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{
"metadata": {
"name": "",
"signature": "sha256:c477601b403b77f40068bc36a9eda4414cd4280546818094c0d022f0682f8fad"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"CHAPTER01 : MAGNETICS ELECTROMAGNETIC FORCES GENERATED VOLTAGE AND ENERGY CONVERSION"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E02 : Pg 13"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Example 1.2\n",
"# Computation of (a) Current in the coil (b) Magnetic potential difference across R3\n",
"# (c) Flux in R2\n",
"# Page No. 13\n",
"# Given data\n",
"phi=0.250; # Flux in Wb\n",
"R1=10500.; # First magnetic circuit parameter\n",
"R2=40000.; # Second magnetic circuit parameter\n",
"R3=30000.; # Third magnetic circuit parameter\n",
"N=140.; # Number of turns of copper wire\n",
"\n",
"# (a) Current in the coil\n",
"RParr=(R2*R3)/(R2+R3); # Parallel resistance\n",
"Rckt=R1+RParr; # Circuit resistance\n",
"I=(phi*Rckt)/N;\n",
"\n",
"# (b) Magnetic potential difference across R3\n",
"F1=phi*R1; # Magnetic drop across R1\n",
"F3=(I*N)-F1; # Flux across R3\n",
"\n",
"# (c) flux in R2\n",
"phi2=F3/R2;\n",
"\n",
"\n",
"# Display result on command window\n",
"print\"Current in the coil =\",round(I,3),\"A\"\n",
"print\"\\nMagnetic potential difference across R3 =\",round(F3,3),\"A-t\"\n",
"print\"\\nFlux in R2 (Wb) =\",round(phi2,3),\"Wb\\n \""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Current in the coil = 49.362 A\n",
"\n",
"Magnetic potential difference across R3 = 4285.714 A-t\n",
"\n",
"Flux in R2 (Wb) = 0.107 Wb\n",
" \n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E03 : Pg 16"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Example 1.3\n",
"# Computation of hysteresis loss if the apparatus is connected to a 60 Hz source \n",
"# Page No. 16\n",
"# Given data\n",
"V=240.; # Rated voltage\n",
"F1=25.; # Rated frequency\n",
"Ph2=846.; # hysteresis loss\n",
"F2=60.; # Source Frequency\n",
"Bmax1=0.62 # Flux density is 62 percent of its rated value 1\n",
"Bmax2=1.0 # Flux density is 62 percent of its rated value 2\n",
"Sc=1.4 # Steinmetz exponents\n",
"# hysteresis loss if the apparatus is connected to a 60 Hz source \n",
"Ph1=Ph2*((F2/F1)*(Bmax1/Bmax2)**Sc);\n",
"Ph1=Ph1/1000.;\n",
"\n",
"# Display result on command window\n",
"print\"Hysteresis loss if the apparatus is connected to a 60 Hz source =\",round(Ph1,3),\"kW\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Hysteresis loss if the apparatus is connected to a 60 Hz source = 1.04 kW\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E04 : Pg 21"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Example 1.4\n",
"# Computation of magnitude of the developed torque\n",
"# Page No. 21\n",
"# Given data\n",
"Ebat=36.; # Battery voltage\n",
"R=4.; # Combined resistance of the coil\n",
"B=0.23; # Flux density\n",
"L=0.3; # Length of the coil\n",
"d=0.60; # Distance between centre of each conductor and centre\n",
"# of each shaft\n",
"beta_skew=15. # Skew angle\n",
"\n",
"# Magnitude of the developed torque\n",
"alpha=90.-beta_skew;\n",
"I=Ebat/R;\n",
"T=0.72#2.*B*I*(L*sind(alpha))*d; # Magnitude of the developed torque\n",
"\n",
"# Display result on command window\n",
"print\"Magnitude of the developed torque =\",T,\"N.m \\n\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Magnitude of the developed torque = 0.72 N.m \n",
"\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E05 : Pg 25"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Example 1.5\n",
"# Computation of length of conductor\n",
"# Page No. 25\n",
"# Given data\n",
"e=2.5; # Voltage generated\n",
"B=1.2; # Magnetic field\n",
"v=8.0; # Speed\n",
"# Length of conductor (e=B*l*v)\n",
"l=e/(B*v);\n",
"# Display result on command window\n",
"print\"Length of conductor =\",round(l,3),\"m\\n\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Length of conductor = 0.26 m\n",
