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{
"metadata": {
"name": ""
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
" Chapter 2:Dynamics of Electric Drives"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example no:2.1,Page no:16"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"\n",
"#variable declaration\n",
"Jo=0.2 # inertia of the motor in kg-m2\n",
"a1=0.1 # reduction gear\n",
"J1=10 # inertia of the load in kg-m2\n",
"Tl1=10 # load torque\n",
"v=1.5 # speed of the translational load \n",
"M1=1000 # mass of the translational load\n",
"N=1420 # speed of the motor\n",
"n1=.9 # efficiency of the reduction gear\n",
"n1_=0.85 # efficiency of the translational load and the motor\n",
"F1=M1*9.81 # force of the translational load \n",
"\n",
"#Calculation\n",
"Wm=N*math.pi/30 #angular speed\n",
"J=Jo+a1**2*J1+ M1*(v/Wm)**2 # total equivalent moment of inertia\n",
"Tl= a1*Tl1/n1+F1/n1_*(v/Wm) # total equivalent torque\n",
"\n",
"#Result\n",
"print\"\\nEquivalent moment of inertia is :\",round(J,1),\"kg-m2\"\n",
"print\"\\nEquivalent load torque :\",round(Tl,2),\"N-m\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"Equivalent moment of inertia is: 0.4 kg-m2\n",
"\n",
"Equivalent load torque : 117.53 N-m\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example no:2.2,Page no:22"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import scipy\n",
"from scipy import integrate\n",
"import math\n",
"\n",
"# variable declaration\n",
"J=10 #moment of inertia of the drive in kg-m2\n",
"print(\"Passive load torque during steady state is :Tl=0.05*N in N-m\")\n",
"print(\"And load torque : T=100-0.1*N in N-m \")\n",
"print(\"load torque when the direction is reversed T=-100-0.1*N in N-m\")\n",
"\n",
"#Calculation\n",
"print(\"T-Tl=0\")\n",
"print(\"100-0.1*N-0.05*N=0\")\n",
"N=100/0.15 #Required speed of the motor in rpm during steady state\n",
"N2=-100/0.15 #During reversal speed is in opposite direction\n",
"print(\"\\nJdWm/dt=-100-0.1*N-0.05*N during reversing\")\n",
"print(\"dN/dt=30/(J*pi)*(-100-0.15*N)\")\n",
"print(\"dN/dt=(-95.49-0.143*N)\")\n",
"N1=N\n",
"N2=N2*0.95 #for speed reversal \n",
"x2 = lambda N: 1/(-95.49-0.143*N)\n",
"t=integrate.quad(x2, round(N1), round(N2))\n",
"\n",
"#result\n",
"print\"\\nHence Time of reversal is :\",round(t[0],2),\"s\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Passive load torque during steady state is :Tl=0.05*N in N-m\n",
"And load torque : T=100-0.1*N in N-m \n",
"load torque when the direction is reversed T=-100-0.1*N in N-m\n",
"T-Tl=0\n",
"100-0.1*N-0.05*N=0\n",
"\n",
"JdWm/dt=-100-0.1*N-0.05*N during reversing\n",
"dN/dt=30/(J*pi)*(-100-0.15*N)\n",
"dN/dt=(-95.49-0.143*N)\n",
"\n",
"Hence Time of reversal is : 25.51 s\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example no:2.3,Page no:27"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"from __future__ import division\n",
"\n",
"#variable declaration\n",
"Tlh=1000 # load torque in N-m\n",
"Tmax=700 # maximum motor torque\n",
"Tll=200 # light load for the motor to regain its steady state\n",
"Tmin=Tll # minimum torque\n",
"t_h=10 # period for which a load torque of 1000 N-m is apllied in sec\n",
"Jm=10 # moment of inertia of the motor in Kg-m2\n",
"No=500 # no load speed in rpm\n",
"Tr=500 # torque at a given no load speed in N-m\n",
"\n",
"#Calculation\n",
"Wmo=No*2*math.pi/60 # angular no load speed in rad/sec\n",
"s=0.05 # slip at a torque of 500 N-m\n",
"Wmr=(1-s)*Wmo # angular speed at a torque of 500 N-m in rad/sec\n",
"\n",
"y=math.log((Tlh-Tmin)/(Tlh-Tmax))\n",
"x=Tr/(Wmo-Wmr)\n",
"\n",
"J=x*t_h/y\n",
"Jf=J-Jm\n",
"\n",
"#Result \n",
"#answer in the book is wrong\n",
"print\"\\n\\nMoment of inertia of the flywheel : \", round(Jf,1),\"Kg-m2\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"\n",
"Moment of inertia of the flywheel : 1937.2 Kg-m2\n"
]
}
],
"prompt_number": 12
}
],
"metadata": {}
}
]
}
|
