.sqrt(3.);\n",
"AC=Iph*pf;\n",
"RC=Iph*math.sin(phi/57.3);\n",
"IAC=IL*pf;\n",
"IRC=IL*math.sin(phi/57.3);\n",
"print(\"\\nP=1500kW \\npf=0.85 (lagging) \\nVL=2.2kV\");\n",
"##For Delta-connected load\n",
"print\"%s %.2f %s\"%(\"\\nP=sqrt(3)*VL*IL*cos(phi) \\nIL=\",IL,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nIph=IL/sqrt(3)= \",Iph,\" A\");\n",
"##AC=Active Component\n",
"print\"%s %.2f %s\"%(\"\\nAC=Iph*cos(phi) = \",AC,\" A\"); ##in each phase of load\n",
"##RC=Reactive Component\n",
"print\"%s %.2f %s\"%(\"\\nRC=Iph*sin(phi) = \",RC,\" A\"); ##in each phase of load\n",
"##For star-connected source\n",
"print\"%s %.2f %s\"%(\"\\nIAC = \",IAC,\" A\"); ## current of AC in each phase of source\n",
"print\"%s %.2f %s\"%(\"\\nIRC = \",IRC,\"A\"); ## current of RC in each phase of source"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"P=1500kW \n",
"pf=0.85 (lagging) \n",
"VL=2.2kV\n",
"\n",
"P=sqrt(3)*VL*IL*cos(phi) \n",
"IL= 463.12 A\n",
"\n",
"Iph=IL/sqrt(3)= 267.38 A\n",
"\n",
"AC=Iph*cos(phi) = 227.27 A\n",
"\n",
"RC=Iph*sin(phi) = 140.85 A\n",
"\n",
"IAC = 393.65 A\n",
"\n",
"IRC = 243.96 A\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex11-pg6.16"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.11 :(pg 6.16)\n",
"import math\n",
"VL=208.;\n",
"P=1800.;\n",
"IL=10.;\n",
"Vph=VL/math.sqrt(3.);\n",
"Zph=(Vph/IL);\n",
"pf=P/(math.sqrt(3.)*VL*IL);\n",
"phi=math.acos(pf)*57.3;\n",
"Rph=Zph*pf;\n",
"Xph=Zph*math.sin(phi/57.3);\n",
"print(\"\\nVL=208 V \\nP=1800 W \\nIL= 10 A\");\n",
"##For a Wye-connected load,\n",
"print\"%s %.2f %s\"%(\"\\nVph = VL/sqrt(3) = \",Vph,\" V\");\n",
"print\"%s %.2f %s\"%(\"\\nIph = IL = \",IL,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nZph=Vph/Iph = \",Zph,\" Ohm\");\n",
"print(\"\\nP=sqrt(3)*VL*IL*cos(phi)\");\n",
"print\"%s %.2f %s\"%(\"\\ncos(phi)= \",pf,\" degrees\");\n",
"print\"%s %.2f %s\"%(\"\\nphi= \",phi,\" degrees\");\n",
"print\"%s %.2f %s\"%(\"\\nRph=Zph*cos(phi) = \",Rph,\" Ohm\");\n",
"print\"%s %.2f %s\"%(\"\\nXph=Zph*sin(phi) = \",Xph,\" Ohm\");"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"VL=208 V \n",
"P=1800 W \n",
"IL= 10 A\n",
"\n",
"Vph = VL/sqrt(3) = 120.09 V\n",
"\n",
"Iph = IL = 10.00 A\n",
"\n",
"Zph=Vph/Iph = 12.01 Ohm\n",
"\n",
"P=sqrt(3)*VL*IL*cos(phi)\n",
"\n",
"cos(phi)= 0.50 degrees\n",
"\n",
"phi= 60.03 degrees\n",
"\n",
"Rph=Zph*cos(phi) = 6.00 Ohm\n",
"\n",
