Presentation on Electric arc

1. Electric
Arc
BY
ATOMIC REACTORS

2. GROUP MEMBERS
1. A. N. M. JuBaer-162-15-7850
2. Muhammad Moinul Islam-162-15-7779
3. Md. Mostafizur Rahman- 162-15-7764
4. Shahabuddin Emon-162-15-7789
5. Mahedi Hasan Niloy-162-15-7763
6. Ashiqur Rahman-162-15-7723
7. Shovon Ahammed-162-15-7671
8. Tanvir Hossen Bappy-162-15-7706

3. • What is Electric Arc?
• History of Electric Arc
• Arc Construction
• Electrical Conductivity In Gases
• Uses of Electric Arc
• Undesired Arcing
• Advantages of Electric Arc &
Environmental Issues
• Arc Suppression

4. WHAT IS ELECTRIC
ARC?
?????

5. Electric arc is a breakdown of electrons of a gas that produces
lights. Currents passes through a nonconductive medium like air
produces plasma , plasma produces visible lights. This happens
between two electrodes separated by a small gap. If voltage and
current reaches the level of arc voltage and arc current then it
will create an electric arc. In nature this happens as lightning.
With proper system electric arc can be used for welding, plasma
cutting and even certain types of lighting such as fluorescent
lighting where a high voltage ionizes the inert gas within a glass
tube; the flow of current across the ionized gas liberates visible
light.

6. MUHAMMAD MOINUL ISLAM
ID 162-15-7779

7. HISTORY OF ELECTRIC ARC
>> The arc discharge phenomenon was described in
1802,as a “special fluid with electrical properties” ,by Vasily
V. Petrov.
>> Sir Humphry Davy first demonstranted the arc early in
the nineteenth century by transmitting an electric current
through two touching carbon rods and then pulling them a
short distance apart .He is credited with naming the arc.
>> Sumio lijima and Bethune reported in 1993 that an arc
discharge with a cathode containing metal catalysts(such as
cobalt , iron or nickel)mixed to graphite powder results in a
deposit containing SWNTs.

8. ARC WELDING
>> The electric arc was discovered by sir Humphry Davy in
1808.
>> N.G. Slavianoffand C.L. Coffin developed metal
electrodes in the late 1800’s.
>> Around 1900, A.P Strohmenger stabilized the arc with
coated metal electrodes
>> In 1919, C. J. Holslag invented AC welding.
ARC FURNACES
>> The first electric arc furnaces were developed by Paul
Heroult , of France, with a commercial plant established in
the United States in 1907.
>> The Sanderson brothers formed the Sanderson Brothers
steel Co.in Syracuse, New York , installing the first electric

9. MD.MOSTAFIZUR RAHMAN
ID:162-15-
7764
DAFFODIL INTERNATIONAL UNIVERSITY

10. ELECTRIC ARC CONSTRUCTION

11. In an electric arc, the energy
needed to produce ionization
comes from an external
source, such as an electric
generator. An intense stream
of electrons flows into the
cathode and then across the
gas-filled gap to the anode.
As these electrons pass
through the gas, they cause
ionization. For ionization the
potential difference 25000v
between anode and
cathode.for this potential
difference an electric arc
created.

12. Various types of electric arcs differ from each other in two
respects: the pressure at which they operate and the
materials of which they are made. Electric arcs can be
enclosed in glass or plastic containers from which air has
been pumped out (vacuum arcs) or to which air or some
other gas has been added (high pressure arcs). The light
produced by an arc depends both on the material from
which the electrodes are made and on the gas that
separates them. Some electrodes have no function other
than to conduct an electric current into and out of the arc.
Other electrodes are chosen because they tend to vaporize
when the arc is used, changing the discharge that is
produced. Various gases are chosen for use in electric arcs
because they too affect the discharges produced. For
instance, each chemical element produces its own
characteristic color when ionized. For every gas, some
minimum amount of energy is needed produced arc.

13. MD.SHAHBUDDIN
EMON
ID:162-15-7789

14. ELECTRICAL CONDUCTIVITY IN
GASES

15. WHAT IS IT?
• We know arc means electron pass in gasses. So
gases should be good
• Conductivity of electricity. Gases consist of
neutral molecules, and are, therefore, good
insulators. Yet under certain conditions, a
breakdown of the insulating property occurs,
and current can pass through the gas.

16. HOW IT WORKS?
• In order to conduct electricity, two conditions are required. First, the
normally neutral gas must create charges or accept them from external
sources, or both. Second, an electric field should exist to produce the
directional motion of the charges. A charged atom or molecule, or ion, can
be positive or negative; electrons are negative charges. In electrical
devices, an electric field is produced between two electrodes, called anode
and cathode, made of conducting materials. The process of changing a
neutral atom or molecule into an ion is called ionization. Ionized gas is
called plasma. Conduction in gases is distinguished from conduction in
solids and liquids in that the gases play an active role in the process. The
gas not only permits free charges to pass though, but itself may produce
charges. Cumulative ionization occurs when the original electron and its
offspring gain enough energy, so each can produce another electron. When
the process is repeated over and over, the resulting process is called an
avalanche.

17. USE OF ARC
MAHEDI HASAN NILOY-162-15-7763

18. Many types of arcs exist, each with its own
applications. For example, arc welders are used for
welding (where a metal is fused and added in a
joint). In some cases, the arc's only function is to
supply heat.. Plasma torches are used for cutting,
spraying, and gas heating. Plasma is a term used for
hot, ionized gases. Cutting a metal with a plasma
torch may be done by means of an arc formed
between the metal itself and an electrode from the
torch.

