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+ "cells": [
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "# Chapter 10 - Three Phase Induction Motors"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 1 - pg 10_14"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 1,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "full load slip (percent) = 6.0\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_1,pg10_14\n",
+ "#calculate the full load slip\n",
+ "#given\n",
+ "P=4.\n",
+ "f=50.\n",
+ "N=1410.\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "s=(Ns-N)/Ns\n",
+ "s=s*100#%s\n",
+ "#results\n",
+ "print\"full load slip (percent) = \",s\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 2 - pg 10_14"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 2,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "full load speed of motor (rpm) = 1440.0\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_2,pg10_14\n",
+ "#calculate the full load speed of motor\n",
+ "#given\n",
+ "P=4.\n",
+ "f=50.\n",
+ "sfl=4/100.\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "Nfl=Ns-sfl*Ns\n",
+ "#results\n",
+ "print\"full load speed of motor (rpm) = \",Nfl\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 3 - pg 10_16"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 3,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "frequency of induced e.m.f (Hz) = 1.0\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_3,pg10_16\n",
+ "#calculate the frequency of induced emf\n",
+ "#given\n",
+ "P=4.\n",
+ "f=50.\n",
+ "N=1470.\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "s=(Ns-N)/Ns\n",
+ "fr=s*f\n",
+ "#results\n",
+ "print\"frequency of induced e.m.f (Hz) = \",fr\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 4 - pg 10_20"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 4,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "full load slip (percent)= 4.0\n",
+ "speed of motor (rpm) = 720.0\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_4,pg10_20\n",
+ "#calculate the full load slip and speed of motor\n",
+ "#given\n",
+ "P=8.\n",
+ "f=50.\n",
+ "fr=2.\n",
+ "#calculations\n",
+ "s=fr/f\n",
+ "s=s*100.\n",
+ "#results\n",
+ "print\"full load slip (percent)= \",s\n",
+ "s=s/100\n",
+ "Ns=120*f/P\n",
+ "N=Ns*(1-s)\n",
+ "print\"speed of motor (rpm) = \",N\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 5 - pg 10_20"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 5,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "frequency of rotor e.m.f (Hz) = 1.5\n",
+ "magnitude of induced e.m.f standstill (V) = 119.8\n",
+ "magnitude of induced e.m.f running (V) = 3.594\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_5,pg10_20\n",
+ "import math\n",
+ "#calculate the frequency of rotor, magnitude of induced emf\n",
+ "#given\n",
+ "P=4.\n",
+ "f=50.\n",
+ "N=1455.\n",
+ "E1line=415.\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "s=(Ns-N)/Ns\n",
+ "fr=s*f\n",
+ "E1ph=E1line/math.sqrt(3)\n",
+ "E2ph=0.5*E1ph#K=2\n",
+ "E2r=s*E2ph\n",
+ "#results\n",
+ "print\"frequency of rotor e.m.f (Hz) = \",fr\n",
+ "print\"magnitude of induced e.m.f standstill (V) = \",round(E2ph,1)\n",
+ "print\"magnitude of induced e.m.f running (V) = \",round(E2r,3)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 6 - pg 10_21"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 6,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ " at start\n",
+ "pf (lagging) = 0.196\n",
+ "I2 (A) = 67.94\n",
+ " on full load\n",
+ "pf (lagging) = 0.9806\n",
+ "I2 (A) = 13.587\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_6,pg10_21\n",
+ "#calculate the rotor current and power factor\n",
