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+{
+ "metadata": {
+ "name": "",
+ "signature": "sha256:f8b31f19cbf3c6b3dce4ba746cfebc233c9801395be699bc2538e86d3ab6c5f4"
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+ {
+ "cells": [
+ {
+ "cell_type": "heading",
+ "level": 1,
+ "metadata": {},
+ "source": [
+ "Chapter 2: Induction Motors(Additional problems)"
+ ]
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 1, Page 225"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "P = 8 #number of poles\n",
+ "f = 50 #Hz\n",
+ "\n",
+ "#Calculations\n",
+ "Ns = (120*f)/P\n",
+ "\n",
+ "#Result\n",
+ "print \"Synchronous speed = %d r.p.m.\"%Ns"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Synchronous speed = 750 r.p.m.\n"
+ ]
+ }
+ ],
+ "prompt_number": 1
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 2, Page 225"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "P = 2 #assumption - number of poles\n",
+ "f = 50 #Hz\n",
+ "\n",
+ "#Calculations\n",
+ "Ns = (120*f)/P\n",
+ "\n",
+ "#Result\n",
+ "print \"Maximum speed = %d r.p.m.\"%Ns"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Maximum speed = 3000 r.p.m.\n"
+ ]
+ }
+ ],
+ "prompt_number": 2
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 3, Page 225"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "Pa = 6 #number of poles in alternator\n",
+ "N = 1000 #rpm\n",
+ "Pi = 16 #number of poles in induction motor\n",
+ "S = 2.5 #slip\n",
+ "\n",
+ "#Calculations\n",
+ "f = (N*Pa)/120 #Hz\n",
+ "Ns = (120*f)/Pi #rpm\n",
+ "Nr = Ns - ((S*Ns)/100)\n",
+ "\n",
+ "#Results\n",
+ "print \"The actual motor speed is %.2f r.p.m.\"%Nr"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "The actual motor speed is 365.62 r.p.m.\n"
+ ]
+ }
+ ],
+ "prompt_number": 3
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 4, Page 225"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "P = 14. #no. of poles\n",
+ "f = 50. #Hz\n",
+ "N = 414. #r.p.m.\n",
+ "\n",
+ "#calculations\n",
+ "Ns = (120*f)/P #rpm\n",
+ "S = ((Ns-N)/Ns)*100\n",
+ "fr = (S*f)/100\n",
+ "\n",
+ "#Results\n",
+ "print \"Rotor frequency = %.2f Hz\"%fr\n",
+ "print \"Slip = %.2f %%\"%S\n",
+ "#Incorrect answers in the textbook"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Rotor frequency = 1.70 Hz\n",
+ "Slip = 3.40 %\n"
+ ]
+ }
+ ],
+ "prompt_number": 4
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 5, Page 225"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "Pi = 50 #motor input - KW\n",
+ "S = 3./100 #slip - %\n",
+ "\n",
+ "#Calculations\n",
+ "Lc = Pi*S #rotor copper loss\n",
+ "Pm = Pi-Lc\n",
+ "\n",
+ "#Result\n",
+ "print \"Total mechanical power = %.1f kW\"%Pm"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Total mechanical power = 48.5 kW\n"
+ ]
+ }
+ ],
+ "prompt_number": 5
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 6, Page 225"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "\n",
+ "#Variable declaration\n",
+ "P = 4 #no. of poles\n",
+ "m = 3\n",
+ "f = 50 #Hz\n",
+ "n = 85 #efficiency %\n",
+ "Po = 17. #useful output power kW\n",
+ "Ls = 900 #stator losses W\n",
+ "Lwf = 1100 #windage&friction losses W\n",
+ "Lrc = 1. #rotor copper loss kW\n",
+ "\n",
+ "#Calculations\n",
+ "Pi = Po/n*100 #input power\n",
+ "Tl = Pi-Po #total losses kW\n",
+ "Lc = Tl - Ls - Lwf #copper loss W\n",
+ "Pir = Pi-Ls #input to rotor kW\n",
+ "S = Lrc/Pi\n",
+ "Ns = 120*f/P #rpm\n",
+ "N = Ns-(S*Ns) #rpm\n",
+ "wT = 19.1*1000 #W\n",
+ "Td = (wT*60)/(math.pi*2*N)\n",
+ "Ta = (Po*1000*60)/(2*math.pi*N)\n",
+ "\n",
+ "#Results\n",
+ "print \"Slip = %.3f\"%S\n",
+ "print \"Torque developed = %.2f N-m\"%Td\n",
+ "print \"Torque available = %.1f N\"%Ta\n",
