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{
"metadata": {
"name": "",
"signature": "sha256:be9aefa42ea24d22209fa6e445a45f49fdad11d5bccd40a3dc326a3a8a516f5d"
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"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"CHAPTER 9 - ELEMENTS OF DC MACHINE DESIGN "
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E1 - Pg 195"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Caption:Find the dimensions of D and L\n",
"#Exa:9.1\n",
"import math\n",
"P=15000.#Power of shunt motor(in watt)\n",
"V=440.#Supplied voltage to motor(in volts)\n",
"n=1500.#Speed of motor(in r.p.m)\n",
"e=88.#Efficiency(in %)\n",
"B=0.65#Average flux density(in webers/m**2)\n",
"q=30000.#Specific electric loading(ampere conductors/m)\n",
"p=4.#Number of poles\n",
"R_f=220.#Field resistance(in ohms)\n",
"P_i=P/(e/100.)\n",
"I=P_i/V\n",
"I_f=V/R_f\n",
"D=170.#Choosing the diameter(in mm)\n",
"L=(P_i)/((math.pi**2.)*((D**2.)*(10.**(-6.)))*B*q*(n/60.)*(10.**(-3.)))\n",
"print '%s %.1f' %('Required dimensions of L (min)=',L)\n",
"print '%s %.f' %(' D(in mm)=',D)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Required dimensions of L (min)= 122.6\n",
" D(in mm)= 170\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E2 - Pg 198"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Caption: Find values of the 5 steps in a 6 stud starter for a d.c. shunt motor\n",
"#Exa:9.2\n",
"P_o=3730.#Output power(in watt)\n",
"V=200.#Voltage supplied to motor(in volts)\n",
"e=88.#Efficiency(in%)\n",
"P_i=P_o/(e/100.)\n",
"I=P_i/V#Full load current\n",
"I_a=I#Neglecting field current\n",
"L=P_i-P_o\n",
"Cu=(1./2.)*L#Copper loss is half the total loss(Given)\n",
"R_a=Cu/(I**2.)\n",
"I_m=(2.*I)#Maximum current is twice full load current(Given)\n",
"R_1=V/I_m\n",
"g=(R_1/R_a)**(1./5.)\n",
"R_2=R_1/g\n",
"r1=R_1-R_2\n",
"R_3=R_2/g\n",
"r2=R_2-R_3\n",
"R_4=R_3/g\n",
"r3=R_3-R_4\n",
"R_5=R_4/g\n",
"r4=R_4-R_5\n",
"R_6=R_5/g\n",
"r5=R_5-R_6\n",
"print '%s %.2f' %('Required resistances r1 (ohms)=',r1)\n",
"print '%s %.2f' %(' r2 (ohms)=',r2)\n",
"print '%s %.2f' %(' r3 (ohms)=',r3)\n",
"print '%s %.2f' %(' r4 (ohms)=',r4)\n",
"print '%s %.2f' %(' r5 (ohms)=',r5)\n",
"print '%s %.2f' %(' R_a (ohms)=',R_a)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Required resistances r1 (ohms)= 1.63\n",
" r2 (ohms)= 1.07\n",
" r3 (ohms)= 0.70\n",
" r4 (ohms)= 0.46\n",
" r5 (ohms)= 0.30\n",
" R_a (ohms)= 0.57\n"
]
}
],
"prompt_number": 2
}
],
"metadata": {}
}
]
}
|
