{ "metadata": { "name": "", "signature": "sha256:a295b23ddf355cc98776039dc2c765e71624b4961371dafae0a82fd3d3a044d3" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 9: Control of Traction Motors" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.1, Page 268" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "V=600.;# in volts\n", "I=350.;#in A\n", "Ts=20.;# in sec\n", "R=0.15;# in ohm\n", "\n", "#Calculations&Results\n", "E_bse=(V/2)-(I*R);\n", "E_bp=V-(I*R);\n", "Tse=(E_bse/E_bp)*Ts;\n", "Tp=Ts-Tse;\n", "Vd=V-(2*I*R);\n", "Ed1=(Vd/2)*I*(Tse/3600);\n", "Ed2=((V/2)/2)*2*I*(Tp/3600);\n", "El=(Ed1+Ed2)*10**-3;\n", "print \"part (a)\"\n", "print \"Energy lost in starting rhestat,El(kWh) = %.4f\"%El\n", "El_1=(2*(I**2)*R*Ts)/(3600*1000);\n", "print \"part (b)\"\n", "print \"Energy lost in motors,El(kWh) = %.3f\"%El_1\n", "#answer is wrong in part b in the textbook\n", "Et=((V*I*Tse)+(2*V*I*Tp))/(3600*1000);\n", "print \"part (c)\"\n", "print \"Total Energy,Et(kWh) = %.3f\"%Et" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "part (a)\n", "Energy lost in starting rhestat,El(kWh) = 0.5372\n", "part (b)\n", "Energy lost in motors,El(kWh) = 0.204\n", "part (c)\n", "Total Energy,Et(kWh) = 1.806\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.2, Page 269" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "V=600.;# in volts\n", "I=300.;#in A\n", "Ts=15.;# in sec\n", "R=0.1;# in ohm\n", "\n", "#Calculations&Results\n", "E_bse=(V/2)-(I*R);\n", "E_bp=V-(I*R);\n", "Tse=(E_bse/E_bp)*Ts;\n", "Tp=Ts-Tse;\n", "Vd=V-(2*I*R);\n", "Ed1=(round((Vd/2)*I*(Tse/3600))*10**-3);#\n", "print \"part (i)\"\n", "print \"rheostatic in series,Ed1(kWh) = %.2f\"%Ed1\n", "Ed2=((V/2)/2)*2*I*(Tp/3600)*10**-3;\n", "print \"rheostatic in parallel,Ed2(kWh) = %.3f\"%Ed2\n", "Vm=29;# in kmph\n", "alfa=Vm/Ts;\n", "S=alfa*Tse;\n", "print \"part (ii)\"\n", "print \"Speed at the end of series period,S(km/h) = %.1f\"%S" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "part (i)\n", "rheostatic in series,Ed1(kWh) = 0.16\n", "rheostatic in parallel,Ed2(kWh) = 0.197\n", "part (ii)\n", "Speed at the end of series period,S(km/h) = 13.7\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.3, Page 270" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "V=600;# in volts\n", "I=200;#in A\n", "Ts=20;# in sec\n", "R=0.1;# in ohm\n", "\n", "#Calculations&Results\n", "E_bse=(V/2)-(I*R);\n", "E_bp=V-(I*R);\n", "Tse=(E_bse/E_bp)*Ts;\n", "Tp=Ts-Tse;\n", "Vd=V-(2*I*R);\n", "Mi=((V*I*Tse)/(2*3600))+((V*I*Tp)/3600);\n", "Er=((Vd/4)*I*(Tse/3600))+(((V/2)/2)*I*(Tp/3600));\n", "El=(I**2*R*Ts)/(3600);\n", "Mo=Mi-Er-El;\n", "eta=(Mo/Mi)*100;\n", "print \"part (a)\"\n", "print \"Starting efficiency = %.1f%%\"%eta\n", "Vm=80;# in kmph\n", "alfa=Vm/Ts;\n", "S=alfa*Tse;\n", "print \"part (b)\"\n", "print \"speed,S(kmph) = %.2f\"%S" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "part (a)\n", "Starting efficiency = 63.7%\n", "part (b)\n", "speed,S(kmph) = 38.62\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.4, Page 271" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "W=150;# in tonne\n", "We=1.1*W;# in