path: root/Electric_Machines_by_C._I._Hubert/CHAPTER12.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# CHAPTER12 : DIRECT GENERATOR CHARACTERISTICS AND OPERATION"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example E01 : Pg 479"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Field circuit resistance = 33.1914893617 Ohm\n",
      "Field rheostat setting that will provide no load voltage of 140V = 10.5585106383 Ohm\n",
      "Armature voltage if the rheostat is set to 14.23 ohm = 130.0 V\n",
      "Field rheostat setting that will cause critical resistance = 59.5744680851 Ohm\n",
      "Armature voltage at 80 percent rated speed (V)= 116\n",
      "Rheostat setting required = 4.3085106383 Ohm\n"
     ]
    }
   ],
   "source": [
    "#  Example 12.1\n",
    "#  Determine (a) Field circuit resistance (b) Field rheostat setting that will \n",
    "#  provide no load voltage of 140V (c) Armature voltage if the rheostat is set \n",
    "#  to 14.23 ohm (d) Field rheostat setting that will cause critical resistance \n",
    "#  (e) Armature voltage at 80 percent rated speed (f) Rheostat setting required \n",
    "#  to obtain no load armature voltage of 140V if shunt field is separately \n",
    "#  excited from a 120V DC source\n",
    "#  Page No. 479\n",
    "#  Given data\n",
    "Ea=156.;               #  No load voltage\n",
    "If=4.7;               #  Shunt field current\n",
    "If140=2.35;           #  New field current at Ea=140V\n",
    "Eanew=140;            #  No load voltage\n",
    "Ifnew=3.2;            #  Field current corresponding to no load voltage\n",
    "Ea1=0;                #  First arbitrary voltage\n",
    "Ea2=100.;              #  Second arbitrary voltage\n",
    "Vf=120.;\n",
    "V=130.;                #  Intersection of I1 and I2\n",
    "Rrheonew=14.42;       #  Rheostat set to new settings\n",
    "Va=116.;               #  Intersection of field resistance line with the low \n",
    "                      #  speed magnetization curve\n",
    "# (a) Field circuit resistance\n",
    "Rf=Ea/If;      #  Field circuit resistance\n",
    "#  (b) Field rheostat setting that will provide no load voltage of 140V\n",
    "Rrheo=(Eanew/Ifnew)-Rf;\n",
    "# (c) Armature voltage if the rheostat is set to 14.23 ohm\n",
    "Rnew=Rf+Rrheonew;      #  New field resistance\n",
    "If1=Ea1/(Rf+Rrheo);    #  Field current corresponding to first arbitrary voltage\n",
    "If2=Ea2/(Rf+Rrheo);    #  Field current corresponding to second arbitrary voltage\n",
    "#  (d) Field rheostat setting that will cause critical resistance \n",
    "Rcr=Eanew/If140;         #  Critical resistance\n",
    "#  (e) Armature voltage at 80 percent rated speed\n",
    "#  Ea80=0.80*Ea;\n",
    "Ea80=116;\n",
    "# (f) Rheostat setting required to obtain no load armature voltage of 140V if \n",
    "#  shunt field is separately excited from a 120V DC source\n",
    "Rrheo1=(Vf/Ifnew)-Rf;   \n",
    "#  Display result on command window\n",
    "print\"Field circuit resistance =\",Rf,\"Ohm\"\n",
    "print\"Field rheostat setting that will provide no load voltage of 140V =\",Rrheo,\"Ohm\"\n",
    "print\"Armature voltage if the rheostat is set to 14.23 ohm =\",V,\"V\"\n",
    "print\"Field rheostat setting that will cause critical resistance =\",Rcr,\"Ohm\"\n",
    "print\"Armature voltage at 80 percent rated speed (V)=\",Ea80\n",
    "print\"Rheostat setting required =\",Rrheo1,\"Ohm\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example E02 : Pg 487"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "No load voltage = 255.0 V\n",
      "Voltage regulation = 6.25 Percent\n",
      "Resistance setting of rheostat necessary = 2.996 Ohm\n"
     ]
    }
   ],
   "source": [
    "#  Example 12.2\n",
    "#  Computation of (a) No load voltage (b) Voltage regulation\n",
    "#  (c) Resistance setting of rheostat necessary to obtain rated voltage \n",
    "#  at rated conditions\n",
    "#  Page No. 487\n",
    "#  Given data\n",
    "P=300000.;               #  Shunt generator power rating\n",
    "VT=240.;                 #  Shunt generator voltage rating\n",
    "Ra=0.00234;             #  Armature winding resistance\n",
    "RIP=0.00080;            #  Resistance of interpole winding\n",
    "Fnet=5100.;              #  Net mmf\n",
