Arc suppression


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.

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 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

Every time an electrical power device turns on or off, its switch, relay or contactor transitions either from a closed to an open state or from an open to a closed state, under load, an electrical arc occurs between the two contact points of the switch. The break arc is typically more energetic and thus more destructive.
The temperature of the resulting electric arc is very high, 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, carbon monoxide, 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 contactors’ points of contact.

Effectiveness

The efficacy of an arc suppression solution for contact protection can be assessed, by comparing the arc intensity with the help of the following methods:
Common devices used to prevent arcs are capacitors, snubbers, diodes, Zener diodes, varistors, and transient voltage suppressors. Contact arc suppression solutions that are considered more effective:
  1. Two-wire contact arc suppressor
  2. Solid state relays are not electromechanical, have no contacts, and, thus, do not create electrical arcs.
  3. Hybrid power relays
  4. Hybrid power contactors

    Benefits of Arc Suppression

Arc suppression techniques can produce a number of benefits:
  1. Minimised contact damage from arcing and therefore reduced maintenance, repair and replacement frequency.
  2. Increased Contact reliability.
  3. Reduced heat generation resulting in less heat management measures such as venting and fans.
  4. Reduced Ozone and pollutant emissions.
  5. Reduced Electromagnetic Interference from arcs - a common source of radiated EMI.