Citizendia
Your Ad Here

"Arc light" redirects here. For the Vietnam bombing campaign, see Operation Arc Light. Operation Arc Light was the 1965 deployment of B-52F Stratofortress as conventional bombers from bases in the US to Guam.
15 kW Xenon short-arc lamp.
15 kW Xenon short-arc lamp. A xenon arc lamp is an artificial light source Powered by Electricity, it uses Ionized Xenon gas to produce a bright white light that closely

An arc lamp or arc light is the general term for a class of lamps that produce light by an electric arc (also called a voltaic arc). An electric arc is an Electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current flowing through normally nonconductive The lamp consists of two electrodes typically made of tungsten which are separated by a gas. An electrode is an Electrical conductor used to make contact with a nonmetallic part of a circuit (e Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 The type of lamp is often named by the gas contained in the bulb; including neon, argon, xenon, krypton, sodium, metal halide, and mercury. Neon (ˈniːɒn is the Chemical element that has the symbol Ne and Atomic number 10 This article pertains to the chemical element For other uses see Argon (disambiguation. Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. Krypton (ˈkrɪptən or /ˈkrɪptɒn/ from kryptos "hidden" is a Chemical element with the symbol Kr and Atomic number 36 Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Metal halide lamps, a member of the High-intensity discharge (HID family of lamps produce high light output for their size making them a compact powerful and efficient Mercury (ˈmɜrkjʊri also called quicksilver or hydrargyrum, is a Chemical element with the symbol Hg ( Latinized hydrargyrum The common fluorescent lamp is actually a low-pressure mercury arc lamp where the inside of the bulb is coated with a light-emitting phosphor. A fluorescent lamp or fluorescent tube is a Gas-discharge lamp that uses Electricity to excite mercury Vapor. High-intensity discharge lamps operate at a higher current than the fluorescent lamp, and come in many varieties depending on the fill material. A High-intensity discharge (HID lamp is a type of electrical lamp which produces light by means of an electric arc between Tungsten Electrodes Lightning could be thought of as a type of natural arc lamp, or at least a flash lamp. Lightning is an atmospheric discharge of Electricity, which typically occurs during Thunderstorms and sometimes during volcanic eruptions or A xenon flash lamp is an Electric glow discharge lamp designed to produce extremely intense incoherent, full-spectrum white light for very short durations

The electric arc in an arc lamp consists of gas which is initially ionized by a voltage and is therefore electrically conductive. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge To start an arc lamp, usually a very high voltage is needed to "ignite" or "strike" the arc. This requires an electrical circuit sometimes called an igniter, which is part of a larger circuit called the ballast. An electrical ballast (sometimes called control gear) is a device intended to limit the amount of current in an electric The ballast supplies a suitable voltage and current to the lamp as its electrical characteristics change with temperature and time. The ballast is typically designed to maintain safe operating conditions and constant light output over the life of the lamp. The temperature of the arc can reach several thousand degrees Celsius. The Celsius Temperature scale was previously known as the centigrade scale.

Contents

Carbon arc lamp

In popular use, the term arc lamp means carbon arc lamp only.

In a carbon arc lamp, the electrodes are carbon rods in free air. To ignite the lamp, the rods are touched together, thus allowing a relatively low voltage to strike the arc. The rods are then slowly drawn apart, and electric current heats and maintains an arc across the gap. The tips of the carbon rods are heated to incandescence, creating light.

Automatic adjustment

The rods are slowly burnt away in use, and need to be regularly adjusted to maintain the arc. Many ingenious mechanisms were invented to effect this automatically, mostly based on solenoids. A solenoid is a three-dimensional Coil. In Physics, the term solenoid refers to a loop of wire often wrapped around a Metallic core which In the simplest form (which was soon superseded by more smoothly acting devices) the electrodes are mounted vertically. The current supplying the arc is passed in series through a solenoid attached to the top electrode. If two or more circuit components are connected end to end like a daisy chain it is said they are connected in series. If the points of the electrodes are touching (as in start up) the resistance falls, the current increases and the increased pull from the solenoid draws the points apart. If the arc starts to fail the current drops and the points close up again.

History

Self-regulating arc lamp proposed by William Edwards Staite and William Petrie in 1847
Self-regulating arc lamp proposed by William Edwards Staite and William Petrie in 1847
An electric arc, demonstrating the “arch” effect.
An electric arc, demonstrating the “arch” effect.

The concept was first demonstrated by Sir Humphry Davy in the early 19th century (1802, 1805, 1807 and 1809 are all mentioned), using charcoal sticks and a 2000-cell battery to create an arc across a 4-inch gap. Sir Humphry Davy 1st Baronet FRS MRIA (17 December 1778 &ndash 29 May 1829 was a British Chemist and inventor In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy In electronics a battery is a combination of two or more Electrochemical cells which store chemical Energy which can be converted into electrical energy He mounted his electrodes horizontally and noted that, because of the strong convection flow of air, the arc formed the shape of an arch. He coined the term "arch lamp", which was contracted to "arc lamp" when the devices came into common usage.

