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+{
+ "metadata": {
+ "name": "",
+ "signature": "sha256:1c4ac592513e221d9ef582b6b080c90b8d233dba2c2d1c00437e9fe2319c3d83"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+ {
+ "cells": [
+ {
+ "cell_type": "heading",
+ "level": 1,
+ "metadata": {},
+ "source": [
+ "Chapter 5 : Three Phase Synchronous Machines"
+ ]
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.1 Page No : 424"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data; \n",
+ "slots = 18.;\n",
+ "p = 2.; #nmber of poles\n",
+ "ph = 3.; #three phase winding\n",
+ "\n",
+ "# Calculations and Results\n",
+ "SA = (360/slots); #slot angle\n",
+ "m = slots/(p*ph); #m = nmber of slots per pole per phase\n",
+ "print \"number of slots per pole per phase, m = %d\"%(m);\n",
+ "print \"emfs of the oils of each phase will have a time-phase difference of %d degree mechanical \"%(SA);\n",
+ "k_d = math.sin(math.radians((m*SA)/2))/(m*math.sin(math.radians(SA/2)));\n",
+ "print \"distribution factor = %f\"%(k_d);\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "number of slots per pole per phase, m = 3\n",
+ "emfs of the oils of each phase will have a time-phase difference of 20 degree mechanical \n",
+ "distribution factor = 0.959795\n"
+ ]
+ }
+ ],
+ "prompt_number": 1
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.2 Page No : 425"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "# Given Data\n",
+ "slots = 36.; #number of slots\n",
+ "poles = 4.; #number of poles\n",
+ "ph = 3.; #math.single layer three phase winding\n",
+ "\n",
+ "# Calculations and Results\n",
+ "SP = slots/ph; #number of slots per phase\n",
+ "print \"number of slots per phase = %d\"%(SP);\n",
+ "m = SP/poles; #munber of slots per pole per phase\n",
+ "print \"number of slots per pole per phase, m = %d\"%(m)\n",
+ "SA_m = 360/slots; #slot angle mechanical\n",
+ "SA_e = (poles/2)*SA_m #slot angle electrical \n",
+ "print \"slot angle = %d degree electrical\"%(SA_e)\n",
+ "k_d = math.sin(math.radians((m*SA_e)/2))/(m*math.sin(math.radians(SA_e/2)));\n",
+ "print \"distribution factor = %f\"%(k_d)"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "number of slots per phase = 12\n",
+ "number of slots per pole per phase, m = 3\n",
+ "slot angle = 20 degree electrical\n",
+ "distribution factor = 0.959795\n"
+ ]
+ }
+ ],
+ "prompt_number": 2
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.3 Page No : 426"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data;\n",
+ "slots = 48.; #number of slots\n",
+ "poles = 4.; #4-pole machine\n",
+ "ph = 3.; #3-phase machine\n",
+ "\n",
+ "# Calculations and Results\n",
+ "SA = 360/slots; #slot angle\n",
+ "print \"total number of slots = %d\"%(slots);\n",
+ "print \"slot angle = %f degree mechanical\"%(SA);\n",
+ "#coil span is 11 slot pitches\n",
+ "#12 slots subtend 180degress, short pitched by 1 slot \n",
+ "Bta = 1*180./12;\n",
+ "k_p = math.cos(math.radians(Bta/2));\n",
+ "print \"pitch factor = %f\"%(k_p)\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "total number of slots = 48\n",
