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diff --git a/Electrical_Machines_II/extra-chapter1.ipynb b/Electrical_Machines_II/extra-chapter1.ipynb new file mode 100755 index 00000000..aa84025a --- /dev/null +++ b/Electrical_Machines_II/extra-chapter1.ipynb @@ -0,0 +1,961 @@ +{ + "metadata": { + "name": "", + "signature": "sha256:73456f874b64111f39ff6e1df283939e5a576ba362e30194dc5083b7ddd99204" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "heading", + "level": 1, + "metadata": {}, + "source": [ + "Chapter 1: Synchronous Machines(Additional problems)" + ] + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 1, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "phase = 3 #three phase winding\n", + "ns = 36. #number of slots\n", + "np = 4 #number of poles\n", + "\n", + "#Calculations\n", + "nsp = ns/phase #number of slots per phase\n", + "npp = nsp/np #number of slots pole/phase\n", + "alpha = 180*np/ns #slot angle\n", + "Kd = math.sin(npp*alpha/2*math.pi/180)/(3*math.sin(alpha/2*math.pi/180))\n", + "\n", + "#Results\n", + "print \"The distribution factor is %.2f\"%Kd" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The distribution factor is 0.96\n" + ] + } + ], + "prompt_number": 1 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 2, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "np = 3 #number of phases\n", + "npl = 4 #number of poles\n", + "ns = 24 #number of slots\n", + "\n", + "#calculaions\n", + "nsp = ns/npl #number of slot/pole\n", + "alpha = 180/nsp #slot pitch(degrees)\n", + "m = ns/(npl*np) \n", + "Kd = math.sin(m*alpha/2*math.pi/180)/(m*math.sin(alpha/2*math.pi/180))\n", + "Kc = math.cos(alpha/2*math.pi/180)\n", + "\n", + "#Results\n", + "print \"Distribution factor = %.2f\"%Kd\n", + "print \"Pitch factor = %.3f degrees\"%Kc" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Distribution factor = 0.97\n", + "Pitch factor = 0.966 degrees\n" + ] + } + ], + "prompt_number": 2 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 3, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "Vl= 11000 #V\n", + "N = 1500 #rpm\n", + "f = 50 #Hz\n", + "\n", + "#Calculations\n", + "P = (120*f)/N\n", + "Vp = Vl/math.sqrt(3)\n", + "\n", + "#Results\n", + "print \"Number of poles = %d\"%P\n", + "print \"Voltage per phase of alternator = %d V\"%Vp" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Number of poles = 4\n", + "Voltage per phase of alternator = 6350 V\n" + ] + } + ], + "prompt_number": 3 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 4, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "P = 4 #number of poles\n", + "ph = 3 #number of phases\n", + "s = 36 #number of slots\n", + "cs = 8 #coil span\n", + "\n", + "#calculations\n", + "nsp = s/P #number of slots/pole\n", + "alpha = 180/nsp #slot pitch\n", + "m = s/(P*ph)\n", + "Kd = math.sin(m*alpha/2*math.pi/180)/(m*math.sin(alpha/2*math.pi/180))\n", + "ns = nsp-cs #no. of slots by which coil is short pitched\n", + "B = 1*alpha\n", + "Kc= math.cos(B/2*math.pi/180)\n", + "\n", + "#Results\n", + "print \"Distribution factor = %.3f\"%Kd\n", + "print \"Pitch factor = %.3f degrees\"%Kc" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Distribution factor = 0.960\n", + "Pitch factor = 0.985 degrees\n" + ] + } + ], + "prompt_number": 4 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 5, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "P= 