WP related to electric machines shop

1. WORKSHOP PRACTICE
Electric shop
Types of cables
Dr. Aneela Wakeel
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2. Electric cables
Electrical cables are the group of wires in a single sheath. cables are
used to carry electrical energy from one point to another point. A wire
is a single conductor, while a cable is defined as a group of
individual insulated wires conductors encased together in a single
sheath. Wires and cables can be made from various materials such as
copper, aluminum, gold, etc.
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3. Electric cable
The cable that is used for the transmission and distribution of
electrical power is known as the electrical power cable.
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The power cable is made of three
main components, namely,
conductor, dielectric, and
sheath. The conducting path for
the current in the cable is
provided by the conductor. The
insulation or dielectric withstands
the service voltage and isolates
the live conductor with other
objects. The sheath does not
allow the moistures to enter and
protects the cables from all
external influences like chemical
or electrochemical attacks and
fire.

4. PROPERTIES
Electric Properties:
- dielectric strength
- insulation resistance
- insulation power factors
Mechanical Properties:
- toughness and flexibility
- tensile, elongation and crushing strengths
- resistance to abrasion or moisture
-Brittleness
Chemical Properties:
- moisture absorption
- resistance to oil, gas, acids and alkalis
-stability when exposed to sunlight, ozone, or flames
Thermal Properties:
- expansion and contraction
- softening and flow temperature
- compatibility with operating, ambient, or emergency overload and
short circuit conditions
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5. CONDUCTOR
MATERIALS
Copper
•The principal electrical conductor due to its excellent conductivity and
reasonable cost.
Aluminum
• Aluminum has 62% of copper conductivity but just 30% weight of
copper. Used in power cables, overhead (ACSR-Aluminium-conductor
steel-reinforced cable), and some building wire.
Copper weld
•A thin coating of copper fused to a steel core. Used in line wire, cable
messengers and stranded with copper for strength or extending flex
life.
Alum weld
•A thin coating of aluminum fused to a steel core. Used in line wire
and cable messengers.
Tinsel
•Flat ribbons of bronze, silver, or copper alloy spiraled around a textile
core of cotton, nylon, etc. Used in telephone and electronics
applications as conductors in line cords, microphone cords.
Thermocouple
•Special matched Alloy Conductors. Used in temperature measuring
applications
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6. TYPES OF CABLES
Coaxial Cable: Coaxial cable is made up of a copper conductor surrounded
by a layer of flexible insulation. This consists of solid copper or steel
conductor plated with copper which is enclosed in the metallic braid and
metallic tape. This is entirely covered with an insulated protective outer
jacket. These types of cables are used for computer networking and audio-
video networking.
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7. Electric cables
Unshielded Twisted Pair(STP)
UTP is a four-pair wire
medium used in a variety of
networks. Each of the eight
copper wires in the UTP cable
is covered by insulating
material. In addition, each pair
of wires is twisted around each
other.
Shielded Twisted Pair (UTP)
STP cable uses cancellation,
shielding, and twisted
wires. Each pair of wires is
wrapped in metallic foil and
those four pairs of wires are
wrapped in an overall
metallic foil.
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8. Differences
UTP
• In UTP, speed offered is about
10 to up to 1000 Mbps.
• It is used for data transmission
within short distance such as for
home and office networks
• Electromagnetic interference is
more in Unshielded Twisted
Pair cable compared to Shielded
Twisted Pair cable.
Usage-
• Telephone wiring
• Local Area Networks and more.
STP
• While in STP speed offered is
about 10 to up to 100 Mbps.
• Generally used for connecting
organizations over a long
distance.
• STP cable reduces
Electromagnetic interference
because of the protective sheath.
• Used in frigid temperatures.
• Used in case of lot of heat
generation like for heavy
industrial applications.
• Employed under high radiation
conditions and more.
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9. ARMORED CABLE
An armoured cable has an extra protective layer of twisted metallic layer of
steel. These steel layers provide extra mechanical strength to the cable. It allows
these cables to work in harsh conditions and prevent any sort of damage.
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10. CONTROL CABLE
Control Cable is a flexible instrumentation cable
designed for measuring, control or regulation in the
field of process automation. It is a highly
flexible multicore cable, with (class
5) copper conductors and a galvanised steel wire
braid (GSWB) for mechanical protection. The cable
is typically manufactured with PVC insulation,
bedding and a transparent PVC sheath. The
transparent sheath means signs of deterioration,
damage or corrosion can be detected with ease.
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11. TELEPHONE CABLE
As the name suggests it
used in telephones. It
consists of a thin copper
conductor surrounded by
insulation. One
telephone cable contains
three to four of these
conductors.
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12. Fiber Optic Cable
Fiber Optic Cable is also known as the Optical Fiber
Cable. It is made up of plastic or glass. It transmits
signals in the form of light. There are 3 basic
components of the optical transmission system which
are as follows:
• Light source
• Transmission media (fiber optics)
• Detector
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13. FIBER OPTIC
Data Carrier
• It carries data in the form of light.
Bandwidth
• It offers higher bandwidth.
Structure
• It is thin, lighter in weight and smaller
in size.
Environment
• It can be laid in different environment
because it is more resistant to
corrosive materials.
Attenuation
• Attenuation is very low.
Interface
• As in this data travel in the form of
light, they are not affected by electrical
and magnetic interface.
COPPER CABLE
• Data Carrier
It carries data in the form of electric
signals.
Bandwidth
• It offers lower bandwidth.
Structure
• It is heavier and thicker.
Environment
• It cannot be laid in different
environment because it is more prone
to corrosive materials.
Attenuation
• Attenuation is high.
Interface
• As in this data travel in the form of
electric signals, they are affected by
electrical and magnetic interface. 13

