Giáo trình Tiếng Anh chuyên ngành - Điện công nghiệp
TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Unit 1: ELECTRICAL MATERIALS
A. Conducting Materials
Conducting materials are classified as low resistivity materials and high resistivity materials.
Low resistivity materials: The conducting materials having resistivity between 10-8 to 10-
6 ohm-m come under this category and are used in transmission and distribution
lines, transformers and motor windings such as copper, aluminium, steel, …
aluminium
steel
Copper
Properties:
a) Low temperature coefficient: For minimum variations in voltage drop and power loss
with the change in temperature, these materials should have low temperature coefficient.
b) Sufficient mechanical strength: These materials must withstand the mechanical stresses
developed during its use for particular applications.
c) Ductility: The material to be used for conductors must be ductile so that it can be drawn
and moulded into different sizes and shapes.
d) Solderability: The conducting materials are required to be joined and the joint must have
minimum contact resistance. These materials must have a good solderability.
e) Resistance to corrosion: The material should have a high resistance to corrosion so that it
should not be corroded when used in different environmental conditions.
High resistivity materials: The conducting materials having resistivity between 10-6 to 10-3
ohm-m come under this category and are used for making resistance elements for
heating devices, precision instruments, rheostats etc such as manganin, nichrome, mercury,
platinum, carbon and tungsten, …
mercury
manganin
Properties:
nichrome
a) Low temperature coefficient: For minimum variations in voltage drop and power loss
with the change in temperature, these materials should have low temperature coefficient.
b) High melting point: These materials, which are used as heating elements should have
high melting point.
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
c) Ductility: The material to be used for conductors must be ductile so that it can be drawn
and moulded into different sizes and shapes.
d) Oxidation resistance: The material should have a high oxidation resistance so that it
should get oxidised when used in different environmental conditions.
e) High mechanical strength: These materials must withstand the mechanical stresses developed
during its use for particular applications.
B. Semiconducting Materials
These are the materials, which possess the electrical resistivity in between that of
conductors and insulators. They are used for the manufacture of diodes and
transistors. Also the number of valence electrons is equal to four. There is a small forbidden
energy gap of about 1eV between the conduction and the valence band. Examples:
germanium, silicon, selenium, etc.
silicon
germanium
Properties:
Substances like carbon, silicon, germanium whose electrical conductivity lies in
between the conductors and insulators are known as semiconductors. The valence
band of these substances is almost filled, but the conduction band is almost empty.
The forbidden energy gap between valence and conduction band is very small (1ev).
Therefore comparatively a smaller electric field is required to push the valence
electrons to the conduction band. This is the reason, why such materials under
ordinary conditions do not conduct current and behaves as an insulator. Even at room
temperature, when some heat energy is imparted to the valence electrons, a few of them
cross over to the conduction band imparting minor conductivity to the semiconductors. As
the temperature is increased, more valence electrons cross over to the conduction band and
the conductivity of the material increases. Thus these materials have negative
temperature co-efficient of resistance.
C. Insulating Materials
These are the materials, which do not allow the current to pass through them
without any appreciable loss. They have very high electrical resistance and are also available
in a large variety to cover different applications. Some of the specific insulating materials
are used for the purpose of storing of an electrical energy and are called dielectric materials
such as mica, ceramic, paper etc. These materials are used as a dielectric in capacitors. Also
the number of valence electrons is more than four. The energy gap between valence
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
and conduction band is very large (more than 5-6 eV). Examples: Mica, rubber, ceramics,
glass, diamond etc.
ceramics
glass
mica
D. Plastic materials
Plastic materials can be classified into thermoplastic and thermosetting plastics.
Thermoplastic materials:
The properties of these plastic materials do not change considerably if they are
melted and then cooled and solidify. They can be repeatedly melted or dissolved in various
solvents. They are more elastic, less brittle and do not lose elasticity when subjected to
prolonged heating. They are less apt to age thermally. They can be remoulded again
and again in any shape after heating. Many of them possess extraordinary high insulating
properties and are water repellent. They are polymers of linear structure, i.e. their molecules
are elongated and are thread like. This, type of structure is fusible, soluble, highly
plastic, capable of forming thin flexible threads and films. Examples are Polytetra
Flouroethylene (P.T.F.E. or Teflon), Polyvinyl Chloride (P.V.C.).