16. #number of poles\n", + "N = 375 #rpm\n", + "s = 144. #number of slots\n", + "c = 10 #number of conductors\n", + "phase = 3\n", + "phi = 0.035 #flux per pole\n", + "\n", + "#Calculations\n", + "f = (P*N)/120 #Hz\n", + "ns = s/P #slot/pole\n", + "m = ns/phase\n", + "alpha = 180/ns #slot angle\n", + "Kd = math.sin(m*alpha/2*math.pi/180)/(m*math.sin(alpha/2*math.pi/180))\n", + "Tc = s*c #total number of conductor\n", + "Tcp = Tc/phase #total number of conductors/phase\n", + "Ncp = Tcp/2 #number of turns/phase\n", + "emf = 4.44*Kd*phi*f*Ncp\n", + "Vl = math.sqrt(3)*emf\n", + "\n", + "#Results\n", + "print \"Frequency = %d Hz\"%f\n", + "print \"E.M.F = %d V\"%emf\n", + "print \"Line voltage = %d V\"%Vl" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Frequency = 50 Hz\n", + "E.M.F = 1789 V\n", + "Line voltage = 3100 V\n" + ] + } + ], + "prompt_number": 5 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 6, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "P = 4 #no. of poles\n", + "s = 36 #no. of slots\n", + "ph = 3 #no. of phases\n", + "cs = 8 #coil span\n", + "\n", + "#Calculations\n", + "ns = s/P #no. of slots/pole\n", + "alpha = 180/ns #slot pitch\n", + "m = s/(P*ph)\n", + "Kd = math.sin(m*alpha/2*math.pi/180)/(m*math.sin(alpha/2*math.pi/180))\n", + "Ns = ns-cs\n", + "Kc = math.cos(alpha/2*math.pi/180)\n", + "\n", + "#Results\n", + "print \"Distribution factor = %.2f\"%Kd\n", + "print \"Pitch factor = %.4f degrees\"%Kc" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Distribution factor = 0.96\n", + "Pitch factor = 0.9848 degrees\n" + ] + } + ], + "prompt_number": 6 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 7, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "El = 6600 #V\n", + "P = 4 #number of poles\n", + "s = 60 #number of slots\n", + "ph = 3 #number of phases\n", + "c = 2 #number of conductors\n", + "sn = 13 #slot number\n", + "f = 50 #Hz\n", + "T = 20 #V\n", + "\n", + "#Calculations\n", + "n = s/P\n", + "m = n/ph\n", + "Zp = (s*c)/ph\n", + "B = 180/n #degrees\n", + "Kd = math.sin(m*B/2*math.pi/180)/(m*math.sin(B/2*math.pi/180))\n", + "Cs = (sn-1)*180/n #degrees\n", + "Kp = math.cos((180-Cs)/2*math.pi/180)\n", + "phi = El/(math.sqrt(3)*4.44*Kd*Kp*f*T)\n", + "\n", + "#Results\n", + "print \"The required flux pole is %.3f V\"%phi" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The required flux pole is 0.943 V\n" + ] + } + ], + "prompt_number": 7 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 8, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Varible declaration\n", + "Vl = 230 #V\n", + "Rt = 10*10**3 #VA\n", + "ph = 3 #no. of phases\n", + "Ra = 0.5 #ohms/phase\n", + "Xs = 1.2 #ohms/phase\n", + "cos_phi = 0.8 #lagging\n", + "sin_phi = 0.6 #leading\n", + "V = 132.8 #V\n", + "\n", + "#Calculations\n", + "I = Rt/(ph*V) #A\n", + "print I\n", + "#Part(a)\n", + "Eo = math.sqrt(((V*cos_phi)+(I*Ra))**2+((V*sin_phi)+(I*Xs))**2)\n", + "Reg1 = (Eo-V)/V*100\n", + "\n", + "#Part(b)\n", + "Eo = math.sqrt((V*cos_phi+I*Ra)**2+(V*sin_phi-I*Xs)**2)\n", + "Reg2 = (Eo-V)/V*100\n", + "\n", + "#Results\n", + "print \"Part(a): Regulation = %.2f %%\"%Reg1\n", + "print \"Part(b): Regulation = %.2f %%\"%Reg2" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "25.1004016064\n", + "Part(a): Regulation = 21.81 %\n", + "Part(b): Regulation = -3.08 %\n" + ] + } + ], + "prompt_number": 8 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 9, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "El = 10000 #V\n", + "Kd = 0.96\n", + "Kp = 1.0\n", + "phi = 15*10**-2 #wb\n", + "f = 50 #Hz\n", + "\n", + "#Calculations\n", + "T = El/(math.sqrt(3)*4.44*Kd*Kp*phi*f)\n", + "Zp = 2*T\n", + "\n", + "#Result\n", + "print \"Number of armature conductors in series/phase = %d\"%Zp\n", + "#Answer differs due to rounding-off errors" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Number of armature conductors in series/phase = 361\n" + ] + } + ], + "prompt_number": 9 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 10, Page 120" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "s = 90 #no. of slots\n", + "P = 10 #no. of poles\n", + "ph = 3 #no. of phases\n", + "E = 11000. #E.M.F(V)\n", + "phi = 0.16 #flux(Wb)\n", + "f = 50 #Hz\n", + "\n", + "#Calculations\n", + "nsp = s/(P*ph) #slot/pole/phase\n", + "alpha = 180/(s/P) #slot angle\n", + "m = s/(P*ph)\n", + "Kd = math.sin(m*alpha/2*math.pi/180)/(m*math.sin(alpha/2*math.pi/180))\n", + "N = E/(math.sqrt(3)*4.44*Kd*phi*f)\n", + "Nc = 2*N\n", + "\n", + "#Result\n", + "print \"Number of conductors/phase are %d\"%Nc\n", + "#Incorrect answer for N in the textbook. Hence the result differs" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Number of conductors/phase are 372\n" + ] + } + ], + "prompt_number": 10 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 11, Page 121" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "Vl = 400 #V\n", + "cos_phi = 1 #pf\n", + "n = 85./100 #efficiency\n", + "Zs = 10 #reactance(ohms)\n", + "\n", + "#Calculations\n", + "out = Zs*735.5 #output\n", + "mi = out/n #motor input(W)\n", + "Il = mi/(math.sqrt(3)*Vl*cos_phi)\n", + "I = Il #since current is minimum when power factor is unity\n", + "Er = I*Zs\n", + "V = Vl/math.sqrt(3)\n", + "E = math.sqrt(V**2+Er**2)\n", + "emf = math.sqrt(3)*E\n", + "\n", + "#Results\n", + "print \"Minimum current = %.1f A\"%I\n", + "print \"Line induces e.m.f. = %d V\"%emf\n", + "#Answers differ due to rounding-off errors" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Minimum current = 12.5 A\n", + "Line induces e.m.f. = 454 V\n" + ] + } + ], + "prompt_number": 11 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 12, Page 121" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "P = 6\n", + "phi = 25*10**-3 #wb\n", + "f = 50 #Hz\n", + "ph = 3 #no. of phases\n", + "s = 12 #no. of slots/pole\n", + "nc = 4 #no. of conductors/slot\n", + "\n", + "#Calculations\n", + "Zph = nc*s*P/ph\n", + "T = Zph/2\n", + "alpha = 180*(1-5./P)\n", + "Kc = math.cos(alpha/2*math.pi/180)\n", + "m = s/ph\n", + "B = 180/s\n", + "Kd = math.sin(m*alpha/2*math.pi/180)/(m*math.sin(alpha/2*math.pi/180))\n", + "Eph = 4.44*Kc*Kd*f*phi*T\n", + "El = math.sqrt(3)*Eph\n", + "\n", + "#Results\n", + "print \"Line e.m.f. = %.1f V\"%El\n", + "#incorrect answer for Kd in the textbook. Hence the result differs" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Line e.m.f. = 372.8 V\n" + ] + } + ], + "prompt_number": 12 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 13, Page 121" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "P = 1200 #kW\n", + "V = 2300 #V\n", + "Ia = 200 #A\n", + "cos_phi_a = 0.9 #lagging\n", + "\n", + "#Calculations\n", + "Pa = V*Ia*cos_phi_a/10**3 #kW\n", + "phi = math.atan(cos_phi_a)\n", + "Pra = Pa*math.tan(phi)\n", + "Pr = 0 #since power factor is