{ "metadata": { "name": "", "signature": "sha256:a0a25762305b1c74ca417d46a7390eaac10578c3f22cb04bddc542c61d85667c" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter6-Turning Moment Diagram and Flywheel" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex1-pg175" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 1 PAGE NO 175\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "\n", "k=1.## radius of gyration of flywheel in m\n", "m=2000.## mass of the flywheel in kg\n", "T=1000.## torque of the engine in Nm\n", "w1=0.## speedin the begining\n", "t=10.## time duration\n", "##==============================\n", "I=m*k**2.## mass moment of inertia in kg-m**2\n", "a=T/I## angular acceleration of flywheel in rad/s**2\n", "w2=w1+a*t## angular speed after time t in rad/s\n", "K=I*w2**2/2.## kinetic energy of flywheel in Nm\n", "##==============================\n", "print'%s %.1f %s %.1f %s '%('Angular acceleration of the flywheel=',a,' rad/s**2'' Kinetic energy of flywheel= ',K,' N-m')\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Angular acceleration of the flywheel= 0.5 rad/s**2 Kinetic energy of flywheel= 25000.0 N-m \n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex2-pg176" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 2 PAGE NO 176\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "import math\n", "pi=3.141\n", "N1=225.## maximum speed of flywheel in rpm\n", "k=.5## radius of gyration of flywheel in m\n", "n=720.## no of holes punched per hour\n", "E1=15000.## energy required by flywheel in Nm\n", "N2=200.## mimimum speedof flywheel in rpm\n", "t=2.## time taking for punching a hole\n", "##==========================\n", "P=E1*n/3600.## power required by motor per sec in watts\n", "E2=P*t## energy supplied by motor to punch a hole in N-m\n", "E=E1-E2## maximum fluctuation of energy in N-m\n", "N=(N1+N2)/2.## mean speed of the flywheel in rpm\n", "m=E/(pi**2./900.*k**2.*N*(N1-N2))\n", "print'%s %.1f %s %.1f %s'%('Power of the motor= ',P,' watts''Mass of the flywheel required= ',m,' kg')\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Power of the motor= 3000.0 wattsMass of the flywheel required= 618.2 kg\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex3-pg176" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 3 PAGE NO 176\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "import math\n", "pi=3.141\n", "d=38.## diameter of hole in cm\n", "t=32.## thickness of hole in cm\n", "e1=7.## energy required to punch one square mm\n", "V=25.## mean speed of the flywheel in m/s\n", "S=100.## stroke of the punch in cm\n", "T=10.## time required to punch a hole in s\n", "Cs=.03## coefficient of fluctuation of speed\n", "##===================\n", "A=pi*d*t## sheared area in mm**2\n", "E1=e1*A## energy required to punch entire area in Nm\n", "P=E1/T## power of motor required in watts\n", "T1=T/(2.*S)*t## time required to punch a hole in 32 mm thick plate\n", "E2=P*T1## energy supplied by motor in T1 seconds\n", "E=E1-E2## maximum fluctuation of energy in Nm\n", "m=E/(V**2.*Cs)## mass of the flywheel required\n", "print'%s %.1f %s'%('Mass of the flywheel required= ',m,' kg')\n", "\n", "\t\t" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Mass of the flywheel required= 1197.8 kg\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex4-pg177" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 4 PAGE NO 177\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "##figure 6.4\n", "import math\n", "##===================\n", "pi=3.141\n", "N=480.## speed of the engine in rpm\n", "k=.6## radius of gyration in m\n", "Cs=.03## coefficient of fluctuaion of speed \n", "Ts=6000.## turning moment scale in Nm per one cm\n", "C=30.## crank angle scale in degrees per cm\n", "a=[0.5,-1.22,.9,-1.38,.83,-.7,1.07]## areas between the output torque and mean resistance line in sq.cm\n", "##======================\n", "w=2.*pi*N/60.## angular speed in rad/s\n", "A=Ts*C*pi/180.