+ "import math\n",
+ "from math import sqrt\n",
+ "#given\n",
+ "P=4\n",
+ "f=50\n",
+ "R2=0.2\n",
+ "X2=1\n",
+ "E2line=120\n",
+ "#calculations and results\n",
+ "E2ph=E2line/sqrt(3)\n",
+ "Ns=120*f/P\n",
+ "#at start\n",
+ "pf=R2/sqrt((R2**2)+(X2**2))#power factor\n",
+ "I2=E2ph/sqrt((R2**2)+(X2**2))\n",
+ "print\" at start\"\n",
+ "print\"pf (lagging) = \",round(pf,3)\n",
+ "print\"I2 (A) = \",round(I2,2)\n",
+ "#on full load\n",
+ "N=1440.\n",
+ "s=(Ns-N)/Ns\n",
+ "pf=R2/sqrt((R2**2)+((s*X2)**2))\n",
+ "I2=E2ph*s/sqrt((R2**2)+((s*X2)**2))\n",
+ "print\" on full load\"\n",
+ "print\"pf (lagging) = \",round(pf,4)\n",
+ "print\"I2 (A) = \",round(I2,3)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 7 - pg 10_24"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 7,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "torque on full load (Nm) = 87.81\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_7,pg10_24\n",
+ "#calculate the torque on full load\n",
+ "import math\n",
+ "#given\n",
+ "P=4.\n",
+ "f=50.\n",
+ "R2=0.1\n",
+ "X2=1.\n",
+ "N=1440.\n",
+ "K=0.5\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "E1line=400.\n",
+ "E1ph=E1line/math.sqrt(3)\n",
+ "E2ph=0.5*E1ph\n",
+ "s=(Ns-N)/Ns\n",
+ "ns=Ns/60#synchronous speed (r.p.s)\n",
+ "T=(3/(2*math.pi*ns))*(s*(E2ph**2)*R2/((R2**2)+((s*X2)**2)))\n",
+ "#results\n",
+ "print \"torque on full load (Nm) = \",round(T,2)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 8 - pg 10_27"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 8,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "starting torque (Nm) = 63.032\n",
+ "slip at which max torque occurs (percent) = 10.0\n",
+ "speed at which max torque occurs (rpm) 1350.0\n",
+ "max torque (Nm) = 318.31\n",
+ "full load torque (Nm) = 219.52\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_8,pg10_27\n",
+ "#calculate the starting torque, max torque, speed\n",
+ "import math\n",
+ "from math import sqrt\n",
+ "P=4.\n",
+ "f=50.\n",
+ "K=1/4.\n",
+ "R2=0.01\n",
+ "X2=0.1\n",
+ "E1line=400.\n",
+ "E1ph=E1line/sqrt(3)\n",
+ "E2=E1ph/4\n",
+ "Ns=120*f/P\n",
+ "#at start\n",
+ "s=1\n",
+ "ns=Ns/60\n",
+ "k=3/(2*math.pi*ns)\n",
+ "Tst=k*(E2**2)*R2/((R2**2)+(X2**2))\n",
+ "print\"starting torque (Nm) = \",round(Tst,3)\n",
+ "\n",
+ "#slip at max torque\n",
+ "sm=R2/X2\n",
+ "sm=sm*100\n",
+ "print\"slip at which max torque occurs (percent) = \",round(sm,0)\n",
+ "#speed at max torque\n",
+ "sm=sm/100\n",
+ "N=Ns*(1-sm)\n",
+ "print\"speed at which max torque occurs (rpm) \",N\n",
+ "\n",
+ "#max. torque\n",
+ "Tm=k*(E2**2)/(2*X2)\n",
+ "sf=0.04\n",
+ "Tfl=k*sf*(E2**2)*R2/((R2**2)+((sf*X2)**2))\n",
+ "print\"max torque (Nm) = \",round(Tm,2)\n",
+ "print\"full load torque (Nm) = \",round(Tfl,2)\t\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 9 - pg 10_33"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 9,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "full load torque to max torque = 0.3824\n",
+ "starting torque to max torque = 0.1203\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_9,pg10_33\n",
+ "#calculate the full load torque and starting torque\n",
+ "#given\n",
+ "P=24.\n",
+ "f=50.\n",
+ "R2=0.016\n",
+ "X2=0.265\n",
+ "N=247.\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "sf=(Ns-N)/Ns\n",
+ "sm=R2/X2\n",
+ "Tfm=2*sm*sf/((sm**2)+(sf**2))\n",
+ "Tsm=2*sm/(1+(sm**2))\n",
+ "#results\n",
+ "print\"full load torque to max torque = \",round(Tfm,4)\n",
+ "print\"starting torque to max torque = \",round(Tsm,4)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 10 - pg 10_36"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 10,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "external resistance (ohm/phase) = 0.0136\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_10,pg10_36\n",