+ "slot angle = 7.500000 degree mechanical\n",
+ "pitch factor = 0.991445\n"
+ ]
+ }
+ ],
+ "prompt_number": 3
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.4 Page No : 426"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data;\n",
+ "slots = 72.; #number of slots\n",
+ "P = 8.; #number of poles\n",
+ "ph = 3.; #3-phase machine\n",
+ "N = 750.; #speed of machine in rpm\n",
+ "\n",
+ "#winding is made with 36 coils having 10 turns\n",
+ "Fp = 0.15; #flux per pole\n",
+ "fre = (P*N)/120;\n",
+ "NCp = 36./ph; #nmber of coils per phase\n",
+ "T = NCp*10; #number of turns per phase\n",
+ "k_p = 1; #math.since full pitched pitch factor is 1\n",
+ "\n",
+ "# Calculations and Results\n",
+ "print \"flux per pole = %fWb\"%(Fp)\n",
+ "print \"number of turns per phase = %d\"%(T);\n",
+ "print \"pitch factor = %f\"%(k_p);\n",
+ "m = slots/(P*ph); #slots per pole per phase\n",
+ "SA_m = 360/slots; #slot angle mechanical\n",
+ "SA_e = (P/2)*SA_m;\n",
+ "k_d = math.sin(math.radians((m*SA_e)/2))/(m*math.sin(math.radians(SA_e/2)));\n",
+ "print \"distribution factor = %f\"%(k_d);\n",
+ "E = 4.44*Fp*fre*T*k_d*k_p;\n",
+ "print \"RMS vale of emf induced per phase = %fV\"%(E)"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "flux per pole = 0.150000Wb\n",
+ "number of turns per phase = 120\n",
+ "pitch factor = 1.000000\n",
+ "distribution factor = 0.959795\n",
+ "RMS vale of emf induced per phase = 3835.341142V\n"
+ ]
+ }
+ ],
+ "prompt_number": 4
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.5 Page No : 427"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "# Given Data;\n",
+ "print (\"E(line to line) = 440V\");\n",
+ "E_l = 440.; #line-to-line voltage\n",
+ "E_p = E_l/(math.sqrt(3));\n",
+ "N = 750.; #speed in rpm\n",
+ "fre = 50.; #frequency\n",
+ "\n",
+ "# Calculations and Results\n",
+ "P = (120*fre)/N;\n",
+ "print \"P = %d\"%(P);\n",
+ "print \"Eper phase) = %dV\"%(E_p);\n",
+ "ph = 3; #3-phase machine\n",
+ "m = 2; #number of slots per pole per phase\n",
+ "slots = m*P*ph; #total number of stator slots\n",
+ "SA_m = 360/slots; #slot angle mechanical\n",
+ "SA_e = (P/2)*SA_m; #slot angle electrical\n",
+ "k_p = 1; #assuming full pitch\n",
+ "print \"slot angle = %d degree electrical\"%(SA_e);\n",
+ "print \"pitch factor = %f\"%(k_p);\n",
+ "k_d = math.sin(math.radians((m*SA_e)/2))/(m*math.sin(math.radians(SA_e/2)));\n",
+ "print \"distribution factor = %f\"%(k_d);\n",
+ "#2 slots per pole per phase\n",
+ "NSp = 2*P; #number of slots per phase\n",
+ "NTc = 4; #number of turns per coil\n",
+ "T = 8*NTc; #number of turns per phase\n",
+ "Fp = E_p/(4.44*fre*T*k_d*k_p);\n",
+ "print \"flux per pole = %fWb\"%(Fp);"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "E(line to line) = 440V\n",
+ "P = 8\n",
+ "Eper phase) = 254V\n",
+ "slot angle = 30 degree electrical\n",
+ "pitch factor = 1.000000\n",
+ "distribution factor = 0.965926\n",
+ "flux per pole = 0.037021Wb\n"
+ ]
+ }
+ ],
+ "prompt_number": 7
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.6 Page No : 428"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "#chapter 5\n",
+ "#example 5.6\n",
+ "#page 428\n",
