{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 8 : Q factor Power and Power Factor" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_1,pg 234" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Q factor of coil\n", "\n", "import math\n", "#Variable declaration\n", "fr= 400.0*10**3 #resonance frequency\n", "C = 400.0*10**-12 #tuned capacitance\n", "R = 10.0 #resistance of coil\n", "n = 40.0 #Cp=nC\n", "\n", "#Calculations\n", "Cp=n*(100.0/400.0)*10**-12 \n", "L=(1.0/(4*(math.pi**2)*(fr**2)*(C+Cp)))\n", "Q=2*math.pi*fr*(L/R)\n", "\n", "#Result\n", "print(\"Inductance:\\nL = %f mH\"%(L*1000))\n", "print(\"Observed Q-factor:\")\n", "print(\"Q = %.2f \"%Q)\n", "# Aanswer do not match with the book" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Inductance:\n", "L = 0.386133 mH\n", "Observed Q-factor:\n", "Q = 97.05 \n" ] } ], "prompt_number": 11 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_2,pg 240" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# truncation error\n", "\n", "import math\n", "#Variable declaration\n", "fs=50*10**3 #sampling rate\n", "delt=2.0 #summation interval\n", "f=50.0 #signal frequency\n", "\n", "#Calculations\n", "n=(fs/delt) #value of samples for 2s\n", "maxer1=100.0/(2*n) #max error for synchronous case\n", "maxer2=(100.0/(2*fs*delt*math.sin((2*math.pi*f)/fs)))\n", "\n", "#Result\n", "print(\"max error for synchronous case:\")\n", "print(\"maxer1 = %.3f%% \\n\"%maxer1)\n", "print(\"max error for asynchronous case:\")\n", "print(\"maxer2 = %.2f%% \"%maxer2)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "max error for synchronous case:\n", "maxer1 = 0.002% \n", "\n", "max error for asynchronous case:\n", "maxer2 = 0.08% \n" ] } ], "prompt_number": 13 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_3,pg 258" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# find ratio errror and phase angle\n", "\n", "import math\n", "#Variable declaration\n", "#assume no iron loss and magnetizing current=1% of 10A, i.e 0.01A\n", "Xs=1.884 #reactance of secondary\n", "Rs=0.5 #resistance of secondary\n", "Xm=2.0 #reactance of meter\n", "Rm=0.4 #reactance of meter\n", "Im=0.01 #magnetizing current\n", "n2=10\n", "n1=1\n", "\n", "#Calculations\n", "B=math.atan((Xs+Xm)/(Rs+Rm))\n", "#nominal ratio (n2/n1)=10/1\n", "R=n2+((Im*math.sin(B))/n1) #actual impedance\n", "R1=0.0097 #practical impedance\n", "perer=(R1/R)*100 #percentage error\n", "theta=((Im*math.cos(B))/n2)\n", "\n", "#Result\n", "print(\"percentage error = %.3f%% \\n\"%perer)\n", "print(\"phase angle:\")\n", "print(\"theta = %.5f rad\"%(math.floor(theta*10**5)/10**5))" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "percentage error = 0.097% \n", "\n", "phase angle:\n", "theta = 0.00022 rad\n" ] } ], "prompt_number": 26 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_4,pg 499" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# inductor Q factor and resistance\n", "\n", "import math\n", "#Variable declaration\n", "Vc=100.0 #voltage across capacitor\n", "Vi=12.0 #input voltage\n", "f=100.0 #frequency of operation\n", "Vl=100.0 #Vc=Vl at resonance\n", "Ir=5.0 #current at resonance\n", "\n", "#Calculations\n", "Q=(Vc/Vi) #Q-factor\n", "Xl=(Vl/Ir) #inductive reactance\n", "L=(Xl/(2*math.pi*f)) #inductance\n", "Rl=(Xl/Q) #resistance\n", "\n", "#Result\n", "print(\"Inductance of coil:\")\n", "print(\"L = %.1f mH\\n\"%(L*1000))\n", "print(\"Q-factor:\")\n", "print(\"Q = %.2f\\n\"%Q)\n", "print(\"Resistance of coil:\")\n", "print(\"Rl = %.1f ohm\"%Rl)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Inductance of coil:\n", "L = 31.8 mH\n", "\n", "Q-factor:\n", "Q = 8.33\n", "\n", "Resistance of coil:\n", "Rl = 2.4 ohm\n" ] } ], "prompt_number": 29 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_5,pg 499" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# actual Q factor and resistance\n", "\n", "import math\n", "# Variable declaration\n", "#when switch is open\n", "C1=0.011*10**-6 #capacitance-1\n", "Q1=10.0 #Q-factor-1\n", "#when switch is closed\n", "C2=0.022*10**-6 #capacitance-2\n", "Q2=100.0 #Q-factor-2\n", "\n", "#Calculations\n", "Qac=((Q1*Q2)/(Q1-Q2))*((C1-C2)/C1) #actual Q-factor\n", "Rp=((Q1*Q2)/(Q2-Q1))*(1/(2*math.pi*C2)) #parallel resistance\n", "\n", "#Result\n", "print(\"actual Q-factor:\")\n", "print(\"Qac = %.2f \\n\"%Qac)\n", "print(\"parallel resistance:\")\n", "print(\"Rp = %.f M-ohm\"%(Rp/10**6))" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "actual Q-factor:\n", "Qac = 11.11 \n", "\n", "parallel resistance:\n", "Rp = 80 M-ohm\n" ] } ], "prompt_number": 32 