+ "#Answers vary due to rounding-off errors"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Slip = 0.050\n",
+ "Torque developed = 127.99 N-m\n",
+ "Torque available = 113.9 N\n"
+ ]
+ }
+ ],
+ "prompt_number": 6
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 7, Page 225"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "\n",
+ "#Variable declaration\n",
+ "P = 6 #no. of poles\n",
+ "f = 60 #Hz\n",
+ "T = 70 #N-m\n",
+ "N = 1152. #rpm\n",
+ "\n",
+ "#Calculations\n",
+ "#Part a\n",
+ "Pi = (2*math.pi*1200*T)/60/1000 #input to rotor W\n",
+ "Ns = (120.*f)/P #rpm\n",
+ "S = (Ns-N)/Ns\n",
+ "\n",
+ "#Part b\n",
+ "Lrc = S*Pi*1000 #W\n",
+ "Td = (2*math.pi*N*T)/60\n",
+ "\n",
+ "#Part c\n",
+ "Pm = Td #W\n",
+ "\n",
+ "#Results\n",
+ "print \"Total input to the rotor = %.1f kW\"%Pi\n",
+ "print \"Rotor copper loss = %d W\"%Lrc\n",
+ "print \"Mechanical power developed = %.2f W\"%Pm\n",
+ "#answers vary due to rounding-off errors"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Total input to the rotor = 8.8 kW\n",
+ "Rotor copper loss = 351 W\n",
+ "Mechanical power developed = 8444.60 W\n"
+ ]
+ }
+ ],
+ "prompt_number": 7
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 8, Page 226"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "\n",
+ "#Variable declaration\n",
+ "Vs = 100 #voltage between two slip rings V\n",
+ "R2 = 0.2 #ohms/phase\n",
+ "Xo = 1 #ohm/phase\n",
+ "S = 0.04 #slip\n",
+ "\n",
+ "#Calculations\n",
+ "Eo = Vs/math.sqrt(3)\n",
+ "I2 = (S*Eo)/math.sqrt(R2**2+(S*Xo)**2)\n",
+ "#During maximum torque,\n",
+ "Sm = R2/Xo \n",
+ "Ir = (Sm*Eo)/math.sqrt(S**2+(S*Xo)**2)\n",
+ "\n",
+ "#Results\n",
+ "print \"Rotor current when slip is 4%% is %.1f A\"%I2\n",
+ "print \"Slip during maximum torque is %.1f\"%Sm\n",
+ "print \"Rotor current during maximum torque is %.1f A\"%Ir #incorrect answer in the textbook"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Rotor current when slip is 4% is 11.3 A\n",
+ "Slip during maximum torque is 0.2\n",
+ "Rotor current during maximum torque is 204.1 A\n"
+ ]
+ }
+ ],
+ "prompt_number": 8
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 9, Page 226"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "S = 1 #slip at the time of starting\n",
+ "X2 = 1 #ohms/pase\n",
+ "X1 = 0.1 #internal rotor resistance ohms/phase\n",
+ "\n",
+ "#Calculations\n",
+ "#Total resistance required for maximum torque is 1 Ohm\n",
+ "Re = X2-X1\n",
+ "\n",
+ "#Result\n",
+ "print \"External resistance needed to be added is %.1f ohms/phase\"%Re"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "External resistance needed to be added is 0.9 ohms/phase\n"
+ ]
+ }
+ ],
+ "prompt_number": 9
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 10, Page 226"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import sympy\n",
+ "from sympy.solvers import solve\n",
+ "from sympy import Symbol\n",
+ "\n",
+ "#Variable declaration\n",
+ "T = 162.8 #maximum torque Nw-m\n",
+ "N = 1365 #speed rpm\n",
+ "f = 50 #Hz\n",
+ "P = 4 #no. of poles\n",
+ "R2 = 0.2 #ohms/phase\n",
+ "\n",
+ "#Calculations\n",
+ "Ns = 120*f/P\n",
+ "S = Ns-N/Ns #slip at maximum torque\n",
+ "X2 = R2/S #ohms\n",
+ "Th = T/2 #half of maximum torque\n",
+ "R2 = Symbol('R2')\n",
+ "x = solve((Th*R2**2-18.1*40*R2+400),R2) #solving the equation\n",
+ "\n",
+ "#Results\n",
+ "print \"Required resistance = \",round(x[0],2),\"ohms\""
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Required resistance = 0.59 ohms\n"
+ ]
+ }
+ ],
+ "prompt_number": 1
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 11, Page 226"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "N = 290. #speed of motor at full load rpm\n",
+ "f = 50 #Hz\n",