unity\n", + "Prb = Pr-Pra\n", + "Pb = P-Pa\n", + "tan_phi = Prb/Pb\n", + "cos_phi_b = math.cos(math.atan(tan_phi))\n", + "Ia = Pb*10**3/(V*cos_phi_b)\n", + "\n", + "#Results\n", + "print \"Power = %d kW\"%Pb\n", + "print \"Power factor = %.3f\"%cos_phi_b\n", + "print \"Current = %.1f A\"%Ia\n", + "#incorrect answers in the textbook" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Power = 786 kW\n", + "Power factor = 0.904\n", + "Current = 378.2 A\n" + ] + } + ], + "prompt_number": 13 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 14, Page 121" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "\n", + "#Part (a) - for lighting load\n", + "P1 = 600 #kW\n", + "cos_phi =1 #power factor\n", + "tan_phi = 0\n", + "Prl = P1*tan_phi\n", + "\n", + "#Part(b) - for inductive load\n", + "P2 = 800 #W\n", + "cos_phi = 0.9\n", + "tan_phi = 0.4843\n", + "Pri = P2*tan_phi\n", + "\n", + "#Part(c) - for capacitive power\n", + "P3 = 800\n", + "cos_phi = 0.8\n", + "tan_phi = 0.75\n", + "Prc = -P3*tan_phi\n", + "\n", + "P = P1+P2+P3\n", + "Pr = Prl+Pri+Prc\n", + "Pa = 1000 #kW\n", + "cos_phi_a = 0.85\n", + "tan_phi_a = math.tan(math.acos(cos_phi_a))\n", + "Pra = Pa*tan_phi_a\n", + "Pb = P-Pa\n", + "Prb = Pr-Pra\n", + "tan_phi_2 = Prb/Pb\n", + "cos_phi_b = math.cos(math.atan(tan_phi_2))\n", + "\n", + "#Results\n", + "print \"Active power supplied by alternator B = %d kW\"%Pb\n", + "print \"Power factor of alternator B = %.4f leading\"%cos_phi_b\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Active power supplied by alternator B = 1200 kW\n", + "Power factor of alternator B = 0.8217 leading\n" + ] + } + ], + "prompt_number": 14 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 15, Page 121" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "E = 1000 #KVa\n", + "Vl = 11000 #V\n", + "ph = 3 #no. of phases\n", + "Ra = 3.5 #armature resistance(ohms)\n", + "Xs = 40 #armature reactance(ohms)\n", + "cos_phi = 0.8\n", + "\n", + "#Calculations\n", + "Ia = round(E*1000/(math.sqrt(3)*Vl),1)\n", + "V = Vl/math.sqrt(3)\n", + "phi = math.degrees(math.acos(cos_phi))\n", + "Rad = round(Ia*Ra) #armature resistance drop/phase\n", + "Xad = round(Ia*Xs) #armature reactance drop per phase\n", + "Er = math.sqrt(Rad**2+Xad**2) #incorrect answer in the textbook\n", + "theta = math.degrees(math.atan(Xs/Ra))\n", + "\n", + "#Part a - Unity p.f.\n", + "Eba = math.sqrt(V**2+Er**2-(2*V*Er*math.cos(theta*math.pi/180)))\n", + "Vla = Eba*math.sqrt(3)\n", + "#From triangle OAB\n", + "alpha_a = math.degrees(math.asin((Er*math.sin(theta*math.pi/180))/Eba))\n", + "\n", + "#Part b - At p.f. 0.8 lagging\n", + "BOA_b = theta-phi\n", + "Ebb = math.sqrt(V**2+Er**2-(2*V*Er*math.cos(BOA_b*math.pi/180)))\n", + "Vlb = Ebb*math.sqrt(3)\n", + "alpha_b = math.degrees(math.asin(Er*math.sin(BOA_b*math.pi/180)/Ebb))\n", + "\n", + "#Part c - At p.f. 0.8 leading\n", + "BOA_c = theta+phi\n", + "Ebc = math.sqrt(V**2+Er**2-(2*V*Er*math.cos(BOA_c*math.pi/180)))\n", + "Vlc = Ebc*math.sqrt(3)\n", + "alpha_c = math.degrees(math.asin(Er*math.sin(BOA_c*math.pi/180)/Ebc))\n", + "\n", + "#Results\n", + "print \"Induced e.m.f. and angular retardation are as below:\"\n", + "print \"Part a : %d V,%.2f degrees\"%(Vla,alpha_a)\n", + "print \"Part b : %d V,%.2f degrees\"%(Vlb,alpha_b)\n", + "print \"Part c : %d V,%.2f degrees\"%(Vlc,alpha_c)\n", + "\n", + "#Incorrect answers in the