"Xph=Zph*sin(phi) = 10.40 Ohm\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex12-pg6.17"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.12 :(pg 6.17)\n",
"P=100.*10**3;\n",
"import math\n",
"IL=80.;\n",
"VL=1100.;\n",
"f=50.;\n",
"Vph=(VL/math.sqrt(3.));\n",
"Iph=IL;\n",
"Zph=(Vph/Iph);\n",
"pf=(P/(math.sqrt(3.)*VL*IL));\n",
"phi=math.acos(pf)*57.3;\n",
"Rph=Zph*pf;\n",
"Xph=Zph*math.sin(phi/57.3);\n",
"C=(1./(2.*math.pi*f*Xph));\n",
"print(\"\\nP=100kW \\nIL=80 A \\nVL=1100 V \\nf=50 Hz\");\n",
"##For a star-connected load\n",
"\n",
"print\"%s %.2f %s\"%(\"\\nIph=IL = \",Iph,\" A\");\n",
"\n",
"\n",
"\n",
"## as current is leading,reactance will be capacitive in nature\n",
"print(\"\\nXC=(1/2*pi*C)\");\n",
"print\"%s %.2e %s\"%(\"\\nC= \",C,\" F\");\n",
"\n",
"print\"%s %.2f %s\"%(\"\\nVph = VL/sqrt(3) = \",Vph,\" V\");\n",
"\n",
"print\"%s %.2f %s\"%(\"\\nZph=Vph/Iph = \",Zph,\" Ohm\");\n",
"print(\"\\nP=sqrt(3)*VL*IL*cos(phi)\");\n",
"print\"%s %.2f %s\"%(\"\\ncos(phi)= \",pf,\" degrees\");\n",
"print\"%s %.2f %s\"%(\"\\nphi= \",phi,\" degrees\");\n",
"print\"%s %.2f %s\"%(\"\\nRph=Zph*cos(phi) = \",Rph,\" Ohm\");\n",
"print\"%s %.2f %s\"%(\"\\nXph=Zph*sin(phi) = \",Xph,\" Ohm\");"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"P=100kW \n",
"IL=80 A \n",
"VL=1100 V \n",
"f=50 Hz\n",
"\n",
"Iph=IL = 80.00 A\n",
"\n",
"XC=(1/2*pi*C)\n",
"\n",
"C= 5.31e-04 F\n",
"\n",
"Vph = VL/sqrt(3) = 635.09 V\n",
"\n",
"Zph=Vph/Iph = 7.94 Ohm\n",
"\n",
"P=sqrt(3)*VL*IL*cos(phi)\n",
"\n",
"cos(phi)= 0.66 degrees\n",
"\n",
"phi= 49.00 degrees\n",
"\n",
"Rph=Zph*cos(phi) = 5.21 Ohm\n",
"\n",
"Xph=Zph*sin(phi) = 5.99 Ohm\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex13-pg6.17"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.13 :(pg 6.17 & 6.18)\n",
"\n",
"import math\n",
"VL=400.;\n",
"IL=34.65;\n",
"P=14.4*10**3;\n",
"Iph=(IL/math.sqrt(3.));\n",
"Zph=(VL/Iph);\n",
"pf=(P/(math.sqrt(3.)*VL*IL));\n",
"phi=math.acos(pf)*57.3;\n",
"Rph=(Zph*pf);\n",
"Xph=(Zph*math.sin(phi/57.3));\n",
"print(\"\\nVL=400 V \\nIL=34.65 A \\nP=14.4kW\");\n",
"##For a Delta-connected load\n",
"print\"%s %.2f %s\"%(\"\\nVL=Vph= \",VL,\" V\");\n",
"print\"%s %.2f %s\"%(\"\\nIph=IL/sqrt(3)= \",Iph,\" A\");\n",
"\n",
"\n",
"print\"%s %.2f %s\"%(\"\\nZph=Vph/Iph = \",Zph,\" Ohm\");\n",
"print(\"\\nP=sqrt(3)*VL*IL*cos(phi)\");\n",
"print\"%s %.2f %s\"%(\"\\ncos(phi)= \",pf,\" degrees\");\n",
