Mechanical and Electrical Systems

companyscourgeΤεχνίτη Νοημοσύνη και Ρομποτική

19 Οκτ 2013 (πριν από 3 χρόνια και 11 μήνες)

56 εμφανίσεις

Muhammad
Ramlee

Kamarudin

Wireless Communication Centre (WCC)

Universiti

Teknologi

Malaysia

Mechanical and Electrical Systems

SKAA
2032

Brief
Biodata

Name




: Muhammad
Ramlee

Kamarudin

Position


: Associate Professor




Affiliation

: Wireless Communication Centre (WCC)

Email
Address


: ramlee@fke.utm.my

Office Address

: Wireless Communication Centre (WCC
),






Universiti

Teknologi

Malaysia,



81310
Skudai
, Johor, Malaysia.

Room Number

:
P15a
-
level 2

Phone Number
:
07
-

5535350 / 019
-
7007001

Personal webpage

:
muhdramlee.wordpress.com

Qualification


PhD:
University of
Birmingham, UK (Sept 2007)


MSc: University of Birmingham, UK (Sept 2004)


B.Eng
:
Universiti

Teknologi

Malaysia (March 2003)

Research
Area

: Antenna Design


Course Outline

1. Power
Supply (AC and DC)



桲s

1.1
Current, Voltage, Power and their
relationships

1.2
Single and Three Phase System (star and
delta)

1.3
Source of Supply, Transmission and Distribution


2. Electrical Machinery (Transformer and Three Phase
Induction Motor)



桲s

2.1 Transformer: Principle
of operation and
application,
Rating
, Losses and Efficiency

2.2
Induction
Motor: Principle
of operation and

application, Synchronous
speed, Rotor speed
and sleep
,
Rating and starting circuits.


Course Outline

3. Electrical Distribution and Wiring



桲s

3.1
Wiring system, Types and size of cables

3.2
Protections and Grounding

3.3
Electrical Load (Estimation)

3.4
Substation, Switchboard and Distribution Board

3.5
Symbols and Single line diagram


References

1
. B. L.
Theraja
, Electrical Technology

2
. Hughes, Electrical Technology, 9th Edition

3
. D. E. Johnson, J.R. Johnson, J.I.
Hilburn
, Electrical Circuit Analysis, Prentice Hall

4
. Thomas L. Floyd, Electric Circuits Fundamentals, 5th Edition, Prentice Hall

5. P.C.
Sen
, Principles of Electrical Machines and Power electronics, 2nd Edition
John Wiley & Sons 1997

6. Stephen J. Chapman, Electrical Machinery Fundamentals, 4th Edition
McGrawHill

2005

7
. Theodore
Wildi
, Electrical Machines, Drives and Power System, 4th Edition,
Prentice Hall


Lecture notes and tutorials will be informed
through email

Course Objectives


To give basic information about electrical
principle, electrical machinery, distribution
system, wiring and protection



Course Assessment


Electrical System (
50%
)


Assignment
:
10%


Midterm Test
:
15%


Final
Exam

:
25
%


Mechanical
System

(
50
%
)


Total:
100%



Students need to attend 80% of the classes to
be in final exam


C
lass replacement :

Class we missed: 29 Oct (I haven’t been told), 5
Nov (Japan) and
3 Dis (Korea)


Class: 19 Nov, 26 Nov, 10 Dis (Not sure,
Melaka), 17 Dis


Replace: 3 Classes….When??

Familiarization With Electricity

Electrical shock!

Electrical Engineering


Professional
engineering discipline that deals
with the study and application of electricity,
electronics
and
electromagnetism


Among subdivisions of electrical engineering
are: power
, optoelectronics, digital
electronics, analog electronics, artificial
intelligence, control systems, electronics,
signal processing and telecommunications.

Electrical Engineering

Power


This field deals with energy production, energy conversion to
and from electrical
form, energy transmission over
long
distances,
and energy distribution to houses
and industrial
complexes.


Control
Systems


This field concern with information gathering from sensors
and
the use of
electrical energy to control physical
process.


Electronics


Electronics is the study and application of materials, devices,
and circuits used in amplifying and switching electrical signals
.





Electrical Engineering

Telecommunications


Transport information in electrical form. Cellular telephones,
radio, satellite television and the internet are examples of
communication systems.


Signal Processing


Is concerned with information
-
bearing electrical signal. Often,
the objective is to extract useful information from electrical
signals derived from sensors. Application are machine vision
and robotics.


Basic of Electrical System


Electricity is a form of
energy. We
use
electricity for various purposes such
as:


Lighting
, heating, cooling and other domestic
electrical appliances used in
home.




Street lighting, flood lighting
of sporting arena, office
building lighting, powering
PCs


Running motors, furnaces of
various kinds, in industries.


Basic of Electrical System


Examples
of energy source
hydro
, coal,
gas,
wind
, nuclear and solar


Electricity can be generated from these
sources.