    "Vnl=255.;                #  No load voltage\n",
    "Vrated=240.;             #  Rated voltage\n",
    "Nf=1020.;                #  Turns per pole\n",
    "Vf=120.;                 #  Source that separately excites the generator\n",
    "If=5.69;\n",
    "Rf=18.1;\n",
    "#  (a) No load voltage\n",
    "Ia=P/VT;               #  Armature current\n",
    "Ea=VT+Ia*(Ra+RIP);     #  Armature emf\n",
    "Ff=Fnet/(1.-0.121);\n",
    "#  (b) Voltage regulation\n",
    "VR=(Vnl-Vrated)*100./Vrated; \n",
    "#  (c) Resistance setting of rheostat necessary to obtain rated voltage at rated conditions\n",
    "If=Ff/Nf;\n",
    "Rrheo=(Vf/If)-Rf; #  Rheostat setting\n",
    "#  Display result on command window\n",
    "print\"No load voltage =\",Vnl,\"V\"\n",
    "print\"Voltage regulation =\",VR,\"Percent\"\n",
    "print\"Resistance setting of rheostat necessary =\",Rrheo,\"Ohm\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example E03 : Pg 492"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Induced emf at rated load = 265.003501075 V\n",
      "No load voltage = 225.0 V\n",
      "Voltage regulation = -10.0 Percent\n",
      "The machine is overcompounded\n"
     ]
    }
   ],
   "source": [
    "#  Example 12.3\n",
    "#  Computation of (a) Induced emf at rated load (b) No load voltage\n",
    "#  (c) Voltage regulation (d) What is the type of compounding?\n",
    "#  Page No. 492\n",
    "#  Given data\n",
    "Pload=320000.;               #  Shunt generator power rating\n",
    "Vrated=250.;                 #  Shunt generator voltage rating\n",
    "Rf=20.2;                    #  Shunt resistance\n",
    "Rrheo=7.70;                 #  Shunt field rheostat value\n",
    "If=8.96;                    #  Field current\n",
    "Iload=1280.;                 #  Load current\n",
    "Ra=0.00817;                 #  Armature resistance\n",
    "Rip=0.00238;                #  Resistance of interpole winding\n",
    "Rse=0.00109;                #  Resistance of series winding\n",
    "Nf=502.;                     #  Turns per pole\n",
    "VNL=225.;                    #  No load voltage\n",
    "\n",
    "#  (a) Induced emf at rated load\n",
    "Iload=Pload/Vrated;          #  Load current\n",
    "If=Vrated/(Rf+Rrheo);        #  Field current\n",
    "Ia=If+Iload;                 #  Armature current\n",
    "Racir=Ra+Rip+Rse;\n",
    "Ea=Vrated+Ia*Racir;\n",
    "\n",
    "#  (b) No load voltage\n",
    "Ff=Nf*If; \n",
    "\n",
    "#  (c) Voltage regulation\n",
    "VR=(VNL-Vrated)*100./Vrated; \n",
    "\n",
    "\n",
    "#  Display result on command window\n",
    "print\"Induced emf at rated load =\",Ea,\"V\"\n",
    "print\"No load voltage =\",VNL,\"V\"\n",
    "print\"Voltage regulation =\",VR,\"Percent\"\n",
    "print\"The machine is overcompounded\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example E04 : Pg 494"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Required resistance of a noninductive diverter = %0.5f Ohm  0.00827333333333\n",
      "Power rating of the diverter = 278.8854624 W \n"
     ]
    }
   ],
   "source": [
    "#  Example 12.4\n",
    "#  Computation of (a) Required resistance of a noninductive diverter that will \n",
    "#  bypass 27 percent of the total armature current(b) Power rating of the \n",
    "#  diverter\n",
    "#  Page No. 494\n",
    "#  Given data\n",
    "Rs=0.00306;               #  Shunt generator resistance rating\n",
    "Is=0.73;                  #  Shunt generator current rating\n",
    "Id1=0.27;                 #  Armature winding resistance\n",
    "Pload=170000.;             #  Load of power\n",
    "VT=250.;                   #  Shunt generator voltage rating\n",
    "Id2=680.;                  #  No load voltage\n",
    "Rd=0.27;                  #  Resistance drop\n",
    "\n",
    "#  (a) Required resistance of a noninductive diverter that will bypass \n",
    "#  27 percent of the total armature current\n",
    "Rd=Rs*Is/Id1;\n",
    "\n",
    "\n",
    "#  (b) Power rating of the diverter\n",
    "Ia=Pload/VT; \n",
    "Pd=((Id1*Id2)**2.)*Rd;\n",
    "\n",
    "\n",
    "\n",
    "# Display result on command window\n",
    "print\"Required resistance of a noninductive diverter = %0.5f Ohm \",Rd\n",