+ "\n",
+ "# Given Data;\n",
+ "slots = 144.; #number of slots\n",
+ "ph = 3.; #3-phase machine\n",
+ "P = 16.; #number of poles\n",
+ "Cp = 10.; #number of conducters per slot\n",
+ "Fp = 0.03; #flux per pole\n",
+ "Ns = 375.; #synchronous speed\n",
+ "\n",
+ "# Calculations and Results\n",
+ "fre = (Ns*P)/120; #frequency\n",
+ "print \"frequency = %d\"%(fre);\n",
+ "m = slots/(P*ph); #number of slots per pole per phase\n",
+ "print \"number of slots per pole per phase, m = %d\"%(m);\n",
+ "SA_m = 360/slots; #slot angle mechanical\n",
+ "SA_e = (P/2)*SA_m; #slot angle electrical\n",
+ "k_p = 1 #no short pitching\n",
+ "print \"short pitch = %d\"%(k_p);\n",
+ "k_d = math.sin(math.radians((m*SA_e)/2))/(m*math.sin(math.radians(SA_e/2)));\n",
+ "print \"distribution factor = %f\"%(k_d);\n",
+ "T = (slots*10)/(2*ph);\n",
+ "print \"number of turns per phase, T = %d\"%(T);\n",
+ "E = 4.44*Fp*fre*T*k_d*k_p;\n",
+ "print \"RMS value of induced emf per phase, E = %fV\"%(E);\n",
+ "print \"induced emf across the linesis %fV \"%(math.sqrt(3)*E);"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "frequency = 50\n",
+ "number of slots per pole per phase, m = 3\n",
+ "short pitch = 1\n",
+ "distribution factor = 0.959795\n",
+ "number of turns per phase, T = 240\n",
+ "RMS value of induced emf per phase, E = 1534.136457V\n",
+ "induced emf across the linesis 2657.202289V \n"
+ ]
+ }
+ ],
+ "prompt_number": 10
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.7 Page No : 428"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data;\n",
+ "slots = 90.; #number of slots\n",
+ "P = 10.; #number of poles\n",
+ "ph = 3.; #3-phase machine\n",
+ "fre = 50.; #frequency\n",
+ "Fp = 0.16; #flux per pole\n",
+ "E_l = 11000.; #line voltage\n",
+ "SA_m = 360/slots; #machanical slot angle\n",
+ "\n",
+ "# Calculations and Results\n",
+ "SA_e = (P/2)*SA_m; #electrical slot angle\n",
+ "m = slots/(ph*P);\n",
+ "print \"slot angle = %d degree elecrical\"%(SA_e)\n",
+ "print \"number of slots per pole per phase, m = %d\"%(m);\n",
+ "k_p = 1; #assuming full pitch\n",
+ "print \"pitch factor = %d\"%(k_p);\n",
+ "k_d = math.sin(math.radians((m*SA_e)/2))/(m*math.sin(math.radians(SA_e/2)));\n",
+ "print \"distribution factor = %f\"%(k_d);\n",
+ "E_p = E_l/math.sqrt(3);\n",
+ "T = E_p/(4.44*Fp*fre*k_p*k_d); \n",
+ "print \"total number of armature conductors, Z = %d\"%(2*T);\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "slot angle = 20 degree elecrical\n",
+ "number of slots per pole per phase, m = 3\n",
+ "pitch factor = 1\n",
+ "distribution factor = 0.959795\n",
+ "total number of armature conductors, Z = 372\n"
+ ]
+ }
+ ],
+ "prompt_number": 11
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.8 Page No : 429"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data;\n",
+ "print (\"P = 6 , f = 50\");\n",
+ "P = 6.;\n",
+ "f = 50.;\n",
+ "Sp = 12.; #slots per pole\n",
+ "Cs = 4.; #conductors per slot\n",
+ "Fp = 1.5; \n",
+ "\n",
+ "# Calculations and Results\n",
+ "TS = Sp*P \n",
+ "print \"total number of slots = %d\"%(TS);\n",
+ "print \"total number of slots per phase = %d\"%( TS/3);\n",
+ "print \"total number of conductors per phase = %d\"%(( TS*Cs)/3);\n",
+ "T = ((TS*Cs)/3)/2;\n",
+ "print \"total number of turns per phase = %d\"%(T)\n",
+ "m = (TS/(P*3));\n",
+ "print \"number of slots per pole per phase, m = %d\"%(m);\n",
+ "SA_m = 360/TS; #slot angle mechanical\n",
+ "SA_e = (P/2)*SA_m;\n",
+ "k_d = math.sin(math.radians((m*SA_e)/2))/(m*math.sin(math.radians(SA_e/2)));\n",
+ "print \"distribution factor = %f\"%(k_d);\n",
+ "print (\"coil pitch is 5/6 of full-pitch\");\n",
+ "bheta = 180-(5./6)*180; #short pitch angle\n",
+ "print \"short pitch angle = %d degrees\"%(bheta)\n",
+ "k_p = math.cos(math.radians(bheta/2));\n",
+ "print \"pitch factor = %f \"%(k_p);\n",
+ "E = 4.44*Fp*f*T*k_d*k_p;\n",
+ "print \"induced per phase = %fV\"%(E)"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "P = 6 , f = 50\n",
+ "total number of slots = 72\n",
+ "total number of slots per phase = 24\n",
+ "total number of conductors per phase = 96\n",
+ "total number of turns per phase = 48\n",
+ "number of slots per pole per phase, m = 4\n",
+ "distribution factor = 0.957662\n",
+ "coil pitch is 5/6 of full-pitch\n",
+ "short pitch angle = 30 degrees\n",
+ "pitch factor = 0.965926 \n",
+ "induced per phase = 14785.689892V\n"
+ ]
+ }
+ ],
+ "prompt_number": 14
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.9 Page No : 439"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data;\n",
+ "OP = 500000.; #output power\n",
+ "V_l = 3300.; #line voltage\n",
+ "\n",
+ "# Calculations and Results\n",
+ "I_l = OP/(math.sqrt(3)*V_l); #line current\n",
+ "print \"line current = %fA\"%(I_l);\n",
+ "#for star connected alternater, line current is equal to phase current\n",
+ "I_a = I_l;\n",
+ "pf = 0.8; #power factor\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "R_a = 0.3; #synchronous resistance\n",
+ "X_s = 4; #synchronous reactance\n",
+ "V_p = V_l/math.sqrt(3);\n",
+ "print \"phase voltage = %fV\"%(V_p)\n",
+ "E = math.sqrt((V_p*math.cos(math.radians(phi))+I_a*R_a)**2+(V_p*math.sin(math.radians(phi))+I_a*X_s)**2);\n",
+ "print \"induced emf = %f V/Phase\"%(E )\n",
+ "PR = ((E-V_p)*100)/V_p;\n",
+ "print \"percentage regulation = %f percent\"%(PR);"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "line current = 87.477314A\n",
+ "phase voltage = 1905.255888V\n",
+ "induced emf = 2152.469556 V/Phase\n",
+ "percentage regulation = 12.975353 percent\n"
+ ]
+ }
+ ],
+ "prompt_number": 15
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.10 Page No : 440"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data\n",
+ "V = 2000.;\n",
+ "V_oc = 500.; #open circuit voltage\n",
+ "I_sc = 100.; #short circuit current\n",
+ "I_a = 100.; \n",
+ "R_s = 0.8; #armature resistance\n",
+ "\n",
+ "# Calculations and Results\n",
+ "Z_s = V_oc/I_sc; #synchronous impedence\n",
+ "print \"Z_s = %d ohm\"%(Z_s);\n",
+ "X_s = math.sqrt(Z_s**2-R_s**2);\n",
+ "print \"X_s = %f ohm\"%(X_s);\n",
+ "pf = 1;\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "print (\"At unity power factor\");\n",
+ "print \"\";\n",