+ "\n",
+ "#Calculations\n",
+ "P = 20 #since motors running at full load\n",
+ "Ns= 120*f/P\n",
+ "S1 = (Ns-N)/Ns*100\n",
+ "#since S is directly proportinal to R2,\n",
+ "#when R2 is doubled, S is also doubled\n",
+ "S = 2*S1\n",
+ "\n",
+ "#Results\n",
+ "print \"The number of poles are %d\"%P\n",
+ "print \"Slip = %.1f %%\"%S1\n",
+ "print \"Slip if the rotor resistance is doubled = %.1f %%\"%S"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "The number of poles are 20\n",
+ "Slip = 3.3 %\n",
+ "Slip if the rotor resistance is doubled = 6.7 %\n"
+ ]
+ }
+ ],
+ "prompt_number": 13
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 12, Page 226"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declarartion\n",
+ "S = 2.5/100 #slip\n",
+ "#Isc=4*If\n",
+ "\n",
+ "#Calculations\n",
+ "'''\n",
+ "Ts Isc ^2\n",
+ "-- = --- * slip\n",
+ "Tf If\n",
+ "'''\n",
+ "Ts_by_Tf = 4**2*S*100\n",
+ "\n",
+ "#Result\n",
+ "print \"Starting torque is %d %% of full load torque\"%Ts_by_Tf"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Starting torque is 40 % of full load torque\n"
+ ]
+ }
+ ],
+ "prompt_number": 14
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 13, Page 226"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "\n",
+ "#Variable declaration\n",
+ "f = 50 #Hz\n",
+ "P = 6 #no. of poles\n",
+ "S = 1 #slip\n",
+ "Eo = 62.8 #phase voltage V\n",
+ "m = 3.\n",
+ "Xo = 6 #rotor reactance ohms\n",
+ "R2 = 1 #resistance ohms\n",
+ "\n",
+ "#Calculations\n",
+ "Ns = 120*f/P #rpm\n",
+ "ws = 2*math.pi*Ns/60 #rad/sec\n",
+ "K = m/ws\n",
+ "Ts = (K*S*Eo**2*R2)/((R2**2)+(S*Xo)**2) #at starting\n",
+ "#For maximum torque\n",
+ "R2 = 1 #ohm\n",
+ "X2 = 6 #ohms\n",
+ "S = R2/X2\n",
+ "Tmax = (K*Eo**2)/(2*X2)\n",
+ "\n",
+ "#Result\n",
+ "print \"The starting torque is %.3f N-m\"%Ts\n",
+ "print \"The maximum torque develped is %.1f N-m\"%Tmax\n",
+ "#Incorrect soltion in the textbook"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "The starting torque is 3.054 N-m\n",
+ "The maximum torque develped is 9.4 N-m\n"
+ ]
+ }
+ ],
+ "prompt_number": 15
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 14, Page 226"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "\n",
+ "#Variable declaration\n",
+ "Vl = 200. #line voltage of stator V\n",
+ "t = 0.67 #turn ratio\n",
+ "Ns = 1500. #rpm\n",
+ "R2 = 0.1 #resistance ohms\n",
+ "S = 0.04 #slip\n",
+ "X = 0.9 #reactance ohms\n",
+ "m = 3. #number of phases\n",
+ "\n",
+ "#Calculations\n",
+ "Vp = Vl/math.sqrt(3) #phase voltage of stator V\n",
+ "E = Vp*t\n",
+ "ws = (2*math.pi*Ns)/60\n",
+ "K = m/ws\n",
+ "T = (K*S*E**2*R2)/(R2**2+(S*X)**2)\n",
+ "\n",
+ "#Result\n",
+ "print \"Total torque = %d N-m\"%T\n",
+ "#Incorrect answer in the textbook"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Total torque = 40 N-m\n"
+ ]
+ }
+ ],
+ "prompt_number": 16
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 15, Page 226"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "P = 8 #number of pos\n",
+ "f = 50. #Hz\n",
+ "S = 0.04 #slip\n",
+ "Po = 15*1000 #oput power W\n",
+ "R2 = 0.2 #rotor resistance Ohms\n",
+ "X = 1.5 #rotor reactance Ohms\n",
+ "N = 400 #ohms\n",
+ "\n",
+ "#Calculations\n",
+ "Ns = (120*f)/P #rpm\n",
+ "S_dash = (Ns-N)/Ns\n",
+ "R2_dash = (R2*S_dash)/S #ohms\n",
+ "R = R2_dash-R2 #resistance to be added\n",
+ "Pi = Po/(1-S) #W\n",
+ "Lc = S_dash*Pi #rotor copper loss W\n",
+ "P = Pi - Lc #ouput power W\n",
+ "\n",
+ "#Results\n",
+ "print \"The external resistance to be connected per phase is %.2f ohms\"%R\n",
+ "print \"Total rotor copper loss = %d W\"%Lc\n",
+ "print \"Ouput power of motor = %d W\"%P\n",
+ "\n",
