An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current flowing through normally nonconductive media such as air. The London Underground is a Metro system serving a large part of Greater London and neighbouring areas of Essex, Hertfordshire and Buckinghamshire Calcium oxide ( CaO) commonly known as burnt lime, lime or quicklime, is a widely used Chemical compound. The term electrical breakdown has several similar but distinctly different meanings In Physics and Chemistry, plasma is an Ionized Gas, in which a certain proportion of Electrons are free rather than being bound Electrostatic discharge ( ESD) is the sudden and momentary Electric current that flows between two objects at different Electrical potentials The term is Electrical conductance is a measure of how easily Electricity flows along a certain path through an Electrical element. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five A synonym is arc discharge. The phenomenon was first described by Vasily V. Petrov, a Russian scientist who discovered it in 1802. Vasily Vladimirovich Petrov ( Василий Владимирович Петров (—1834 was a Russian experimental Physicist, self-taught electrical technician Year 1802 ( MDCCCII) was a Common year starting on Friday of the Gregorian calendar or a Common year starting on Wednesday of the An archaic term is voltaic arc as used in the phrase "voltaic arc lamp".
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Overview
The various shapes of electric arc are emergent properties of nonlinear patterns of current and electric field. For other uses see Emergence (disambiguation, Emergent, and Emergency. Electric current is the flow (movement of Electric charge. The SI unit of electric current is the Ampere. In Physics, the space surrounding an Electric charge or in the presence of a time-varying Magnetic field has a property called an electric field (that can The arc occurs in the gas-filled space between two conductive electrodes (often made of carbon) and it results in a very high temperature, capable of melting or vaporizing most materials. An electrode is an Electrical conductor used to make contact with a nonmetallic part of a circuit (e Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature Melting is a process that results in the phase change of a substance from a Solid to a Liquid. Evaporation is the process by which Molecules in a Liquid state (e An electric arc is a continuous discharge, while a similar electric spark discharge is momentary. An electric arc may occur either in direct-current circuits or in alternating current circuits. In the latter case, the arc may re-strike on each half cycle of the current. An electric arc differs from a glow discharge in that the current density is quite high, and the voltage drop within the arc is low; at the cathode the current density may be as high as one million amps per square centimeter. Electric glow discharge is a type of plasma formed by passing a current at 100 V to several kV through a gas usually Argon or another Noble A cathode is an Electrode through which (positive Electric current flows out of a polarized electrical device [1]
Uses
Industrially, electric arcs are used for welding, plasma cutting, for electrical discharge machining, as an arc lamp in movie theater projectors, and Followspots in stage lighting. Welding is a fabrication process that joins materials usually Metals or Thermoplastics by causing coalescence. This article is about the common Manufacturing process For various fictional weapons see Plasma rifle and Directed-energy weapon. Electrical Discharge Machining (or EDM) is a machining method primarily used for hard metals or those that would be impossible to machine with traditional techniques This article is concerned with technical aspects of moving film projection A followspot, sometimes known as a Spot Light, is a powerful stage light which can be controlled by a human Spotlight operator to "follow" actors Modern stage lighting is a flexible Tool in the production of Theatre, Dance, Opera and other Performance arts Electric arc furnaces are used to produce steel and other substances. An electric arc furnace (EAF is a Furnace that heats charged material by means of an Electric arc. Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 Calcium carbide is made in this way as it requires a large amount of energy to promote an endothermic reaction (at temperatures of 2500 °C). Calcium carbide is a Chemical compound with the Chemical formula of Ca[[Carbide C2]] In Thermodynamics, the word endothermic "within-heating" describes a process or reaction that absorbs Energy in the form of Heat. A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called The Celsius Temperature scale was previously known as the centigrade scale.
Low-pressure electric arcs are used for lighting, e. g. , fluorescent tubes, mercury and sodium street lamps, and camera flash lamps. A fluorescent lamp or fluorescent tube is a Gas-discharge lamp that uses Electricity to excite mercury Vapor. A street light, lamppost, street lamp, light standard or lamp standard, is a raised source of Light on the edge of a Road
Electric arcs have been studied for electric propulsion of spacecraft. Electric propulsion is a form of Spacecraft propulsion used in Outer space.
Undesired arcing
Undesired or unintended electric arcing can have detrimental effects on electric power transmission and distribution systems and electronic equipment. Electric power transmission, a process in the delivery of Electricity to consumers is the bulk transfer of electrical power Electricity distribution is the penultimate stage in the delivery (before retail) of Electricity to end users Electronics refers to the flow of charge (moving Electrons through Nonmetal conductors (mainly Semiconductors, whereas electrical Undesired arcing in electrical contactors can be suppressed by various devices, including:
- immersion in oil, inert gas or vacuum
- arc chutes
- magnetic blowouts
An electric arc has a non-linear relationship between current and voltage. In semiconductor testing, contactor can also refer to the specialised socket that connects the Device under test. Transformer oil is usually a highly- refined Mineral oil that is stable at high temperatures and has excellent electrical insulating properties "Inert gases" is also used in a narrower sense for Noble gases An inert gas is any Gas that is not reactive with elements This vacuum means "absence of matter" or "an empty area or space" for the cleaning appliance see Vacuum cleaner. A circuit breaker is an automatically-operated electrical Switch designed to protect an electrical circuit from damage caused by overload or In semiconductor testing, contactor can also refer to the specialised socket that connects the Device under test. Once the arc is established (either by progression from a glow discharge [2] or by momentarily touching the electrodes then separating them), increased current results in a lower voltage between the arc terminals. This negative impedance effect requires that some positive form of impedance to be placed in the circuit, if it is desired to maintain a stable arc. This property is the reason uncontrolled electrical arcs in apparatus become so destructive, since once initiated an arc will draw more and more current from a fixed-voltage supply until the apparatus is destroyed.
See also
References
- ^ A. The arc converter, sometimes called the arc transmitter or Poulsen arc after its inventor Valdemar Poulsen, is a device used to convert DC energy Arc welding uses a Welding power supply to create an Electric arc between an electrode and the base material to melt the metals at the welding point A spark gap consists of an arrangement of two conducting Electrodes separated by a gap usually filled with a Gas such as Air. A vacuum arc can arise when the surfaces of Metal Electrodes in contact with a good Vacuum begin to emit Electrons either through heating ( H. Howatson, An Introduction to Gas Discharges, Pergamon Press, Oxford pgs. 80-95
- ^ Princples of Electronics By V. K. Mehta ISBN 8121924502 pages 101-107
External links
- Arc Analysis
- Unusual Arcing Photos
- Some more info about making electric arcs using a welder. A welder (also weldor, which term distinguishes the Tradesman from the equipment used to make welds is a Tradesman who specialises in Welding
- Videos of 230,000 volt 3-phase "Jacobs Ladder" and unintentional 500,000 volt power arc
- High Voltage Arc Gap Calculator to calculate the length of an arc knowing the voltage or vice versa