{
"metadata": {
"name": "",
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"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": {}
}
]
}