+ "#calculate the external resistance\n",
+ "#given\n",
+ "import math\n",
+ "R2=0.04\n",
+ "X2=0.2\n",
+ "#for Tm=Tst, sm=1\n",
+ "#calculations\n",
+ "R21=X2\n",
+ "Rex=R2-R21\n",
+ "#for Tst=Tm/2........(1)\n",
+ "#Tst=k*(E2**2)*R21/((R21**2)+(X2**2))......(2)with added resistance\n",
+ "#from (1) and (2)\n",
+ "#(R21**2)-0.8*R21+0.04=0\n",
+ "a=1\n",
+ "b=-0.8\n",
+ "c=0.04\n",
+ "R21=(-b-math.sqrt((b**2)-4*a*c))/(2*a)#neglecting higher value\n",
+ "Rex=R21-R2\n",
+ "#results\n",
+ "print\"external resistance (ohm/phase) = \",round(Rex,4)"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 11 - pg 10_42"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 11,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "rotor copper loss (W) = 469.326\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_11,pg10_42\n",
+ "#calculate the rotor copper loss\n",
+ "#given\n",
+ "import math\n",
+ "Tsh=190.\n",
+ "P=8.\n",
+ "f=50.\n",
+ "fr=1.5\n",
+ "ML=700.\n",
+ "#calculations\n",
+ "s=fr/f\n",
+ "Ns=120*f/P\n",
+ "N=Ns*(1-s)\n",
+ "Po=Tsh*(2*math.pi*N/60.)\n",
+ "Pm=Po+ML\n",
+ "Pc=Pm*s/(1-s)\n",
+ "#results\n",
+ "print\"rotor copper loss (W) = \",round(Pc,3)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 12 - pg 10_43"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 12,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "full load efficiency (percent) = 92.78\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_12,pg10_43\n",
+ "#calculate the full load efficiency\n",
+ "#given\n",
+ "P=4.\n",
+ "f=50.\n",
+ "Pi=50.*10**3\n",
+ "N=1440.\n",
+ "Sl=1000.\n",
+ "Fl=650.\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "s=(Ns-N)/Ns\n",
+ "P2=Pi-Sl\n",
+ "Pc=s*P2\n",
+ "Pm=P2-Pc\n",
+ "Po=Pm-Fl\n",
+ "n=Po*100/Pi\n",
+ "#results\n",
+ "print\"full load efficiency (percent) = \",n\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 13 - pg 10_44"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 14,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "slip (percent) = 4.0\n",
+ "net output power (kW) = 45.2389\n",
+ "rotor copper loss per phase (W) = 733.0383\n",
+ "rotor efficiency (percent) = 96.0\n",
+ "rotor resistance per phase (ohm/phase) = 0.2036\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_13,pg10_44\n",
+ "#calculate the net output power, rotor copper loss,efficiency and resistance per phase\n",
+ "#given\n",
+ "import math\n",
+ "P=4.\n",
+ "f=50.\n",
+ "Tsh=300.\n",
+ "Tlost=50.\n",
+ "fr=120/60.#Hz\n",
+ "#calculations\n",
+ "s=fr/f\n",
+ "s=s*100.\n",
+ "print\"slip (percent) = \",s\n",
+ "Ns=120.*f/P\n",
+ "s=s/100.\n",
+ "N=Ns*(1-s)\n",
+ "Po=Tsh*2*math.pi*N/60\n",
+ "Fl=Tlost*2*math.pi*N/60\n",
+ "Pm=Po+Fl\n",
+ "Pc=Pm*s/(1-s)\n",
+ "Rcl=Pc/3#rotor copper loss per phase\n",
+ "P2=Pc/s\n",
+ "n=Pm*100./P2\n",
+ "I2r=60\n",
+ "R2=Rcl/(I2r**2)\n",
+ "#results\n",
+ "print\"net output power (kW) = \",round(Po/1000.,4)\n",
+ "print\"rotor copper loss per phase (W) = \",round(Rcl,4)\n",
+ "print\"rotor efficiency (percent) = \",n\n",
+ "print\"rotor resistance per phase (ohm/phase) = \",round(R2,4)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 14 - pg 10_45"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 16,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "gross mechanical power (W) = 25850.0\n",
+ "rotor copper losses (W) = 1650.0\n",
+ "rotor resistance per phase (ohm/phase) = 0.13\n",
+ "full load efficiency (percent) = 82.49\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_14,pg10_45\n",
