{
"metadata": {
"name": "",
"signature": "sha256:e71bef33b0871199556c73182ec6cd28497a9d9d16612973a23ee2cceda4b35b"
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 26: D.C. Generators"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.3, Page Number:912"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"i=450#A\n",
"v=230#v\n",
"rs=50#ohm\n",
"ra=.03#ohm\n",
"\n",
"#calculations\n",
"ish=v/rs\n",
"ia=i+ish\n",
"va=ia*ra\n",
"E=v+va\n",
"\n",
"#result\n",
"print \"e.m.f. generated in the armature= \",E,\" V\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"e.m.f. generated in the armature= 243.62 V\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.4, Page Number:913"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"i=50#A\n",
"v=500#v\n",
"rs=250#ohm\n",
"ra=.05#ohm\n",
"rseries=0.03#ohm\n",
"b=1#V\n",
"\n",
"#calculations\n",
"ish=v/rs\n",
"ia=i+ish\n",
"vs=ia*rseries\n",
"va=ia*ra\n",
"vb=ish*b\n",
"E=v+va+vs+vb\n",
"\n",
"#result\n",
"print \"generated voltage in the armature= \",E,\" V\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"generated voltage in the armature= 506.16 V\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.5, Page Number:913"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"i=30#A\n",
"v=220#v\n",
"rs=200#ohm\n",
"ra=.05#ohm\n",
"rseries=0.30#ohm\n",
"b=1#V\n",
"\n",
"#calculations\n",
"vs=i*rseries\n",
"vshunt=v+vs\n",
"ish=vshunt/v\n",
"ia=i+ish\n",
"vb=b*2\n",
"E=v+vs+vb+(ia*ra)\n",
"\n",
"#result\n",
"print \"generated voltage in the armature= \",E,\" V\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"generated voltage in the armature= 232.552045455 V\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.6, Page Number:913"
]
},
{
"cell_type": "code",
"collapsed": true,
"input": [
"#variable declaration\n",
"v=230.0#v\n",
"i=150.0#A\n",
"rs=92.0#ohm\n",
"rseries=0.015#ohm\n",
"rd=0.03#ohm(divertor)\n",
"ra=0.032#ohm\n",
"\n",
"#calculations\n",
"ish=v/rs\n",
"ia=i+ish\n",
"sdr=(rd*rseries)/(rd+rseries)\n",
"tr=ra+sdr\n",
"vd=ia*tr\n",
"Eg=v+vd\n",
"tp=Eg*ia\n",
"pl=(ia*ia*ra)+(ia*ia*sdr)+(v*ish)+(v*i)\n",
"\n",
"#resuts\n",
"print \"i) Induced e.m.f.= \",Eg,\" V\"\n",
"print \"ii)Total power generated= \",tp,\" W\"\n",
"print \"iii)Distribution of the total power:\"\n",
"print \" power lost in armature= \", ia*ia*ra\n",
"print \"power lost in series field and divider= \", ia*ia*sdr\n",
"print \"power dissipated in shunt winding= \", v*ish\n",
"print \"power delivered to load= \", v*i\n",
"print \" ------------\"\n",
"print \"Total= \", pl"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"i) Induced e.m.f.= 236.405 V\n",
"ii)Total power generated= 36051.7625 W\n",
"iii)Distribution of the total power:\n",
" power lost in armature= 744.2\n",
"power lost in series field and divider= 232.5625\n",
"power dissipated in shunt winding= 575.0\n",
"power delivered to load= 34500.0\n",
" ------------\n",
"Total= 36051.7625\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.7, Page Number:914"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=300000.0#w\n",
"v=600.0#v\n",
"sr=75.0#ohm\n",
"abr=0.03#ohm\n",
"cr=0.011#ohm\n",
"rseries=0.012#ohm\n",
"dr=0.036#ohm\n",
"\n",
"#calculatons\n",
"io=p/v#output current\n",
"ish=v/sr\n",
"ia=io+ish\n",
"sdr=(rseries*dr)/(rseries+dr)\n",
"tr=abr+cr+sdr\n",
"vd=ia*tr\n",
"va=v+vd\n",
"pg=va*ia\n",
"W=pg/1000\n",
"\n",
"#result\n",
"print \"Voltage generatedby the armature= \",va,\" V\"\n",