"print\"%s %.2f %s\"%(\"\\nphi= \",phi,\" degrees\");\n",
"print\"%s %.2f %s\"%(\"\\nRph=Zph*cos(phi) = \",Rph,\" Ohm\");\n",
"print\"%s %.2f %s\"%(\"\\nXph=Zph*sin(phi) = \",Xph,\" Ohm\");"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"VL=400 V \n",
"IL=34.65 A \n",
"P=14.4kW\n",
"\n",
"VL=Vph= 400.00 V\n",
"\n",
"Iph=IL/sqrt(3)= 20.01 A\n",
"\n",
"Zph=Vph/Iph = 19.99 Ohm\n",
"\n",
"P=sqrt(3)*VL*IL*cos(phi)\n",
"\n",
"cos(phi)= 0.60 degrees\n",
"\n",
"phi= 53.15 degrees\n",
"\n",
"Rph=Zph*cos(phi) = 11.99 Ohm\n",
"\n",
"Xph=Zph*sin(phi) = 16.00 Ohm\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex14-pg6.18"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.14 :(pg 6.18)\n",
"P=10.44*10**3;\n",
"import math\n",
"VL=200.;\n",
"pf=0.5;\n",
"x=math.acos(pf)*57.3;\n",
"IL=(P/(math.sqrt(3.)*VL*pf));\n",
"Iph=(IL/math.sqrt(3.));\n",
"Zph=(VL/Iph);\n",
"Rph=(Zph*pf);\n",
"Xph=(Zph*math.sin(x/57.3));\n",
"Q=(math.sqrt(3.)*VL*IL*math.sin(x/57.3));\n",
"print(\"\\nP=10.44kW \\nVL=200 V \\npf=0.5(leading)\");\n",
"## For a delta-connected load,\n",
"\n",
"print\"%s %.2f %s\"%(\"\\nP=qrt(3)*VL*IL*cos(phi) \\nIL= \",IL,\" A\");\n",
"\n",
"\n",
"print\"%s %.2f %s\"%(\"\\nQ=sqrt(3)*VL*IL*sin(phi) = \",Q,\" VAR\");\n",
"\n",
"\n",
"print\"%s %.2f %s\"%(\"\\nVL=Vph= \",VL,\" V\");\n",
"print\"%s %.2f %s\"%(\"\\nIph=IL/sqrt(3)= \",Iph,\" A\");\n",
"\n",
"\n",
"print\"%s %.2f %s\"%(\"\\nZph=Vph/Iph = \",Zph,\" Ohm\");\n",
"\n",
"print\"%s %.2f %s\"%(\"\\nRph=Zph*cos(phi) = \",Rph,\" Ohm\");\n",
"print\"%s %.2f %s\"%(\"\\nXph=Zph*sin(phi) = \",Xph,\" Ohm\");"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"P=10.44kW \n",
"VL=200 V \n",
"pf=0.5(leading)\n",
"\n",
"P=qrt(3)*VL*IL*cos(phi) \n",
"IL= 60.28 A\n",
"\n",
"Q=sqrt(3)*VL*IL*sin(phi) = 18082.61 VAR\n",
"\n",
"VL=Vph= 200.00 V\n",
"\n",
"Iph=IL/sqrt(3)= 34.80 A\n",
"\n",
"Zph=Vph/Iph = 5.75 Ohm\n",
"\n",
"Rph=Zph*cos(phi) = 2.87 Ohm\n",
"\n",
"Xph=Zph*sin(phi) = 4.98 Ohm\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex17-pg6.20"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.17 :(pg 6.20)\n",
"import math\n",
"Po=200.*10**3;\n",
"f=50.;\n",
"VL=440.;\n",
"N=0.91;\n",
"pf=0.86;\n",
"phi=math.acos(pf)*57.3;\n",
"Pi=(Po/N);\n",
"IL=(Pi/(math.sqrt(3.)*VL*pf));\n",
"Iph=(IL/math.sqrt(3.));\n",
"AC=(Iph*pf);\n",
"RC=(Iph*math.sin(phi/57.3));\n",
"print(\"\\nPo=200 kW \\nf=50Hz \\nVL= 440 V \\nN=0.91 \\npf=0.86\");\n",