+ "#calculate the gross mechanical power, rotor copper losses, resistance and full load efficiency\n",
+ "#given\n",
+ "Po=25.*10**3\n",
+ "f=50.\n",
+ "P=4.\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "N=1410\n",
+ "s=(Ns-N)/Ns\n",
+ "Ml=850\n",
+ "Pm=Po+Ml\n",
+ "Pc=Pm*s/(1-s)\n",
+ "I2r=65\n",
+ "R2=Pc/(3*(I2r**2))\n",
+ "Sl=1.7*Pc\n",
+ "P2=Pc/s\n",
+ "Pin=P2+Sl\n",
+ "n=Po*100/Pin\n",
+ "#results\n",
+ "print\"gross mechanical power (W) = \",Pm\n",
+ "print\"rotor copper losses (W) = \",Pc\n",
+ "print\"rotor resistance per phase (ohm/phase) = \",round(R2,2)\n",
+ "print\"full load efficiency (percent) = \",round(n,2)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 15 - pg 10_47"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 17,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "shaft torque (N-m) = 318.31\n",
+ "gross torque (N-m) = 331.573\n",
+ "rotor copper losses (W) = 1041.67\n",
+ "stator copper losses (W) = 974.7\n",
+ "stator iron losses (W) = 1950.6\n",
+ "overall efficiency (percent) = 82.85\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_15,pg10_47\n",
+ "#calculate the shaft torque, gross, rotor copper losses, stator copper and iron losses and overall efficiency \n",
+ "#given\n",
+ "import math\n",
+ "Po=24.*10**3\n",
+ "Il=57.\n",
+ "Is=Il\n",
+ "P=8.\n",
+ "N=720.\n",
+ "f=50.\n",
+ "Vl=415.\n",
+ "pf=0.707\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "s=(Ns-N)/Ns\n",
+ "Ml=1000.\n",
+ "Pm=Po+Ml\n",
+ "Pc=Pm*s/(1-s)\n",
+ "Tsh=Po*60/(2*math.pi*N)\n",
+ "T=Pm*60/(2*math.pi*N)\n",
+ "Rcl=1041.66#rotor copper loss\n",
+ "P2=Pc/s\n",
+ "Pi=math.sqrt(3)*Vl*Il*pf\n",
+ "Rs=0.1\n",
+ "Scl=3*(Is**2)*Rs#stator copper loss\n",
+ "Sl=Pi-P2\n",
+ "Sil=Sl-Scl#stator iron loss\n",
+ "n=Po*100/Pi\n",
+ "#results\n",
+ "print\"shaft torque (N-m) = \",round(Tsh,3)\n",
+ "print\"gross torque (N-m) = \",round(T,3)\n",
+ "print\"rotor copper losses (W) = \",round(Pc,2)\n",
+ "print\"stator copper losses (W) = \",Scl\n",
+ "print\"stator iron losses (W) = \",round(Sil,2)\n",
+ "print\"overall efficiency (percent) = \",round(n,2)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 16 - pg 10_52"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 18,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "supply current (times Ifl) = 3.33\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_16,pg10_52\n",
+ "#calculate the supply current\n",
+ "#given\n",
+ "import math\n",
+ "sf=0.05\n",
+ "#Tst=Tfl\n",
+ "Ifs=1/6.#Isc/Ifl=6\n",
+ "#calculations\n",
+ "x=math.sqrt((Ifs**2)/sf)#tapping on transformer\n",
+ "t=x*100\n",
+ "Ist=(x**2)*6\n",
+ "#results\n",
+ "print \"supply current (times Ifl) = \",round(Ist,2)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 17 - pg 10_54"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 19,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "ratio of starting torque to full load torque = 0.165\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_17,pg10_54\n",
+ "#calculate the ratio of starting torque to full load torque\n",
+ "#given\n",
+ "R2=0.4\n",
+ "X2=4.\n",
+ "#Tm=k*(E2**2)/(2*X2)\n",
+ "#Tfl=Tm/2.5\n",
+ "#Tfl=k*(E2**2)/20\n",
+ "#Tst=k*(E2**2)*R2/((R2**2)+(X2**2))\n",
+ "#E2=E2/sqrt(3)\n",
+ "T=20*R2/(3*(((R2**2)+(X2**2))))\n",
+ "#results\n",
+ "print \"ratio of starting torque to full load torque = \",round(T,3)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 18 - pg 10_57"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 20,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "rotor current at start (A) = 800.85\n",
+ "rotor power factor lagging (answer in book is wrong)= 0.0499\n",
