4. A conductor is something which allows electricity to flow
through.
An example of a conductor is:
Scissors
Paper clip
Aluminum foil
Iron
Steel
Copper
5. In physics and electrical engineering, a conductor is an
object or type of material that allows the flow of an
electrical current in one or more directions..
A metal wire is a common electrical conductor.
Electrical current is generated by the flow of negatively
charged electrons, positively charged holes, and positive or
negative ions in some cases.
6. Conduction materials include metals, electrolytes , superconductors ,
semiconductors, plasmas and some nonmetallic conductors such as graphite
and conductive polymers
Silver is more ‘conductive’ than copper, but due to cost it is not practical in
most cases. However, it is used in specialized equipment, such as satellites, and
as a thin plating to mitigate skin effect losses at high frequencies.
Copper has a high conductivity. Annealed copper is the international standard to
which all other electrical conductors are compared.
Aluminum wire, which has 61% of the conductivity of copper, has been used in
building wiring for its lower cost. By weight, aluminum has higher conductivity
than copper, but it has properties that cause problems when used for building
wiring. It can form a resistive oxide within connections that makes wiring
terminals heat. Aluminum can "creep", slowly deforming under load, eventually
causing
7.
8.
9.
10. An electrical insulator is a material whose internal electric charges do not flow
freely, and therefore make it nearly impossible to conduct an electric current under
the influence of an electric field.
The property that distinguishes an insulator is its resistivity insulators have higher
resistivity than semiconductors or conductors.
All insulators become electrically conductive when a sufficiently large voltage is
applied that the electric field tears electrons away from the atoms.
This is known as the breakdown voltage of an insulator.
Some materials such as glass, paper and Teflon which have high resistivity are very
good electrical insulators.
Insulators are used in electrical equipment to support and separate
electrical conductors without allowing current through themselves.
11. Insulators used for high-voltage power transmission are made
from glass , porcelain or composite polymer materials
Porcelain insulators are made from clay
, quartz or alumina and feldspar , and are covered with a
smooth glaze to shed water.
Insulators made from porcelain rich in alumina are used where
high mechanical strength is a criterion.
Porcelain has a dielectric strength of about 4–10 kV/mm.
Glass has a higher dielectric strength, but it attracts
condensation and the thick irregular shapes needed for
insulators are difficult to cast without internal strains.
Some insulator manufacturers stopped making glass insulators
in the late 1960s, switching to ceramic materials.
12. PIN TYPE INSULATOR
POST INSULATOR
SUSPENSION INSULATOR
STRAIN INSULATOR
SHACKLE INSULATOR
13.
14. As the name suggests, the pin type insulator is mounted on a pin on
the cross-arm on the pole.
There is a groove on the upper end of the insulator.
The conductor passes through this groove and is tied to the insulator
with annealed wire of the same material as the conductor.
Pin type insulators are used for transmission and distribution of
communications, and electric power at voltages up to 33 kV.
Insulators made for operating voltages between 33kV and 69kV tend
to be very bulky and have become uneconomical in recent years.
15.
16.
17. For voltages greater than 33 kV, it is a usual
practice to use suspension type insulators,
consisting of a number of glass or porcelain discs
connected in series by metal links in the form of a
string.
The conductor is suspended at the bottom end of
this string while the top end is secured to the cross-
arm of the tower.
The number of disc units used depends on the
voltage.
18.
19. A dead end or anchor pole or tower is used where a straight section
of line ends, or angles off in another direction. These poles must
withstand the lateral (horizontal) tension of the long straight section
of wire. In order to support this lateral load, strain insulators are
used. For low voltage lines (less than 11 kV), shackle insulators are
used as strain insulators. However, for high voltage transmission
lines, strings of cap-and-pin (suspension) insulators are used,
attached to the cross arm in a horizontal direction. When the tension
load in lines is exceedingly high, such as at long river spans, two or
more strings are used in parallel.
20.
21. In early days, the shackle insulators were used as
strain insulators. But now a day, they are frequently
used for low voltage distribution lines. Such
insulators can be used either in a horizontal
position or in a vertical position. They can be
directly fixed to the pole with a bolt or to the cross
arm.
22. Here we discussed about conductors and insulators
Studied about different types conductors
◦ Silver
◦ Copper
◦ Aluminum
Studied about different types of insulators
◦ Pin type insulator
◦ Post insulator
◦ Suspension insulator
◦ Strain insulator
◦ Shackle insulator