"print \"Power generated by the armature= \",W, \"kW\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Voltage generatedby the armature= 625.4 V\n",
"Power generated by the armature= 317.7032 kW\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.8, Page Number:915"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#variable declaration\n",
"phi=7*math.pow(10,-3)\n",
"z=51*20\n",
"a=p=4\n",
"n=1500#r.p.m\n",
"\n",
"#calculations\n",
"Eg=(phi*z*n*p)/(a*60)\n",
"\n",
"#result\n",
"print \"Voltage generated= \",Eg,\" V\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Voltage generated= 178.5 V\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.9, Page Number:916"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=a=8\n",
"phi=0.05#Wb\n",
"n=1200#rpm\n",
"N=500#armature conductor\n",
"\n",
"#calculations\n",
"E=phi*(n/60)*(p/a)*N\n",
"\n",
"#result\n",
"print \"e.m.f generated= \",E,\" V\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"e.m.f generated= 500.0 V\n"
]
}
],
"prompt_number": 22
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.10, Page Number:916"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"v=127#v\n",
"vt=120#v(terminal voltage)\n",
"r=15#ohms\n",
"i1=8.47#A\n",
"ra=0.02#ohms\n",
"fi=8#A\n",
"\n",
"#calculations\n",
"Eg=v+(i1*ra)\n",
"ia=(Eg-vt)/ra\n",
"il=ia-fi\n",
"\n",
"#result\n",
"print \"Load current \",il,\" A\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Load current 350.47 A\n"
]
}
],
"prompt_number": 24
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.11(a), Page Number:917"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=8\n",
"z=778\n",
"n=500\n",
"ra=0.24\n",
"rl=12.5\n",
"r=250\n",
"v=250\n",
"a=2\n",
"#calculations\n",
"il=v/rl\n",
"si=v/r\n",
"ai=il+si\n",
"emf=v+(ai*ra)\n",
"phi=(emf*60*a)/(p*z*n)\n",
"\n",
"#result\n",
"print \"armature current= \",ai,\" A\"\n",
"print \"induced e.m.f.= \",emf,\" V\"\n",
"print \"flux per pole= \",round(phi*1000,2),\" mWb\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"armature current= 21.0 A\n",
"induced e.m.f.= 255.04 V\n",
"flux per pole= 9.83 mWb\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.11(b), Page Number:916"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=a=4\n",
"P=5000.0#w\n",
"P2=2500.0#W\n",
"v=250.0#v\n",
"ra=0.2#ohm\n",
"r=250.0#ohm\n",
"z=120\n",
"N=1000#rpm\n",
"\n",
"#calculations\n",
"gc=P/v\n",
"li=P2/v\n",
"ti=gc+li\n",
"fc=1\n",
"ai=ti+fc\n",
"ard=ai*ra\n",
"emf=v+ard+2\n",
"phi=(emf*60*a)/(p*z*N)\n",
"ac_perparralelpath=ai/p\n",
"\n",
"#result\n",
"print \"Flux per pole= \",phi*1000,\" mWb\"\n",
"print \"Armature current per parallel path= \",ac_perparralelpath,\" A\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Flux per pole= 129.1 mWb\n",
"Armature current per parallel path= 7.75 A\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.12, Page Number:918"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"i=200.0#A\n",
"v=125.0#V\n",
"n1=1000#rpm\n",
"n2=800#rpm\n",
"ra=0.04#ohm\n",
"bd=2.0#V(brush drop)\n",
"\n",
"#calculations\n",
"R=v/i\n",
"E1=v+(i*ra)+bd\n",
"E2=(E1*n2)/n1\n",
"il=(E2-bd)/0.675\n",
"\n",
"#result\n",
"print \"Load current when speed drops to 800 r.p.m.= \",round(il,2),\" A\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Load current when speed drops to 800 r.p.m.= 157.04 A\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.13, Page Number:918"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#variable declaration\n",
