Outline
Fundamentals of energy conversion
Linear electro-mechanical system
Rotating electro-mechanical system
Fundamentals of DC and AC machine
Electrical energy
Mechanical energy
Relays, actuators (intermittent energy conversion)
Motors (continuous ener
Outline
Introduction
Construction and Working principle
Analysis of Synchronous machine
Equivalent circuit and Parameter determination
Phasor diagrams
Performance characteristics
Developed Power and Torque
Torque-speed characteristic
Load/torque/power ang
ELEC3105
Electrical Energy
Tutorial 2: Three-phase AC circuit and Transformers
Part I: Three-phase AC circuits
1.
Three similar coils each having a resistance of 5 and an inductance of 0.02H are connected
(a) in star, (b) in delta to a 415V, 3-phase, 50 H
ELEC3105
Electrical Energy
Tutorial 3. Energy conversion
and DC machines
Part I: Energy Conversion
Question 1.
A simplified cross section of a 2-pole DC machine is indicated in figure 1. The B field in the air
gap is produced by a field winding which is s
ELEC 3105
Tutorial 2
Q2. Two three-phase wye-connected balanced loads are in parallel across a
three-phase supply. The first load draws a phase current of 20A at 0.9 power
factor leading, and the second load draws a phase current of 30A at 0.8
power facto
Outline
4.1. Fundamentals
4.1.1 Ideal and non-ideal transformer: working principle
4.1.2 Impedance transfer
4.1.3 Equivalent circuit and Phasor diagram
4.1.4 Determination of parameters of equivalent circuit.
4.2 Ratings and performance
4.2.1Rating of tra
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THE UNIVERSITY OF NEW SOUTH WALES
School of Electrical Engineering & Telecommunications
FINAL
EXAMINATION
Session 2 2014
ELEC3105
Electrical Energy
TIME ALLOWED:
TOTAL MARKS:
TOTAL NUMBER OF QUESTIONS:
3 hours
100
6
THIS
Name: _
Student ID: _
Signature: _
THE UNIVERSITY OF NEW SOUTH WALES
School of Electrical Engineering & Telecommunications
FINAL
EXAMINATION
Session 2 2013
ELEC3105
Electrical Energy
TIME ALLOWED:
TOTAL MARKS:
TOTAL NUMBER OF QUESTIONS:
3 hours
100
6
THIS
Outline
Fundamentals of Electricity Generation
Energy Resources
Brief overview of
Fossil fuel plants
Nuclear power plant
Generation from renewable sources:
Hydro power plant
Solar (Photovoltaic and Solar Thermal)
Wind
Others
Check out-
d
What is the funda
Topic 4: Tryouts-2
Tutoriaal 2
Q10.
Thhree single-phase 50-KVA , 2400:240V tran
nsformers, with a total
equuivalent im
mpedancee of 1.42 + j1.82 reeferred to the high voltage siide, are
connnected Y-
Y in a 3-phase 1550-kVA baank to steep down thhe voltag
Outline:
Part I :Fundamentals
Introduction and Construction
Production of rotating magnetic field in 3-phase AC machines
Working principle Equivalent circuit and Parameter determination
Part II: Performance analysis
Efficiency
Torque-speed characteristics
ELEC
C 3105 : Topic
T
2
Exerciise: Magn
netic circu
uit
Considder the maagnetic cirrcuit madee with soliid ferromaagnetic corre shown in the
figure below. Thhe depth of
o the coree is 5 cm. Assume
A
th
hat the relaative
permeaability of the core iss 1000
ELEC3105
Electrical Energy
Tutorial 4: Induction Machines
1.
A conveyor belt is to be driven at a constant velocity of approximately 2 m/sec by
means of a pulley whose diameter is equal to 0.16m. The force required is estimated to
be 500 N. Specify the ou
ELEC3105
Electrical Energy
Tutorial 5. Synchronous Machines
1. The open circuit characteristic (OCC) and short circuit characteristic (SCC) of
a 36MVA, 20.8kV, Y-connected synchronous machine are shown in Figure
5.1. The excitation current If of the machi
Outline
Three-phase AC circuit
Balanced three-phase systems and connections
Wye-Delta transformation in three-phase circuits
AC power Analysis Single and three-phase
Power factor correction in three-phase AC circuits
Balanced Three-phase voltages
A
Week 2 Lecture 1
Outline
Magnetic field: Amperes law
Magnetic Materials
Magnetic circuit and Graphical methods
Magnetization or excitation current and inductance
Magnetization currents waveform
Magnetic hysteresis
Losses: Hysteresis and Eddy current loss
Tutorial 2
Draw the approximate equivalent circuit of a single phase transformer referred
to primary side.