"##For a delta connected load (induction motor)\n",
"print\"%s %.2f %s\"%(\"\\nVph =VL = \",VL,\"\");\n",
"print(\"\\nN=(Po/Pi)\");##efficiency\n",
"print\"%s %.2f %s\"%(\"\\nPi= \",Pi,\" W\");##Input power\n",
"print\"%s %.2f %s\"%(\"\\nPi=sqrt(3)*VL*IL*cos(phi) \\nIL= \",IL,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nAC = (Iph*cos(phi))= \",AC,\" A\");##Active component of phase current\n",
"print\"%s %.2f %s\"%(\"\\nRC=(Iph*sin(phi)) = \",RC,\" A\");##Reactive component of phase current"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"Po=200 kW \n",
"f=50Hz \n",
"VL= 440 V \n",
"N=0.91 \n",
"pf=0.86\n",
"\n",
"Vph =VL = 440.00 \n",
"\n",
"N=(Po/Pi)\n",
"\n",
"Pi= 219780.22 W\n",
"\n",
"Pi=sqrt(3)*VL*IL*cos(phi) \n",
"IL= 335.33 A\n",
"\n",
"AC = (Iph*cos(phi))= 166.50 A\n",
"\n",
"RC=(Iph*sin(phi)) = 98.80 A\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex18-pg6.21"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.18 :(pg 6.20)\n",
"VL=400.;\n",
"import math\n",
"Po=112.*10**3;\n",
"pf=0.86;\n",
"phi=(math.acos(pf)*57.3);\n",
"N=0.88; ##Efficiency\n",
"Pi=(Po/N);\n",
"IL=(Pi/(math.sqrt(3.)*VL*pf));\n",
"Iph=(IL/math.sqrt(3.));\n",
"AC=(Iph*pf);\n",
"RC=(Iph*math.sin(phi/57.3));\n",
"Aac=(IL*pf);\n",
"Arc=(IL*math.sin(phi/57.3));\n",
"print(\"\\nVL=400 V \\nPo=112kW \\npf=0.86 \\nN=0.88\");\n",
"##For a mesh-connected load (induction motor)\n",
"print\"%s %.2f %s\"%(\"\\nVph=VL= \",VL,\" V\");\n",
"print\"%s %.2f %s\"%(\"\\nN=Po/Pi \\nPi= \",Pi,\" W\");##Input power\n",
"print\"%s %.2f %s\"%(\"\\nPi=sqrt(3)*VL*IL*cos(phi) \\nIL= \",IL,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nIph=IL/sqrt(3) = \",Iph,\" A\");\n",
"##current in star-connected load=line current drawn by motor\n",
"print\"%s %.2f %s\"%(\"\\nIA= \",IL,\" A\");##current in alternate phase\n",
"print\"%s %.2f %s\"%(\"\\nAC=Iph*cos(phi) = \",AC,\" A\");##active component in each phase of motor\n",
"print\"%s %.2f %s\"%(\"\\nRC=Iph*sin(phi) = \",RC,\" A\");##Reactive component in each phase of motor\n",
"print\"%s %.2f %s\"%(\"\\nAac= \",Aac,\" A\");##active component in each alternate phase\n",
"print\"%s %.2f %s\"%(\"\\nArc= \",Arc,\" A\");##reactive component in each alternate phase\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"VL=400 V \n",
"Po=112kW \n",
"pf=0.86 \n",
"N=0.88\n",
"\n",
"Vph=VL= 400.00 V\n",
"\n",
"N=Po/Pi \n",
"Pi= 127272.73 W\n",
"\n",
