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Diffstat (limited to 'Electric_Machines_by_Nagrath_&_Kothari/Chapter10.ipynb')
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diff --git a/Electric_Machines_by_Nagrath_&_Kothari/Chapter10.ipynb b/Electric_Machines_by_Nagrath_&_Kothari/Chapter10.ipynb new file mode 100755 index 00000000..5b64b11d --- /dev/null +++ b/Electric_Machines_by_Nagrath_&_Kothari/Chapter10.ipynb @@ -0,0 +1,364 @@ +{
+ "metadata": {
+ "name": ""
+ },
+ "nbformat": 3,
+ "nbformat_minor": 0,
+ "worksheets": [
+ {
+ "cells": [
+ {
+ "cell_type": "heading",
+ "level": 1,
+ "metadata": {},
+ "source": [
+ "Chapter 10 : Fractional Kilowatt Motors"
+ ]
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 10.1, Page No 148"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "#initialisation of variables\n",
+ "# to compute the ratio of E_mf/E_mb,V_f/V_b,T_f/T_b,gross total torque,T_f/total torque, T_b/total torque\n",
+ "\n",
+ " \n",
+ "R_lm=3.0 \n",
+ "X_lm=5.0 \n",
+ "R_2=1.5 \n",
+ "X_2=2.0 \n",
+ "s=1-.97 #slip\n",
+ "\n",
+ "#Calculations\n",
+ "a=complex(R_2/s,X_2) \n",
+ "b=complex(R_2/(2-s),X_2) \n",
+ "c=abs(a)/abs(b) \n",
+ "print(c,'E_mf/E_mb') \n",
+ "a=(1.0/2)*complex((R_lm+R_2/s),(X_lm+X_2)) \n",
+ "b=(1.0/2)*complex((R_lm+R_2/(2-s)),(X_lm+X_2)) \n",
+ "c=abs(a)/abs(b) \n",
+ "print(c,'V_f/V_b') \n",
+ "d=(2.0-s)/s \n",
+ "print(d,'T_f/T_b') \n",
+ "Z_tot=a+b \n",
+ "V=220.0 \n",
+ "I_m=V/abs(Z_tot) \n",
+ "P=6.0 \n",
+ "f=50.0 \n",
+ "n_s=120.0*f/P \n",
+ "w_s=2*math.pi*n_s/60 \n",
+ "T_f=(I_m**2*R_2/(2*w_s))*(1/s) \n",
+ "T_b=(I_m**2*R_2/(2*w_s))*(1/(2-s)) \n",
+ "T_tot=T_f-T_b \n",
+ "print(T_tot,'gross total torque(Nm)') \n",
+ "a=T_f/T_tot \n",
+ "b=T_b/T_tot \n",
+ "\n",
+ "#Results\n",
+ "print(a,'T_f/T_total') \n",
+ "print(b,'T_b/T_total') \n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "(23.38275544101299, 'E_mf/E_mb')\n",
+ "(6.727447444111447, 'V_f/V_b')\n",
+ "(65.66666666666661, 'T_f/T_b')\n",
+ "(13.316745850891841, 'gross total torque(Nm)')\n",
+ "(1.0154639175257731, 'T_f/T_total')\n",
+ "(0.015463917525773207, 'T_b/T_total')\n"
+ ]
+ }
+ ],
+ "prompt_number": 1
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 10.2, Page No 149"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "#initialisation of variables\n",
+ "# to calculate parameters of the ckt model, line current, power factor, shaft torque and efficiency\n",
+ "\n",
+ " \n",
+ "V_0=215.0 \n",
+ "I_0=3.9 \n",
+ "P_0=185.0 \n",
+ "R_1=1.6 \n",
+ "V_sc=85 \n",
+ "I_sc=9.8 \n",
+ "P_sc=390.0 \n",
+ "X=(V_0/I_0)*2.0 #magnetisation reactance\n",
+ "phi_sc=math.degrees(math.acos(P_sc/(V_sc*I_sc)))\n",
+ "I_e=V_sc/complex(0,X) \n",
+ "I_SC=I_sc*complex(math.cos(math.radians(phi_sc*(-1))),math.sin(math.radians(phi_sc*(-1)))) \n",
+ "I_m=I_SC-I_e \n",
+ "Z=V_sc/I_m \n",
+ "R_2=(Z.real)-R_1 #real(Z)=R=R1+R2\n",
+ "print(R_2,'R_2(ohm)') \n",
+ "print((Z.imag),'X_1+X_2(ohm)') \n",
+ "\n",
