Enameled wire for winding coils are currently one of th […]
Enameled wire for winding coils are currently one of the basic materials for the power industry. This article gives a brief overview of the manufacturing, testing methods and problems associated with the chemical and physical structure of insulating varnishes.
One of the basic materials for the electrical industry is insulated copper wire for winding coils, transformers, rotors, stators and the like. Rubber or cotton is used for this purpose, but now almost all enameled wire is used. The biggest advantage of using enamel insulation is that the insulation is very thin, so a coil with a higher "space factor" can be obtained.
Various requirements of the electrical industry for the enamelled wire lead to differences in the chemical composition of many types of enamel layers. The Pope's factory in Venlo has the following main areas four types of paint: enameled wire, the oldest enameled wire type; "Povin" wire, very sturdy; "Posyn" wire, which can be easily soldered: the enamel layer can easily be removed when the wire is immersed in molten solder; "Potermo" , High temperature (up to 155 °C).
All of the above types of wires are made more or less the same way with different chemical coatings. This article begins with a brief description of the manufacturing process. Then consider the requirements of the enameled wire and test whether the method meets these requirements. After this section on practical issues, a theoretical discussion of the relationship between the most important properties of the various types of conductors and the structure of their insulating layers is made. Finally, we pay special attention to a recent survey that showed the existence and the dangers of microscopic "defects" in the enamel layer.
A good enameled wire needs to be applied to the wire as thinly as possible, otherwise it will drip and thus be unevenly distributed over the wire. It is therefore necessary to coat the multilayer lacquer one after the other in order to obtain the required insulation thickness, which may for example be 16 fl. For 0.1 mm diameter copper wire. It is common practice to route the wire alternately through a paint can and a muffle furnace: the wire is covered with a thin layer of liquid paint as it passes through the paint can; then it is dried in the oven, Return to the tank for a new paint layer, etc. until the enamel layer has the desired thickness.