What is the Function of an Electric Arc?
The electric arc is a gas discharge phenomenon, an instantaneous spark created by the passage of an electric current through some insulating medium, such as air. The electric arc is self-sustaining gas conduction (electrical conduction in an ionized gas), and most of its charge carriers are electrons generated by primary electron emission. Electrons escape from the metal surface of the contact due to primary electron emission (thermionic emission, field emission, or photoemission), and gas atoms or molecules in the gap will generate electrons and ions due to ionization (collision ionization, photoionization, and thermal ionization). In addition, the bombardment of the emitting surface with electrons or ions can in turn cause secondary electron emission. When the ion concentration in the gap is large enough, the gap is electrically broken down and an arc occurs.
Conditions under which arcing occurs
1. The occurrence of arc when the circuit is broken
When the contacts begin to separate, the contact pressure acting between them will decrease, the contact area will also shrink, and the contact resistance and heat released in the contacts will increase. Heat is concentrated in a small volume, and the metal is heated to high temperatures and melted. A liquid metal bridge is formed between the contacts, and finally, the metal bridge is pulled apart, creating a transitional or stable arc between the contacts. If the discharge is stable, it is called breaking the arc. Discharge stability is related to many factors, such as the current being interrupted, the characteristics of the contact circuit, the speed of contact separation, etc. In order for the arc to ignite, a certain minimum current value is required.
2. The occurrence of arc when the contacts are closed
3. Breakdown of vacuum and gas gap
4. The transition from glow discharge to arc discharge
5. The transition from spark discharge to arc discharge
Arc Spray Metal Anticorrosion
(1) According to the type of current, it can be divided into AC arc, DC arc, and pulse arc.
(2) According to the state of the arc, it can be divided into the free arc and compression arc (such as the plasma arc).
(3) According to the electrode material, can be divided into melting electrode arc and non-melting electrode arc.
It has strong electrical conductivity, concentrated energy, high temperature, high brightness, lightweight, volatility, etc.
The electric arc can be used as an intense light source such as an arc lamp, an ultraviolet source such as a sun lamp, or an intense heat source such as an electric arc furnace.
The arc has a thermal effect.