1. The potential of the copper enameled wire and aluminum enameled wire is different. The contact part of the copper enameled wire and the aluminum enameled wire will accelerate the oxidation of the aluminum wire due to the reaction of the primary battery. After a long time, the copper enameled wire aluminum enameled wire connector will have poor contact. If you want to connect them together, you must use copper enameled wire and aluminum enameled wire to over clamp or over tube.
2. This is a chemical problem. The chemical properties of metals are relatively active and inactive. For example, gold never rusts. This means that gold is chemically inactive, iron is easy to rust, and iron is more active than gold. Putting the metal together will accelerate the oxidation of the active metal. Compared with the copper enameled wire, the aluminum enameled wire is more active. The two cable connections will accelerate the aluminum oxidation (that is, rust) and affect the use.
3. When the copper and aluminum conductors are directly connected, the contact surface of these two metals can easily form an electrolyte under the action of moisture, carbon dioxide and other impurities in the air, thereby forming a primary battery with aluminum as the negative electrode and copper as the positive electrode , Causing galvanic corrosion of aluminum, resulting in increased contact resistance at the connection between copper and aluminum.
In addition, because the elastic modulus and thermal expansion coefficient of copper enameled wire and aluminum enameled wire are very different, after running multiple cold and hot cycles (power on and off) during operation, a large gap will be generated at the contact point and affect the contact. It also increases the contact resistance. An increase in contact resistance will cause a temperature increase during operation. Corrosion and oxidation will intensify at high temperature, resulting in a vicious cycle, which will further deteriorate the quality of the connection, resulting in excessive contact point temperature or even smoke, burnout and other accidents.