"Pi=sqrt(3)*VL*IL*cos(phi) \n",
"IL= 213.61 A\n",
"\n",
"Iph=IL/sqrt(3) = 123.33 A\n",
"\n",
"IA= 213.61 A\n",
"\n",
"AC=Iph*cos(phi) = 106.06 A\n",
"\n",
"RC=Iph*sin(phi) = 62.93 A\n",
"\n",
"Aac= 183.70 A\n",
"\n",
"Arc= 109.00 A\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex19-pg6.21"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.19 :(pg 6.21 & 6.22)\n",
"\n",
"import math\n",
"VL=400.;\n",
"IL=5.;\n",
"Vph=(VL/math.sqrt(3.));\n",
"Zph=(Vph/IL);\n",
"Iph=(IL/math.sqrt(3));\n",
"Vph1=(Iph*Zph);\n",
"print(\"\\nVl=400 V \\nIL=5 A\");\n",
"##For a star-connected load\n",
"print\"%s %.2f %s\"%(\"\\nVph=VL/sqrt(3) = \",Vph,\" V\");\n",
"print\"%s %.2f %s\"%(\"\\nIph=IL= \",IL,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nZph=Rph=Vph/Iph = \",Zph,\" Ohm\");\n",
"##For a delta connected load\n",
"print\"%s %.2f %s\"%(\"\\nIL=5 A \\nRph= \",Zph,\" Ohm\");\n",
"print\"%s %.2f %s\"%(\"\\nIph=IL/sqrt(3)= \",Iph,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nVph=Iph*Rph \\n= \",Vph1,\" V\");\n",
"##Voltage needed is 1/3 of the star value\n",
"\n",
"\n",
"\n",
"\n",
"\n",
"\n",
"\n",
"\n",
"\n",
"\n",
"\n",
"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"Vl=400 V \n",
"IL=5 A\n",
"\n",
"Vph=VL/sqrt(3) = 230.94 V\n",
"\n",
"Iph=IL= 5.00 A\n",
"\n",
"Zph=Rph=Vph/Iph = 46.19 Ohm\n",
"\n",
"IL=5 A \n",
"Rph= 46.19 Ohm\n",
"\n",
"Iph=IL/sqrt(3)= 2.89 A\n",
"\n",
"Vph=Iph*Rph \n",
"= 133.33 V\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex20-pg6.22"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.20 :(pg 6.22 & 6.23)\n",
"VL=400;\n",
"import math\n",
"Zph=100.;\n",
"Vph=(VL/math.sqrt(3.));\n",
"Iph=(Vph/Zph);\n",
"pf=1.;\n",
"P=(math.sqrt(3.)*VL*Iph*pf);\n",
"Iph1=(VL/Zph);\n",
"IL1=(math.sqrt(3.)*Iph1);\n",
"P1=(math.sqrt(3.)*VL*IL1*pf);\n",
"I1=(VL/200.);\n",
"Pa=(VL*I1);\n",
"I2=(VL/100.);\n",
"Pb=(VL*I1*I2);\n",
"print(\"\\nVL=400 V \\nZph = 100 Ohm\");\n",
"##For a star connected load\n",
"print\"%s %.2f %s\"%(\"\\nVph=VL/sqrt(3) = \",Vph,\" V\");\n",
"print\"%s %.2f %s\"%(\"\\nIph = VL/Zph = \",Iph,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nIL=Iph = \",Iph,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\ncos(phi)=1 \\nP=sqrt(3).VL.IL.cos(phi) = \",P,\" W\");\n",
"##For a delta connected load\n",
"print\"%s %.2f %s\"%(\"\\nVph=VL= \",VL,\" V\");\n",
"print\"%s %.2f %s\"%(\"\\nIph=Vph/Zph = \",Iph1,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nIL=sqrt(3)*Iph = \",IL1,\" A\");\n",
