Sähkökaari

Sähkökaari, often translated as electric arc, is a phenomenon that occurs when a sufficiently high voltage is applied across a gap between two conductors, causing the insulating medium, usually air, to break down and become conductive. This breakdown results in a continuous, luminous electrical discharge. The process begins with ionization of the gas molecules in the gap, which then allows for the flow of current. The intense heat generated by the current vaporizes the material at the electrodes, further contributing to the plasma state of the arc.

Electric arcs are characterized by high temperatures, often reaching several thousand degrees Celsius, and they emit significant amounts of light and ultraviolet radiation. This luminescence is a result of the excited atoms and molecules in the plasma returning to their ground state. The voltage across a stable arc is typically lower than the initial breakdown voltage, and it can be maintained as long as a sufficient current flows and the electrodes remain intact.

Sähkökaari has both beneficial and detrimental applications. In industry, it is utilized in electric arc welding, where the high temperatures are used to melt and join metal parts. Electric arc furnaces are also employed in metallurgy for smelting and refining metals. However, uncontrolled electric arcs can be hazardous, causing damage to electrical equipment and posing fire risks. They are also responsible for phenomena like lightning. Understanding and controlling sähkökaari is crucial in electrical engineering for safety and for harnessing its power effectively.