"p=4\n",
"n=900 #rpm\n",
"V=220#V\n",
"E=240#V\n",
"ra=0.2#ohm\n",
"phi=10#mWb\n",
"N=8\n",
"\n",
"#calculations\n",
"ia=(E-V)/ra\n",
"Z=(E*600*2)/(phi*math.pow(10,-3)*n*p)\n",
"#since there ae 8 turns in a coil,it means there are 16 active conductor\n",
"number_of_coils=Z/16\n",
"\n",
"#result\n",
"print \"armature current= \",ia,\" A\"\n",
"print \"number of coils= \",number_of_coils"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"armature current= 100.0 A\n",
"number of coils= 500.0\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.14, Page Number:919"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"V=120.0#V\n",
"ra=0.06#ohm\n",
"rs=25#ohm\n",
"rsw=0.04#ohm(series winding)\n",
"il=100.0#A\n",
"#i)Long shunt\n",
"ish=V/rs\n",
"ia=il+ish\n",
"vd=ia*rsw\n",
"vda=ia*ra\n",
"E=V+vd+vda\n",
"\n",
"print \"Induced e.m.f. when the machine is connected to long shunt= \",E,\" V\"\n",
"print \"Armature current when the machine is connected to long shunt=\",ia,\" A\"\n",
"\n",
"#i)Short shunt\n",
"vds=il*rsw\n",
"vs=V+vds\n",
"ish=vs/rs\n",
"ia=il+ish\n",
"vd=ia*rsw\n",
"vda=ia*ra\n",
"E=V+vd+vda\n",
"\n",
"print \"Induced e.m.f. when the machine is connected to short shunt= \",E,\" V\"\n",
"print \"Armature current when the machine is connected to short shunt=\",ia,\" A\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Induced e.m.f. when the machine is connected to long shunt= 130.48 V\n",
"Armature current when the machine is connected to long shunt= 104.8 A\n",
"Induced e.m.f. when the machine is connected to short shunt= 130.496 V\n",
"Armature current when the machine is connected to short shunt= 104.96 A\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.15, Page Number:920"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=25000.0#W\n",
"V=500.0#V\n",
"ra=0.03#ohm\n",
"rs=200.0#ohm\n",
"rseries=0.04#ohm\n",
"vb=1.0#V\n",
"n=1200#rpm\n",
"phi=0.02#Wb\n",
"\n",
"#calculations\n",
"i=p/V\n",
"ish=V/rs\n",
"ia=i+ish\n",
"p=4\n",
"vds=ia*rseries\n",
"vda=ia*ra\n",
"vdb=vb*2\n",
"E=V+vds+vda+vdb\n",
"Z=(E*60*4)/(phi*n*p)\n",
"\n",
"#result\n",
"print \"The e.m.f. generated= \",E,\" V\"\n",
"print \"The number of conductors=\",Z"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The e.m.f. generated= 505.675 V\n",
"The number of conductors= 1264.1875\n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.16, Page Number:920"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=4\n",
"n=750#rpm\n",
"e=240.0#V\n",
"z=792\n",
"phi=0.0145#Wb\n",
"\n",
"#calculations\n",
"phi_working=(e*60*2)/(n*z*p)\n",
"lambda_=phi/phi_working\n",
"\n",
"#results\n",
"print \"Leakage coefficient= \",round(lambda_,1)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Leakage coefficient= 1.2\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.17, Page Number:920"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=a=4\n",
"phi=0.07#Wb\n",
"t=220\n",
"rt=0.004#ohm\n",
"n=900#rpm\n",
"ia=50.0#A\n",
"\n",
"#calculations\n",
"z=2*t\n",
"E=(phi*z*n*p)/(60*a)\n",
"rtotal=t*rt\n",
"r_eachpath=rtotal/p\n",
"ra=r_eachpath/a\n",
"vda=ia*ra\n",
"V=E-vda\n",
"\n",
"#result\n",
"print \"Terminal Voltage= \",V, \" V\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Terminal Voltage= 459.25 V\n"
]
}
],
"prompt_number": 27
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.18, Page Number:920"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=a=4\n",
"phi=0.07#Wb\n",
"t=220\n",
"rturn=0.004#ohm\n",