textbook" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Induced e.m.f. and angular retardation are as below:\n", + "Part a : 11284 V,18.80 degrees\n", + "Part b : 8984 V,17.62 degrees\n", + "Part c : 13294 V,13.49 degrees\n" + ] + } + ], + "prompt_number": 17 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 16, Page 121" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "Em = 6000 #V\n", + "Xs = 1.5 #ohms/phase\n", + "Il = 1000 #amps\n", + "sin_phi = 1 #power factor\n", + "\n", + "#Calculations\n", + "#Since load is inductive\n", + "Vt = Em-Il*Xs\n", + "Vl = round(math.sqrt(3)*Vt) #since winding is connected in star\n", + "Pr = math.sqrt(3)*Vl*Il*sin_phi/10**6\n", + "\n", + "#Results\n", + "print \"Reactive power supplied to the load is %.2f MVAR\"%Pr\n", + "#Incorrect answer in textbook" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Reactive power supplied to the load is 13.50 MVAR\n" + ] + } + ], + "prompt_number": 18 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 17, Page 121" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "V = 7000 #V\n", + "I = 1400 #amps\n", + "Xs = 1.2 #ohms\n", + "f = 50 #Hz\n", + "Po = 4 #number of poles\n", + "cos_phi = 1 #power factor, since load is resistive\n", + "\n", + "#Calculations\n", + "E = math.sqrt(V**2+(I*Xs)**2) #V\n", + "P = 3*V*I*cos_phi #W\n", + "N = 120*f/Po #rpm\n", + "w = (2*math.pi*N)/60 #rad/sec\n", + "T = P/(w*9.81)\n", + "\n", + "#Result\n", + "print \"The required torque is %.2e kg-meter\"%T" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The required torque is 1.91e+04 kg-meter\n" + ] + } + ], + "prompt_number": 19 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 18, Page 122" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#Variable declaration\n", + "Ep = 5700 #V\n", + "Xs = 1.5 #ohms\n", + "\n", + "#Calculations\n", + "#Since windings are connected in star\n", + "Ip = Ep/Xs #phase current(A)\n", + "Il = Ip\n", + "\n", + "#Result\n", + "print \"The current per phase is %d Amps\"%Il" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The current per phase is 3800 Amps\n" + ] + } + ], + "prompt_number": 20 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Problem 19, Page 122" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "\n", + "#Variable declaration\n", + "Vt = 15 #KV\n", + "Ps = 100*10**6 #power supplied by generator VA\n", + "cos_phi = 0.8 #power factor(lagging)\n", + "Xs = 0.7 #ohm per phase\n", + "Vl = 15 #KV\n", + "f = 50 #Hz\n", + "Po = 2 #no. of poles\n", + "\n", + "#Calculations\n", + "Vp = Vl/math.sqrt(3) #KV\n", + "AC = Vp*cos_phi\n", + "sin_phi = 0.6\n", + "BC = Vp*sin_phi #KV\n", + "Il = Ps/(math.sqrt(3)*Vl*10**3) #amps\n", + "Vd = Il*Xs #voltage drop in synchronous reactance KV\n", + "BL = 2.697\n", + "LC = BL+BC #V\n", + "AL = math.sqrt(AC**2+LC**2) #V\n", + "Em = AL*math.sqrt(3) #V\n", + "Ns = (120*f)/Po #rpm\n", + "P = Ps*cos_phi #W\n", + "wT = 80*10**6\n", + "T = (wT*60)/(2*math.pi*Ns)\n", + "print \n", + "#Result\n", + "print \"Induced e.m.f. = %.2f V\"%Em\n", + "print \"Torque = %.2e Nw-m\"%T\n", + "print \"Speed = %d rpm\"%Ns\n", + "#Answers differ due to rounding-off errors" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "\n", + "Induced e.m.f. = 18.19 V\n", + "Torque = 2.55e+05 Nw-m\n", + "Speed = 3000 rpm\n" + ] + } + ], + "prompt_number": 21 + } + ], + "metadata": {} + } + ] +}
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