{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 11 : Some Applications" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 11.1, Page No 622" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#initialisation of variables\n", "V_s=11000.0\n", "V_ml=math.sqrt(2)*V_s\n", "f=50.0\n", "\n", "#Calculations\n", "w=2*math.pi*f\n", "I_d=300\n", "R_d=1\n", "g=20 #g=gamma\n", "a=math.degrees(math.acos(math.cos(math.radians(g))+math.pi/(3*V_ml)*I_d*R_d)) \n", "L_s=.01\n", "V_d=(3/math.pi)*((V_ml*math.cos(math.radians(a)))-w*L_s*I_d) \n", "\n", "#Results\n", "print(\"firing angle=%.3f deg\" %a)\n", "print(\"rectifier o/p voltage=%.1f V\" %V_d)\n", "print(\"dc link voltage=%.3f V\" %(2*V_d/1000))" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "firing angle=16.283 deg\n", "rectifier o/p voltage=13359.3 V\n", "dc link voltage=26.719 V\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 11.2, Page No 623" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#initialisation of variables\n", "V_d=(200.0+200)*10**3\n", "P=1000.0*10**6\n", "\n", "#Calculations\n", "I_d=P/V_d\n", " #each thristor conducts for 120deg for a periodicity of 360deg\n", "a=0\n", "V_d=200.0*10**3\n", "V_ml=V_d*math.pi/(3*math.cos(math.radians(a)))\n", "\n", "#Results\n", "print(\"rms current rating of thyristor=%.2f A\" %(I_d*math.sqrt(120/360)))\n", "print(\"peak reverse voltage across each thyristor=%.2f kV\" %(V_ml/2/1000))" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "rms current rating of thyristor=0.00 A\n", "peak reverse voltage across each thyristor=104.72 kV\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 11.3 Page No 627" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#initialisation of variables\n", "V_m=230.0\n", "V_s=230/math.sqrt(2)\n", "pf=0.8\n", "P=2000.0\n", "\n", "#Calculations\n", "I_m=P/(V_s*pf)\n", "I_Tr=I_m/math.sqrt(2)\n", "I_TA=2*I_m/math.pi\n", "fos=2 #factor of safety\n", "PIV=V_m*math.sqrt(2)\n", "I_Tr=I_m/(2)\n", "I_TA=I_m/math.pi\n", "\n", "#Results\n", "print(\"rms value of thyristor current=%.2f A\" %(fos*I_Tr))\n", "print(\"avg value of thyristor current=%.3f A\" %(fos*I_TA))\n", "print(\"voltage rating of thyristor=%.2f V\" %PIV)\n", "print(\"rms value of diode current=%.3f A\" %(fos*I_Tr))\n", "print(\"avg value of diode current=%.3f A\" %(fos*I_TA))\n", "print(\"voltage rating of diode=%.2f V\" %PIV)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "rms value of thyristor current=15.37 A\n", "avg value of thyristor current=9.786 A\n", "voltage rating of thyristor=325.27 V\n", "rms value of diode current=15.372 A\n", "avg value of diode current=9.786 A\n", "voltage rating of diode=325.27 V\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 11.4, Page No 629" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#initialisation of variables\n", "V=200.0\n", "I=10.0\n", "\n", "#Calculations\n", "R_L=V/I \n", "I_h=.005 #holding current\n", "R2=V/I_h \n", "t_c=20*10**-6\n", "fos=2 #factor of safety\n", "C=t_c*fos/(R_L*math.log(2)) \n", "\n", "#Results\n", "print(\"value of load resistance=%.0f ohm\" %R_L)\n", "print(\"value of R2=%.0f kilo-ohm\" %(R2/1000))\n", "print(\"value of C=%.3f uF\" %(C*10**6))" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "value of load resistance=20 ohm\n", "value of R2=40 kilo-ohm\n", "value of C=2.885 uF\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 11.5 Page No 646" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#initialisation of variables\n", "u_r=10\n", "f=10000.0 #Hz\n", "p=4.0*10**-8 #ohm-m\n", "\n", "#Calculations\n", "dl=(1/(2*math.pi))*math.sqrt(p*10**7/(u_r*f)) \n", "l=0.12 #length of cylinder\n", "t=20.0 #no of turns\n", "I=100.0\n", "H=t*I/l\n", "P_s=2*math.pi*H**2*math.sqrt(u_r*f*p*10**-7) \n", "d=.02 #diameter\n", "P_v=4*H**2*p/(d*dl) \n", "\n", "#Results\n", "print(\"depth of heat of penetration=%.5f mm\" %(dl*1000))\n", "print(\"heat generated per unit cylinder surface area=%.3f W/m**2\" %P_s)\n", "print(\"heat generated per unit cylinder volume=%.0f W/m**3\" %P_v)\n", " #answer of P_v varies as given in book as value of d is not taken as in formulae. " ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "depth of heat of penetration=0.31831 mm\n", "heat generated per unit cylinder surface area=34906.585 W/m**2\n", "heat generated per unit cylinder volume=6981317 W/m**3\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 11.6 Page No 646" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#initialisation of variables\n", "f=3000.0\n", "\n", "#Calculations\n", "t_qmin=30.0*10**-6\n", "f_r=f/(1-2*t_qmin*f)\n", "R=0.06\n", "L=20.0*10**-6\n", "C=1/(L*((2*math.pi*f_r)**2+(R/(2*L))**2)) \n", "\n", "#Results\n", "print(\"required capacitor size=%.4f F\" %(C*10**6))\n", " #Answers have small variations from that in the book due to difference in the rounding off of digits." ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "required capacitor size=94.2215 F\n" ] } ], "prompt_number": 6 } ], "metadata": {} } ] }