tonnes\n", "Vm=30;#kmph\n", "V=600;# in volts\n", "r=10;# N/tonne\n", "I=300;#in A\n", "R=0.1;# in ohm\n", "Ft=4*15000;# in N\n", "G=1;#gradient in %\n", "\n", "#Calculations&Results\n", "alfa=(Ft-(W*r)-(98.1*W*G))/(277.8*We);\n", "Ts=Vm/alfa;\n", "E_bse=(V/2)-(I*R);\n", "E_bp=V-(I*R);\n", "Tse=(E_bse/E_bp)*Ts;\n", "print \"part (a)\"\n", "print \"Duration of starting period,Ts(seconds) = %.1f\"%Ts\n", "print \"Duration for Series running,Tse(seconds) = %.1f\"%Tse\n", "sptr=alfa*Tse;#in kmph\n", "print \"part (b)\"\n", "print \"speed of train at transition in kmph is %.2f\"%sptr\n", "sptr=alfa*Tse;#in kmph\n", "rls=((V-(2*I*R))/2)*(2*I)*(Tse/3600);#watts hours\n", "rlp=((V/2)/2)*(4*I)*((Ts-Tse)/3600);#watts hours\n", "tl=rls+rlp;#\n", "print \"part (c)\"\n", "print \"rheostat losses during series operation is %.1f W-hours\"%rls\n", "print \"rheostat losses during parallel operation is %.f W-hours\"%rlp\n", "print \"total losses in W-hours is %.1f \"%tl" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "part (a)\n", "Duration of starting period,Ts(seconds) = 31.4\n", "Duration for Series running,Tse(seconds) = 14.9\n", "part (b)\n", "speed of train at transition in kmph is 14.21\n", "part (c)\n", "rheostat losses during series operation is 669.4 W-hours\n", "rheostat losses during parallel operation is 826 W-hours\n", "total losses in W-hours is 1495.9 \n" ] } ], "prompt_number": 12 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.5, Page 272" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "nf=1.; \n", "n2=1.25*nf; \n", "of=1; \n", "of2=nf/n2; \n", "isef=1; \n", "ise2=0.66667; \n", "\n", "#Calculations\n", "ia2=(1./ise2); \n", "idiv=ia2-ise2; \n", "rdiv=ise2/idiv; \n", "\n", "#Result\n", "print \"diverter resistance required as percentage of the field resistance is %.f%%\"%(rdiv*100)\n", "#answer is wrong in the textbook" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "diverter resistance required as percentage of the field resistance is 80%\n" ] } ], "prompt_number": 16 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 9.6, Page 272" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#Variable declaration\n", "Ia=[60,80,100,120,160,180];# in amperes\n", "sp1=[47.4,40.3,35.8,33.9,29.8,28.5];#in kmph\n", "dpk=[440,700,970,1245,1800,2360];#in kg\n", "sp2=[58.1,50,45,40.3,35,32];#\n", "\n", "#Calculations&Results\n", "for i in range(0,6):\n", " dpk1= ((dpk[i])*(sp1[i]))/(sp2[i]);#\n", " print \"For current = \",Ia[i],\"A, speed is \",sp2[i],\"kmph and drawbar pull is\",round(dpk1),\"kg\"\n", " \n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "For current = 60 A, speed is 58.1 kmph and drawbar pull is 359.0 kg\n", "For current = 80 A, speed is 50 kmph and drawbar pull is 564.0 kg\n", "For current = 100 A, speed is 45 kmph and drawbar pull is 772.0 kg\n", "For current = 120 A, speed is 40.3 kmph and drawbar pull is 1047.0 kg\n", "For current = 160 A, speed is 35 kmph and drawbar pull is 1533.0 kg\n", "For current = 180 A, speed is 32 kmph and drawbar pull is 2102.0 kg\n" ] } ], "prompt_number": 33 } ], "metadata": {} } ] }