Thermosetting Plastic Materials:
They undergo great changes when subjected to high temperatures for quite
sometimes. They are said to be baked and no longer can melt or be dissolved. They are
less elastic, more brittle and lose their elasticity when subjected to prolonged heating.
So they cannot be remoulded in different shapes once they are set and hardened.
They are used, when an insulation is to withstand high temperatures without melting
or losing its shape and mechanical strength. Thermosetting plastic substances are
space-polymers and the molecules branch off in various directions during
polymerisation.
Examples of the natural insulating materials are cotton, rubber, wood, mica.
Rubber
cotton
wood
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
E. Magnetic Materials
Soft magnetic materials:
They have small enclosed area of hysteresis loop, high permeability, high
saturation value, low eddy current losses which are achieved by using laminated
cores, less residual magnetism. Soft magnetic materials retain their magnetism as long as
they are energised by an external magnetic field; Example: Alpha iron, super
permalloy (Ni-Fe-Mo), silicon ferrite. Soft magnetic materials are used for the
construction of cores for electrical machines, transformers, electromagnets reactors and
cores of audio frequency couplings and matching transformers in telecommunication.
Hard Magnetic materials:
They have a gradually rising magnetization curve with large hysteresis loop area and
hence large energy losses. They have high value of retentivity and high value of coercivity
and low permeability. To saturate the hard magnetic materials, a high magnetizing
force is required. Hard magnetic materials have the property of retaining their magnetism
even after the magnetising field is removed. Example: Alnico (Al-Ni-Co), Cobalt DE04
steel and retaining the same for a long time. Due to this property they are used in
the manufacture of permanent magnets.
F. Special Materials
Each of the special materials described below has a definite game effect. Some
creatures have damage reduction based on their creature type or core concept. Some are
resistant to all but a special type of damage, such as that dealt by evil-aligned weapons or
bludgeoning weapons. Others are vulnerable to weapons of a particular material. Characters
may choose to carry several different types of weapons, depending upon the campaign and
types of creatures they most commonly encounter.
Adamantine: This ultrahard metal adds to the quality of a weapon or suit of armor.
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Unit 2: ELECTRIC EQUIPMENT
Heat pump
Lightning arrester
Sockets and switch
Magnetic starter
Microwave oven
Circuit breaker
Electrical system
Oxygen generator
controller
Overload protector
Actuator
Thermal relay
Auto- starter
Automatic vacuum pump
Dispenser
Amplifier
Fuse
Electric cable
Electric pipeline
Relay
Ceiling roses
Synchronous machine
Alarm bell
Surge arrester
Lightning arrester
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Three phase circuit breaker
Step- down transformer
Stepless transformer
Universal electricmeter
Cable ladder
Magnetic contactor
Voltage regulator
Underground cable
Power capacitor
PLC programmer
Cable tray
Force sensor
Frequency converter Bolt, nut and washes
Hand drill
Insulated pliers
Hydraulic pump
Spanner
Adjustable wrench
Screwdriver
Synchronous generator
Magnetic brake
clutch
Gear box
Gear motor
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Medium voltage fuses
Busbar
Central control box
Ceramic insulator
Disconnect switch
Band conveyor
Electric fan
Electric iron
Electric cooker
Pressure cooker
Light bulb
Flourescent tube
Oil- immersed transformer
Resistor
Rheostat
Varistor
Dry- type transformer Current transformer
Ammeter
Voltmeter
Wattmeter
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Unit 3: TEST AND REPAIR INSTRUMENT
1. General Safety Considerations
It is SLAC policy to comply with Occupational Safety and Health Administration
(OSHA) regulations, the National Electrical Code (NEC), and other established safety
standards to reduce or eliminate the dangers associated with the use of electrical energy.
Every person on the SLAC site is exposed to electricity to some extent. The SLAC electrical
safety program provides the SLAC community with the minimum knowledge of safety and
recommended practices necessary to protect against electrical shock or burns. The electrical
safety program also provides hazard awareness information to those who use electrical
equipment.