    "print\"Power rating of the diverter =\",Pd,\"W \""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example E05 : Pg 500"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "New bus voltage = 3.81944444444 V\n",
      "Current supplied by generator A = 1311.11111111 A\n",
      "Current supplied by generator B = 1188.88888889 A\n",
      "Macine A is overloaded by 9.25925925926 Percent\n"
     ]
    }
   ],
   "source": [
    "#  Example 12.5\n",
    "#  Computation of (a) New bus voltage (b) Current supplied by each generator\n",
    "# Page No. 500\n",
    "#  Given data\n",
    "p1=300000.;               #  Rated power in generator A\n",
    "p2=400000.;               #  Rated power in generator B\n",
    "v=250.;                   #  Rated voltage in machine\n",
    "p3=350000.;               #  Rated power in generator C\n",
    "Ibnew=2500.;\n",
    "\n",
    "#  (a) New bus voltage\n",
    "\n",
    "IArated=p1/v;               #  Rated current in generator A\n",
    "IBrated=p2/v;               #  Rated current in generator B\n",
    "IBorig=p3/v;                #  Original bus current\n",
    "IbDelta=Ibnew-IBorig;       #  Current difference\n",
    "DelVbus=IbDelta/(160.+128.);  #  Voltage difference\n",
    "\n",
    "\n",
    "#  (b) Current supplied by each generator\n",
    "DelIA=160.*DelVbus;          #  Generator A current difference\n",
    "DelIB=128.*DelVbus;          #  Generator A current difference\n",
    "Vbus=v-DelVbus;             #  Voltage across the bus\n",
    "IA=700.+DelIA;               #  Current in generator A\n",
    "IB=700.+DelIB;               #  Current in generator B\n",
    "\n",
    "Loading= (IA-IArated)*100./IArated;\n",
    "\n",
    "\n",
    "#  Display result on command window\n",
    "print\"New bus voltage =\",DelVbus,\"V\"\n",
    "print\"Current supplied by generator A =\",IA,\"A\"\n",
    "print\"Current supplied by generator B =\",IB,\"A\"\n",
    "print\"Macine A is overloaded by\",Loading,\"Percent\""
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Example E06 : Pg 502"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "The increment increase in load on machine A = 100.0 A\n",
      "The increment increase in load on machine B = 300.0 A\n",
      "Current carried by machine A = 300.0 A\n",
      "Current carried by machine B = 800.0 A\n"
     ]
    }
   ],
   "source": [
    "#  Example 12.6\n",
    "#  Determine (a) The increment increase in load on each machine if an \n",
    "#  additional 400 A load is connected to the bus (b) Current carried \n",
    "#  by each machine\n",
    "#  Page No. 502\n",
    "#  Given data\n",
    "p1=100000.;                #  Rated power in generator A\n",
    "p2=300000.;                #  Rated power in generator B\n",
    "v=250.;                    #  Rated voltage in machine\n",
    "p3=30000.;                 #  Rated power in generator C\n",
    "Ibnew=400.;                #  New bus current\n",
    "I1=200.;\n",
    "I2=500.;\n",
    "\n",
    "#  (a) The increment increase in load on each machine if an additional 400 A \n",
    "#  load is connected to the bus\n",
    "\n",
    "IArated=p1/v;                      #  Rated current in generator A\n",
    "IBrated=p2/v;                      #  Rated current in generator B\n",
    "Ib=p3/v;                           #  Original bus current\n",
    "DelVbus=Ibnew/(40.+120.);            #  Change in bus current\n",
    "DelIA=40.*DelVbus;\n",
    "DelIB=120.*DelVbus;\n",
    "\n",
    "\n",
    "#  (b) Current carried by each machine\n",
    "\n",
    "IA=I1+DelIA;                #  Current in generator A\n",
    "IB=I2+DelIB;                #  Current in generator B\n",
    "\n",
    "\n",
    "#  Display result on command window\n",
    "print\"The increment increase in load on machine A =\",DelIA,\"A\"\n",
    "print\"The increment increase in load on machine B =\",DelIB,\"A\"\n",
    "print\"Current carried by machine A =\",IA,\"A\"\n",
    "print\"Current carried by machine B =\",IB,\"A\""
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python [Root]",
   "language": "python",
   "name": "Python [Root]"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 2
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython2",
   "version": "2.7.12"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 0
}