"rs=100.0#ohm\n",
"rsc=0.02#ohm\n",
"n=900#rpm\n",
"ia=50.0#A\n",
"\n",
"#calculations\n",
"z=2*t\n",
"E=(phi*z*n*p)/(60*a)\n",
"ra=0.055#ohm\n",
"ra=ra+rsc\n",
"va=ia*ra\n",
"v=E-va\n",
"ish=v/rs\n",
"i=ia-ish\n",
"output=v*i\n",
"\n",
"#result\n",
"print \"Output= \",round(output/1000,3),\" kW\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Output= 20.813 kW\n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.19, Page Number:921"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"n1=1200#rpm\n",
"ia=200#A\n",
"v=125#V\n",
"n2=1000#rpm\n",
"ra=0.04#ohm\n",
"vb=2#V\n",
"\n",
"#calculations\n",
"E1=v+vb+(ia*ra)\n",
"E2=E1*n2/n1*0.8\n",
"\n",
"#results\n",
"print \"Generated e.m.f. when field current is reduced to 80%=\",E2,\" V\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Generated e.m.f. when field current is reduced to 80%= 90.0 V\n"
]
}
],
"prompt_number": 35
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.20(a), Page Number:921"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=4\n",
"rs=100.0#ohm\n",
"ra=1.0#ohm\n",
"z=378\n",
"phi=0.02#Wb\n",
"rl=10.0#ohm\n",
"n=1000#rpm\n",
"a=2\n",
"\n",
"#calculations\n",
"E=(phi*z*n*p)/(60*a)\n",
"V=(100.0/111.0)*E\n",
"il=V/rl\n",
"P=il*V\n",
"\n",
"#result\n",
"print \"Power absorbed by the load is= \",P,\" W\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power absorbed by the load is= 5154.12710007 W\n"
]
}
],
"prompt_number": 50
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.20(b), Page Number:921"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=a=4\n",
"z=300\n",
"phi=0.1#Wb\n",
"n=1000#rpm\n",
"ra=0.2#rpm\n",
"rf=125#ohm\n",
"il=90#A\n",
"\n",
"#calculations\n",
"E=(phi*z*n*p)/(60*a)\n",
"ifield=E/rf\n",
"ia=ifield+il\n",
"V=E-(ia*ra)\n",
"\n",
"#result\n",
"print \"Terminal voltage= \",V,\" V\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Terminal voltage= 481.2 V\n"
]
}
],
"prompt_number": 51
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.21(a), Page Number:922"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=6\n",
"n=1200#rpm\n",
"e=250.0#V\n",
"d=350.0#mm\n",
"air_gap=3.0#mm\n",
"al=260.0#mm\n",
"fringing=0.8\n",
"coils=96\n",
"t=3\n",
"\n",
"#calculations\n",
"z=t*coils*2\n",
"a=p*2\n",
"phi=(e*60*a)/(n*z*p)\n",
"di=d+air_gap\n",
"pole_arc=(3.14*di*fringing)/6\n",
"B=phi/(pole_arc*0.000001*al)\n",
"\n",
"#result\n",
"print \"flux per pole= \",phi,\" Wb\"\n",
"print \"effective pole arc lenght= \",pole_arc*0.001,\" m\"\n",
"print \"flux density= \",B,\" T\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"flux per pole= 0.0434027777778 Wb\n",
"effective pole arc lenght= 0.147789333333 m\n",
"flux density= 1.12953862717 T\n"
]
}
],
"prompt_number": 57
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.21(b), Page Number:922"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#variable declaration\n",
"p=a=4\n",
"z=1200\n",
"e=250.0#v\n",
"n=500#rpm\n",
"b=35.0#cm\n",
"ratio=0.7\n",
"lpole=20.0#cm\n",
"\n",
"#calculations\n",
"pole_pitch=(b*3.14)/p\n",
"polearc=ratio*pole_pitch\n",
"pole_area=polearc*lpole\n",
"phi=(e*60*a)/(n*z*p)\n",
"mean_flux=phi/(pole_area*math.pow(10,-4))\n",
" \n",
"#result\n",
"print \"Mean flux density= \",mean_flux,\" Wb/m2\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Mean flux density= 0.649941505265 Wb/m2\n"
]
}
],
"prompt_number": 67
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.21(d), Page Number:923"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"i=200.0#A\n",