All electrical wiring and equipment must comply with NEC, OSHA regulations, and
numerous other established safety and engineering standards. This chapter should not be
construed as a synopsis of all electrical requirements or as a substitute for formal study,
training, and experience in electrical design, construction, and maintenance.
2. Some electronic equipment used to test and repair
Digital voltmeter checking a prototype
The following items are used for basic
measurement of voltages, currents, and components
in the circuit under test.
e.g.,
VOM
(Volt-Ohm-
Milliameter) or DMM (Digital Multimeter)
(Measures all of the above)
The following are used for stimulus of the circuit under test:
The following analyze the response of the circuit under test:
And connecting it all together:
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Advanced or less commonly used equipment
Meters
A multimeter with a built in clamp facility.
Pushing the large button at the bottom
opens the lower jaw of the clamp, allowing
the clamp to be placed around a conductor
(wire).
Howard piA digital multimeter
Solenoid voltmeter (Wiggy)
Clamp meter (current transducer)
Wheatstone bridge (Precisely measures resistance)
Capacitance meter (Measures capacitance)
LCR meter (Measures inductance, capacitance, resistance and combinations thereof)
EMF Meter (Measures Electric and Magnetic Fields)
Electrometer (Measures charge)
Probes
RF probe
Signal tracer
Analyzers
Logic analyzer (Tests digital circuits)
Spectrum analyzer (SA) (Measures spectral energy of signals)
Protocol analyzer (Tests functionality, performance and conformance of protocols)
Vector signal analyzer (VSA) (Like the SA but it can also perform many more useful
digital demodulation functions)
Time-domain reflectometer (Tests integrity of long cables)
Semiconductor curve tracer
Signal-generating devices
Signal generator
Frequency synthesiser
Function generator
Digital pattern generator
Pulse generator
Signal injector
Leader Instruments LSG-15 signal
generator
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Miscellaneous devices
Continuity tester
Cable tester
Test light
Transistor tester
Tube tester
Hipot tester
Network
characterize
complete computer networks)
3. Some kinds of test
analyzer (used to
Electrical tester pen
Receptacle tester
components or
Electrical testing can be taken in situations (mostly low voltage, ie not exceeding 1000
V ac or 1500 V dc) where equipment like domestic appliances is being tested. Most of this
equipment will be used on mains supply voltages of 230 V ac single phase and 400 V ac
three phase.
Check and Inspection of some specific equipment:
Check and Inspection
Item
Acceptance
Criteria
No
Steps
1.1 2.2KV 1. Basic
Switch Inspection
- Fill out the check list
IFC DWG
Gear
2. Insulation
- 6000V Megger for main circuit 200m
( with circuit breaker )
Resistance Test
- 500V Megger for control circuit
5m
( phase to earth with remain
phase)
3. High Voltage
Test
DC 38KV for 1 min-phase to
earth with remain phases
- To be carried out on SWGR
busbar connection and earth
system joints. And bolt torque to
be as per V/D requirement
- All features switchboard
function as intended to be
demonstrated by power
to withstand
4. Conductivity
Test
less than
200%
5. Function Test
6. Relay Test
IFC DWG
All protection relay be tested at
the normal setting to verify their
operation parameters, with
secondary injection.
approved
relay setting
and curves
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
- Protection Relay Check
- Stap setting as per Samsung
Setting Record
- Tripping time setting as per
Samsung Setting Record
- Traveling Time at selected
T/D tap
- Verify the operation of the
switching devices tripping
mechnism and all alams and
intertrips.
