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{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 7 - Power Controllers - Their Applications"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex 7.1 page 260"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"\n",
" Speed of motor = 517 rpm\n"
]
}
],
"source": [
"from __future__ import division\n",
"from math import sqrt,cos,pi\n",
"N1=1000 # rpm\n",
"Va1=200 # V\n",
"alfa=60 # degree\n",
"Va2=230 # V\n",
"\n",
"N2=2*Va2*sqrt(2)*cos(alfa*pi/180)*N1/Va1/pi\n",
"print '\\n Speed of motor = %d rpm'%(N2)\n",
"# ans in the textbook is not accurate."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex 7.2 page 260"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"\n",
" duty ratio = 0.82\n"
]
}
],
"source": [
"from __future__ import division\n",
"\n",
"N1=1100 # rpm\n",
"Va1=220 # V\n",
"N2=900 # rpm\n",
"\n",
"Va2=Va1*N2/N1 # V\n",
"delta=Va2/Va1 # duty ratio\n",
"print '\\n duty ratio = %.2f'%(delta)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex 7.3 page 261"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"\n",
" triggering angle = 57.9 degree\n"
]
}
],
"source": [
"from __future__ import division\n",
"from math import sqrt,cos,pi,acos\n",
"\n",
"N1=900 # rpm\n",
"Va1=198 # V\n",
"N2=500 # rpm\n",
"Vs=230 # V\n",
"\n",
"Va2=Va1*N2/N1 # V\n",
"# 2*sqrt(2)*Vs*cos(alfa)/pi=Va2\n",
"alfa=acos(Va2/(2*sqrt(2)*Vs)*pi)*180/pi # degree\n",
"\n",
"print '\\n triggering angle = %.1f degree'%(alfa)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Ex 7.4 page 261"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"\n",
" average armature current = 9.35 A\n",
"\n",
" torque = 4.674 Nm\n"
]
}
],
"source": [
"from __future__ import division\n",
"from math import pi\n",
"Vs=230 # V\n",
"Ton=10 # ms\n",
"Toff=25 # ms\n",
"Ra=2 # ohm\n",
"N=1400 # rpm\n",
"k=0.5 # V/rad/s (back emf constant)\n",
"kt=0.5 # NM-A**-1 (torque constant)\n",
"\n",
"Eb=N*2*pi*k/60 # V\n",
"Va=Vs*Ton/(Toff) # V\n",
"Ia=(Va-Eb)/Ra # A\n",
"T=kt*Ia # Nm\n",
"print '\\n average armature current = %.2f A'%( Ia)\n",
"print '\\n torque = %.3f Nm'%( T)"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 2",
"language": "python",
"name": "python2"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 2
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython2",
"version": "2.7.9"
}
},
"nbformat": 4,
"nbformat_minor": 0
}
|