19. Electric arcs are often used as lamps because of the
amount of light they produce. That light comes from
hot, glowing electrodes (carbon arcs) and,
sometimes, from heated gases (flame arcs). The
carbon arc, in which two carbon rods serve as
electrodes, was the first practical commercial
lighting device. It remains one of the brightest
sources of light and is still used in theater motion-
picture projectors, large searchlights, and
lighthouses. Flame arcs are used in color
photography and in photochemical processes
because they closely approximate natural sunshine.
The carbon is saturated with chemicals that boil off
easily. These chemicals become luminous when they
evaporate and are heated by the arc.
.

20. The color of flame arcs depends on the material
of which the electrodes are made. For example,
calcium arcs give off a red glow, while barium
arcs give off a green glow. In some flame arcs,
the radiation produced is outside the visible
range. Mercury arcs at high pressure produce
ultraviolet radiation. They also can produce
visible light in a low pressure tube if the internal
walls of the tube are coated with a fluorescent
material known as a phosphor. The phosphor
emits visible light when struck by ultraviolet
radiation from the mercury

21. Shovon Ahammed
162-15-7671

22. Advantages of electric Arc
& Environmental issues

23. • The use of EAFs allows steel to be made from a
100% scrap metal feedstock.
• This greatly reduces the energy required to
make steel when compared with primary
steelmaking from ores
• . Another benefit is flexibility: while blast
furnaces cannot vary their production by much
and can remain in operation for years at a
time,

24. • EAFs can be rapidly started and stopped,
allowing the steel mill to vary production
according to demand.
• During the peak of global financial meltdown
in 2009, an estimated quantity of only 1
million tonne was produced in USA employing
EAF technique.
• Although steelmaking arc furnaces generally
use scrap steel as their primary feedstock,

25. • if hot metal from a blast furnace or direct-
reduced iron is available economically, these
can also be used as furnace feed.
• A typical steelmaking arc furnace is the
source of steel for a mini-mill, which may
make bars or strip product. Mini-mills can be
sited relatively near to the markets for steel
products, and the transport requirements are
less than for an integrated mill, which would
commonly be sited near a harbour for access
to shipping.

26. ENVIRONMENTAL ISSUES
• Although the modern electric arc furnace is a highly efficient recycler of
steel scrap, operation of an arc furnace shop can have adverse
environmental effects. Much of the capital cost of a new installation will be
devoted to systems intended to reduce these effects, which include:
• Enclosures to reduce high sound levels
• Dust collector for furnace off-gas
• Slag production
• Cooling water demand
• Heavy truck traffic for scrap, materials handling, and product
• Environmental effects of electricity generation
• Because of the very dynamic quality of the arc furnace load, power systems
may require technical measures to maintain the quality of power for other
customers; flicker and harmonic distortion are common side-effects of arc
furnace operation on a power system.

27. MD ASHIKUR
RAHMAN
ID NO:
162-15-7723

28. UNDESIRED ARCING

29. RELAY APPLICATION
CONSIDERATIONS
WITHOUT ADEQUATE CONTACT PROTECTION, THE
OCCURRENCE OF ELECTRIC CURRENT ARCING
CAUSES SIGNIFICANT DEGRADATION OF THE
CONTACTS IN RELAYS, WHICH SUFFER SIGNIFICANT
AND VISIBLE DAMAGE.

30. Undesired or unintended electric arcing can
have detrimental effects on electric power
transmission, distribution systems and
electronic equipment. Devices which may cause
arcing include switches, circuit breakers, relay
contacts, fuses and poor cable terminations.
Switching devices susceptible to arcing are
normally designed to contain and extinguish an
arc, and snubber circuits can supply a path for
transient currents, preventing arcing.

31. Md Tanvir Hossen
Bappy
ID No
162-15-7706

32. ARC
SUPPRESSION

33. WHAT IS IT??
ARC SUPPRESSION IS A METHOD OF
ATTEMPTING TO REDUCE TO NEAR
ELIMINATION THE ELECTRICAL ARC.IT
IS THE REDUCTION OF SPARKS FORMED
WHEN CURRENT-CARRYING CONTACTS
ARE SEPARATED. THE SPARK IS A
LUMINOUS DISCHARGE OF HIGHLY
ENERGIZED ELECTRON AND IONS, AND
IS AN ELECTRIC ARC

34. EFFECTIVENES
S
ARC SUPPRESSION IS AN AREA OF
INTEREST IN ENGINEERING BECAUSE
OF THE DESTRUCTIVE EFFECTS OF THE
ELECTRICAL ARC TO
ELECTROMECHANICAL POWER
SWITCHES, RELAYS AND CONTACTORS
POINTS OF CONTACT. THE EFFICACY
OF AN ARC SUPPRESSION SOLUTION
FOR CONTACT PROTECTION CAN BE
ASSESSED, BY COMPARING THE ARC
INTENSITY

35. BENEFITS OF ARC
SUPPRESSION
 MINIMISED CONTACT DAMAGE FROM
ARCING AND THEREFORE REDUCED
MAINTENANCE, REPAIR AND
REPLACEMENT FREQUENCY.
 INCREASED CONTACT RELIABILITY.
 REDUCED OZONE AND POLLUTANT
EMISSIONS.
 REDUCED ELECTROMAGNETIC
INTERFERENCE (EMI) FROM ARCS.

36. THANKS ALL …
THE END