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What is the arc? Can the arc lighter be able to die?

Time:2019-04-22

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  What is an electric arc

  An electric arc is a gas discharge phenomenon in which an electric current is generated by a momentary spark generated by some insulating medium such as air. An electric arc is a self-contained gas that conducts electricity (electrical conduction in an ionized gas), and most of its carriers are electrons generated by one electron emission. The metal surface of the contact causes electrons to escape due to primary electron emission (thermionic emission, field emission or photoemission), and gas atoms or molecules in the gap generate electrons and ions by ionization (impingement ionization, photoionization and thermal ionization). In addition, electron or ion bombardment of the emitting surface in turn causes secondary electron emission. When the ion concentration in the gap is sufficiently large, the gap is electrically broken down to cause an arc.

  Part of the arc

  The arc is usually divided into three areas: cathode area, arc column area, and anode area.

  Cathode and cathode regions

  The current in the arc is microscopically the result of the movement of electrons and positive ions under the action of an electric field, where the movement of electrons constitutes a major part of the current. The function of the cathode is to emit a large amount of electrons, which tend to be in the direction of the anode under the action of an electric field to constitute a current in the cathode region.

  The cathode region of the arc is of great importance for the occurrence and physical process of the arc, and most of the electrons that form the arc discharge are generated in the cathode region or emitted by the cathode itself. In the arc discharge, not all the cathodes actually participate in the discharge process. The discharge on the cathode surface is concentrated in only a few small areas. This small area is called the cathode spot, which is a very concentrated, small area of bright area. Its current density is large. It is the source of powerful electron flow in arc discharge.

  There are two mechanisms for the cathode to emit electrons: thermal emission and field emission.

  Arc column

  The surface of the cathode is electrically emitted to generate only the current of the cathode region. The partial conduction of the arc column requires a large amount of free electrons to appear in the region of the arc column, which requires the gas atoms in the arc column region to be free. The way in which gas atoms are free is usually either electric field free or hot free.

  Similar to a reversible chemical reaction. In the arc, on the one hand, positive ions and electrons increase due to heat release. At the same time, there is also a de-free action, which reduces the positive ions and electrons. De-freeing includes both recombination and diffusion.

  The characteristics and physical processes of the arc column play an important role in the arc. The main research in switching arc is the characteristics of the arc column.

  Anode and anode regions

  The anode can be divided into two types: passive type and active type.

  In the passive type. The anode only serves to collect electrons. In the active type, the anode not only collects electrons but also generates metal vapor, and thus can also supply charged particles to the arc column.

  There are also anode spots on the anode surface.

  The effects of the above three regions on the arc vary depending on the condition of the arc. For arcs that are only a few millimeters in length. The arc voltage is mainly composed of the pressure drop in the cathode region and the pressure drop in the anode region, wherein the physical process plays a major role in the arc. This arc is called a short arc. For a large arc, the arc column plays a major role, and the process of the cathode and the anode does not have a primary effect or even negligence. This arc is called a long arc. The arc in the switch is generally a long arc.



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