+ "#Calculations\n",
+ "n=1500.0 \n",
+ "nn=1440 \n",
+ "s=(n-nn)/n \n",
+ "a=1.55/s \n",
+ "b=1.55/(2-s) \n",
+ "Z_ftot=(complex(0,X/2))*(complex(a+.8,(Z.imag)/2))/((complex(0,X/2))+(complex(a+.8,(Z.imag)/2))) \n",
+ "Z_btot=(complex(0,X/2))*(complex(b+.8,(Z.imag)/2))/((complex(0,X/2))+(complex(b+.8,(Z.imag)/2))) \n",
+ "Z_tot=Z_ftot+Z_btot \n",
+ "I_m=V_0/Z_tot \n",
+ "I_L=abs(I_m) \n",
+ "print(I_L,'line current(A)') \n",
+ "pf=math.cos(math.radians(math.degrees(math.atan((I_m.real)/(I_m.imag)))))\n",
+ "print(pf,'pf') \n",
+ "P_in=V_0*I_L*pf \n",
+ "I_mf=I_m*complex(0,X/2)/complex(39.55,59.12) \n",
+ "I_mb=I_m*complex(0,X/2)/complex(1.59,59.12) \n",
+ "T=(1/157.1)*(abs(I_mf)**2*38.75-abs(I_mb)**2*.79) \n",
+ "P_m=157.1*(1-s)*T \n",
+ "P_L=185 \n",
+ "P_out=P_m-P_L \n",
+ "eff=P_out/P_in \n",
+ "\n",
+ "#Results\n",
+ "print(eff*100,'efficiency(%)') \n",
+ "T_shaft=P_out/157.1 \n",
+ "print(T_shaft,'shaft torque(Nm)') \n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "(3.0828571185946845, 'R_2(ohm)')\n",
+ "(8.051321578491317, 'X_1+X_2(ohm)')\n",
+ "(6.261296470855541, 'line current(A)')\n",
+ "(0.6818110490832134, 'pf')\n",
+ "(72.4748020932455, 'efficiency(%)')\n",
+ "(4.234260916702234, 'shaft torque(Nm)')\n"
+ ]
+ }
+ ],
+ "prompt_number": 2
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 10.3, Page No 149"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "#initialisation of variables\n",
+ "#to compute ampitudes of forward and backward stator mmf waves,magnitude of auxillary currrent and its ph angle diff\n",
+ "\n",
+ " \n",
+ "N_m=80.0\n",
+ "N_a=100.0 \n",
+ "I_m=15*complex(math.cos(math.radians(0)),math.sin(math.radians(0))) \n",
+ "I_aa=7.5*complex(math.cos(math.radians(45)),math.sin(math.radians(45))) \n",
+ "I_a=7.5*complex(math.cos(math.radians(60)),math.sin(math.radians(60))) \n",
+ "F_m=N_m*I_m \n",
+ "F_a=N_a*I_a \n",
+ "F_aa=N_a*I_aa #mmf at 45 angle\n",
+ "\n",
+ "#Calculations\n",
+ "F_f=(1.0/2)*(F_m+1j*F_aa) \n",
+ "a=abs(F_f) \n",
+ "print(a,'forward field(AT)') \n",
+ "F_b=(1.0/2)*(F_m-1j*(F_aa)) \n",
+ "b=abs(F_b) \n",
+ "print(b,'backward field(AT)') \n",
+ "#1200+100*I_a*complex(sind(a),cosd(a))=0\n",
+ "#equating real and imaginery parts\n",
+ "#100*I_a*cosd(a)=0 \n",
+ "a=90 \n",
+ "print(a,'phase angle diff') \n",
+ "I_a=-1200.0/(100*math.sin(math.radians(a))) \n",
+ "\n",
+ "#Results\n",
+ "print(I_a,'auxillery current(A)') \n"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "(427.1146783547173, 'forward field(AT)')\n",
+ "(904.8884193832665, 'backward field(AT)')\n",
+ "(90, 'phase angle diff')\n",
+ "(-12.0, 'auxillery current(A)')\n"
+ ]
+ }
+ ],
+ "prompt_number": 3
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 10.4 Page No 150"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "#initialisation of variables\n",
+ "#to determine value of capacitor\n",
+ "\n",
+ " \n",
+ "f=50.0 \n",
+ "w=2*math.pi*f \n",
+ "Z_lm=complex(3,2.7) \n",
+ "Z_la=complex(7,3) \n",