"v=100.0#V\n",
"ra=0.04#ohm\n",
"rseries=0.03#ohm\n",
"rs=60.0#ohm\n",
"\n",
"#calculations\n",
"va=v+(i*rseries)\n",
"ish=va/rs\n",
"ia=i+ish\n",
"e=va+(ia*ra)\n",
"\n",
"#long shunt\n",
"ishunt=v/rs\n",
"vd=ia*(ra+rseries)\n",
"e2=v+vd\n",
"\n",
"#result\n",
"print \"emf generated(short shunt)\",e,\" V\"\n",
"print \"emf generated(long shunt)\",e2,\" V\"\n",
"\n",
"\n",
"#result\n",
"print "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"emf generated(short shunt) 114.070666667 V\n",
"emf generated(long shunt) 114.123666667 V\n",
"\n"
]
}
],
"prompt_number": 73
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.22, Page Number:923"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"n=1000#rpm\n",
"w=20000.0#W\n",
"v=220.0#v\n",
"ra=0.04#ohm\n",
"rs=110.0#ohm\n",
"rseries=0.05#ohm\n",
"efficiency=.85\n",
"\n",
"#calculations\n",
"il=w/v\n",
"i_f=v/rs\n",
"ia=il+i_f\n",
"ip=w/efficiency#input power\n",
"total_loss=ip-w\n",
"copper_loss=(ia*ia*(ra+rseries))+(i_f*i_f*rs)\n",
"ironloss=total_loss-copper_loss\n",
"omega=2*3.14*n/60\n",
"T=ip/omega\n",
"\n",
"#omega\n",
"print \"Copper loss= \",copper_loss,\" W\"\n",
"print \"Iron and friction loss= \",ironloss,\" W\"\n",
"print \"Torque developed by the prime mover= \",T,\"Nw-m\"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Copper loss= 1216.88892562 W\n",
"Iron and friction loss= 2312.52283909 W\n",
"Torque developed by the prime mover= 224.803297115 Nw-m\n"
]
}
],
"prompt_number": 75
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.23, Page Number:928"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declartaion\n",
"power=10000.0#W\n",
"v=250.0#V\n",
"p=a=6\n",
"n=1000.0#rpm\n",
"z=534\n",
"cu_loss=0.64*1000#W\n",
"vbd=1.0#V\n",
"\n",
"#calculations\n",
"ia=power/v\n",
"ra=cu_loss/(ia*ia)\n",
"E=v+(ia*ra)+vbd\n",
"phi=(E*60*a)/(n*z*p)\n",
"\n",
"#result\n",
"print \"flux per pole= \",phi*1000,\" mWb\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"flux per pole= 30.0 mWb\n"
]
}
],
"prompt_number": 25
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.24(a), Page Number:928"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"i=195#A\n",
"pd=250#V\n",
"ra=0.02#ohm\n",
"rsh=50#ohm\n",
"p=250#W\n",
"strayloss=950#W\n",
"#calculations\n",
"ish=pd/rsh\n",
"ia=i+ish\n",
"vda=ia*ra\n",
"E=pd+vda\n",
"cu_loss=(ia*ia*ra)+(pd*ish)\n",
"output_prime=(pd*i)+strayloss+cu_loss\n",
"power_a=output_prime-strayloss\n",
"neu_m=(power_a/output_prime)\n",
"neu_e=(pd*i)/((pd*i)+cu_loss)\n",
"neu_c=(pd*i)/output_prime\n",
"\n",
"#result\n",
"print \"a)e.m.f. generated= \",E,\" V\"\n",
"print \" b)Cu losses= \",cu_loss,\" W\"\n",
"print \" c)output of prime mover= \",output_prime,\" W\"\n",
"print \" d)mechanical efficiency= \",neu_m*100,\" %\"\n",
"print \" electrical efficiency= \",neu_e*100,\" %\"\n",
"print \" commercial efficiency= \",neu_c*100,\" %\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a)e.m.f. generated= 254.0 V\n",
" b)Cu losses= 2050.0 W\n",
" c)output of prime mover= 51750.0 W\n",
" d)mechanical efficiency= 98.1642512077 %\n",
" electrical efficiency= 95.9645669291 %\n",
" commercial efficiency= 94.2028985507 %\n"
]
}
],
"prompt_number": 30
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.24(b), Page Number:929"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"v=500.0#V\n",
"i=5.0#A\n",
"ra=0.15#ohm\n",
"rf=200.0#ohm\n",
"il=40.0#A\n",
"\n",
"#calculations\n",
"output=v*il\n",
