1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
|
{
"metadata": {
"name": "",
"signature": "sha256:b878fc066fefa58833a7b2835f2e845d255863cbc07b67c34a50477d1af138d4"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 7 : Induction Machines"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 7.1 Page No : 7.4"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"P = 4.;\t\t\t\t#no. of poles\n",
"f = 50;\t\t\t\t#Hz\n",
"S = 4./100;\t\t\t\t#slip\n",
"N = 600;\t\t\t\t#rpm\n",
"p = P/2;\t\t\t\t#pair of poles\n",
"\n",
"# Calculations and Results\n",
"#(a)\n",
"Ns = 60*f/p;\t\t\t\t#rpm(Synchronous speed)\n",
"print \"(a) Synchronous speed(rpm) : %.2f\"%Ns\n",
"\n",
"#(b)\n",
"Nr = Ns-S*Ns;\t\t\t\t#rpm(Rotor speed)\n",
"print \"(b) Rotor speed(rpm) : %.2f\"%Nr\n",
"\n",
"#(c)\n",
"Sdash = (Ns-N)/Ns;\t\t\t\t#per unot slip\n",
"fr = f*Sdash;\t\t\t\t#Hz(Rotor frequency)\n",
"print \"Rotor frequency(Hz) : %.2f\"%fr\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"(a) Synchronous speed(rpm) : 1500.00\n",
"(b) Rotor speed(rpm) : 1440.00\n",
"Rotor frequency(Hz) : 30.00\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 7.2 Page No : 7.4"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"# Variables\n",
"Zs = 240.;\t\t\t\t#no. of conductors in stator winding\n",
"Zr = 48.;\t\t\t\t#no. of conductors in rotor winding\n",
"Rr = 0.013;\t\t\t\t#ohm/phase(ressmath.tance rotor windig)\n",
"XL = 0.048;\t\t\t\t#ohm/phase(leakega reacmath.tance)\n",
"Vs = 400.;\t\t\t\t#V\n",
"\n",
"# Calculations and Results\n",
"#(a)\n",
"Eo = Vs*Zr/Zs;\t\t\t\t#V(rotor emf)\n",
"print \"(a) Rotor emf(V) : %.2f\"%Eo\n",
"\n",
"#(b)\n",
"S = 4./100;\t\t\t\t#slip\n",
"Eo = Eo*S;\t\t\t\t#V(rotor emf for 4% slip)\n",
"print \"(b) Rotor emf at 4%% slip(V) : %.2f\"%Eo\n",
"\n",
"Z = math.sqrt(Rr**2+(S*XL)**2);\t\t\t\t#ohm/phase(rotor impedence at 4% slip)\n",
"Ir = Eo/Z;\t\t\t\t#A(Rotor curren at 4% slip)\n",
"print \"(b) Rotor curren at 4%% slip(A) : %.2f\"%Ir\n",
"\n",
"#(c)\n",
"fi_r = math.degrees(math.atan(S*XL/Rr));\t\t\t\t#degree\n",
"print \"(c) Phase difference at 4%% slip(degree) : %.2f\"%fi_r\n",
"\n",
"S = 100./100;\t\t\t\t#100% slip\n",
"fi_r = math.degrees(math.atan(S*XL/Rr));\t\t\t\t#degree\n",
"print \"(c) Phase difference at 100%% slip(degree) : %.2f\"%fi_r\n",
"\n",
"# note : rounding off error."
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"(a) Rotor emf(V) : 80.00\n",
"(b) Rotor emf at 4% slip(V) : 3.20\n",
"(b) Rotor curren at 4% slip(A) : 243.51\n",
"(c) Phase difference at 4% slip(degree) : 8.40\n",
"(c) Phase difference at 100% slip(degree) : 74.85\n"
]
}
],
"prompt_number": 3
}
],
"metadata": {}
}
]
}
|