+ "E = math.sqrt((V*math.cos(math.radians(phi))+I_a*R_s)**2+(V*math.sin(math.radians(phi))+I_a*X_s)**2);\n",
+ "print \"induced emf = %fV\"%(E);\n",
+ "R = ((E-V)*100)/V;\n",
+ "print \"regulation = %f percent\"%(R);\n",
+ "pf = 0.71;\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "print (\"At 0.71 lagging power factor\");\n",
+ "print \"\";\n",
+ "E = math.sqrt((V*math.cos(math.radians(phi))+I_a*R_s)**2+(V*math.sin(math.radians(phi))+I_a*X_s)**2);\n",
+ "print \"induced emf = %fV\"%(E);\n",
+ "R = ((E-V)*100)/V;\n",
+ "print \"regulation = %fpercent\"%(R);\n",
+ "pf = 0.8;\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "print (\"At 0.8 leading power factor\");\n",
+ "print \"\";\n",
+ "E = math.sqrt((V*math.cos(math.radians(phi))+I_a*R_s)**2+(V*math.sin(math.radians(phi))-I_a*X_s)**2);\n",
+ "print \"induced emf = %fV\"%(E);\n",
+ "R = ((E-V)*100)/V;\n",
+ "print \"regulation = %fpercent\"%(R);\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Z_s = 5 ohm\n",
+ "X_s = 4.935585 ohm\n",
+ "At unity power factor\n",
+ "\n",
+ "induced emf = 2137.755833V\n",
+ "regulation = 6.887792 percent\n",
+ "At 0.71 lagging power factor\n",
+ "\n",
+ "induced emf = 2422.283821V\n",
+ "regulation = 21.114191percent\n",
+ "At 0.8 leading power factor\n",
+ "\n",
+ "induced emf = 1822.487197V\n",
+ "regulation = -8.875640percent\n"
+ ]
+ }
+ ],
+ "prompt_number": 18
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.11 Page No : 441"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "\n",
+ "# Given Data;\n",
+ "print (\"field exitation current = 10A\");\n",
+ "V_oc = 900.; #induced emf on open circuit\n",
+ "I_sc = 150.; #short circuit current\n",
+ "\n",
+ "# Calculations and Results\n",
+ "Z_s = V_oc/I_sc; #synchronous impedence\n",
+ "print \"synchronous impedence, Z_s = %d ohm\"%(Z_s);\n",
+ "I_a = 60;\n",
+ "print \"internal voltage drop when the load current is 60amp = %d V\"%(I_a*Z_s);"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "field exitation current = 10A\n",
+ "synchronous impedence, Z_s = 6 ohm\n",
+ "internal voltage drop when the load current is 60amp = 360 V\n"
+ ]
+ }
+ ],
+ "prompt_number": 19
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.12 Page No : 441"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data;\n",
+ "KVA = 2000.;\n",
+ "V = 6600.; #rating\n",
+ "V_p = 6600./math.sqrt(3);\n",
+ "I_a = (KVA*1000)/(math.sqrt(3)*V);\n",
+ "R_a = 0.4; #armature resistance\n",
+ "X_s = 4.5 #synchronous reactance\n",
+ "pf = 0.8;\n",
+ "\n",
+ "# Calculations and Results\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "print \"V/phase = %dV \"%(V_p)\n",
+ "E = math.sqrt((V_p*math.cos(math.radians(phi))+I_a*R_a)**2+(V_p*math.sin(math.radians(phi))+I_a*X_s)**2)\n",
+ "print \"E = %f V per phase\"%(E);\n",
+ "R = ((E-V_p)*100)/V_p;\n",
+ "print \"percentage change in terminal voltage = %f percent\"%(R);"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "V/phase = 3810V \n",
+ "E = 4378.515597 V per phase\n",
+ "percentage change in terminal voltage = 14.906234 percent\n"
+ ]
+ }
+ ],
+ "prompt_number": 20
