When a low voltage arc is drawn between two electrodes of copper and graphite, a few different phenomena occur. The first is the formation of a plasma. Plasma is the fourth state of matter, and it occurs when a gas is ionized to the point that it becomes conductive. When an arc is formed between two electrodes, the gas between them is ionized, creating a plasma that is rich in charged particles.
The second phenomenon that occurs is Joule heating. Joule heating is the process by which the electric current flowing through the arc heats up the electrodes. In the case of copper and graphite electrodes, the copper electrode heats up much faster than the graphite electrode. This is because copper is a much better conductor of electricity than graphite. As a result, the resistance of the copper electrode is much lower, causing it to heat up more quickly.
The third phenomenon is the emission of light. When the plasma between the electrodes is excited by the electric current, it emits light in a variety of colors. This phenomenon is what gives an arc welder its characteristic bright light.
The result of the low voltage arc between copper and graphite electrodes is dependent on electrode polarity. When the copper electrode is positive (+) and the graphite electrode is negative (-), the arc will tend to travel towards the graphite electrode. This is because the plasma is negatively charged and is attracted to the positive copper electrode.
On the other hand, when the graphite electrode is positive (+) and the copper electrode is negative (-), the arc will tend to travel towards the copper electrode. This is because the plasma is positively charged and is attracted to the negative copper electrode.
Now let’s talk about graphite electrodes and their diameter. Graphite electrodes are used in a variety of industrial applications, including in steelmaking, aluminum smelting, and electric arc furnaces. Graphite electrodes are used because they can withstand extremely high temperatures and are highly conductive.
The diameter of a graphite electrode is crucial in different industrial applications. In steelmaking, for example, the larger the diameter of the electrode, the larger the furnace can be, and the greater the amount of steel that can be produced. In contrast, in aluminum smelting, smaller diameter electrodes are used to create a high-energy electric arc that melts the aluminum. This requires a high current density, which is achieved through the use of small diameter electrodes.
In conclusion, the low voltage arc between copper and graphite electrodes is a fascinating phenomenon that results in the formation of plasma, Joule heating, and the emission of light. The result of the arc is dependent on electrode polarity, with the plasma attracted to the positive electrode. Graphite electrodes are used in industrial applications because of their high conductivity and ability to withstand high temperatures. The diameter of graphite electrodes is crucial in different industrial applications, with larger diameters used in steelmaking and smaller diameters used in aluminum smelting.