+ "\n",
+ "#Calculations\n",
+ "I_m=(-1)*math.degrees(math.atan((Z_lm.imag)/(Z_la.imag))) \n",
+ "a=90.0 \n",
+ "I_a=a+I_m \n",
+ "c=1/(w*((Z_lm.real)-(Z_la.real)*math.cos(math.radians((-1)*I_a)))) \n",
+ "\n",
+ "#Results\n",
+ "print(c,'value of capacitor(F)') "
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "(-0.0018916018169502632, 'value of capacitor(F)')\n"
+ ]
+ }
+ ],
+ "prompt_number": 4
+ },
+ {
+ "cell_type": "heading",
+ "level": 2,
+ "metadata": {},
+ "source": [
+ "Example 10.6, Page No 151"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "collapsed": false,
+ "input": [
+ "import math\n",
+ "#initialisation of variables\n",
+ "#to calculate starting torque and atarting current,motor performance\n",
+ "\n",
+ " \n",
+ "V_a=110*complex(math.cos(math.radians(90)),math.sin(math.radians(90))) \n",
+ "V_m=220*complex(math.cos(math.radians(0)),math.sin(math.radians(0))) \n",
+ "R_1=3 \n",
+ "R_2=2.6 \n",
+ "X_1=2.7 \n",
+ "X_2=2.7 \n",
+ "X=110 \n",
+ "V_f=(1.0/2)*(V_m-1j*V_a)\n",
+ "V_b=(1.0/2)*(V_m+1j*V_a) \n",
+ "\n",
+ "#Calculations\n",
+ "Z_f=(complex(0,X)*complex(R_2,X_2))/(complex(0,X)+complex(R_2,X_2)) \n",
+ "Z_b=Z_f \n",
+ "Z_ftot=complex(R_1,X_1)+Z_f \n",
+ "Z_btot=complex(R_1,X_1)+Z_b \n",
+ "I_f=V_f/Z_ftot \n",
+ "I_b=V_b/Z_btot \n",
+ "T_s=(2/157)*(Z_f.real)*(abs(I_f)**2-abs(I_b)**2) \n",
+ "print(T_s,'starting torque(Nm)') \n",
+ "I_m=I_f+I_b \n",
+ "I_a=1j*(I_f-I_b) \n",
+ "print(abs(I_a),'starting current(A)') \n",
+ "s=0.04 \n",
+ "\n",
+ "Z_f=(complex(0,X)*complex(R_2/s,X_2))/(complex(0,X)+complex(R_2/s,X_2)) \n",
+ "Z_b=(complex(0,X)*complex(R_2/(2-s),X_2))/(complex(0,X)+complex(R_2/(2-s),X_2)) \n",
+ "Z_ftot=complex(R_1,X_1)+Z_f \n",
+ "Z_btot=complex(R_1,X_1)+Z_b \n",
+ "I_f=V_f/Z_ftot \n",
+ "I_b=V_b/Z_btot \n",
+ "w_s=157.1 \n",
+ "T_s=(2/157.1)*(abs(I_f)**2*(Z_f.real)-abs(I_b)**2*(Z_b.real)) \n",
+ "print(T_s,'starting torque(Nm)') \n",
+ "I_m=I_f+I_b \n",
+ "m=math.degrees(math.atan((I_m.imag)/(I_m.real)))\n",
+ "I_a=1j*(I_f-I_b) \n",
+ "a=math.degrees(math.atan((I_a.imag)/(I_a.real)))\n",
+ "P_m=w_s*(1.0-s)*T_s \n",
+ "P_L=200.0 \n",
+ "P_out=P_m-P_L \n",
+ "P_min=V*abs(I_m)*math.cos(math.radians(m)) \n",
+ "P_ain=V*abs(I_a)*math.cos(math.radians(a))\n",
+ "P_in=P_min+P_ain \n",
+ "n=P_out/P_in \n",
+ "print(n,'efficiency') \n",
+ "\n",
+ "r=Z_ftot/Z_btot #r=V_mf/V_bf\n",
+ "#V_mf+V_bf=220\n",
+ "V_mf=220/(1+r) \n",
+ "V_mb=220-V_mf \n",
+ "V_a=1j*(V_mf-V_mb) \n",
+ "\n",
+ "#Results\n",
+ "print(abs(V_a),'V_a(V)')"
+ ],
+ "language": "python",
+ "metadata": {},
+ "outputs": [
+ {
+ "output_type": "stream",
+ "stream": "stdout",
+ "text": [
+ "(0.0, 'starting torque(Nm)')\n",
+ "(14.313452498677325, 'starting current(A)')\n",
+ "(3.5887587638431966, 'starting torque(Nm)')\n",
+ "(0.12798421082025385, 'efficiency')\n",
+ "(176.4417668704772, 'V_a(V)')\n"
+ ]
+ }
+ ],
+ "prompt_number": 5
+ }
+ ],
+ "metadata": {}
+ }
+ ]
+}
\ No newline at end of file |