+ "rotor current at slip 0.03 (A) = 412.55\n",
+ "external resistance (ohm/ph) (answer in book is wrong) = 0.7665\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_18,pg10_57\n",
+ "#calculate the rotor power factor, external resistance and current\n",
+ "#given\n",
+ "import math\n",
+ "from math import sqrt\n",
+ "Vl=1000.\n",
+ "f=50.\n",
+ "K=3.6\n",
+ "R2=0.01\n",
+ "X2=0.2\n",
+ "E1line=1000.\n",
+ "#calculations and results\n",
+ "E1=E1line/sqrt(3)\n",
+ "E2=E1/K\n",
+ "#at start,s=1\n",
+ "I2=160.37/sqrt((R2**2)+(X2**2))\n",
+ "pf=R2/sqrt((R2**2)+(X2**2))\n",
+ "print\"rotor current at start (A) = \",round(I2,2)\n",
+ "print\"rotor power factor lagging (answer in book is wrong)= \",round(pf,4)\n",
+ "#at s=0.03\n",
+ "s=0.03\n",
+ "I2r=s*160.37/sqrt((R2**2)+((s*X2)**2))\n",
+ "print\"rotor current at slip 0.03 (A) = \",round(I2r,2)\n",
+ "I2=200.\n",
+ "R21=sqrt(((E2/I2)**2)-(X2**2))\n",
+ "Rex=R21-R2\n",
+ "print\"external resistance (ohm/ph) (answer in book is wrong) = \",round(Rex,4)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 19 - pg 10_58"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 21,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "starting torque (Nm) = 103.54\n",
+ "full load torque (Nm) = 15.576\n",
+ "maximum torque (Nm) = 117.342\n",
+ "speed at max torque (rpm) = 200.0\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_19,pg10_58\n",
+ "#calculate the starting torque, full load torque, maximum torque and speed at max torque\n",
+ "import math\n",
+ "#given\n",
+ "P=12.\n",
+ "f=50.\n",
+ "R2=0.15\n",
+ "X2=0.25\n",
+ "E2=32.\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "ns=Ns/60\n",
+ "Tst=3*(E2**2)*R2/((2*math.pi*ns)*((R2**2)+(X2**2)))\n",
+ "N=480.\n",
+ "s=(Ns-N)/Ns\n",
+ "Tfl=3*s*(E2**2)*R2/((2*math.pi*ns)*((R2**2)+((s*X2)**2)))\n",
+ "Tm=3*(E2**2)/(2*math.pi*ns*2*X2)\n",
+ "sm=R2/X2\n",
+ "N=Ns*(1-sm)\n",
+ "#results\n",
+ "print\"starting torque (Nm) = \",round(Tst,2)\n",
+ "print\"full load torque (Nm) = \",round(Tfl,3)\n",
+ "print\"maximum torque (Nm) = \",round(Tm,3)\n",
+ "print\"speed at max torque (rpm) = \",N\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 20 - pg 10_59"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 22,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "efficiency on full load (percent) = 85.78\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_20,pg10_59\n",
+ "#calculate the efficiency in full load\n",
+ "#given\n",
+ "Po=50.*735.5#(in W)\n",
+ "s=0.04\n",
+ "#calculations\n",
+ "#Rcl=X...............rotor copper loss\n",
+ "#Sil=1.25X...........stator iron loss\n",
+ "#Ml=Y, Y=(Y+1.25X)/3, Y=0.625X\n",
+ "#TL=Sil+Rcl+Scl+Ml, TL=3.875X.........(a)\n",
+ "#Pm=Po+Y, 36775+625X..........(1)\n",
+ "#Pc=Pm*s/(1-s).............(2)\n",
+ "#Pc=X, from (1) and (2)\n",
+ "X=(s*Po)/(1-s-s*0.625)\n",
+ "TL=3.875*X#from (a)\n",
+ "n=Po*100./(Po+TL)\n",
+ "#results\n",
+ "print\"efficiency on full load (percent) = \",round(n,2)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 21 - pg 10_61"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 23,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "new speed of motor (rpm) = 1392.0\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_21,pg10_61\n",
+ "#calculate the new speed of motor\n",
+ "#given\n",
+ "import math\n",
+ "P=4.\n",
+ "f=50.\n",
+ "R2=0.25\n",
+ "X2=0.55\n",
+ "N1=1440\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "s1=(Ns-N1)/Ns\n",
+ "Rex=0.2\n",
+ "R21=R2+Rex\n",
+ "#T1 at s1=T2 at s2\n",
+ "#0.3025*s2^2-2.8342*s2+0.2025=0, s1=0.04\n",
+ "a=0.3025\n",
+ "b=-2.8342\n",
+ "c=0.2025\n",
+ "s2=(-b-math.sqrt((b**2)-4*a*c))/(2*a)#neglecting higher value\n",