+ "#Incorrect answers in the textbook"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "The external resistance to be connected per phase is 2.13 ohms\n",
+ "Total rotor copper loss = 7291 W\n",
+ "Ouput power of motor = 8333 W\n"
+ ]
+ }
+ ],
+ "prompt_number": 17
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 16, Page 227"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "n = 0.8 #efficiency \n",
+ "O = 20*735.5 #load/output\n",
+ "\n",
+ "#Calculations\n",
+ "i = O/n #input W\n",
+ "Tl = i - O #total losses W\n",
+ "#since total losses is a sum of rotor copper loss+stator copper loss+iron loss+mechanical loss\n",
+ "K = (Tl*3)/10 #rotor copper loss W\n",
+ "Ri = O+(K/3)+K #input to the rotor W \n",
+ "S = K/Ri #slip\n",
+ "\n",
+ "#Result \n",
+ "print \"Slip = %.3f\"%S"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Slip = 0.068\n"
+ ]
+ }
+ ],
+ "prompt_number": 18
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 17, Page 227"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "\n",
+ "#Variable declaration\n",
+ "Pi = 20 #input power KW\n",
+ "N = 960. #speed rpm\n",
+ "f = 50 #Hz\n",
+ "P = 6 #number of poles\n",
+ "R2 = 1./3 #resistance ohms\n",
+ "\n",
+ "#Calculations\n",
+ "Ns = 1000.\n",
+ "S = (Ns-N)/Ns #slip\n",
+ "Lrc = S*Pi*1000 #rotor copper loss W\n",
+ "Lrc_ph = Lrc/3 #rotor copper loss per phase\n",
+ "I2 = math.sqrt(Lrc_ph/R2)\n",
+ "\n",
+ "#Result\n",
+ "print \"Rotor current per phase = %.1f A\"%I2"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Rotor current per phase = 28.3 A\n"
+ ]
+ }
+ ],
+ "prompt_number": 19
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 18, Page 227"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "P = 4 #number of poles \n",
+ "f = 50. #Hz\n",
+ "N = 645. #speed rpm\n",
+ "R2 = 0.04 #rotor resistance ohms\n",
+ "\n",
+ "#Calculations\n",
+ "Ns = (120*f)/P #rpm\n",
+ "S = (Ns-N)/Ns #slip\n",
+ "X2 = R2/S #rotor reactance ohms\n",
+ "a = R2/X2\n",
+ "St_by_mt = (2*a)/(a*2+1) #starting torque/maximum torque\n",
+ "S = 0.03\n",
+ "Flt_by_mt = (2*a*S)/(a**2+S**2) #full load torque/maximum torque\n",
+ "\n",
+ "#Results\n",
+ "print \"Maximum torque at starting is %d %%\"%(St_by_mt*100)\n",
+ "print \"Maximum torque when slip is 3%% is %d %%\"%(Flt_by_mt*100)\n",
+ "\n",
+ "#Value of Ns ic wrongly calculated in the textbook. Hence the answers vary"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "Maximum torque at starting is 53 %\n",
+ "Maximum torque when slip is 3% is 10 %\n"
+ ]
+ }
+ ],
+ "prompt_number": 20
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Problem 20, Page 227"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "#Variable declaration\n",
+ "R2 = 0.5 #rotor resistance ohms\n",
+ "X2 = 5 #rotor reactance ohms\n",
+ "Tm_by_tfl = 2.5 #max torque/full load torque\n",
+ "\n",
+ "#Calculations\n",
+ "#Tfl = Tm/2.5 = KE^2/2.5*2*X2\n",
+ "#Part a\n",
+ "Tst_by_Tfl_a = (25*R2)/(R2**2+X2**2)\n",
+ "\n",
+ "#Part b\n",
+ "Tst_by_Tfl_b = (25*R2)/(3*(R2**2+X2**2))\n",
+ "\n",
+ "#Part c\n",
+ "#Rotor voltage at starting = 0.75E2\n",
+ "Tst_by_Tfl_c = (0.75**2*25*R2)/(R2**2+X2**2)\n",
+ "\n",
+ "#Results\n",
+ "print \"The ratio of starting torque to full load torque for the given cases are as below:\"\n",
+ "print \"Part a: %.2f\"%Tst_by_Tfl_a\n",
+ "print \"Part a: %.2f\"%Tst_by_Tfl_b\n",
+ "print \"Part a: %.2f\"%Tst_by_Tfl_c"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "The ratio of starting torque to full load torque for the given cases are as below:\n",
+ "Part a: 0.50\n",
+ "Part a: 0.17\n",
+ "Part a: 0.28\n"
+ ]
+ }
+ ],
+ "prompt_number": 21
+ }
+ ],
+ "metadata": {}
+ }
+ ]
+} \ No newline at end of file
generated by cgit (git 2.34.1) at 2025-03-12 02:49:33 +0000