Basic of Electrical System


Electrical
systems
permit
us to easily
transmit energy
from a source of
supply to a point of
application

Basic of Electrical System

1. The
source
-

to provide energy for the
electrical system,
e.g
. Battery, generator, socket
outlet

2
. The load
-

to absorb the electrical energy
supplied
by the
source,
e.g
. Lamps,
air
-
cond.

3
. The transmission system
-

conducts energy
from the
source
to the load,
e.g
. Insulated wire

4
. The control apparatus
-

permits energy to
flow or
interrupts
the flow,
e.g
. switch

Basic of Electrical System

Example of Electrical
System

Electrical Power Systems

Electrical
engineer
design systems
objective:


To gather, store, process, transport, and
present
information


To
distribute, store, and convert energy
between various form

Manipulation of energy

Manipulation of information

interdependent

Mechanical and Electrical Systems

SKAA
2032

Power
Supply (AC and DC)


Power Supply (AC and DC)


Electricity is the movement of free electrons in
a material toward an area of positive (+)
charges.


The
conduction of those electrons is
determined by the type of material. Some
conduct well, while other materials prevent
the movement of electrons.


Electricity
can take the form of static
electricity, direct current (DC) electricity, or
alternating current (AC) electricity.

Power Supply (AC and DC)


What

are

free

electrons
?



What

determines

the

conduction

of

electricity?




What

are

the

different

types

of

electricity?


Free electrons


All matter is made up of
atoms


The basic atom consists of a nucleus surrounded by
electrons going round the nucleus in
orbit







The
nucleus consists of:


Protons
which are positively charged


Neutrons that have no charge.


The electrons
have a negative (
-
) electrical charge

Lithium atom

Proton charge= 1.602 x 10
-
19

Coulomb

Elec. charge=
-
1.602 x 10
-
19

Coulomb

Free electrons


Most electrons are bound in orbit around atoms.


But
in many substances, there are electrons that
are not connected to any atom and are roaming
freely throughout the material.


These electrons may have been knocked free in
the creation of ions or may be the result of a
collision of a high energy particle, such as from
radioactive materials or cosmic rays.

Free electrons


Atoms
with an excess of electrons are called
negative ions and those that are missing
electrons in the shells or orbits are called positive
ions
.


An electric force field causes particles with
opposite charges to attract each other.


A
buildup of opposite charges creates an electric
potential.


Release
of the potential energy results in the
movement of free electrons, which is called
electricity.


Valence electrons


Valence electrons are the electrons contained in the
outermost, or valence, electron shell of an atom.


I
mportant
in determining how an element reacts
chemically with other
elements.


The
fewer valence electrons an atom holds, the less
stable it becomes and the more likely it is to react.

Proton charge= 1.602 x 10
-
19

Coulomb

Elec. charge=
-
1.602 x 10
-
19

Coulomb

Conductors


Conductors
are materials that permit electrons to
flow freely from atom to atom and molecule to
molecule.


An object made of a conducting material will permit
charge to be transferred across the entire surface of
the object


This relative mobility of
electrons within a material is
known as electric conductivity.

Conductors


Solid metals are good conductors of electricity,
because electrons are allowed to move freely
throughout the material.


Copper and gold are some of the best
conductors of electricity.


Although iron is a good conductor, iron oxide
(rust) is not.


In the solid state, the atoms of metals are held
in place and only vibrate. This allows free
electrons to roam about the material.


Semiconductors and Nonconductors

S
emiconductors


H
as
electrical conductivity intermediate to that of a conductor
and an
insulator


This behavior is useful in in designing
computer chips

the
electrons have limitations to their movement, such as only being
allow to move in one direction or in one plane
.

Nonconductors/insulators



P
revent
the movement of electrons within the material. But they
often do allow electrons and ions to collect on their surfaces.


Examples of nonconductors or electrical insulators are:
Plastic
,
Rubber, Glass, Most metal oxides (like rust), Air, Oil, Pure
, de
-
ionized
water


Gases are not good conductors of electricity because of the
distances between atoms
.


Energy bands

Types of electricity


Common types of electricity
are:


static
electricity,


direct
current (DC)
electricity


alternating
current (AC) electricity.


Static electricity


Static electricity refers to the built up electric charge
on the surface of
objects or excess
of electric charge
(imbalance) trapped
on the surface of an object
.


Charge exchange can happen when any two surfaces
come into
contact or rubbed.



When the materials are
separated they retain this
charge imbalance.


Since opposite charges attract,
there is a tendency for the
electrons to attract toward the
positive
ions.


AC electricity


Electrons
will flow from an area of an excess negative (
-
)
charges to an area of positive (+) charges.


Alternating
current (AC) is when the electrons flow in both
directions


AC
terminals constantly switch their polarity
from (+) to (
-
) and back
again.






An AC voltage is continually changing between positive (+)
and negative (
-
).


Electrical
power grids that provide electricity to homes and
other buildings use
AC.


DC electricity


In direct current (DC, also dc), the flow of electric
charge is only in one direction. It may increases or
decreases.


Sources of
DC voltage are
include cells
, batteries and
regulated
power supply.