+ "N2=Ns*(1-s2)\n",
+ "#results\n",
+ "print\"new speed of motor (rpm) = \",round(N2,0)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 22 - pg 10_62"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 24,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "rotor current at start (A) = 9.4916\n",
+ "rotor current for rheostat of 6 ohm (A) = 4.0324\n",
+ "full load rotor current (A) = 2.2456\n",
+ "full load power factor (lagging) = 0.9724\n",
+ "rotor e.m.f on full load (V) = 1.1547\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_22,pg10_62\n",
+ "#calculate the rotor current, full load current , power factor and rotor emf\n",
+ "#given\n",
+ "import math\n",
+ "from math import sqrt\n",
+ "E2line=50.\n",
+ "R2=0.5\n",
+ "X2=3.\n",
+ "E2=E2line/sqrt(3)\n",
+ "#calculations and results\n",
+ "#at start\n",
+ "s=1\n",
+ "I2r=s*E2/(sqrt((R2**2)+((s*X2)**2)))\n",
+ "print\"rotor current at start (A) = \",round(I2r,4)\n",
+ "Rx=6.\n",
+ "I2r=s*E2/(sqrt(((R2+Rx)**2)+((s*X2)**2)))\n",
+ "print\"rotor current for rheostat of 6 ohm (A) = \",round(I2r,4)\n",
+ "#at full load\n",
+ "s=0.04\n",
+ "I2r=s*E2/(sqrt((R2**2)+((s*X2)**2)))\n",
+ "pf=R2/(sqrt((R2**2)+((s*X2)**2)))\n",
+ "print\"full load rotor current (A) = \",round(I2r,4)\n",
+ "print\"full load power factor (lagging) = \",round(pf,4)\n",
+ "E2r=s*E2\n",
+ "print\"rotor e.m.f on full load (V) = \",round(E2r,4)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 23 - pg 10_63"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 25,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "starting torque (Nm) = 103.54\n",
+ "full load torque (Nm) = 15.576\n",
+ "maximum torque (Nm) = 117.342\n",
+ "speed at max torque (rpm) = 200.0\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_23,pg10_63\n",
+ "#calculate the starting,full load, maximum torque and speed\n",
+ "#given\n",
+ "import math\n",
+ "P=12.\n",
+ "f=50.\n",
+ "R2=0.15\n",
+ "X2=0.25\n",
+ "E2=32.\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "ns=Ns/60.\n",
+ "k=3.\n",
+ "Tst=k*(E2**2)*R2/((2*math.pi*ns)*((R2**2)+(X2**2)))\n",
+ "N=480.\n",
+ "s=(Ns-N)/Ns\n",
+ "Tfl=k*s*(E2**2)*R2/((2*math.pi*ns)*((R2**2)+((s*X2)**2)))\n",
+ "Tm=k*(E2**2)/(2*math.pi*ns*2*X2)\n",
+ "sm=R2/X2\n",
+ "N=Ns*(1-sm)\n",
+ "#results\n",
+ "print\"starting torque (Nm) = \",round(Tst,2)\n",
+ "print\"full load torque (Nm) = \",round(Tfl,3)\n",
+ "print\"maximum torque (Nm) = \",round(Tm,3)\n",
+ "print\"speed at max torque (rpm) = \",N\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 24 - pg 10_64"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 27,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "full load torque (Nm) = 202.52\n",
+ "ratio of Tst to Tfl = 0.817\n",
+ "ratio of Tm to Tfl = 2.043\n",
+ "external resistance required (ohm/ph) = 1.6\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_24,pg10_64\n",
+ "#calculate the full load torque and external resistance required\n",
+ "#given\n",
+ "import math\n",
+ "P=4.\n",
+ "f=50.\n",
+ "R2=0.4\n",
+ "X2=2.\n",
+ "E2b=520.#between slip rings\n",
+ "#calculations\n",
+ "E2ph=E2b/math.sqrt(3)\n",
+ "Ns=120*f/P\n",
+ "N=1425.\n",
+ "sf=(Ns-N)/Ns\n",
+ "ns=Ns/60.\n",
+ "Tfl=3*sf*(E2ph**2)*R2/((2*math.pi*ns)*((R2**2)+((sf*X2)**2)))\n",
+ "Tst=3*(E2ph**2)*R2/((2*math.pi*ns)*((R2**2)+((X2)**2)))\n",
+ "T=Tst/Tfl\n",
+ "Tm=3*(E2ph**2)/((2*math.pi*ns)*((R2**2)+((X2)*2)))\n",
+ "T1=Tm/Tfl\n",
+ "#at start\n",
+ "sm=1\n",
+ "R21=X2\n",
+ "Rex=R21-R2\n",
+ "#results\n",
+ "print\"full load torque (Nm) = \",round(Tfl,2)\n",
+ "print\"ratio of Tst to Tfl = \",round(T,3)\n",
+ "print\"ratio of Tm to Tfl = \",round(T1,3)\n",
