Winding wires are often made of copper but can also be produced out of aluminium or special alloys. Winding wires can be round and rectangular in cross-section and are usually insulated to prevent the wire from short-circuiting. Sometimes it is not possible to obtain all the desired properties at the same time by having one layer of enamel, so quite often winding wires have several layers of wire enamels. For example, the first layer of insulation can provide good electrical and physical properties, while the second layer will increase mechanical strength and resistance to aggressive environments. Copper winding wires with round cross-section and enamel insulation are the most widely used type of the winding wires. Winding wires are often used in electrical appliances, electric motors, motors, air conditioners, refrigerators, generators, TV sets and many other industrial and household appliances.

Application of the varnishes for enamelling of winding wires

The use of insulating varnishes for enamelling winding wires has some nuances, depending on the technology and equipment of the manufacturer, but the typical method of applying varnishes on copper wires includes:

1. Annealing. The heat treatment temperature, the purpose of which is to soften copper and increase its plasticity, depends on the properties, diameter, and cross section of the wires
2. Applying varnishes to the wires. At this stage, varnishes are applied to the wires, to create a coating
3. Enamel polymerization. The wires coated with the specified amount of varnish are sent to the furnace, where the solvent evaporates, and the enamel is cured. The temperature in the furnace can reach 700 C, but because the wires coated with the varnish spend a noticeably short time in the furnace, the enamel temperature usually does not exceed 300 C. It is worth noting that the furnace temperature, as well as the amount of time that the wires spend in the furnace may vary greatly depending on the technology and equipment of the wire manufacturer. This process is repeated until the desired enamel thickness is reached
4. Cooling of the wires. At this stage, the wires are cooled, often using fans. Sometimes, at this stage, grease is also applied to the wires
5. The wires are than assembled into coils

It is important to note that in the production of the wires, other enamelling methods are often used. Each manufacturer of winding coils has its own nuances in the production and equipment used. Diveng works closely with its customers and partners, which allows it to adapt each product to the customer's needs, regardless of the type and application, special requirements or the end use of the finished product. Our specialists will be glad to analyse, in detail, the available applications and varnishes used, to provide samples of more competitive varnishes for wire enamelling and to introduce a solution that is fully adapted to your needs and requirements.

Varieties of wire enamels

Wire enamels differ in terms of temperature classes and their composition. Usually wire enamels are made of polyester, polyamide, polyvinyl formal, polyester, polyimide, and other polymers. Depending on the main component, wire enamels have different temperature classes, which can range from 105 C to 250 + C. Varnishes and enamels are also divided into single and double-layer coatings. Composite coatings use two types of insulation, for example modified polyester insulating varnish, THEIC EL 25 can be used as the only coating for wire enamelling, but it can also be used as a primer in the composite enamelling, where the top layer can be polyester amide or polyamide amide.

Below you can find a general description of the products we supply:

Diveng also supplies wire enamels for the rectangular and aluminium wires. Our technical specialists will be glad to access your company`s needs, analyse the currently used varnishes and offer competitive alternatives, also for the rectangular and aluminium wires.

Diveng also supplies “PV” product series that are based on Polyvinyl Formal. “PV” product series have good resistance to chemicals and excellent mechanical, thermal and electrical properties and hence they are frequently used in formulations containing other ingredients such as phenolic resins. Polyvinyl Formal is highly versatile, having various outstanding properties, which makes it suitable for a wide range of applications. Specifically, Polyvinyl Formal is widely used for both, rectangular and round conductors. Polyvinyl Formal is also a key component in PVA based wire enamels that have outstanding resistance to transformer oil. These enamels provide excellent toughness, flexibility, and abrasion resistance. This material is available in five “PV” specifications with different molecular weights and different viscosities to suit various end usages.