EEL4205 Fall2012 Exam 1
Name: _
Problem 1. (50 points)
Consider the magnetic circuit shown below. Here, we neglect any flux outside the core area and
suppose that the air gap has 5% fringing.
(1) Find the reluctance of the core;
(2) Find the reluctance of
EEL4205 Exam 2
Name:_
Problem 1. (50 points)
A 60 Hz single phase transformers equivalent circuit is shown in the Figure. It has a nameplate
voltage rating of 5-kV:50-kV (turns ratio is 1:10). An open-circuit test is conducted from the
low-voltage primary
Magnetic Circuits and Materials
Ampere's Circuital Law
dl
I L
H
H dl I
L
enclosed
length d
H dl
NI
Hd NI NI H d NI B d
Constitutive Relationship
In isotropic media
r
B H 0 r H
permeability relative permeability
r 1, 1 : diamagneti c material r 1 : v
Magnetic Circuits (II)
Example 3
r=2000
5% cross-section increase for
fringing in airgap
Find: (a) total reluctance of the flux path;
(b) current required to produce B = 0.5 T in the air gap;
(c) inductance of the coil.
Example 4
N = 400, A = 150 cm2
lc =
Three Phase Circuits (I)
Time-harmonic Signal
v (t ) 2V cos(t v ) V and I are rms values.
i (t )
i (t ) 2 I cos(t i )
j v
v (t ) Re[ 2Ve e
jt
+
]
v(t )
_
Phasor Domain
V Ve
ji
i (t ) Re[ 2 Ie e
I Ie
j v
jt
ji
or
V V v
rms
I Ii
rms
]
or
Z (t )
Instantaneou
Magnetic Circuits (I)
Amperes Circuital Law
I
L
dl
H dl I
H
enclosed
L
length d
H dl
NI
Hd NI
NI
H
d
NI
B
d
Constitutive Relationship
In isotropic media
B H 0 r H
r
permeability
relative permeability
r 1, 1 : diamagneti c material
r 1 : vacuum
Introduction
UCF
EEL4205 Electric Machinery
Course website:
http:/www.eecs.ucf.edu/~tomwu/course/eel4205/eel4205.htm
Or Google: Thomas Wu
Required Software:
MatLab/SimuLink Student Version (2010a and later)
MatLab tutorial website:
http:/www.mathworks.com
Elliott Kozlowski
Musci
Music Influence paper
Nov. 13th 2013
The Beach Boys.
In 1961 the great American band The Beach Boys was created. The Beach boys started
their journey in music in 1961, and later became known as one of the best bands in the history
Kozlowski 1
Elliott Kozlowski
Word
Count:1,206
Professor Meyers
ENC1102
4/1/13
Seat belts in Tallahassee
Driving down the road without my seatbelt isnt that big of a deal, its just down the
road., WRONG, driving anytime without a seatbelt is unsafe and da
Three Phase Circuits (II)
Analysis of Three Phase Balanced
Circuits: Y-Y Connection (1)
Analysis of Three Phase Balanced
Circuits: Y-Y Connection (2)
A
a
B
VAN
b
VBN
N
n
VCN
C
c
Analysis of Three Phase Balanced
Circuits: Y-Y Connection (3)
Per phase circu
Faradays Law
Faradays Law (I)
d
d
E dl = dt B dS = dt
C
S
B
dl
C
n
E
S
Electromotive Force (emf)
- V
emf = E dl
C
Total Magnetic Flux
=
- Wb
B dS
S
Faradays Law (II)
d
d
E dl = dt B dS = dt
C
S
B
dl
C
n
E
S
The emf generated around a closed contour C
Chapter 3: Transformers
3-1.
The secondary winding of a transformer has a terminal voltage of v s (t ) = 282.8 sin 377t V . The turns
ratio of the transformer is 50:200 (a = 0.25). If the secondary current of the transformer is
i s (t ) = 7.07 sin ( 377t
% Fall 2013 Exam 2 Problem 1
clear all; close all; clc;
% Input open circuit and short circuit testing results:
kV = 1000;
kW = 1000;
absVOC = 7.2*kV/sqrt(3); % Open circuit phase voltage
absIOC = 16; % For Y connection, the line current is equal to phase
% Add at beginning of code:
% d2r = @(x) (x*pi/180);
% r2d = @(x) (x*180/pi);
To convert polar to rectangular
Given: 7.07 angle -36.87 = 7.07cos(377t-36.87)
-Matlab: 7.07*exp(1j*d2r(-36.87) and then run the code.
-Matlab: [real(Is) imag(Is)]
-Calc.: (
Cheat Sheetfor Exam 1
clear all; close all; clc;
cm = 0.01; % 1 cm = 0.1 m
mu0 = 4*pi*10^(-7);
-Current that will produce a flux of _ Wb.