+ "print\"external resistance required (ohm/ph) = \",Rex"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 25 - pg 10_65"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 28,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "slip at full load = 0.04\n",
+ "rotor frequency (Hz) = 2.0\n",
+ "rotor copper loss per phase (kW) = 486.53\n",
+ "total copper loss (kW) = 1.4596\n",
+ "efficiency at full load (percent) = 89.02\n",
+ "line current drawn (A) = 68.361\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_25,pg10_65\n",
+ "#calculate the slip, rotor frequency, copper loss and efficiency\n",
+ "#given\n",
+ "import math\n",
+ "Po=33.73*10**3\n",
+ "P=4.\n",
+ "Vl=400.\n",
+ "f=50.\n",
+ "Nfl=1440.\n",
+ "pf=0.8\n",
+ "Ml=1.3*10**3\n",
+ "#calculations\n",
+ "Ns=120*f/P\n",
+ "s=(Ns-Nfl)/Ns\n",
+ "fr=s*f\n",
+ "Pm=Po+Ml\n",
+ "Pc=Pm*s/(1-s)\n",
+ "Pcp=Pc/3#copper loss per phase\n",
+ "P2=Pc/s\n",
+ "Sl=1.4*10**3\n",
+ "Pi=P2+Sl\n",
+ "n=Po*100/Pi\n",
+ "Il=Pi/(math.sqrt(3)*Vl*pf)\n",
+ "#results\n",
+ "print\"slip at full load = \",s\n",
+ "print\"rotor frequency (Hz) = \",round(fr,1)\n",
+ "print\"rotor copper loss per phase (kW) = \",round(Pcp,2)\n",
+ "print\"total copper loss (kW) = \",round(Pc/1000.,4)\n",
+ "print\"efficiency at full load (percent) = \",round(n,2)\n",
+ "print\"line current drawn (A) = \",round(Il,3)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 26 - pg 10_66"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 29,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "power factor of rotor (lagging) = 0.989\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_26,pg10_66\n",
+ "#calculate the power factor of rotor\n",
+ "#given\n",
+ "import math\n",
+ "R2=0.04\n",
+ "X2=0.2\n",
+ "sfl=0.03\n",
+ "#at Tst, s=1\n",
+ "#Tfl=Tst\n",
+ "#(R21**2)-1.3633*R21+0.04=0\n",
+ "a=1\n",
+ "b=-1.3633\n",
+ "c=0.04\n",
+ "#calculations\n",
+ "R21=(-b+math.sqrt((b**2)-4*a*c))/(2*a)\n",
+ "Rex=R21-R2\n",
+ "pf=R21/math.sqrt((R21**2)+(X2**2))\n",
+ "#results\n",
+ "print\"power factor of rotor (lagging) = \",round(pf,3)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 27 - pg 10_67"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 30,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "full load speed (rpm) = 1318.7\n",
+ "speed at max. torque (rpm) = 823.0\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_27,pg10_67\n",
+ "#calculate the full load speed, speed at max torque\n",
+ "#given\n",
+ "import math\n",
+ "P=4.\n",
+ "f=50.\n",
+ "Po=8.*10**3\n",
+ "#Tst=1.5*Tfl and Tm=2*Tfl\n",
+ "#(R2**2)+((sfl*X2)**2)=1.5*sfl*((R2**2)+(X2**2)).................(1)\n",
+ "#(R2**2)+((sfl*X2)**2)=2*(sfl/sm)*((R2**2)+((sm*X2)**2))..........(2)\n",
+ "#dividing (1) and (2) by (X2**2) on both sides and R2/X2=sm\n",
+ "#(sm**2)+(sfl**2)=5*(1+(sm**2))*sfl.............(3)\n",
+ "#(sm**2)+(sfl**2)=2*(2*(sm**2))*(sfl/sm)=4*sm*sfl...........(4)\n",
+ "#dividing (3) by (4)\n",
+ "#(sm**2)-2.667*sm+1=0\n",
+ "a=1\n",
+ "b=-2.667\n",
+ "c=1\n",
+ "#calculations\n",
+ "sm=(-b-math.sqrt((b**2)-4*a*c))/(2*a)\n",
+ "Ns=120*f/P\n",
+ "#substituting sm in (4)\n",
+ "#(sfl**2)-1.8052*sfl+0.2036=0\n",
+ "a=1\n",
+ "b=-1.8052\n",
+ "c=0.2036\n",
+ "sfl=(-b-math.sqrt((b**2)-4*a*c))/(2*a)\n",
+ "N=Ns*(1-sfl)\n",
+ "Nm=Ns*(1-sm)\n",
+ "#results\n",
+ "print\"full load speed (rpm) = \",round(N,1)\n",
+ "print\"speed at max. torque (rpm) = \",round(Nm,2)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 28 - pg 10_68"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 32,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "starting torque (Nm) = 34.8\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_28,pg10_68\n",