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.13 Page No : 442"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data;\n",
+ "KVA = 1200.; #output power\n",
+ "print \"output power = %d\"%(KVA)\n",
+ "V_l = 3300.; #line voltage\n",
+ "R_a = 0.25; #armature resistance\n",
+ "\n",
+ "# Calculations and Results\n",
+ "I_l = (KVA*1000)/(math.sqrt(3)*V_l); #line current\n",
+ "#for star connected I_l = I_a\n",
+ "I_a = I_l;\n",
+ "V_p = V_l/math.sqrt(3);\n",
+ "print \"V per phase = %dV\"%(V_p)\n",
+ "#field current of 40A produces short circuit current of 200A and open circuit emf 1100\n",
+ "v_l = 1100;\n",
+ "i_s = 200;\n",
+ "Z_s = v_l/(math.sqrt(3)*i_s); #synchronous impedence\n",
+ "print \"Synchronous impedance, Zs = %f ohm\"%(Z_s)\n",
+ "X_s = math.sqrt(Z_s**2-R_a**2); #synchronous reactance\n",
+ "print (\"(a)for 0.8 lagging power facor\");\n",
+ "pf = 0.8;\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "E = math.sqrt((V_p*math.cos(math.radians(phi))+I_a*R_a)**2+(V_p*math.sin(math.radians(phi))+I_a*X_s)**2)\n",
+ "print \"induced emf, E = %f V\"%(E);\n",
+ "R = ((E-V_p)*100)/V_p;\n",
+ "print \"regulation = %f percent\"%(R);\n",
+ "pf = 0.8;\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "print (\"(b)For leading power factor load\")\n",
+ "E = math.sqrt((V_p*math.cos(math.radians(phi))+I_a*R_a)**2+(V_p*math.sin(math.radians(phi))-I_a*X_s)**2)\n",
+ "print \"induced emf, E = %f V\"%(E);\n",
+ "R = ((E-V_p)*100)/V_p;\n",
+ "print \"regulation = %f percent\"%(R);"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "output power = 1200\n",
+ "V per phase = 1905V\n",
+ "Synchronous impedance, Zs = 3.175426 ohm\n",
+ "(a)for 0.8 lagging power facor\n",
+ "induced emf, E = 2398.732590 V\n",
+ "regulation = 25.900810 percent\n",
+ "(b)For leading power factor load\n",
+ "induced emf, E = 1647.716860 V\n",
+ "regulation = -13.517293 percent\n"
+ ]
+ }
+ ],
+ "prompt_number": 21
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.14 Page No : 443"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data;\n",
+ "print (\"star connected alternator\")\n",
+ "KVA = 1500.; #rating\n",
+ "ph = 3.; #3-phase\n",
+ "V_l = 6600.; #voltage\n",
+ "Ra = 0.4 #armature resistance\n",
+ "Xs = 6.; #reactance\n",
+ "\n",
+ "# Calculations and Results\n",
+ "Ia = (KVA*1000)/(math.sqrt(3)*V_l);\n",
+ "print \"Full-load current = %d A\"%(Ia);\n",
+ "V = V_l/math.sqrt(3);\n",
+ "print \"Voltage per phase = %d V\"%(V);\n",
+ "print (\"for 0.8 lagging power facor\");\n",
+ "pf = 0.8; #power factor\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "E = math.sqrt((V*math.cos(math.radians(phi))+Ia*Ra)**2+(V*math.sin(math.radians(phi))+Ia*Xs)**2)\n",
+ "print \"induced emf = %f V\"%(E);\n",
+ "print (\"then at 0.8 leading power factor\");\n",
+ "Vt = 4743; #solved manually \n",
+ "print \"termial Voltage, line-to-line = %d V\"%(math.sqrt(3)*Vt)"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "star connected alternator\n",
+ "Full-load current = 131 A\n",
+ "Voltage per phase = 3810 V\n",
+ "for 0.8 lagging power facor\n",
+ "induced emf = 4366.072552 V\n",
+ "then at 0.8 leading power factor\n",