There were attempts to produce the lamps commercially after 1850 but the lack of a constant electricity supply thwarted efforts. Thus electrical engineers began focusing on the problem of improving Faraday's dynamo. Michael Faraday, FRS ( September 22 1791 – August 25 1867) was an English In Electricity generation, an electrical generator is a device that converts Mechanical energy to Electrical energy, generally using Electromagnetic The concept was improved upon by a number of people including William Staite and Charles F. Brush. Charles Francis Brush ( March 17, 1849 &ndash June 15, 1929) was a U It was not until the 1870s that lamps such as the Yablochkov candle were more commonly seen. A Yablochkov candle (sometimes electric candle) is a type of electric carbon Arc lamp, invented in 1876 by Pavel Yablochkov. In 1877, the Franklin Institute conducted a comparative test of dynamo systems. This article is about the science museum in Philadelphia For the Boston school see Benjamin Franklin Institute of Technology. The one developed by Brush performed best, and Brush immediately applied his improved dynamo to arc-lighting. In 1880, he established the Brush Electric Company. Brush Electrical Machines is a manufacturer of large Generators for Gas turbine and Steam turbine drive applications based at Loughborough in

The harsh and brilliant light was found most suitable for public areas, being around 200 times more powerful than contemporary filament lamps. The incandescent light bulb, incandescent lamp or incandescent light globe is a source of electric Light that works by Incandescence, (a general There were three major advances in the 1880s:

In the US, patent protection of arc-lighting systems and improved dynamos proved difficult and as a result the arc-lighting industry became highly competitive. Brush's principal competition was from the team of Elihu Thomson and Edwin J. Houston. Elihu Thomson ( March 29, 1853  – March 13, 1937) was an engineer and Inventor who was instrumental in the founding Edwin J Houston (Alexandria Virginia 1847&ndash New York 1914 was an American electrical inventor These two had formed the American Electric Company in 1880, but it was soon bought up by Charles A. Coffin, moved to Lynn, Massachusetts, and renamed the Thomson-Houston Electric Company. Charles Albert Coffin ( Fairfield Maine, 31 December 1844-14 July 1926 was the first President of General Electric corporation Lynn is a city in Essex County, Massachusetts, United States. The Thomson-Houston Electric Company was formed in 1883 when a group of Lynn Massachusetts investors led by Charles A Thomson remained, though, the principal inventive genius behind the company patenting improvements to the lighting system. Under the leadership of Thomson-Houston's patent attorney, Frederick P. Fish, the company protected its new patent rights. Coffin's management also led the company towards an aggressive policy of buy-outs and mergers with competing manufacturers. Both strategies reduced competition in the electrical lighting manufacturing industry. By 1890, the Thomson-Houston company was the dominant electrical manufacturing company in the US (Noble, 6-10). Nikola Tesla received U. There have already been discussions about Tesla's ethnicity on the talk page S. Patent 447920, "Method of Operating Arc-Lamps" (March 10, 1891), that describes a 10,000 cycles per second alternator to suppress the disagreeable sound of power-frequency harmonics produced by arc lamps operating on frequencies within the range of human hearing.

Around the turn of the century arc-lighting systems were in decline but nonetheless, Thomson-Houston controlled key patents to urban lighting systems. This control slowed the expansion of incandescent lighting systems being developed by Thomas Edison's Edison General Electric Company. Conversely, Edison's control of direct current distribution and generating machinery patents blocked further expansion of Thomson-Houston. The roadblock to expansion was removed when the two companies merged in 1892 to form the General Electric Company (Noble, 6-10).

Arc lamps were also used in some early motion-picture studios to illuminate interior shooting; one problem was that such lights were so intense that many early film actors and actresses needed to wear sunglasses when not in front of the camera to relieve sore eyes resulting from the extremely brillant light in the studio. Sunglasses or sun glasses are a visual aid variously termed Spectacles or Glasses, which feature lenses that are coloured or darkened to prevent strong By the dawn of the "talkies", arc lamps had been replaced in film studios with other forms of bright lights.

The arc lamps were soon superseded by the more efficient and longer-lasting filament lamps in most roles, remaining in only certain niche markets such as cinema projection and searchlights but even in these applications, conventional carbon arc lamps are finally being pushed into obsolescence by xenon arc lamps. Cinemaaustraliajpg|thumb|A movie theater in Australia ]]A movie theater, movie theatre, picture theatre or cinema is a venue This article is concerned with technical aspects of moving film projection A searchlight is an apparatus with Reflectors for projecting a powerful beam of Light of approximately parallel rays in a particular A xenon arc lamp is an artificial light source Powered by Electricity, it uses Ionized Xenon gas to produce a bright white light that closely

Glowing carbon rods in a shut off arc lamp.
Glowing carbon rods in a shut off arc lamp.

See also

References

External Links


Dictionary

arc lamp

-noun

  1. An electric arc arranged so as to produce useful light.
© 2009 citizendia.org; parts available under the terms of GNU Free Documentation License, from http://en.wikipedia.org
 Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic