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Electrical breakdown

The term electrical breakdown has several similar but distinctly different meanings. The term may apply to a failure of an electric circuit or system with consequent lack of function. Alternately, it may refer to a rapid reduction in the resistance of an electrical insulator that can lead to a spark Spark

The word spark has several meanings: ... 

 jumping around or through the insulator. This may be a momentary event , or may lead to a continuous arc Electric arc

An electric arc is an electrical breakdown [i] of a gas which produces an ongoing plasma [i] discharge [i] ... 

 discharge if protective devices fail to interrupt the current in a high power circuit.

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Encyclopedia


The term electrical breakdown has several similar but distinctly different meanings. The term may apply to a failure of an electric circuit or system with consequent lack of function.
Alternately, it may refer to a rapid reduction in the resistance of an electrical insulator that can lead to a spark Spark

The word spark has several meanings:
... 

 jumping around or through the insulator. This may be a momentary event , or may lead to a continuous arc Electric arc

An electric arc is an electrical breakdown [i] of a gas which produces an ongoing plasma [i] discharge [i] ... 

 discharge if protective devices fail to interrupt the current in a high power circuit.

Electrical system failure


The most common meaning is related to automobile Automobile

An automobile is a wheel [i]ed passenger [i] vehicle [i] that carries its own motor [i]. ... 

s and is the failure of an electric circuit or associated device resulting in a loss of vehicle function . Common problems include battery discharge, alternator Alternator

[i]
[i]
... 

 failure, broken wires, blown fuses, and a failed fuel pump Fuel pump

A fuel pump is an essential component on a car [i] or other internal combustion engine [i]d d ... 

.

Failure of electrical insulation


The second meaning is more specifically a reference to the breakdown of the insulation Electrical insulation

An insulator is a material or object which contains no movable electrical charges [i].... 

 of an electrical wire Wire

A wire is a single, usually cylindrical [i], elongated strand of drawn [i] metal [i]. ... 

 or other electrical component. Such breakdown usually results in a short circuit Short circuit

A short circuit is an accidental low-resistance [i] connection between two nodes o... 

 and/or a blown fuse. Actual insulation breakdown is more generally found in high-voltage High voltage

The term high voltage characterizes electrical circuits, in which the voltage used is the cause of parti... 

 applications, where it sometimes causes the opening of a protective circuit breaker Circuit breaker

A circuit breaker is an automatically-operated electrical [i] switch [i] which is designed to protect an ... 

. Electrical breakdown is often associated with the failure of solid or liquid insulating materials used inside high voltage transformer Transformer

A transformer is an electrical device that transfers energy from one circuit [i] to a ... 

s or capacitors Capacitor

A capacitor is an electric [i]al device that can store energy [i] in the electric field [i] between a pair of ... 

 in the electricity distribution Electricity distribution

Electricity distribution is the penultimate stage in the delivery [i] of electricity [i]... 

 grid. Electrical breakdown can also occur across the strings of insulators that suspend overhead power lines Electric power transmission

Electric power transmission is one process in the transmitting of electricity [i] to consumers. ... 

, within underground power cables, or lines arcing to nearby branches of trees. Under sufficient electrical stress, electrical breakdown can occur within solids, liquids, or gases. However, the specific breakdown mechanisms are significantly different for each phase of dielectric Dielectric

A dielectric, or electrical insulator [i], is a substance that is highly resistant to electric current [i] ... 

.

Electrical breakdown occurs within a gas when the dielectric strength of the gas is exceeded. Regions of high electrical stress can cause nearby gas to partially ionize and begin conducting. This is done deliberately in low pressure discharges such as in fluorescent light Fluorescent lamp

A fluorescent lamp is a gas-discharge lamp [i] that uses electricity [i] to excite mercury [i] vapor [i] ... 

s. ' or in an electrostatic precipitator.

Partial electrical breakdown of the air causes the "fresh air" smell of ozone Ozone

Ozone is a triatomic molecule [i], consisting of three oxygen atom [i]s. ... 

 during thunderstorms or around high-voltage equipment. Although air is normally an excellent insulator, when stressed by a sufficiently high voltage , air can begin to break down, becoming partially conductive. If the voltage is sufficiently high, complete electrical breakdown of the air will culminate in an electrical spark Spark

The word spark has several meanings:
... 

 or arc Electric arc

An electric arc is an electrical breakdown [i] of a gas which produces an ongoing plasma [i] discharge [i] ... 

 that bridges the entire gap. While the small sparks generated by static electricity may barely be audible, larger sparks are often accompanied by a loud snap or bang. Lightning Lightning

Lightning is a powerful natural electrostatic discharge [i] produced during a thunderstorm [i]. ... 

 is an example of an immense spark that can be many miles long. The color of the spark depends upon the gases that make up the gaseous media.

If a fuse or circuit breaker Circuit breaker

A circuit breaker is an automatically-operated electrical [i] switch [i] which is designed to protect an ... 

 fails to interrupt the current flowing through a spark in a power circuit, current may continue to flow, forming a very hot electric arc Electric arc

An electric arc is an electrical breakdown [i] of a gas which produces an ongoing plasma [i] discharge [i] ... 

. The color of an arc depends primarily upon the conductor materials . Although sparks and arcs are usually undesirable, they can be useful in everyday applications such as spark plugs Spark plug

A spark plug is an electrical device that fits into the cylinder head [i] of some internal combustion engine [i] ... 

 for gasoline engines, electrical welding Welding

Welding is a fabrication [i] process that joins materials, usually metal [i]s or thermoplastic [i] ... 

 of metals, or for metal melting in an electric arc furnace Electric arc furnace

An electric arc furnace is a system that heats charged material by means of an electric arc [i].... 

.

Corona breakdown


Partial breakdown of the air occurs as a corona discharge on high voltage conductors at points with the highest electrical stress . Corona is sometimes seen as a bluish glow around high voltage wires and heard as a sizzling sound along high voltage power lines. Corona also generates radio frequency noise that can also be heard as 'static' or buzzing on radio receivers. Corona can also occur naturally at high points during thunderstorms as St. Elmo's Fire St. Elmo's fire

St. Elmo's fire is an electro [i]-luminescent [i] corona discharge [i] caus ... 

.
Although corona discharge is usually undesirable, until recently it was essential in the operation of photocopiers and laser printers Laser printer

A laser printer is a common type of computer printer [i] that rapidly produces high quality text and gra ... 

. Many modern copiers and laser printers now charge the photoconductor drum with an electrically conductive roller, reducing undesirable indoor ozone pollution.

See also


  • Breakdown voltage
  • Avalanche breakdown




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