14. thermocouple
• A Thermocouple is a device used for the measurement
of temperature.
• It can be even considered as a sensor for the
measurement of temperature. The main principles that
governs the operation of thermocouple are SEEBECK
EFFECT
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15. SEEBECK Effect
• The working principle of a
thermocouple follows the
Seebeck effect, or
thermoelectric effect, which
refers to the process in which
thermal energy is converted
into electrical energy. The
effect describes the electrical
voltage that occurs when two
different conductors are
connected, and how the
voltage produced varies with
temperature.
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16. Seebeck effect
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17. • The basic design of a thermocouple involves two dissimilar metal wires,
each with different electrical properties at different temperatures. The
two metals are in contact – touching, twisted, or welded – at one end;
this is the measuring point. At the other end is the connection point, so
called because it connects to the voltage reader. When the temperature
changes at the measuring point, so does the electron density of each
metal wire. This varying electron density is the voltage, which is
measured at the connection point.
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18. Thermocouple working
Note that thermocouples do not actually measure the absolute temperature.
Instead, they measure the differential temperature between the measuring point
and the connection point. That’s why thermocouples also need a cold junction
compensation, which ensures that the ambient temperature at the connection
terminals of the cold junction does not alter the measuring result, thus allowing
for more accurate readings.
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19. TYPES OF THERMOCOUPLES
TYPE E
TYPE J
TYPE K
TYPE M
TYPE N
TYPE T
TYPE B
TYPE R
TYPE S
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20. Type E Thermocouple
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Constantan is a proprietary name for a copper–nickel alloy also known as Eureka, Advance, and Ferry. It usually
consists of 55% copper and 45% nickel.

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22. TYPE-K
Type K thermocouples usually work in most applications as they are
nickel based and exhibit good corrosion resistance. It is the most
common sensor calibration type providing the widest operating
temperature range. This type of thermocouple should be protected with
a suitable metal or ceramic protection tube, especially in reducing
atmospheres. In oxidizing atmospheres, such as electric furnaces, tube
protection is not always necessary when other conditions are suitable;
however, it is recommended for cleanliness and general mechanical
protection.
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26. Official Email Id
aneela.wakeel@uettaxila.edu.pk
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