+ "termial Voltage, line-to-line = 8215 V\n"
+ ]
+ }
+ ],
+ "prompt_number": 23
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.15 Page No : 450"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "#chapter 5\n",
+ "#example 5.15\n",
+ "#page 450\n",
+ "\n",
+ "# Given Data;\n",
+ "L = 8000.; #load\n",
+ "La = 5000.;\n",
+ "pf = 0.8;\n",
+ "\n",
+ "# Calculations and Results\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "print \"math.tan phi = %f\"%(math.degrees(math.atan(phi)));\n",
+ "print (\"FOR ALTERNATOR A\");\n",
+ "pf_a = 0.9;\n",
+ "phi_a = math.degrees(math.acos(pf_a));\n",
+ "print \"math.tan phi_a = %f\"%(math.degrees(math.atan(phi_a)));\n",
+ "print (\"reactive load = active load*math.tan phi\");\n",
+ "print (\"Active load = 8000kW\");\n",
+ "print \"reactive load = %d KVAr\"%(8000*math.degrees(math.atan(phi_a)));\n",
+ "print (\"Active Load A = 5000kW\");\n",
+ "print \"Reactive load A = %dkVAr\"%(5000*math.degrees(math.atan(phi_a)));\n",
+ "print \"Active load of B = %dkW\"%(L-La);\n",
+ "a = ((8000*math.degrees(math.atan(phi)))-(5000*math.degrees(math.atan(phi_a))))\n",
+ "print \"Reactive load of B = %dkVAr\"%(a);\n",
+ "B = a/(L-La);\n",
+ "phi_b = math.degrees(math.atan(B));\n",
+ "print \"phi_b = %f\"%(phi_b)\n",
+ "print \"Power Factor of B = %f\"%(math.cos(math.radians(phi_b)));"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "math.tan phi = 88.446382\n",
+ "FOR ALTERNATOR A\n",
+ "math.tan phi_a = 87.783943\n",
+ "reactive load = active load*math.tan phi\n",
+ "Active load = 8000kW\n",
+ "reactive load = 702271 KVAr\n",
+ "Active Load A = 5000kW\n",
+ "Reactive load A = 438919kVAr\n",
+ "Active load of B = 3000kW\n",
+ "Reactive load of B = 268651kVAr\n",
+ "phi_b = 89.360211\n",
+ "Power Factor of B = 0.011166\n"
+ ]
+ }
+ ],
+ "prompt_number": 27
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.16 Page No : 451"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "\n",
+ "# Given Data\n",
+ "V = 6600.;\n",
+ "ph = 3.; #3-phase alternators \n",
+ "power = 10000.; #total load\n",
+ "\n",
+ "# Calculations and Results\n",
+ "print (\"Two alternators in parallel connection\");\n",
+ "pf = 0.8;\n",
+ "Ia = 438; #armature current\n",
+ "Il = (power*1000)/(math.sqrt(3)*V*pf); #load current\n",
+ "print \"load current = %fA\"%(Il);\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "Ac = (Il*math.cos(math.radians(phi)));\n",
+ "Rc = (Il*math.sin(math.radians(phi)));\n",
+ "print \"Active component of current = %fA\"%(Ac);\n",
+ "print \"Reactive component of current = %fA\"%(Rc);\n",
+ "print \"Current supplied by each alternator = %fA\"%(Il/2);\n",
+ "print \"Active component of current supplied by each alternator = %fA\"%(Ac/2);\n",
+ "print \"Reactive component of current supplied by each alternator = %fA\"%(Rc/2);\n",
+ "print (\"Since steam supply is same,the active component remain the same \");\n",
+ "RIl = math.sqrt(Ia**2-(Ac/2)**2);\n",
+ "print \"Reactive component of Il = %dA\"%(RIl);\n",
+ "RI2 = (Rc-RIl);\n",
+ "print \"reactive component of I2 = %fA\"%(RI2);\n",
+ "I2 = math.sqrt((Ac/2)**2+(RI2)**2);\n",
+ "print \" I2 = %fA\"%(I2);\n",
