{
"metadata": {
"name": "",
"signature": "sha256:b09b7fb5366e8af61b1c0396c23ff3a998c9bd372716836d0d1fda9706db6296"
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 6 : DC Machines"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.1 Page No : 6.3"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"# Variables\n",
"P = 4;\t\t\t\t#no. of poles\n",
"c = 2;\t\t\t\t#no. of parallel paths\n",
"p = 4./2;\t\t\t\t#no. of pair of poles\n",
"S = 51;\t\t\t\t#no. of slots\n",
"C = 12;\t\t\t\t#conductors per slot\n",
"N = 900;\t\t\t\t#rpm(speed)\n",
"fi = 25./1000;\t\t\t\t#Wb\n",
"\n",
"# Calculations\n",
"Z = S*C;\t\t\t\t#total no. of conductors\n",
"E = 2*Z/c*N*p/60*fi;\t\t\t\t#V\n",
"\n",
"# Results\n",
"print \"Generated emf(V): %.2f\"%E\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Generated emf(V): 459.00\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.2 Page No : 6.4"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"P = 8.;\t\t\t\t#no. of poles\n",
"c = 8.;\t\t\t\t#no. of parallel paths\n",
"p = 8./2;\t\t\t\t#no. of pair of poles\n",
"E = 260.;\t\t\t\t#V(generated emf)\n",
"fi = 0.05;\t\t\t\t#Wb\n",
"S = 120;\t\t\t\t#no. of slots\n",
"N = 350;\t\t\t\t#rpm(speed)\n",
"\n",
"# Calculations\n",
"Z = E/(2./c*N*p/60*fi);\t\t\t\t#V\n",
"\n",
"# Results\n",
"print \"No. of conductors per slot\",int(Z)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"No. of conductors per slot 891\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.3 Page No : 6.6"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"Ra = 0.1;\t\t\t\t#ohm(Armature Resistance)\n",
"Vs = 250;\t\t\t\t#V(supply voltage)\n",
"\n",
"# Calculations and Results\n",
"#part(a)\n",
"I = 80;\t\t\t\t#A\n",
"Vdrop = Ra*I;\t\t\t\t#V\n",
"emf = Vs+Vdrop;\t\t\t\t#V(Generated emf)\n",
"print \"Part(a) Generated emf(V) : %.2f\"%emf\n",
"\n",
"#part(b)\n",
"I = 60;\t\t\t\t#A(current taken by Motor)\n",
"Vdrop = Ra*I;\t\t\t\t#V\n",
"emf = Vs-Vdrop;\t\t\t\t#V(Generated emf)\n",
"print \"Part(b) Generated emf(V) : %.2f\"%emf\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Part(a) Generated emf(V) : 258.00\n",
"Part(b) Generated emf(V) : 244.00\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.4 Page No : 6.7"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"P = 4;\t\t\t\t#no. of poles\n",
"Vs = 440;\t\t\t\t#V\n",
"c = 2;\t\t\t\t#no. of parallel paths\n",
"p = 4./2;\t\t\t\t#no. of pair of poles\n",
"Ia = 50;\t\t\t\t#A\n",
"Ra = 0.28;\t\t\t\t#ohm\n",
"Z = 888;\t\t\t\t#conductors\n",
"fi = 0.023;\t\t\t\t#Wb\n",
"\n",
"# Calculations\n",
"emf = Vs-Ia*Ra;\t\t\t\t#V\n",
"N = emf/(2*Z/c*p/60*fi);\t\t\t\t#rpm\n",
"\n",
"# Results\n",
"print \"Speed in rpm\",round(N)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Speed in rpm 626.0\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.5 Page No : 6.7"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"# Variables\n",
"N = 900;\t\t\t\t#rpm\n",
"Vs = 460.;\t\t\t\t#V\n",
"Vs_new = 200;\t\t\t\t#V\n",
"fi_ratio = 0.7;\t\t\t\t#ratio of new flux to original flux\n",
"\n",
"# Calculations\n",
"kfi = Vs/N;\t\t\t\t#for original flux\n",
"Nnew = Vs_new/kfi/fi_ratio;\t\t\t\t#rpm(new speed)\n",
"\n",
"# Results\n",
"print \"Speed in rpm\",round(Nnew)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Speed in rpm 559.0\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.6 Page No : 6.8"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"# Variables\n",
"Ia = 110;\t\t\t\t#A\n",
"Vs = 480;\t\t\t\t#V\n",
"Ra = 0.2;\t\t\t\t#ohm\n",
"P = 6.;\t\t\t\t#no. of poles\n",
"c = 6.;\t\t\t\t#no. of parallel paths\n",
"p = P/2;\t\t\t\t#no. of pair of poles\n",
"Z = 864;\t\t\t\t#no. of conductors\n",
"fi = 0.05;\t\t\t\t#Wb\n",
"\n",
"# Calculations and Results\n",
"emf = Vs-Ia*Ra;\t\t\t\t#V\n",
"N = emf/(2*Z/c*p/60*fi);\t\t\t\t#rpm\n",
"print \"(a) Speed in rpm\",round(N)\n",
"\n",
"Pm = Ia*emf;\t\t\t\t#W(Mechanical power developed)\n",
"M = Pm/(N/60)/(2*math.pi);\t\t\t\t#Nm(Torque)\n",
"print \"(b) Gross torque developed(Nm) : %.f\"%M\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"(a) Speed in rpm 636.0\n",
"(b) Gross torque developed(Nm) : 756\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.7 Page No : 6.9"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"# Variables\n",
"N = 15;\t\t\t\t#rps\n",
"M = 2*1000;\t\t\t\t#Nm(Torque required)\n",
"Loss = 8*1000;\t\t\t\t#W\n",
"\n",
"# Calculations\n",
"P = 2*math.pi*M*N;\t\t\t\t#W(Power required)\n",
"Pa = P-Loss;\t\t\t\t#W(Power generated in armature)\n",
"\n",
"# Results\n",
"print \"Power generated in armature(kW) : %.2f\"%(Pa/1000)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power generated in armature(kW) : 180.50\n"
]
}
],
"prompt_number": 10
}
],
"metadata": {}
}
]
}