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_6,pg 499" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# find Q factor\n", "\n", "import math\n", "#Variable declaration\n", "Cr=0.01*10**-6 #capacitance at resonance\n", "Cu=0.014*10**-6 #capacitance at upper half\n", "Cl=0.008*10**-6 #capacitance at lower half\n", "\n", "#Calculations\n", "Qac=((2*Cr)/(Cu-Cl)) #actual Q-factor\n", "\n", "#Result\n", "print(\"actual Q-factor:\")\n", "print(\"Qac = %.2f \"%Qac)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "actual Q-factor:\n", "Qac = 3.33 \n" ] } ], "prompt_number": 12 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_7,pg 499" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# find lag\n", "\n", "import math\n", "#Variable declaration\n", "V=10.0 #v=10sin6280t\n", "I=1.0 #current peak\n", "P=3.1 #active power\n", "\n", "#Calculations\n", "phi=math.acos((P*2)/V) #phase in radian\n", "w=6280.0 #v=10sin6280t\n", "lag=(phi/w) #lag\n", "\n", "#Result\n", "print(\"lag = %.2f ms\"%(lag*10**3))\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "lag = 0.14 ms\n" ] } ], "prompt_number": 33 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_8,pg 500" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# find truncation error\n", "\n", "import math\n", "#Variable declaration\n", "V=4.0 #peak voltage\n", "I=0.4 #peak current\n", "f=1*10**3 #operating frequency\n", "fs=40*10**3 #sampling rate\n", "delt=2.2 #time interval\n", "\n", "#Calculations\n", "phi=((2*math.pi*f)/fs) #phase \n", "Et=(V*I*phi)/(4*math.pi*f*delt*math.sin(phi))\n", "\n", "#Result\n", "print(\"truncation error:\")\n", "print(\"Et = %.1f * 10^-6 \"%(Et*10**6))" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "truncation error:\n", "Et = 58.1 * 10^-6 \n" ] } ], "prompt_number": 36 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_9,pg 500" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# find frequency of PF meter\n", "\n", "import math\n", "#Variable declaration\n", "ar=1.0 #gain of rectifier\n", "nc=40.0 #turns ratio (1:40)\n", "Vm=4.0 #peak load voltage\n", "PF=0.85 #power factor\n", "\n", "#Calculations\n", "f=(1/math.pi)*ar*Vm*nc*PF #frequency\n", "\n", "#Result\n", "print(\"frequency of digital power meter:\")\n", "print(\"f = %.1f Hz\"%f)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "frequency of digital power meter:\n", "f = 43.3 Hz\n" ] } ], "prompt_number": 37 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_10,pg 500" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# calculate ratio error and phase angle\n", "\n", "import math\n", "#Variable declaration\n", "Rp=94.0 #primary resistance\n", "Xp=64.3 #primary reactance\n", "Rs=0.85*10**2 #secondary resistance\n", "Im=31*10**-3 #magnetizing current\n", "PF=0.4 #power factor\n", "n=10.0 #PT ratio\n", "Is=1.0 #load current\n", "Vs=110.0 #n=(Vp/Vs)\n", "\n", "#Calculations\n", "B=math.acos(PF)\n", "beta = math.floor(math.sin(B)*10)/10\n", "R=Rp+Rs #total resistance\n", "nerr=n+((((Is/n)*((R*PF)+(Xp*beta)))+Im*Xp)/Vs)\n", "theta=((PF*(Xp/n))-(beta*(R/n))-(Im*Rp))/(Vs*n)\n", "\n", "#Result\n", "print(\"ratio error:\")\n", "print(\"nerr = %.3f\\n\"%nerr)\n", "print(\"phase angle:\")\n", "print(\"theta = %.3f\"%theta)\n", "#Answer for theta do not match with the book" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "ratio error:\n", "nerr = 10.136\n", "\n", "phase angle:\n", "theta = -0.015\n" ] } ], "prompt_number": 52 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example8_11,pg 500" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# calculate ratio error and phase angle\n", "\n", "import math\n", "#Variable declaration\n", "n=20.0 #(Vs/Is)\n", "Is=5.0 #n=(Vs/Is)\n", "Vs=100.0 #n=(Vs/Is)\n", "N=0.25 #resistance to reactance ratio\n", "Bur=15.0 #burden of CT=15VA (rating)\n", "IL=0.13 #iron loss\n", "Im=1.3 #magnetizing current\n", "\n", "#Calculations\n", "V=(Bur/Is) #voltage rating\n", "B=math.atan(N) #cos(B)-> power factor\n", "#B=B*(180/math.pi) #conversion into degree\n", "I=(Bur/Vs) #current rating\n", "I1=(IL/I)\n", "Rac=0.23 #actual value\n", "R=n+((I1*math.cos(B)+Im*math.sin(B))/Is)\n", "theta=((Im*math.cos(B)-I1*math.sin(B))/Vs)\n", "nerr=-(Rac/R)*100 #ratio error\n", "\n", "# Result\n", "print(\"ratio error:\")\n", "print(\"nerr = %.3f%%\\n \"%nerr)\n", "print(\"phase angle \\n\")\n", "print(\"theta = %.4f\u00b0 \"%theta)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "ratio error:\n", "nerr = -1.137%\n", " \n", "phase angle \n", "\n", "theta = 0.0105\u00b0 \n" ] } ], "prompt_number": 56 } ], "metadata": {} } ] }