+ "phi_2 = math.degrees(math.atan(RI2/(Ac/2)));\n",
+ "print \"phi 2 = %f degrees\"%(phi_2);\n",
+ "print \"math.cos phi 2 = %f\"%(math.cos(math.radians(phi_2)));\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Two alternators in parallel connection\n",
+ "load current = 1093.466419A\n",
+ "Active component of current = 874.773135A\n",
+ "Reactive component of current = 656.079851A\n",
+ "Current supplied by each alternator = 546.733209A\n",
+ "Active component of current supplied by each alternator = 437.386568A\n",
+ "Reactive component of current supplied by each alternator = 328.039926A\n",
+ "Since steam supply is same,the active component remain the same \n",
+ "Reactive component of Il = 23A\n",
+ "reactive component of I2 = 632.906796A\n",
+ " I2 = 769.336091A\n",
+ "phi 2 = 55.352588 degrees\n",
+ "math.cos phi 2 = 0.568525\n"
+ ]
+ }
+ ],
+ "prompt_number": 28
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 5.17 Page No : 455"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math \n",
+ "# Given Data;\n",
+ "print (\"power factor of existing load is 0.8 lagging\");\n",
+ "pf = 0.8; #power factor\n",
+ "\n",
+ "# Calculations and Results\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "print \"phi = %d degree\"%(phi);\n",
+ "L = 800.; #load\n",
+ "kVAr1 = (L*math.degrees(math.atan(phi)));\n",
+ "print \"kVAr1 = %d \"%(kVAr1);\n",
+ "print (\"output for the synchronous motor is 200kW\");\n",
+ "output = 200.;\n",
+ "efficiency = 0.9;\n",
+ "kW = (output/efficiency);\n",
+ "print \"Input to the synchronous motor = %fkW\"%(kW);\n",
+ "TL = (L+kW); # total load\n",
+ "print \"Total load on the system = %fkW\"%(TL);\n",
+ "print (\"overall power factor of the load is to be raised to 0.92 lagging\");\n",
+ "pf = 0.92;\n",
+ "phi = math.degrees(math.acos(pf));\n",
+ "kVAr2 = (TL*math.degrees(math.atan(phi)))\n",
+ "print \"kVAr2 = %f\"%(kVAr2);\n",
+ "kVAr = kVAr1-kVAr2;\n",
+ "print \"lagging kVAr of synchronous codenser = %f\"%(kVAr);\n",
+ "print \"leading kVAr supplied by the motor = %f\"%(kVAr);\n",
+ "phi = math.degrees(math.atan(kVAr/kW));\n",
+ "print \"phi = %d degree\"%(phi);\n",
+ "print \"Power factor of the synchronos motor = %f leading \"%(math.cos(math.radians(phi)));\n",
+ "print \"KVA rating of the synchronous motor = %f\"%(kW/math.cos(math.radians(phi)));\n",
+ "\n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "power factor of existing load is 0.8 lagging\n",
+ "phi = 36 degree\n",
+ "kVAr1 = 70757 \n",
+ "output for the synchronous motor is 200kW\n",
+ "Input to the synchronous motor = 222.222222kW\n",
+ "Total load on the system = 1022.222222kW\n",
+ "overall power factor of the load is to be raised to 0.92 lagging\n",
+ "kVAr2 = 89463.266068\n",
+ "lagging kVAr of synchronous codenser = -18706.160461\n",
+ "leading kVAr supplied by the motor = -18706.160461\n",
+ "phi = -89 degree\n",
+ "Power factor of the synchronos motor = 0.011879 leading \n",
+ "KVA rating of the synchronous motor = 18707.480373\n"
+ ]
+ }
+ ],
+ "prompt_number": 29
+ }
+ ],
+ "metadata": {}
+ }
+ ]
+} \ No newline at end of file