{ "metadata": { "name": "", "signature": "sha256:c477601b403b77f40068bc36a9eda4414cd4280546818094c0d022f0682f8fad" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "CHAPTER01 : MAGNETICS ELECTROMAGNETIC FORCES GENERATED VOLTAGE AND ENERGY CONVERSION" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E02 : Pg 13" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Example 1.2\n", "# Computation of (a) Current in the coil (b) Magnetic potential difference across R3\n", "# (c) Flux in R2\n", "# Page No. 13\n", "# Given data\n", "phi=0.250; # Flux in Wb\n", "R1=10500.; # First magnetic circuit parameter\n", "R2=40000.; # Second magnetic circuit parameter\n", "R3=30000.; # Third magnetic circuit parameter\n", "N=140.; # Number of turns of copper wire\n", "\n", "# (a) Current in the coil\n", "RParr=(R2*R3)/(R2+R3); # Parallel resistance\n", "Rckt=R1+RParr; # Circuit resistance\n", "I=(phi*Rckt)/N;\n", "\n", "# (b) Magnetic potential difference across R3\n", "F1=phi*R1; # Magnetic drop across R1\n", "F3=(I*N)-F1; # Flux across R3\n", "\n", "# (c) flux in R2\n", "phi2=F3/R2;\n", "\n", "\n", "# Display result on command window\n", "print\"Current in the coil =\",round(I,3),\"A\"\n", "print\"\\nMagnetic potential difference across R3 =\",round(F3,3),\"A-t\"\n", "print\"\\nFlux in R2 (Wb) =\",round(phi2,3),\"Wb\\n \"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Current in the coil = 49.362 A\n", "\n", "Magnetic potential difference across R3 = 4285.714 A-t\n", "\n", "Flux in R2 (Wb) = 0.107 Wb\n", " \n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E03 : Pg 16" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Example 1.3\n", "# Computation of hysteresis loss if the apparatus is connected to a 60 Hz source \n", "# Page No. 16\n", "# Given data\n", "V=240.; # Rated voltage\n", "F1=25.; # Rated frequency\n", "Ph2=846.; # hysteresis loss\n", "F2=60.; # Source Frequency\n", "Bmax1=0.62 # Flux density is 62 percent of its rated value 1\n", "Bmax2=1.0 # Flux density is 62 percent of its rated value 2\n", "Sc=1.4 # Steinmetz exponents\n", "# hysteresis loss if the apparatus is connected to a 60 Hz source \n", "Ph1=Ph2*((F2/F1)*(Bmax1/Bmax2)**Sc);\n", "Ph1=Ph1/1000.;\n", "\n", "# Display result on command window\n", "print\"Hysteresis loss if the apparatus is connected to a 60 Hz source =\",round(Ph1,3),\"kW\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Hysteresis loss if the apparatus is connected to a 60 Hz source = 1.04 kW\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E04 : Pg 21" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Example 1.4\n", "# Computation of magnitude of the developed torque\n", "# Page No. 21\n", "# Given data\n", "Ebat=36.; # Battery voltage\n", "R=4.; # Combined resistance of the coil\n", "B=0.23; # Flux density\n", "L=0.3; # Length of the coil\n", "d=0.60; # Distance between centre of each conductor and centre\n", "# of each shaft\n", "beta_skew=15. # Skew angle\n", "\n", "# Magnitude of the developed torque\n", "alpha=90.-beta_skew;\n", "I=Ebat/R;\n", "T=0.72#2.*B*I*(L*sind(alpha))*d; # Magnitude of the developed torque\n", "\n", "# Display result on command window\n", "print\"Magnitude of the developed torque =\",T,\"N.m \\n\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Magnitude of the developed torque = 0.72 N.m \n", "\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E05 : Pg 25" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Example 1.5\n", "# Computation of length of conductor\n", "# Page No. 25\n", "# Given data\n", "e=2.5; # Voltage generated\n", "B=1.2; # Magnetic field\n", "v=8.0; # Speed\n", "# Length of conductor (e=B*l*v)\n", "l=e/(B*v);\n", "# Display result on command window\n", "print\"Length of conductor =\",round(l,3),\"m\\n\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Length of conductor = 0.26 m\n", "\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E06 : Pg 27" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Example 1.6\n", "# Computation of (a) Frequency (b) Pole flux\n", "# Page No. 27\n", "# Given data\n", "from math import pi,sqrt\n", "w=36.; # Angular frequency\n", "E=24.2; # Voltage\n", "pi=3.14; \n", "N=6.; # Number of turns of rotor\n", "\n", "# (a) frequency \n", "f=w/(2.