Arc suppression is the reduction of sparks formed when current-carrying contacts are separated. The spark is a luminous discharge of highly energized electrons and ions, and is an

electric arc An electric arc, or arc discharge, is an electrical breakdown of a gas that produces a prolonged electrical discharge. The current through a normally nonconductive medium such as air produces a plasma; the plasma may produce visible light. ...

Uses

There are several possible areas of use of arc suppression methods, among them metal film deposition and sputtering, arc flash protection, electrostatic processes where electrical arcs are not desired (such as

powder painting Powder painting is the art of using ground glass in powdered form to create kilnformed glass art. The process differs from enameling in many respects. Firstly, the powder is actually ground glass typically from a single manufacturer who supplie ...

air purification An air purifier or air cleaner is a device which removes contaminants from the air in a room to improve indoor air quality. These devices are commonly marketed as being beneficial to allergy sufferers and asthmatics, and at reducing or eliminating ...

polyvinylidene fluoride Polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is a highly non-reactive thermoplastic fluoropolymer produced by the polymerization of vinylidene difluoride. PVDF is a specialty plastic used in applications requiring the highest pur ...

(PVDF) film poling) and contact current arc suppression. In industrial, military and consumer electronic design, the latter method generally applies to devices such as electromechanical power switches, relays and contactors. In this context, arc suppression is

contact protection Contact protection methods are designed to mitigate the wear and degradation occurring during the normal use of contacts within an electromechanical switch, relay or contactor and thus avoid an excessive increase in contact resistance or switch fa ...

Contact protection

Every time an electrical power device (for example: heaters, lamps, motors, transformers or similar power loads) turns on or off, its switch, relay or

contactor :''In semiconductor testing, contactors can also be referred to as the specialized socket that connects the device under test.'' :''In process industries, a contactor is a vessel where two streams interact, for example, air and liquid. See Gas ...

transitions either from a closed to an open state (break arc) or from an open to a closed state (make arc and bounce arc), under load, an electrical arc occurs between the two contact points (electrodes) of the switch. The break arc is typically more energetic and thus more destructive. The temperature of the resulting

is very high (tens of thousands of degrees), causing the metal on the contact surfaces to melt, pool and migrate with the current. The high temperature of the arc cracks the surrounding gas molecules creating

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the l ...

carbon monoxide Carbon monoxide ( chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simpl ...

, and other compounds. The arc energy slowly destroys the contact metal, causing some material to escape into the air as fine particulate matter. This very activity causes the material in the contacts to degrade quickly, resulting in device failure. Arc suppression is an area of interest in engineering because of the destructive effects of the electrical arc to electromechanical power switches, relays and

s’ points of contact.

Effectiveness

The efficacy of an arc suppression solution for

can be assessed, by comparing the arc intensity with the help of the following methods: *Visual inspection of the arc: The electrical arc can be visually observed on an electromechanical power switch, relay and contactor, with visible contacts, while the contacts are opening and closing under load. *Graphical representation of measurements obtained by an oscilloscope: The electrical arc can be observed by using an oscilloscope to trace the voltage wave form across the contact terminals while the contacts are opening and closing under load.

Common devices

Common devices used to prevent arcs are

capacitors A capacitor is a device that stores electrical energy in an electric field by virtue of accumulating electric charges on two close surfaces insulated from each other. It is a passive electronic component with two terminals. The effect of a ...

snubber A snubber is a device used to suppress ("snub") a phenomenon such as voltage transients in electrical systems, pressure transients in fluid systems (caused by for example water hammer) or excess force or rapid movement in mechanical systems. Ele ...

diodes A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance); it has low (ideally zero) resistance in one direction, and high (ideally infinite) resistance in the other. A diode ...

, Zener diodes,

varistor A varistor is an electronic component with an electrical resistance that varies with the applied voltage. Also known as a voltage-dependent resistor (VDR), it has a nonlinear, non- ohmic current–voltage characteristic that is similar to that ...

s, and transient voltage suppressors. Contact arc suppression solutions that are considered more effective: #Two-wire contact arc suppressor #

Solid state relay Solid state contactor PCB mount solid-state DIL relay A solid state relay (SSR) is an electronic switching device that switches on or off when an external voltage (AC or DC) is applied across its control terminals. They serve the same function ...

s are not electromechanical, have no contacts, and, thus, do not create electrical arcs. #Hybrid power relays #Hybrid power contactors

Benefits of arc suppression

Arc suppression techniques can produce a number of benefits: #Minimised contact damage from arcing and therefore reduced maintenance, repair and replacement frequency. #Increased contact reliability. #Reduced heat generation resulting in less heat management measures such as venting and fans. #Reduced ozone and pollutant emissions. #Reduced

electromagnetic interference Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrost ...

(EMI) from arcs - a common source of radiated EMI.

References

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