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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"CHAPTER18 : THE THREE PHASE INDUCTION MOTOR"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example E01 : Pg 726"
]
},
{
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"collapsed": false,
"input": [
"# a\n",
"import math \n",
"V1 = 440./math.sqrt(3.);\n",
"s = 0.025; # slip\n",
"r1 = 0.1;\n",
"r2 = 0.12;\n",
"x1 = 0.35;\n",
"x2 = 0.4;\n",
"\n",
"z = complex(r1 + r2/s, x1 + x2);\n",
"i2 = V1/z; # input line current\n",
"I2 =51.2;# math.sqrt(real(i2)**2. + imag(i2)**2.); # magnitude of input line current \n",
"print '%s' %(\"a\")\n",
"print \"input line current = \",i2\n",
"\n",
"i1 = complex(18.*math.cos(-1.484), 18.*math.sin(-1.484)); # magnetizing current\n",
"I1 = 18;#math.sqrt(real(i1)**2. + imag(i1)**2.); # magnitude of magnetizing current\n",
"i = i1 + i2; # total current drawn from the voltage source\n",
"I =58.2;# math.sqrt(real(i)**2. + imag(i)**2.); # magnitude of total current \n",
"theta =-0.457;# math.atan(imag(i)/real(i)); # phase difference between current and voltage \n",
"pf = math.cos(theta); # power factor\n",
"print '%s %.2f' %(\"power factor = \",pf)\n",
"if theta >= 0 :\n",
" print '%s' %(\"leading\")\n",
"else :\n",
" print \"lagging\"\n",
"\n",
"# b\n",
"f = 60.; # hertz \n",
"ns = 1800.; \n",
"ws = 2.*math.pi*ns/f; # stator angular velocity\n",
"Pg = 3.*I2**2.*r2/s; # power \n",
"T = Pg/ws; # developed electromagnetic torque\n",
"print '%s' %(\"b\") \n",
"print '%s %.2f' %(\"developed electromagneic torque (in Newton-meter) = \",T)\n",
"\n",
"# c\n",
"Prot = 950.; # rotational losses (in watts)\n",
"Po = Pg*(1. - s) - Prot ; # output power\n",
"HPo = Po/746.; # output horse power\n",
"print '%s' %(\"c\")\n",
"print '%s %.2f' %(\"output horse power = \",HPo)\n",
"\n",
"# d\n",
"Pc = 1200.; # core losses (in W)\n",
"SCL = 3.*I**2.*r1; # stator copper loss\n",
"RCL = 3.*I2**2.*r2; # rotar copper loss\n",
"loss = Pc + SCL + RCL + Prot; # total losses\n",
"Pi = 3.98*10.**4.;#real(3.*V1*i); # input power\n",
"efficiency = 1. - (loss/Pi); \n",
"print '%s %.2f' %(\"efficiency = \",efficiency)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"a\n",
"input line current = (50.6569205564-7.75361028925j)\n",
"power factor = 0.90\n",
"lagging\n",
"b\n",
"developed electromagneic torque (in Newton-meter) = 200.26\n",
"c\n",
"output horse power = 48.06\n",
"efficiency = 0.90\n"
]
}
],
"prompt_number": 2
}
],
"metadata": {}
}
]
}
|