"print\"%s %.2f %s\"%(\"\\nP=sqrt(3)*VL*IL*cos(phi) = \",P1,\" W\");\n",
"##When resistors are open circuited\n",
"##(i)Star connection\n",
"print\"%s %.2f %s\"%(\"\\nI= \",I1,\" A\");##Current in lines\n",
"print\"%s %.2f %s\"%(\"\\nP= \",Pa,\" W\");##Power taken from mains\n",
"##(ii)Delta connection\n",
"print\"%s %.2f %s\"%(\"\\nI= \",I2,\"A\");##Current in each phase\n",
"print\"%s %.2f %s\"%(\"\\nP= \",Pb,\" W\");##Power taken from mains"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"VL=400 V \n",
"Zph = 100 Ohm\n",
"\n",
"Vph=VL/sqrt(3) = 230.94 V\n",
"\n",
"Iph = VL/Zph = 2.31 A\n",
"\n",
"IL=Iph = 2.31 A\n",
"\n",
"cos(phi)=1 \n",
"P=sqrt(3).VL.IL.cos(phi) = 1600.00 W\n",
"\n",
"Vph=VL= 400.00 V\n",
"\n",
"Iph=Vph/Zph = 4.00 A\n",
"\n",
"IL=sqrt(3)*Iph = 6.93 A\n",
"\n",
"P=sqrt(3)*VL*IL*cos(phi) = 4800.00 W\n",
"\n",
"I= 2.00 A\n",
"\n",
"P= 800.00 W\n",
"\n",
"I= 4.00 A\n",
"\n",
"P= 3200.00 W\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex27-pg6.30"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.27 :(pg 6.30 & 6.31)\n",
"import math\n",
"W1=2000.;\n",
"W2=500.;\n",
"W3=-500.;\n",
"x=(math.sqrt(3.)*((W1-W2)/(W1+W2)));\n",
"phi=math.atan(x)*57.3;\n",
"pf=math.cos(phi/57.3);\n",
"y=(math.sqrt(3.)*((W1-W3)/(W1+W3)));\n",
"phi1=math.atan(y)*57.3;\n",
"pf1=math.cos(phi1/57.3);\n",
"print(\"\\nW1 = 2000W \\nW2 = 500 W\");\n",
"##(i) When both readings are same\n",
"print(\"\\nWhen W1 &W2 are same \\nW1 = 2000W \\nW2 = 500 W\");\n",
"print\"%s %.2f %s\"%(\"\\ntan(phi)= sqrt(3).(W1-W2/W1+W2) = \",x,\"\");\n",
"print\"%s %.2f %s\"%(\"\\nphi= \",phi,\" degrees\");\n",
"print\"%s %.2f %s\"%(\"\\npf=cos(phi)=\",pf,\"\");##Power factor\n",
"##(ii) When the latter reading is obtained after reversing the connection to the current coil of 1 instrument\n",
"print(\"\\nWhen W2 is reversed \\nW1= 2000 W \\nW2= -500 W\");\n",
"print\"%s %.2f %s\"%(\"\\ntan(phi)= sqrt(3).(W1-W2/W1+W2) =\",y,\"\");\n",
"print\"%s %.2f %s\"%(\"\\nphi= \",phi1,\" degrees\");\n",
"print\"%s %.2f %s\"%(\"\\npf=cos(phi)= \",pf1,\"\");##Power factor"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"W1 = 2000W \n",
"W2 = 500 W\n",
"\n",
"When W1 &W2 are same \n",
"W1 = 2000W \n",
"W2 = 500 W\n",
"\n",
"tan(phi)= sqrt(3).(W1-W2/W1+W2) = 1.04 \n",
"\n",
"phi= 46.11 degrees\n",
"\n",
"pf=cos(phi)= 0.69 \n",
"\n",