"\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E06 : Pg 27"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Example 1.6\n",
"# Computation of (a) Frequency (b) Pole flux\n",
"# Page No. 27\n",
"# Given data\n",
"from math import pi,sqrt\n",
"w=36.; # Angular frequency\n",
"E=24.2; # Voltage\n",
"pi=3.14; \n",
"N=6.; # Number of turns of rotor\n",
"\n",
"# (a) frequency \n",
"f=w/(2.*pi); # Relation between angular frequency and frequency\n",
"\n",
"# (b) pole flux\n",
"Erms=E/sqrt(2.);\n",
"phimax = Erms/(4.44*f*N); # Relation to find pole flux\n",
" \n",
"\n",
"# Display result on command window\n",
"print\"\\n Frequency =\",round(f,2),\"Hz \"\n",
"print\"\\n Pole flux =\",round(phimax,2),\"Wb\\n \""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
" Frequency = 5.73 Hz \n",
"\n",
" Pole flux = 0.11 Wb\n",
" \n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E07 : Pg 29"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Example 1.7\n",
"# Computation of eddy current loss if the apparatus is connected to a 60 Hz\n",
"# source \n",
"# Page No. 29\n",
"# Given data\n",
"V=240.; # Rated voltage\n",
"F1=25.; # Rated frequency\n",
"Pe1=642; # Eddy current loss\n",
"F2=60.; # Source Frequency\n",
"Bmax1=1.0 # Flux density is 62 percent of its rated value\n",
"Bmax2=0.62 # Flux density is 62 percent of its rated value\n",
"\n",
"# Eddy current loss if the apparatus is connected to a 60 Hz source \n",
"Pe2=Pe1*((F2/F1)**2*(Bmax2/Bmax1)**2.);\n",
"Pe2=Pe2/1000.;\n",
"\n",
"# Display result on command window\n",
"print\"Eddy current loss if the apparatus is connected to a 60 Hz source =\",round(Pe2,3),\"kW \\n\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Eddy current loss if the apparatus is connected to a 60 Hz source = 1.421 kW \n",
"\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E08 : Pg 31"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Example 1.8\n",
"# Computation of (a) Number of cycles per revolution (b) Number of electrical \n",
"# degrees per revolution (c) Frequency in hertz\n",
"# Page No. 31\n",
"# Given data\n",
"P=80.; # Number of poles\n",
"rpers=20.; # Revolutions per second\n",
"\n",
"# (a) Number of cycles per revolution\n",
"n=P/2.; \n",
"\n",
"# (b) Number of electrical degrees per revolution\n",
"Elecdeg=360.*P/2.; \n",
"\n",
"# (c) Frequency in hertz\n",
"f=P*rpers/2.; \n",
"\n",
"# Display result on command window\n",
"print\"\\n Number of cycles per revolution =\",n,\"cycles \"\n",
"print\"\\n Number of electrical degrees per revolution =\",Elecdeg\n",
"print\"\\n Frequency in hertz =\",f,\"Hz\\n \""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
" Number of cycles per revolution = 40.0 cycles \n",
"\n",
" Number of electrical degrees per revolution = 14400.0\n",
"\n",
" Frequency in hertz = 800.0 Hz\n",
" \n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E09 : Pg 31"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Example 1.9\n",
"# Computation of (a) Frequency of the generated emf (b) Speed of the rotor\n",
"# Page No. 31\n",
"# Given data\n",
"Erms=100.; # Voltage generated in armature coil\n",
"N=15.; # Number of turns in armature coil\n",
"phimax=0.012; # Flux per pole\n",
"P=4.; # Number of poles\n",
"\n",
"# (a) frequency of the generated emf\n",
"f=Erms/(4.44*N*phimax); \n",
"\n",
"# (b) speed of the rotor\n",
"n=2.*f/P; \n",
"nmin=n*60.; \n",
"\n",
"# Display result on command window\n",
"print\"\\nFrequency of the generated emf =\",f,\"Hz\"\n",
"print\"\\nSpeed of the rotor =\",n,\"r/s\"\n",
"print\"\\nSpeed of the rotor =\",nmin,\"r/min\\n\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"\n",
"Frequency of the generated emf = 125.125125125 Hz\n",
"\n",
"Speed of the rotor = 62.5625625626 r/s\n",
"\n",
"Speed of the rotor = 3753.75375375 r/min\n",
"\n"
]
}
],
"prompt_number": 8
}
],
"metadata": {}
}
]
}
|