7. Phase Rotation - Disconnect 22KV cable and
Clock Wire
Test
apply 400V 3
+ Phase temp: power, and check
phases
- Rotation All terminals
to be carried out on diff . Relay
CTs before Function Test
8. CT Polarity
Check
same as V/D
drawing
2.1 22KV
cable
1. Basic
- Fill out the check list
IFC DWG
Inspection
2.2 22KV
cable
2. Insulation
Resistance Test
and Continuiry
- 5000V Megger for phase to
earth with remain phases
200M
DC 30.4KV for 1 min-phase to
earth with remain phases (cable to
be disconnected )
3. High Voltage
Test
to withstand
3.1 22/6.6 1. Basic
KV
Inspection
- Fill out the check list
IFC DWG
75 M
TR
2.Insulation
Resistance Test
5000V Megger for primary
( oil
Immer
sed )
2500V Megger for secondary
1. Times Measurement
Fill out the check list
75M
3.Oil Test
30KV/2.5mm
IFC DWG
4. Function Test
4.1 22kv/4 1. Basic
00V
TR (
oil
Inspection
Fill out the check list
IFC DWG
75 M
2.Insulation
Resistance Test
3.Oil Test
5000V Megger for primary
500V Megger for secondary
1. Times Measurement
Fill out the check list
75 M
Immer
sed
30KV/2.5mm
IFC DWG
IFC DWG
4. Function Test
5.1 6.6KV. 1. Basic
Fill out the check list
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
SWGR Inspection
2.Insulation
2500V Megger for main circuit (
Resistance Test
with circuit breaker )
500V Megger for control circuit (
phase to earth with remain
phases)
200M
5M
3. High Voltage DC 16.5KV for 1 min- phase to to withstand
Test
Earth with remain phases (
voltage transformer and load to be
disconnected)
4. Conductivity to be carried out on SWGR less than 20%
Test
busbar
Connection and earth
system joint. And bolt Torque to
be as per V/D requirement.
All features of switchboard
function as Intended to be
demonstrated by temp power
All protection relays shall be
tested at the normal setting to
verify their operation parameters,
with secondary
5.Function Test
6.Relay Test
IFC DWG
injection.
1- Protection Relay Check
- Stap setting as per Samsung
Setting Record
- Tripping Time Setting as per
samsung Setting Record
- Travelling time at selected
T/D and Tap
- Verify the operation of the
switching devices tripping
mechnism and all alarms and
intertrips
7. Phase Rotation Disconnect 22Kv cable and
clock wise
Test
apply 400V 3Phase temp: power,
and check phases
Rotation All Terminals
8. CT Polarity to be carried out on diff . Relay
Check CTs before Function Test
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Unit 4: SAFETY IN INDUSTRIAL ELECTRICAL APPLICATION
1. The cause and effect of accident in electric field
Electrical injuries can be caused by a wide range of voltages but the risk of injury is
generally greater with higher voltages and is dependent upon individual circumstances. Torch
batteries can ignite flammable substances.
Alternating current (AC) and Direct Current (DC) electrical supplies can cause a range of
injuries including:
Electrical burns
Electric shock
A voltage as low as 50 volts applied
between two parts of the human body
causes a current to flow that can block the
electrical signals between the brain and
the muscles. This may have a number of
effects including:
Stopping the heart beating properly
Preventing the person from breathing
Causing muscle spasms
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The exact effect is dependent upon a large number of things including the size of the voltage,
which parts of the body are involved, how damp the person is, and the length of time the
current flows.
Electric shocks from static electricity such as those experienced when getting out of a car or
walking across a man-made carpet can be at more than 10,000 volts, but the current flows for
such a short time that there is no dangerous effect on a person. However, static electricity can
cause a fire or explosion where there is an explosive atmosphere (such as in a paint spray
booth).
Electrical burns
When an electrical current passes through the
human body it heats the tissue along the length of
the current flow. This can result in deep burns that
often require major surgery and are permanently
disabling. Burns are more common with higher
voltages but may occur from domestic electricity
supplies if the current flows for more than a few
fractions of a second.
Thermal burns
Overloaded, faulty, incorrectly maintained, or
shorted electrical equipment can get very hot,
and some electrical equipment gets hot in normal
operation. Even low voltage batteries (such as
those in motor vehicles) can get hot and may
explode if they are shorted out.
People can receive thermal burns if they get too near hot surfaces or if they are near an
electrical explosion. Other injuries may result if the person pulls quickly away from hot
surfaces whilst working at height or if they then accidentally touch nearby machinery.