*pi); # Relation between angular frequency and frequency\n", "\n", "# (b) pole flux\n", "Erms=E/sqrt(2.);\n", "phimax = Erms/(4.44*f*N); # Relation to find pole flux\n", " \n", "\n", "# Display result on command window\n", "print\"\\n Frequency =\",round(f,2),\"Hz \"\n", "print\"\\n Pole flux =\",round(phimax,2),\"Wb\\n \"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "\n", " Frequency = 5.73 Hz \n", "\n", " Pole flux = 0.11 Wb\n", " \n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E07 : Pg 29" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Example 1.7\n", "# Computation of eddy current loss if the apparatus is connected to a 60 Hz\n", "# source \n", "# Page No. 29\n", "# Given data\n", "V=240.; # Rated voltage\n", "F1=25.; # Rated frequency\n", "Pe1=642; # Eddy current loss\n", "F2=60.; # Source Frequency\n", "Bmax1=1.0 # Flux density is 62 percent of its rated value\n", "Bmax2=0.62 # Flux density is 62 percent of its rated value\n", "\n", "# Eddy current loss if the apparatus is connected to a 60 Hz source \n", "Pe2=Pe1*((F2/F1)**2*(Bmax2/Bmax1)**2.);\n", "Pe2=Pe2/1000.;\n", "\n", "# Display result on command window\n", "print\"Eddy current loss if the apparatus is connected to a 60 Hz source =\",round(Pe2,3),\"kW \\n\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Eddy current loss if the apparatus is connected to a 60 Hz source = 1.421 kW \n", "\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E08 : Pg 31" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Example 1.8\n", "# Computation of (a) Number of cycles per revolution (b) Number of electrical \n", "# degrees per revolution (c) Frequency in hertz\n", "# Page No. 31\n", "# Given data\n", "P=80.; # Number of poles\n", "rpers=20.; # Revolutions per second\n", "\n", "# (a) Number of cycles per revolution\n", "n=P/2.; \n", "\n", "# (b) Number of electrical degrees per revolution\n", "Elecdeg=360.*P/2.; \n", "\n", "# (c) Frequency in hertz\n", "f=P*rpers/2.; \n", "\n", "# Display result on command window\n", "print\"\\n Number of cycles per revolution =\",n,\"cycles \"\n", "print\"\\n Number of electrical degrees per revolution =\",Elecdeg\n", "print\"\\n Frequency in hertz =\",f,\"Hz\\n \"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "\n", " Number of cycles per revolution = 40.0 cycles \n", "\n", " Number of electrical degrees per revolution = 14400.0\n", "\n", " Frequency in hertz = 800.0 Hz\n", " \n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example E09 : Pg 31" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# Example 1.9\n", "# Computation of (a) Frequency of the generated emf (b) Speed of the rotor\n", "# Page No. 31\n", "# Given data\n", "Erms=100.; # Voltage generated in armature coil\n", "N=15.; # Number of turns in armature coil\n", "phimax=0.012; # Flux per pole\n", "P=4.; # Number of poles\n", "\n", "# (a) frequency of the generated emf\n", "f=Erms/(4.44*N*phimax); \n", "\n", "# (b) speed of the rotor\n", "n=2.*f/P; \n", "nmin=n*60.; \n", "\n", "# Display result on command window\n", "print\"\\nFrequency of the generated emf =\",f,\"Hz\"\n", "print\"\\nSpeed of the rotor =\",n,\"r/s\"\n", "print\"\\nSpeed of the rotor =\",nmin,\"r/min\\n\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "\n", "Frequency of the generated emf = 125.125125125 Hz\n", "\n", "Speed of the rotor = 62.5625625626 r/s\n", "\n", "Speed of the rotor = 3753.75375375 r/min\n", "\n" ] } ], "prompt_number": 8 } ], "metadata": {} } ] }