{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter 4: Introduction to Rotating Machines" ] }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 4.2, Page number: 199" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from math import *\n", "\n", "#Variable declaration:\n", "uo=4*pi*10**-7 #Permeabolity of free space(H/m)\n", "g=0.7*10**-3 #Length of air gap(m)\n", "p=4 #no. of poles\n", "Ba=1.6 #Magnetic flux density(T)\n", "Kr=0.935 #Winding constant\n", "N=263 #No. of turns\n", "\n", "#Calculations:\n", "Ir=(pi*g*p/(4*uo*Kr*N))*1.6\n", "\n", "\n", "#Results:\n", "print \"Rotor winding current:\",round(Ir,1),\"A\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Rotor winding current: 11.4 A\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 4.3, Page number: 208" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from math import *\n", "\n", "#Variable declaration:\n", "fc=60 #frequency of the current(Hz)\n", "p=[2, 4, 6] #matrix of no. of poles\n", "\n", "#Calculations:\n", "ns=[0]*3\n", "ws=[0]*3\n", "wc=2*pi*fc\n", "for n in range(0,3,1):\n", " ws[n]=round((2/p[n])*wc,0)\n", " \n", "for i in range(0,3,1):\n", " ns[i]=round(120*fc/p[i],0)\n", "\n", "\n", "#Results:\n", "print \"The synchronous angular velocities:\",ws, \"rad/sec\"\n", "print \"The speed of the rotor:\",ns,\"r/min\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The synchronous angular velocities: [377.0, 188.0, 126.0] rad/sec\n", "The speed of the rotor: [3600.0, 1800.0, 1200.0] r/min\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 4.5, Page number: 212" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from math import *\n", "\n", "#Variable declaration:\n", "Nf=68 #Field winding\n", "Na=18 #Armature winding\n", "r=0.53 #mean air gap radius(m)\n", "l=3.8 #Armature winding length(m)\n", "Kf=0.945 #Winding factor of field winding\n", "Ka=0.933 #Winding factor of armature winding\n", "g=4.5*10**-2 #Air gap length(m)\n", "p=2 #No. of poles\n", "If=720 #field current(A)\n", "uo=4*pi*10**-7 #Permeability of free space(H/m)\n", "f=60 #Frequency curent(Hz)\n", "\n", "#Calculations:\n", "Fag1_peak=4*Kf*Nf*If/(pi*p)\n", "Bag1_peak=uo*Fag1_peak/g\n", "Qp=2*Bag1_peak*l*r\n", "Erms=sqrt(3)*sqrt(2)*pi*f*Ka*Na*Qp\n", "\n", "\n", "#Results:\n", "print \"The peak fundamental mmf,Fag1_peak: \",round(Fag1_peak/10000,2),\"* 10^4 A.turns/pole\"\n", "print \"\\nThe flux density in the air gap,Bag1_peak: \",round(Bag1_peak,2),\"T\"\n", "print \"\\nThe fundamental flux per pole, Qp:\" ,round(Qp,2),\"Wb\"\n", "print \"\\nThe rms value of open circuit voltage,Erms: \",round(Erms/1000,1),\"KV\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The peak fundamental mmf,Fag1_peak: 2.95 * 10^4 A.turns/pole\n", "\n", "The flux density in the air gap,Bag1_peak: 0.82 T\n", "\n", "The fundamental flux per pole, Qp: 3.31 Wb\n", "\n", "The rms value of open circuit voltage,Erms: 25.7 KV\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 4.8, Page number: 225" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from math import *\n", "\n", "#Variable Declaration:\n", "ns=1800 #Speed of rotor(rpm)\n", "f=60 #Frequency(Hz)\n", "g=1.2*10**-3 #Air gap length(m)\n", "D=0.27 #Avg diameter of the gap(m)\n", "Kr=0.976 #Winding factor\n", "l=0.32 #Axial length(m)\n", "I=18 #Rotor current(A)\n", "p=4 #No of poles\n", "Nr=786 #Rotor windings\n", "B_max=1.5 #Max. flux densiity(T)\n", "\n", "\n", "#Calculations:\n", "Fr_max=4*Kr*Nr*I/(pi*p)\n", "T_max=p*pi*D*l*B_max*Fr_max/4\n", "wm=ns*pi/30\n", "P=wm*T_max\n", "\n", "\n", "#Results:\n", "print \"Maximum torque, T_max:\",round(T_max,0),\"Nm\"\n", "print \"Maximum power,P:\",round(P/1000,0),\"kW\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Maximum torque, T_max: 1790.0 Nm\n", "Maximum power,P: 337.0 kW\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "Example 4.9, Page number: 229" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from math import *\n", "\n", "#Variable Declaration:\n", "b=0.5 #Wavelength of wnding(m)\n", "l=1.5 #Winding length(m)\n", "I=700 #Currents in windings(A)\n", "N=45 #No. of turns\n", "K=0.92 #winding factor\n", "p=3 #No. of phases\n", "uo=4*pi*10**-7\n", "g=0.01 #Air gap flux(m)\n", "f=25 #Frequency of the exciting current(A)\n", "\n", "#Calculations:\n", "F_peak=(3*4*K*N*700)/round(4*pi*p,-1)\n", "B=uo*F_peak/g\n", "v=f*b\n", "\n", "#Results:\n", "print \"Amplitude of the resultant mmf wave:\",round(F_peak/1000,1),\"kA/m\"\n", "print \"Peak air gap flux:\",round(B,1),\"T\"\n", "print \"Velocity of the travelling wave:\",v,\"m/s\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Amplitude of the resultant mmf wave: 8.7 kA/m\n", "Peak air gap flux: 1.1 T\n", "Velocity of the travelling wave: 12.5 m/s\n" ] } ], "prompt_number": 5 } ], "metadata": {} } ] }