"total_loss=(v*i*0.5)+((il+i*0.5)*(il+i*0.5)*ra)+(v*i*0.5)\n",
"efficiency=output/(output+total_loss)\n",
"\n",
"#result\n",
"print \"Efficiency= \",efficiency*100,\" %\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Efficiency= 87.8312542029 %\n"
]
}
],
"prompt_number": 39
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.25, Page Number:929"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#variable declaration\n",
"i=196#A\n",
"v=220#V\n",
"stray_loss=720#W\n",
"rsh=55#ohm\n",
"e=0.88\n",
"\n",
"#calculations\n",
"output=v*i\n",
"inpute=output/e\n",
"total_loss=inpute-output\n",
"ish=v/rsh\n",
"ia=i+ish\n",
"cu_loss=v*ish\n",
"constant_loss=cu_loss+stray_loss\n",
"culoss_a=total_loss-constant_loss\n",
"ra=culoss_a/(ia*ia)\n",
"I=math.sqrt(constant_loss/ra)\n",
"\n",
"#result\n",
"print \"Load curent corresponding to maximum efficiency\",I,\" A\" "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Load curent corresponding to maximum efficiency 122.283568103 A\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.26, Page Number:929"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"n=1000#rpm\n",
"p=22*1000#w\n",
"v=220#V\n",
"ra=0.05#ohm\n",
"rsh=110#ohm\n",
"rseries=0.06#ohm\n",
"efficiency=.88\n",
"\n",
"#calculations\n",
"ish=v/rsh\n",
"I=p/v\n",
"ia=ish+I\n",
"vdseries=ia*rseries\n",
"cu_loss=(ia*ia*ra)+(ia*ia*rseries)+(rsh*ish*ish)\n",
"total_loss=(p/efficiency)-p\n",
"strayloss=total_loss-cu_loss\n",
"T=(p/efficiency*60)/(2*3.14*n)\n",
"\n",
"#result\n",
"print \"a)cu losses= \",cu_loss,\" W\"\n",
"print \"b)iron and friction loss= \",strayloss,\" W\"\n",
"print \"c)Torque exerted by the prime mover= \",T,\" N-m\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a)cu losses= 1584.44 W\n",
"b)iron and friction loss= 1415.56 W\n",
"c)Torque exerted by the prime mover= 238.853503185 N-m\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.27, Page Number:930"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=4\n",
"i=20#A\n",
"r=10#ohm\n",
"ra=0.5#ohm\n",
"rsh=50#ohm\n",
"vdb=1#V(voltage drop per brush)\n",
"\n",
"#calculations\n",
"v=i*r\n",
"ish=v/rsh\n",
"ia=i+ish\n",
"E=v+(ia*ra)+(2*vdb)\n",
"totalpower=E*ia\n",
"output=v*i\n",
"efficiency=output/totalpower\n",
"\n",
"#result\n",
"print \"induced e.m.f.= \",E,\" V\"\n",
"print \"efficiency= \",efficiency*100,\" %\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"induced e.m.f.= 214.0 V\n",
"efficiency= 77.8816199377 %\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.28, Page Number:930"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"v=240#V\n",
"i=100#A\n",
"ra=0.1#ohm\n",
"rseries=0.02#ohm\n",
"ri=0.025#ohm\n",
"rsh=100#ohm\n",
"ironloss=1000#W\n",
"frictionloss=500#W\n",
"\n",
"#calculations\n",
"output=v*i\n",
"totalra=ra+rseries+ri\n",
"ish=v/rsh\n",
"ia=i+ish\n",
"copperloss=ia*ia*totalra\n",
"shculoss=ish*v\n",
"total_loss=copperloss+ironloss+frictionloss+shculoss\n",
"efficiency=output/(output+total_loss)\n",
"\n",
"#result\n",
"print \"F.L. efficiency of the machine= \",efficiency*100,\" %\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"F.L. efficiency of the machine= 87.3089843128 %\n"
]
}
],
"prompt_number": 25
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.29, Page Number:930"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from sympy.solvers import solve\n",
"from sympy import Symbol\n",
"#variable declaration\n",
"A=Symbol('A')\n",
"B=Symbol('B')\n",
"ironloss=8#kW\n",