"When W2 is reversed \n",
"W1= 2000 W \n",
"W2= -500 W\n",
"\n",
"tan(phi)= sqrt(3).(W1-W2/W1+W2) = 2.89 \n",
"\n",
"phi= 70.90 degrees\n",
"\n",
"pf=cos(phi)= 0.33 \n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex28-pg6.31"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.28 :(pg 6.31)\n",
"W1=5.*10**3;\n",
"import math\n",
"W2=-(0.5*10**3);\n",
"P=(W1+W2);\n",
"x=(math.sqrt(3.)*((W1-W2)/(W1+W2)));\n",
"phi=math.atan(x)*57.3;\n",
"pf=math.cos(phi/57.3);\n",
"print(\"\\nW1=5kW \\W2=0.5kW\");\n",
"## When the latter readings are obtained after the reversal of the current coil terminals of the wattmeter\n",
"print(\"\\nWhen W2 is reversed \\nW1=5kW \\nW2=-0.5kW\");\n",
"print\"%s %.2f %s\"%(\"\\nP=W1+W2 = \",P,\" W\");##Power\n",
"print\"%s %.2f %s\"%(\"\\ntan(phi)=sqrt(3)*(W1-W2/W1+W2) =\",x,\"\");\n",
"print\"%s %.2f %s\"%(\"\\nphi= \",phi,\" degrees \");\n",
"print\"%s %.2f %s\"%(\"\\npf=cos(phi) =\",pf,\"\");##Power factor\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"W1=5kW \\W2=0.5kW\n",
"\n",
"When W2 is reversed \n",
"W1=5kW \n",
"W2=-0.5kW\n",
"\n",
"P=W1+W2 = 4500.00 W\n",
"\n",
"tan(phi)=sqrt(3)*(W1-W2/W1+W2) = 2.12 \n",
"\n",
"phi= 64.72 degrees \n",
"\n",
"pf=cos(phi) = 0.43 \n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex29-pg6.31"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.29 :(pg 6.31)\n",
"import math\n",
"S=10*10**3;\n",
"pf=0.342;\n",
"x=(S/math.sqrt(3.));\n",
"phi=math.acos(pf)*57.3;\n",
"W1=x*math.cos(30+phi)/(57.3);\n",
"W2=x*math.cos(30-phi)/(57.3);\n",
"print(\"\\nS=10kVA \\npf=0.342 \\nS=sqrt(3)*VL*IL\");\n",
"print\"%s %.2f %s\"%(\"\\nVL*IL= \",x,\"VA\");\n",
"print\"%s %.2f %s\"%(\"\\ncos(phi)=\",pf,\"\");\n",
"print\"%s %.2f %s\"%(\"\\nphi= \",phi,\" degrees\");\n",
"##(i)when power factor is leading\n",
"print\"%s %.2f %s\"%(\"\\npf leading \\nW1=VL.IL.cos(30+phi)= \",W1,\" W\");\n",
"print\"%s %.2f %s\"%(\"\\n \\nW2=VL.IL.cos(30-phi)= \",W2,\" W\");\n",
"##(i)when power factor is lagging\n",
"print\"%s %.2f %s\"%(\"\\npf lagging \\nW1=VL.IL.cos(30-phi)= \",W2,\" W\");\n",
"print\"%s %.2f %s\"%(\"\\n \\nW2=VL.IL.cos(30+phi)=\",W1,\" W\");"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"S=10kVA \n",
"pf=0.342 \n",
"S=sqrt(3)*VL*IL\n",
"\n",
"VL*IL= 5773.50 VA\n",
"\n",
"cos(phi)= 0.34 \n",
"\n",
"phi= 70.01 degrees\n",
"\n",
"pf leading \n",
"W1=VL.IL.cos(30+phi)= 87.21 W\n",
"\n",
" \n",
"W2=VL.IL.cos(30-phi)= -67.68 W\n",