## 1 cm**2 of turning moment diagram in Nm\n", "E1=a[0]## max energy at B refer figure\n", "E2=a[0]+a[1]+a[2]+a[3]\n", "E=(E1-E2)*A## fluctuation of energy in Nm\n", "m=E/(k**2.*w**2*Cs)## mass of the flywheel in kg\n", "print'%s %.1f %s'%('Mass of the flywheel= ',m,' kg')\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Mass of the flywheel= 195.8 kg\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex5-pg178" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 5 PAGE NO 178\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "##==============\n", "pi=3.141\n", "P=500.*10**3.## power of the motor in N\n", "k=.6## radius of gyration in m\n", "Cs=.03## coefficient of fluctuation of spped \n", "OA=750.## REFER FIGURE\n", "OF=6.*pi## REFER FIGURE\n", "AG=pi## REFER FIGURE\n", "BG=3000.-750.## REFER FIGURE\n", "GH=2.*pi## REFER FIGURE\n", "CH=3000.-750.## REFER FIGURE\n", "HD=pi## REFER FIGURE\n", "LM=2.*pi## REFER FIGURE\n", "T=OA*OF+1./2.*AG*BG+BG*GH+1./2.*CH*HD## Torque required for one complete cycle in Nm\n", "Tmean=T/(6.*pi)## mean torque in Nm\n", "w=P/Tmean## angular velocity required in rad/s\n", "BL=3000.-1875.## refer figure\n", "KL=BL*AG/BG## From similar trangles\n", "CM=3000.-1875.## refer figure\n", "MN=CM*HD/CH##from similar triangles\n", "E=1./2.*KL*BL+BL*LM+1./2.*CM*MN## Maximum fluctuaion of energy in Nm\n", "m=E*100./(k**2*w**2.*Cs)## mass of flywheel in kg\n", "print'%s %.1f %s'%('Mass of the flywheel= ',m,' kg')\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Mass of the flywheel= 1150.3 kg\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex6-pg179" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 6 PAGE NO 179\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "import math\n", "pi=3.141\n", "PI=180.##in degrees\n", "theta1=0.\n", "theta2=PI\n", "m=400.## mass of the flywheel in kg\n", "N=250.## speed in rpm\n", "k=.4## radius of gyration in m\n", "n=2.*250./60000.## no of working strokes per minute\n", "W=1000.*pi-150.*math.cos((2*theta2)/57.3)-250.*math.sin((2*theta2)/57.3)-(1000.*theta1-150.*math.cos((2*theta1)/57.3)-250.*math.sin((2*theta1)/57.3))## workdone per stroke in Nm\n", "P=W*n## power in KW\n", "Tmean=W/pi## mean torque in Nm\n", "twotheta=math.atan((500/300)/57.3)## angle at which T-Tmean becomes zero\n", "THETA1=twotheta/2.\n", "THETA2=(180.+twotheta)/2.\n", "E=-150.*math.cos((2.*THETA2)/57.3)-250.*math.sin((2.*THETA2)/57.3)-(-150*math.cos((2.*THETA1)/57.3)-250.*math.sin((2*THETA1)/57.3))## FLUCTUATION OF ENERGY IN Nm\n", "w=2.*pi*N/60.## angular speed in rad/s\n", "Cs1=E*100./(k**2.*w**2.*m)## fluctuation range\n", "Cs=Cs1/2.## tatal percentage of fluctuation of speed\n", "Theta=60.\n", "T1=300.*math.sin((2*Theta)/57.3)-500.*math.cos((2*Theta)/57.3)## Accelerating torque in Nm(T-Tmean)\n", "alpha=T1/(m*k**2.)## angular acceleration in rad/s**2\n", "print'%s %.1f %s %.3f %s %.3f %s '%('Power delivered=',P,' kw''Total percentage of fluctuation speed=',Cs,' ''Angular acceleration=',alpha,'rad/s**2')\n", "#in book ans is given wrong \n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Power delivered= 26.2 kwTotal percentage of fluctuation speed= 0.342 Angular acceleration= 7.965 rad/s**2 \n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex7-pg181" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 7 PAGE NO 181\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "\n", "pi=3.141\n", "m=200.## mass of the flywheel in kg\n", "k=.5## radius of gyration in m\n", "N1=360.## upper limit of speed in rpm\n", "N2=240.## lower limit of speed in rpm\n", "##==========\n", "I=m*k**2.## mass moment of inertia in kg m**2\n", "w1=2.*pi*N1/60.\n", "w2=2.*pi*N2/60.\n", "E=1./2.*I*(w1**2.-w2**2.)## fluctuation of energy in Nm\n", "Pmin=E/(4.*1000.)## power in kw\n", "Eex=Pmin*12.*1000.## Energy expended in performing each operation in N-m\n", "print'%s %.1f %s %.1f %s '%('Mimimum power required= ',Pmin,' kw' ' Energy expended in performing each operation= ',Eex,' N-m')\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Mimimum power required= 4.9 kw Energy expended in performing each operation= 59195.3 N-m \n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex8-pg182" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 8 PAGE NO 182\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "import math\n", "pi=3.141\n", "b=8.## width of the strip in cm\n", "t=2.## thickness of the strip in cm\n", "w=1.2*10**3.## work required per square cm cut\n", "N1=200.## maximum speed of the flywheel in rpm\n", "k=.80## radius of gyration in m\n", "N2=(1.-.15)*N1## minimum speed of the flywheel in rpm\n", "T=3.## time required to punch a hole\n", "##=======================\n", "A=b*t## area cut of each stroke in cm**2\n", "W=w*A## work required to cut a strip in Nm\n", "w1=2.*pi*N1/60.## speed before cut in rpm\n", "w2=2.*pi*N2/60.## speed after cut in rpm\n", "m=2.*W/(k**2.*(w1**2.-w2**2.))## mass of the flywheel required in kg\n", "a=(w1-w2)/T## angular acceleration in rad/s**2\n", "Ta=m*k**2.*a## torque required in Nm\n", "print'%s %.1f %s %.1f %s '%('Mass of the flywheel= ',m,' kg'' Amount of Torque required=',Ta,'Nm')\n", "\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Mass of the flywheel= 493.1 kg Amount of Torque required= 330.4 Nm \n" ] } ], "prompt_number": 9 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex9-pg182" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 9 PAGE NO 182\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "\n", "pi=3.141\n", "P=5.*10**3.## power delivered by motor in watts\n", "N1=360.## speed of the flywheel in rpm\n", "I=60.## mass moment of inertia in kg m**2\n", "E1=7500.## energy required by pressing machine for 1 second in Nm\n", "##========================\n", "Ehr=P*60.*60.## energy sipplied per hour in Nm\n", "n=Ehr/E1\n", "E=E1-P## total fluctuation of energy in Nm\n", "w1=2.*pi*N1/60.## angular speed before pressing in rpm \n", "w2=((2.*pi*N1/60.)**2.-(2.*E/I))**.5## angular speed after pressing in rpm \n", "N2=w2*60./(2.*pi)\n", "R=N1-N2## reduction in speed in rpm\n", "print'%s %.1f %s %.1f %s '%('No of pressings that can be made per hour= ',n,' Reduction in speed after the pressing is over= ',R,' rpm ')\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "No of pressings that can be made per hour= 2400.0 Reduction in speed after the pressing is over= 10.7 rpm \n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex10-pg183" ] }, { "cell_type": "code", "collapsed": false, "input": [ "##CHAPTER 6 ILLUSRTATION 10 PAGE NO 183\n", "##TITLE:Turning Moment Diagram and Flywheel\n", "import math\n", "pi=3.141\n", "Cs=.02## coefficient of fluctuation of speed \n", "N=200.## speed of the engine in rpm\n", "\n", "theta1=math.acos(0/57.3)\n", "theta2=math.asin((-6000/16000)/57.3)\n", "theta2=180.-theta2\n", "##===============================================\n", "##largest area,representing fluctuation of energy lies between theta1 and theta2\n", "E=6000.*math.sin(theta2/57.3)-8000./2.*math.cos((2*theta2)/57.3)-(6000.*math.sin((theta1)/57.3)-8000./2.*math.cos((2*theta1)/57.3))## total fluctuation of energy in Nm\n", "Theta=180## angle with which cycle will be repeated in degrees\n", "Theta1=0\n", "Tmean=1/pi*((15000*pi+(-8000*math.cos((2*Theta)/57.3))/2.)-((15000*Theta1+(-8000*math.cos((2*Theta1)/57.3))/2.)))## mean torque of engine in Nm\n", "P=2*pi*N*Tmean/60000.## power of the engine in kw\n", "w=2*pi*N/60.## angular speed of the engine in rad/s\n", "I=E/(w**2.*Cs)## mass moment of inertia of flywheel in kg-m**2\n", "print'%s %.1f %s %.1f %s '%('Power of the engine= ',P,' kw'' minimum mass moment of inertia of flywheel=',-I,' kg-m**2'' E value calculated in the textbook is wrong. Its value is -15,124. In textbook it is given as -1370.28')\n", "\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Power of the engine= 314.1 kw minimum mass moment of inertia of flywheel= 19.5 kg-m**2 E value calculated in the textbook is wrong. Its value is -15,124. In textbook it is given as -1370.28 \n" ] } ], "prompt_number": 11 } ], "metadata": {} } ] }