+ "#calculate the starting torque\n",
+ "import math\n",
+ "#given\n",
+ "Po=10*735.5#(in W)\n",
+ "Nfl=1410.\n",
+ "P=4.\n",
+ "f=50.\n",
+ "#calculations\n",
+ "Ns=120.*f/P\n",
+ "sfl=(Ns-Nfl)/Ns\n",
+ "Nm=1200.\n",
+ "sm=(Ns-Nm)/Ns\n",
+ "T=2*sfl*sm/((sm**2)+(sfl**2))#Tfl/Tm\n",
+ "T1=(1+(sm**2))/(2*sm)#Tm/Tst\n",
+ "T2=T1*T#Tfl/Tst\n",
+ "Tfl=Po*60./(2*math.pi*Nfl)\n",
+ "Tst=Tfl/T2\n",
+ "#results\n",
+ "print\"starting torque (Nm) = \",round(Tst,1)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 29 - pg 10_70"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 33,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "maximum torque (Nm) = 330.5\n",
+ "speed (r.p.m) = 1250.0\n",
+ "external resistance (ohm/ph) = 0.125\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_29,pg10_70\n",
+ "#calculate the maximum torque, speed and external resistance\n",
+ "#given\n",
+ "P=4.\n",
+ "f=50.\n",
+ "R2=0.025\n",
+ "X2=0.15\n",
+ "sfl=0.04\n",
+ "Tfl=150.\n",
+ "#calculations\n",
+ "sm=R2/X2\n",
+ "Tm=Tfl*((R2**2)+((sfl*X2)**2))*sm/(sfl*((R2**2)+((sm*X2)**2)))\n",
+ "Ns=120*f/P\n",
+ "N=Ns*(1-sm)\n",
+ "#at start\n",
+ "R21=X2\n",
+ "Rex=R21-R2\n",
+ "#results\n",
+ "print\"maximum torque (Nm) = \",Tm\n",
+ "print\"speed (r.p.m) = \",N\n",
+ "print\"external resistance (ohm/ph) = \",Rex\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 30 - pg 10_70"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 35,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "motor output (kW) = 16.54099\n",
+ "copper loss in rotor (W) = 575.54\n",
+ "motor input (kW) = 20.0147\n",
+ "efficiency of motor (percent) = 82.644\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_30,pg10_70\n",
+ "#calculate the motor output, copper loss and efficiency\n",
+ "#given\n",
+ "import math\n",
+ "Tsh=162.84\n",
+ "P=6.\n",
+ "f=50.\n",
+ "Tlost=20.36\n",
+ "fr=1.5\n",
+ "#calculations\n",
+ "s=fr/f\n",
+ "Ns=120*f/P\n",
+ "N=Ns*(1-s)\n",
+ "Po=Tsh*(2*math.pi*N)/60\n",
+ "Fl=Tlost*(2*math.pi*N)/60\n",
+ "Pm=Po+Fl\n",
+ "Pc=Pm*s/(1-s)\n",
+ "P2=Pc/s\n",
+ "Sl=830\n",
+ "Pi=P2+Sl\n",
+ "n=Po*100/Pi\n",
+ "#results\n",
+ "print\"motor output (kW) = \",round(Po/1000.,5)\n",
+ "print\"copper loss in rotor (W) = \",round(Pc,3)\n",
+ "print\"motor input (kW) = \",round(Pi/1000.,4)\n",
+ "print\"efficiency of motor (percent) = \",round(n,3)\n"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Example 31 - pg 10_71"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 36,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "ratio of max to full load torque = 1.45\n",
+ "speed at max torque (rpm) = 675.0\n"
+ ]
+ }
+ ],
+ "source": [
+ "#Chapter-10,Example10_31,pg10_71\n",
+ "#calculate the ratio of max to full load torque and speed at max torque\n",
+ "#given\n",
+ "f=50.\n",
+ "P=8.\n",
+ "R2=0.01\n",
+ "X2=0.1\n",
+ "sfl=0.04\n",
+ "#calculations\n",
+ "#for Tmax\n",
+ "sm=R2/X2\n",
+ "#for Tfl\n",
+ "s=sfl\n",
+ "T=sm*R2*((R2**2)+((sfl*X2)**2))/((sfl*R2)*((R2**2)+((sm*X2)**2)))#Tmax/Tfl\n",
+ "Ns=120*f/P\n",
+ "sm=0.1\n",
+ "N=Ns*(1-sm)\n",
+ "#results\n",
+ "print\"ratio of max to full load torque = \",T\n",
+ "print\"speed at max torque (rpm) = \",N\n"
+ ]
+ }
+ ],
+ "metadata": {
+ "kernelspec": {
+ "display_name": "Python 2",
+ "language": "python",
+ "name": "python2"
+ },
+ "language_info": {
+ "codemirror_mode": {
+ "name": "ipython",
+ "version": 2
+ },
+ "file_extension": ".py",
+ "mimetype": "text/x-python",
+ "name": "python",
+ "nbconvert_exporter": "python",
+ "pygments_lexer": "ipython2",
+ "version": "2.7.9"
+ }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
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