Find the Reluctance R for each side:
R = l/(mu*A)
*mu = mur*mu0
*A = depth*thickness
Find total Reluctance R
Autotransformer
UCF
Autotransformer (1)
Autotransformer (2)
UCF
VC
= n,
VSE
VL = VC
VH = VC + VSE
I L = I C + I SE
I H = I SE
I SE
=n
IC
VC
n
VL
=
=
= n'
VH
VC + VSE n + 1
I C + I SE n + 1 1
IL
=
=
=
IH
I SE
n
n'
n' =
n
n +1
Autotransformer (3)
UCF
VL = V
Transformer Voltage Regulation
UCF
Transformer Voltage Regulation (1)
Ideal:
VP
n
VS
n
Non-ideal:
NP
NS
UCF
Transformer Voltage Regulation (2)
No load (open circuit):
Full load : VP
n
VP
VSnl
n
VSfl ( Reqs jX eqs )I S
Voltage regulation: VR
VSnl VSfl
V
Non-ideal Transformer
UCF
Non-Ideal Transformer (1)
(1) r
Rcore = N pi p N sis
=
N pi p N sis
d
d N pi p N sis
= Np
= Np
vp
Rcore
dt
dt
2
Np d
Ns
is
ip
Rcore dt
Np
Rcore
Non-Ideal Transformer (2)
UCF
2
Np d
Ns
ip
is
vp =
Np
Rcore dt
Defi
Introduction to Transformer
UCF
Introduction to Transformer (1)
Transformer: A device that changes AC electric power at one
voltage level to ac electric power at another voltage level
through the action of a magnetic field.
Shell-form transformer
UCF
Core
Kozlowski 1
Elliott Kozlowski
Mrs. Evans
ENC1102
11 February 2013
Smoking In Public: A Law or a Choice?
Since the earliest of times, smoking cigarettes and tobacco products has been part of our
society. As time has elapsed, we have found out many things a
Elliott Kozlowski
Mrs. Evans
ENC1102
10, February 2013
Rogerian Argument : Genetic Engineering
Just imagine the scene: and newlywed wife and husband are sitting down with a catalog,
browsing joyously, pointing and awing at all the different options, fanta
EEL4205 Fall2012 Exam 1 Problem 1. (50 points)
Name: _
Consider the magnetic circuit shown below. Here, we neglect any flux outside the core area and suppose that the air gap has 5% fringing. (1) Find the reluctance of the core; (2) Find the reluctance of
EEL4205 Exam 2
Name:_
Problem 1. (50 points) A 60 Hz single phase transformer's equivalent circuit is shown in the Figure. It has a nameplate voltage rating of 5-kV:50-kV (turns ratio is 1:10). An open-circuit test is conducted from the low-voltage primar
EEL4205 Exam 3 Problem 1. (50 points) A 480 V (terminal voltage), 500 kVA, 60 Hz, four pole, Y connected synchronous generator has a synchronous reactance of 0.08 and an armature resistance of 0.02 . At 60Hz, its friction and windage losses are 8 kW, and
EEL4205 Final Exam
Fall2012
1. (20 points) A 480 V (terminal voltage), Y-connected, 60 Hz, synchronous motor has a
synchronous reactance of 2.5 and a negligible armature resistance. Its friction and windage losses are 2.2kW and its core losses are 0.8kW.
Department of Electrical Engineering and Computer Science
EEL4205 Electric Machinery
Homework Set No. 5 Names: (1)_; (2)_ (3) _
Problem 1. A 4 pole motor is supplying 60 N.m torque to its load. The shaft speed of the motor is 4000 rpm. The rotor outer dia
Department of Electrical Engineering and Computer Science
EEL4205 Electric Machinery
Homework Set No. 6 Names: (1)_; (2)_ (3) _
Problem 1. A 2300 V (terminal voltage), 1000 kVA, 0.8 PF lagging, 60-Hz, two pole, Y connected synchronous generator has a sync
Department of Electrical Engineering and Computer Science
EEL4205 Electric Machinery
Homework Set No. 7 Names: (1)_; (2)_ (3) _
Problem 1. A 480 V, 60 Hz, 400 hp, six pole, connected synchronous motor has a synchronous reactance of 1.1 and negligible arma
Department of Electrical Engineering and Computer Science
EEL4205 Electric Machinery
Homework Set No. 8 Names: (1)_; (2)_ (3) _
Problem 1. A 220 V, three phase, two pole, 50 Hz induction motor is running at a slip of 5 percent. Find: (1) the speed of the
EEL4205 Exam 3
Problem 1. (50 points)
A 480 V (terminal voltage), 500 kVA, 60 Hz, four pole, Y connected synchronous generator has a
synchronous reactance of 0.08 and an armature resistance of 0.02 . At 60Hz, its friction and
windage losses are 8 kW, and
Elliott Kozlowski
Mrs Brown
Music
September 16, 2013
Reflection Essay #2
In the beginning of the 1800s one of the most popular music being played was piano
sheet music. As time progressed in the 1800s this type of music began to evolve in many
different a
From: Elliott Kozlowski
To: Tallahassee Government
Cover Letter
Dear Tallahassee Government, Ive noticed that people all over Tallahassee fail to wear
their seatbelts while driving, this has been an ongoing problem for a while now and has actually
increas
Elliott Kozlowski
Dr. Meyer
ENC1102
01/10/2013
Journal One
As someone who wasnt too interested in writing and reading at a younger age, I have
grown into a person that doesnt really read on a regular basis, unless studying for school or
completing assignm
Elliott Kozlowski
2.
Chan, S., Hadjistavropoulos, T., Carleton, R., & Hadjistavropoulos, H. (2012). Predicting
adjustment to chronic pain in older adults. Canadian Journal Of Behavioural Science/Revue
Canadienne Des Sciences Du Comportement, 44(3), 192-19
Kozlowski 1
Elliott Kozlowski
Stephen Powers
POS1041 MWF 11:15
30, Nov. 2012
Part 3
* What is the official stated purpose of the group?
A1: Center for Education Reform: they make structural changes to the Education Reform
A2: Center for Immigration Studie