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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 14 : Magnetic Properties and Materials"
]
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 14.1 pageno : 358"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"x = 1500.;\t\t\t#susceptibility\n",
"h = 2400.;\t\t\t#mafnetic field in A/m\n",
"\n",
"# Calculations\n",
"u_r = 1+x;\n",
"m = x*h;\t\t\t #in A/m\n",
"u_0 = 4*3.14*10**-7;\n",
"b = u_0*u_r*h;\t\t\t#in T\n",
"\n",
"# Results\n",
"print \"relative permeability = \",u_r\n",
"print \"Intensity of magnetisation (in A/m)\",m\n",
"print \"Remanance (in T) = \",b\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"relative permeability = 1501.0\n",
"Intensity of magnetisation (in A/m) 3600000.0\n",
"Remanance (in T) = 4.5246144\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 14.2 page no : 368"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"# Variables\n",
"w = 80. + 80;\t\t\t#width of loop in A/m from graph\n",
"h = 0.15 + .15;\t\t\t#height of loop in Wb/sqm\n",
"\n",
"# Calculations\n",
"a = w*h;\t\t\t #area of the loop in J\n",
"\n",
"# Results\n",
"print \"Hysteresis energy loss per unit volume of magnetic material during one cycle (in J) = %d J\"%a\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Hysteresis energy loss per unit volume of magnetic material during one cycle (in J) = 48 J\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 14.3 pageno : 370"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"a = 600.;\t\t\t#loop area in J/sqm\n",
"f = 50.;\t\t\t#in Hz\n",
"v = 0.01\t\t\t#volume in cu. m\n",
"\n",
"# Calculations\n",
"w = a*f*v;\t\t\t#in W\n",
"\n",
"# Results\n",
"print \"Power loss due to Hysteresis (in W) = %.f watt\"%w\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power loss due to Hysteresis (in W) = 300 watt\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 14.4 pageno : 370"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"w_h1 = 300.; # hysteresis loss\n",
"b_1 = 0.9; # max. flux density\n",
"\n",
"y = b_1**1.7;\n",
"b_2 = 1.1; #raised flux density(Wb/m^2)\n",
"x = b_2**1.7;\n",
"f1 = 50*10**-7; #frequency(Hz)\n",
"f2 = 40*10**-7; #frequency(Hz)\n",
"\n",
"# Calculations\n",
"w_h2 = (w_h1*x*f2)/(y*f1);\n",
"\n",
"\n",
"# Results\n",
"print \"Loss at 40 Hz (in W) = %.f W\"%w_h2\n",
"\n",
"# Note : Answer in book is wrong. Please calculate manually."
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Loss at 40 Hz (in W) = 338 W\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 14.5 pageno : 376"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"m = 6000.; # megnetization\n",
"u_r = 200000.; # relative permeability\n",
"\n",
"# Calculations\n",
"x = u_r-1;\n",
"h = m/x;\n",
"u_0 = 4*3.14*10**-7;\n",
"b = u_0*u_r*h;\n",
"\n",
"# Results\n",
"print \"Magnetic strength (in T) = %.5f tesla\"%b\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Magnetic strength (in T) = 0.00754 tesla\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 14.6 pageno : 376"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"b = 9.27*10**-24;\t\t\t#Bohr Magneton in A/sqm\n",
"m = 0.6*b;\n",
"\n",
"# Calculations\n",
"a = 0.35*10**-9;\n",
"n = 4.;\t\t\t#FCC\n",
"m_g = n*m/a**3;\t\t\t#in A/m\n",
"\n",
"# Results\n",
"print \"Saturation Magnetisation (in A/m) = %.2e A/m\"%m_g\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Saturation Magnetisation (in A/m) = 5.19e+05 A/m\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 14.9 page no : 381"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"f = 50.;\t\t\t#in Hz\n",
"L = 100.;\t\t\t#Eddy current loss in transformer in W\n",
"f1 = 60.;\t\t\t#in Hz\n",
"f2 = 100;\t\t\t#in Hz\n",
"\n",
"# Calculations\n",
"w_e = L*(f1/f)**2;\t\t\t#in W\n",
"w_ee = L*(f2/f)**2;\t\t\t#in W\n",
"\n",
"# Results\n",
"print \"Eddy current loss at 60 Hz (in W) = %.1f W\"%w_e\n",
"print \"Eddy current loss at 100 Hz (in W) = %.1f W\"%w_ee\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Eddy current loss at 60 Hz (in W) = 144.0 W\n",
"Eddy current loss at 100 Hz (in W) = 400.0 W\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"Example 14.13 pageno : 382"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"l = .25;\t\t\t#in m\n",
"n = 400.;\t\t\t#turns\n",
"i = 15.;\t\t\t#in A\n",
"\n",
"# Calculations\n",
"u_0 = 1.257*10**-6;\t\t\t#in H/m\n",
"h = n*i/l;\t\t\t#in AT/m\n",
"u_r = 1;\t\t\t#relative permeability\n",
"b = u_0*u_r*h;\t\t\t#in wB/sqm\n",
"\n",
"# Results\n",
"print \"Magnetic field strength (in AT/m) = %.1f AT/m\"%h\n",
"print \"Flux density (in Wb/sq m) = %.2f Wb/m**2\"%b\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Magnetic field strength (in AT/m) = 24000.0 AT/m\n",
"Flux density (in Wb/sq m) = 0.03 Wb/m**2\n"
]
}
],
"prompt_number": 12
}
],
"metadata": {}
}
]
}