"r=0.25#reduction in speed\n",
"n_ironloss=5#kW\n",
"\n",
"#calculations\n",
"ans=solve([ironloss-(A*1+B*1**2),n_ironloss-(A*(1-r)+B*(1-r)**2)],[A,B])\n",
"wh=ans[A]\n",
"we=ans[B]\n",
"wh2=ans[A]*0.5\n",
"we2=ans[B]*0.5**2\n",
"\n",
"#result\n",
"print \"i)full speed:\"\n",
"print \"Wh=\",round(wh,3),\"kW\"\n",
"print \"We=\",round(we,3),\"kW\"\n",
"print \"ii)half speed:\"\n",
"print \"Wh=\",round(wh2,3),\"kW\"\n",
"print \"We=\",round(we2,3),\"kW\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"i)full speed:\n",
"Wh= 2.667 kW\n",
"We= 5.333 kW\n",
"ii)half speed:\n",
"Wh= 1.333 kW\n",
"We= 1.333 kW\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.30, Page Number:931"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from sympy.solvers import solve\n",
"from sympy import Symbol\n",
"#variable declaration\n",
"N=Symbol('N')\n",
"n=1000.0#rpm\n",
"wh=250.0#w\n",
"we=100.0#w\n",
"\n",
"#calculations\n",
"A=wh/(n/60)\n",
"B=we/((n/60)**2)\n",
"new_loss=(wh+we)/2\n",
"ans=solve([new_loss-A*N-B*(N**2)],[N])\n",
"\n",
"#result\n",
"print \"Speed at which total loss will be halved=\",ans[1],\"r.p.s\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Speed at which total loss will be halved= (9.50045787200216,) r.p.s\n"
]
}
],
"prompt_number": 29
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.31, Page Number:931"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"output=10.0*1000#W\n",
"v=240.0#V\n",
"ra=0.6#ohm\n",
"rsh=160.0#ohm\n",
"mechcoreloss=500.0#W\n",
"culoss=360.0#W\n",
"\n",
"#calculations\n",
"ish=v/rsh\n",
"i=output/v\n",
"ia=ish+i\n",
"culossa=ia*ia*ra\n",
"totalloss=culoss+mechcoreloss+culossa\n",
"inputp=output+totalloss\n",
"efficiency=output/inputp\n",
"\n",
"#result\n",
"print \"Power required= \",inputp*0.001,\" kW\"\n",
"print \"efficinecy= \",efficiency*100,\" %\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power required= 11.9780166667 kW\n",
"efficinecy= 83.486275552 %\n"
]
}
],
"prompt_number": 30
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.32, Page Number:932"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=110*1000#W\n",
"v=220#V\n",
"ra=0.01#ohm\n",
"rse=0.002#ohm\n",
"rsh=110#ohm\n",
"\n",
"#calculations\n",
"il=p/v\n",
"ish=v/rsh\n",
"ia=il+ish\n",
"E=v+ia*(ra+rse)\n",
"\n",
"#result\n",
"print \"induced emf= \",E,\" V\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"induced emf= 226.024 V\n"
]
}
],
"prompt_number": 31
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.33 Page Number:932"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=4\n",
"E=216.0#V\n",
"n=600.0#rpm\n",
"slots=144\n",
"con=6\n",
"n2=500.0#rpm\n",
"\n",
"#calculations\n",
"z=con*slots\n",
"a=p\n",
"phi=(E*60*a)/(n*z*p)\n",
"a=2\n",
"armatureE=(phi*z*n2*p)/(60*a)\n",
"\n",
"#result\n",
"print \"the armature emf= \",armatureE,\" V\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"the armature emf= 360.0 V\n"
]
}
],
"prompt_number": 34
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example Number 26.34 Page Number:933"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#variable declaration\n",
"p=4\n",
"r=0.15#ohm\n",
"\n",
"#calculations\n",
"ar=p*r\n",
"\n",
"#result\n",
"print \"armature resistance=\",ar"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"armature resistance= 0.6\n"
]
}
],
"prompt_number": 30
},
{
"cell_type": "code",
"collapsed": false,
"input": [],
"language": "python",
"metadata": {},
"outputs": []
}
],
"metadata": {}
}
]
}