"\n",
"pf lagging \n",
"W1=VL.IL.cos(30-phi)= -67.68 W\n",
"\n",
" \n",
"W2=VL.IL.cos(30+phi)= 87.21 W\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex30-pg6.31"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.30 :(pg 6.31 & 6.32)\n",
"VL=2000.;\n",
"import math\n",
"N=0.9;##efficiency\n",
"W1=300.*10**3;\n",
"W2=100.*10**3;\n",
"P=W1+W2;\n",
"x=(math.sqrt(3.)*((W1-W2)/(W1+W2)));\n",
"phi=math.atan(x)*57.3;\n",
"pf=math.cos(phi/57.3);\n",
"IL=(P/(math.sqrt(3.)*VL*pf));\n",
"print(\"\\nVL=2000 V \\nN=0.9 \\nW1=300kW \\nW2=100kW\");\n",
"print\"%s %.2f %s\"%(\"\\nP=W1+W2 = \",P,\" W\");##Input Power\n",
"print\"%s %.2f %s\"%(\"\\ntan(phi)=(sqrt(3)*(W1-W2/W1+W2)) =\",x,\"\");\n",
"print\"%s %.2f %s\"%(\"\\nphi= \",phi,\" degrees \");\n",
"print\"%s %.2f %s\"%(\"\\ncos(phi)=\",pf,\"\");##Power factor\n",
"print\"%s %.2f %s\"%(\"\\nP=sqrt(3)*VL*IL*cos(phi) \\nIL= \",IL,\" A\");\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"VL=2000 V \n",
"N=0.9 \n",
"W1=300kW \n",
"W2=100kW\n",
"\n",
"P=W1+W2 = 400000.00 W\n",
"\n",
"tan(phi)=(sqrt(3)*(W1-W2/W1+W2)) = 0.87 \n",
"\n",
"phi= 40.90 degrees \n",
"\n",
"cos(phi)= 0.76 \n",
"\n",
"P=sqrt(3)*VL*IL*cos(phi) \n",
"IL= 152.75 A\n"
]
}
],
"prompt_number": 14
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex31-pg6.32"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"## Three-Phase Circuits :example 6.31 :(pg 6.32)\n",
"import math\n",
"VL=220.;\n",
"Po=11.2*10**3;\n",
"N=0.88;##efficiency\n",
"IL=38.;\n",
"Pi=(Po/N);\n",
"x=(Pi/(math.sqrt(3.)*VL*IL));\n",
"phi=math.acos(x)*57.3;\n",
"W1=(VL*IL*math.cos(30-phi)/57.3);\n",
"W2=(VL*IL*math.cos(30+phi)/57.3);\n",
"print\"%s %.2f %s\"%(\"\\nVL=220 V \\nPo=11.2kW \\nN=0.88 \\nIL=38A \\N=(Po/Pi)= \",Pi,\" W\");\n",
"print\"%s %.2f %s\"%(\"\\nPi=sqrt(3)*VL*IL*cos(phi) \\ncos(phi)= \",x,\" lagging\");\n",
"print\"%s %.2f %s\"%(\"\\nphi=\",phi,\" degrees\");\n",
"print\"%s %.2f %s\"%(\"\\nW1 =VL*IL*cos(30-phi) = \",W1,\" W\");\n",
"print\"%s %.2f %s\"%(\"\\nW2 =VL*IL*cos(30+phi) = \",W2,\" W\");"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"VL=220 V \n",
"Po=11.2kW \n",
"N=0.88 \n",
"IL=38A \\N=(Po/Pi)= 12727.27 W\n",
"\n",
"Pi=sqrt(3)*VL*IL*cos(phi) \n",
"cos(phi)= 0.88 lagging\n",
"\n",
"phi= 28.49 degrees\n",
"\n",
"W1 =VL*IL*cos(30-phi) = 8.15 W\n",
"\n",
"W2 =VL*IL*cos(30+phi) = -52.16 W\n"
]
}
],
"prompt_number": 15
}
],
"metadata": {}
}
]
}