A single low voltage torch battery can generate a spark powerful enough to cause a fire or
explosion in an explosive atmosphere such as in a paint spray booth, near fuel tanks, in
sumps, or many places where aerosols, vapours, mists, gases, or dusts exist.
a. Safety equipments
Personal protective equipment (PPE)
Personal protective equipment (PPE) is clothing, equipment or substances designed to
be worn by someone to protect them from risks of injury or illness.
PPE should only be considered as a control measure when exposure to a risk cannot be
minimised in another way, or when used in conjunction with other control measures as a
final barrier between the worker and the hazard. PPE does not control the hazard at the
source. PPE can include:
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Ey
Hearing protective
devices, such as ear
muffs and ear plugs
e and face protection, such as goggles
Respirators
Safety helmets and sun
hats
Safety boots
Gloves
High visibility vest
Life jackets
2. The methods of advoiding accidents
→ Equipment must be locked
out and tagged out before
preventive maintenance or
servicing is performed.
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
A variety of possible solutions may be implemented
to reduce or eliminate the risk of injury associated
with electrical work. Examples of solutions include
the use of insulation, guarding, grounding, electrical
protective devices, and safe work practices.
→
Lockout devices are
available in various shapes
and sizes that allow for the
lockout of standard control
devices.
→ Lockout/tagout kits comply
with OSHA lockout/tagout
standards.
→ Clothing should fit snugly
to avoid danger of becoming
entangled
in
moving
machinery or creating a
tripping or stumbling hazard.
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
→ Always use the correct fire
Extinguisher for the class of
fire.
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
The use of electrical equipment can create serious health and safety risks in the hairdressing,
nail and beauty industry, particularly in wet conditions. Damage to equipment increases this
risk. Electrical shock can result in electrocution, burns and injuries from falls.
Extension leads and flexible cables must be protected from damage, including from liquid.
Electrical equipment must be either:
inspected, tested and tagged or
connected to a residual current device (RCD).
Inspecting, testing and tagging by a competent person
A competent person must inspect, test and attach
a durable tag to the equipment every 12 months.
If the equipment is safe to use, the tag must show
the date by which the equipment must be
inspected and tested again;
If the equipment is not safe to use, the tag must
warn people not to use the equipment.
The equipment must also be immediately
withdrawn from use.
Residual current device (RCD)
If the equipment is to be connected to an RCD,
(known as a safety switch), the device may be
either portable, or installed at the switchboard.
An RCD must be tested immediately after
connection and at least every 3 months.
A competent person must also test the device
at least every 2 years.
If a portable RCD is not working properly, it
must be tagged to warn people not to use the
device and immediately withdrawn from use.
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Employ a competent person
You are encouraged to employ an
electrician to perform these tasks to ensure
electrical equipment is safely maintained.
The advantage of using an electrician is
that if the equipment is faulty, the
electrician is licensed to repair it.
Control measures
Substitution
Use splash proof or waterproof electrical equipment instead of standard equipment if
work must be carried out in wet conditions.
Use power boards instead of double adaptors.
waterproof electrical equipment
power boards
Redesign
Install additional socket outlets to avoid overloading power outlets.
Administrative controls
Make sure workers are trained in the use of equipment and that manufacturer’s
instructions are followed.
Store and operate equipment away from damp areas when not in use.
Make sure leads do not run across wet surfaces or any place where they may be easily
damaged.
Run leads along the edges of corridors to minimise the possibility of trips and falls.
Keep leads away from heat, oil and chemicals to prevent insulation damage.
Clean up liquid spills as soon as possible.
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TIẾNG ANH CHUYÊN NGÀNH ĐIỆN CÔNG NGHIỆP
Conduct regular (monthly intervals or more frequently if necessary) visual inspections
of equipment to check that the equipment (including accessories, connecting lead and
plug) has no obvious external damage or inadequate temporary repairs.
Make a list containing the description, make and serial number of all equipment and
the date when tested to assist you in ensuring all electrical items are tested.
When adjusting or cleaning equipment, SWITCH OFF the power and pull out the plug
¿ NOT by the cord.
Do not touch equipment with wet hands or use a wet cloth to clean sockets.
Make sure flexible cords are fully unwound and kept clear of work traffic.
Do not run too many pieces of equipment from one socket.
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