Draw the approximate equivalent circuit of a single phase transformer referred
to secondary side.
Q.7.
(i) Calculate the values of Rc, Xm, Req and X
Lecture 1 Week 7, Tuesday
Outline
Introduction
Construction features
Torque and induced voltage equations
Brush-commutation
Armature reaction
Classification of DC motors and their characteristics
Classification of DC generator and their characteristics
Lo
ELEC3105
Electrical Energy
Tutorial 1 Introduction to Energy system and Magnetic
Circuits
Part I: Introduction to Energy system
1.
An ideal PV cell with a reverse saturation current of 1nA is operating at 30C. The solar
photon current, Iph at 30C is 1A. C
Name: _
Student ID: _
Signature: _
THE UNIVERSITY OF NEW SOUTH WALES
School of Electrical Engineering & Telecommunications
FINAL
EXAMINATION
Session 2 2012
ELEC3105
Electrical Energy
TIME ALLOWED:
TOTAL MARKS:
TOTAL NUMBER OF QUESTIONS:
3 hours
100
6
THIS
THE UNIVERSITY OF NEW SOUTH WALES
SCHOOL OF ELECTRICAL ENGINEERING AND
TELECOMMUNICATIONS
FINAL EXAMINATION 2009 SEMESTER 2
ELEC3105 ELECTRICAL ENERGY
1. TIME ALLOWED - 3 hours
2. READING TIME 10 minutes
3. THIS EXAMINATION PAPER HAS - 5 PAGES
4. TOTAL NU
Name: _
Student ID: _
Signature: _
THE UNIVERSITY OF NEW SOUTH WALES
School of Electrical Engineering & Telecommunications
FINAL
EXAMINATION
Session 2 2010
ELEC3105
Electrical Energy
TIME ALLOWED:
TOTAL MARKS:
TOTAL NUMBER OF QUESTIONS:
3 hours
100
6
THIS
ANSWERS MUST BE WRITTEN IN INK. EXCEPT
WHERE THEY ARE EXPRESSLY REQUIRED,
PENCILS MAY ONLY BE USED FOR DRAWING,
SKETCHING AND GRAPHICAL WORK
THE UNIVERSITY OF NEW SOUTH WALES
FINAL EXAMINATION
JUNE 2004
ELEC3005
ELECTRICAL ENERGY 1
Time allowed - 3 hours
6
DC Machines
6.1
Geometry
A turn, coil and winding can be seen in Figure 10. Within a given coil, all the turns are connected
in series. Each side of a turn is called a conductor. Each of the two sides of a coil are held in a slot,
which may also hold th
Question 1
Part 1.a
Magnetic Circuit (Reluctance) Method: Calculate the magnetic reluctance of each part of
the system using RS = , treat the values of R as the values of resistors in a circuit. The
current is ux (). If there is a coil with current, is be
6.3
6.3.1
Machine Types
Series
The equivalent circuit for a series connected machine is shown in Figure 12.
Rf
Lf
Ra
La
Ia
+
+
Va
Ea
Figure 12: Equivalent circuit for series DC machine
2
T = kt kf Ia
2
Note: T Ia
Ea = ke kf Ia m
The equation for the torqu
The 4 important equations which can be used to solve any magnetic circuit problem (in this course):
R = N I
Ronnie
RS =
(1)
Russel
LI = N =
Lion
= BS
(2)
Phi is Bullshit
Where
0 = 4 107 H m1 .
= N = Li is ux linkage
N I = M M F is magnetomotive force
T
Forward Torque
Net Torque
Backwards Torque
Figure 22: Single phase induction machine torque speed characteristic
Sb = 2 Sf is the slip of the backward component.
7.3.1
Power
Air gap power is given by:
0.5R 2
S
0.5R 2
2
= I 2b
2S
Pagf = I
Pagb
8
2
2f
For