A DC voltage is always positive (or always negative
).


Unit Used in Electrical Quantities


Charge


Force


Work


Electric current


Electrical Potential


Power


Resistance


Conductance







Charge


The unit of charge is the Coulomb (C).


The coulomb is defined as the quantity of
electricity which flows past a given point in an
electric circuit when a current of one ampere
is maintained for one second
.


Charge, in coulombs:
Q=It


I

is the current in ampere


t

is the time in seconds


Force


The unit of force is the newton (N).


One newton is one kilogram meter per second
squared
( kg∙m∙s
-
2
)


Force, in newton:

F=ma


m

is the mass in kg


a

is the acceleration in ms
-
2

Work


The unit of work or energy is the joule (J)


Joule is defined as the work done or energy
transferred when a force of one newton is
exerted through a distance of one meter.


The work done, in joules:
W=
Fs


F
is the force in
newtons


s

is the distance in meter

Electric current


Electric
current is the
rate of charge flow past a given point in
an electric circuit
, measured in coulombs/second which is
named amperes.


In most DC electric circuits, it can be assumed that the
resistance to current flow is a constant so that the current in
the circuit is related to voltage and resistance by Ohm's law.


Electrical potential and
e.m.f
.


The unit of electric potential is the volt (V)


The potential difference indicates the flow of
electric current (from high to low)


The potential
difference is also called voltage.

Analogy

Electrical potential and
e.m.f
.

The units of the
potential
difference
is given by


Volts
= watts/amperes




=
joules/
amperes∙second


=
joules/coulombs


A device that maintains potential difference between
two points is said to develop and electromotive force
(
e.m.f
.).

Power


The unit of power is watt (W)


One watt is one joule per second


Power, in watts :

P=W
/
t


W
is the work done


t
is the time in second


DC electrical
power, in watts:
P=VI


V is the voltage across the load


I is the current flows through the load


Energy, in joules,

W=
Pt

Resistance


The unit of electric resistance is the ohm (
Ω
)


It is defined as the property of a substance due
to which it opposes the flow of electricity (or
electrons) through it.


Resistivity, in
ohms∙meter

(
Ω·
m)

:
ρ=
AR
/
l


A

is the cross section of the conductor


L
is the length of the conductor


Note that the resistance is dependent on the
nature of the material and also the temperature.

Resistance


R = 0 Ω


short circuit (large current flow)


R =


Ω


open
circuit (no current flow)






The reciprocal of resistance is called
conductance and is measured in
siemens

(S).


Conductance, in
siemens
: G=1/R


Open circuit

Short circuit

Ohm's Law for Electrical
Circuits


Ohm's

Law

states

that

in

a

simple

electrical

circuit,

the

voltage

equals

the

electrical

current

times

the

resistance
.


where
:

V

is

the

voltage

in

volts



I

is

the

current

in

amperes

or

amps


R

is

the

resistance

in

ohms


IR

is

I

times

R


V = IR

Example


How many amperes of current are in the
circuit below?


Vs

R

100 V

20 Ω

I =

Vs

R

=

Using
Ohm’s

law:

100 V

20 Ω

=

5 A

Examples

1
. An electric bulb uses 0.5 A of current with
voltage generated being 120 V. Determine the
value of resistance.


2
. If a current of 0.5 A flows through resistor of
15 Ω, calculate the voltage drop across the
resistor.


1.
Ans
; R = V/I = 120/0.5 = 240
Ω

2. Ans; V = IR = 0.5 x 15 = 7.5 V

Examples

3
. (
i
) For the circuit shown,
determine current flowing and
power absorbed by the resistor
if the resistance is 1


and
voltage across it is 10 V

(
ii) If the current flowing
through the circuit is 3A and
power absorbed is 72 W,
determine the resistor value
and voltage across it.

DC Power


The electric power in watts
represents
the rate
at which energy is converted from the electrical
energy of the moving charges to some other
form, e.g., heat, mechanical energy, or energy
stored in electric fields or magnetic fields.


For
a resistor in a
DC circuit,
the power is given
by the product of applied voltage and the
electric current :



Power (watts) = Voltage (volts) x Current (amperes)


P = VI

DC Power


Although the unit of energy is the joule
(
W=
Pt
)
, when dealing with large amounts of
energy, the unit used is the kilowatt hour
(kWh) where
:


1kWh = 1000 watt hour



= 1000 X 3600
wat

seconds (or joules)



= 3 600 000 J

Electricity Bill =
E
lectricity (kWh
) x
tariff rates (
sen
/kWh)

Calculating your electric
bill

Computer : 500 watts (12
hours usage)

TV : 400 watts (5
hours
usage
)

Lighting : 3
units x
15 watt = 45 watts (6
hours
usage
)

Others : 100 watts (2
hours
usage
)

Power consumed :

(500 x 12) + (400 x 5) + (45 x 6) + (100 x 2) = 8470
wh

= 8.47kWh

Electricity
bill per month :

8.47
kWh x RM 0.218/kWh x 30 =
RM 55.50

Summary of terms, units and symbols