Aluminum wire for transformers winding generally refers to the insulated wire used to manufacture coils or windings in electrical goods, so it is called winding wire. It is necessary to meet the needs of a variety of application and manufacturing skills. The former includes its shape, specification, ability to work at high temperature for a short time and a long time, as well as bearing severe oscillation in some occasions and centrifugal force at high speed, corona and breakdown resistance under high voltage, chemical corrosion resistance of electrical wire rod under special atmosphere, etc; The latter includes the needs of stretching, bending and wear during winding and embedding, as well as swelling and erosion during impregnation and drying.


 
Aluminum wire for transformer windings can also be classified according to its basic composition, conductive core and electrical insulation layer. Generally, it is divided into enamelled wire, wrapped wire, enamelled wrapped wire and inorganic insulated wire according to the insulating materials and manufacturing methods used in the electrical insulating layer.
 
The conductor is coated with corresponding paint solution, and then made by solvent transpiration, curing and cooling of paint film. Aluminum wire for transformer windings can be divided into polyester enamelled wire, polyester imide enamelled wire, polyamide imide enamelled wire, polyimide enamelled wire, polyester imide / polyamide imide enamelled wire, corona resistant enamelled wire, oily paint, acetal paint, polyurethane enamelled wire, etc. Sometimes it is also classified according to the particularity of its use, such as self-adhesive enamelled wire, refrigerant resistant enamelled wire, etc.
 
Glass filament is an important variety of winding wire. In the early stage, cotton yarn and silk, called yarn wrapped wire and silk wrapped wire, were used in motors and electrical appliances. Due to the large insulation thickness and low heat resistance, most of them have been replaced by enamelled wires. At that time, it was only used as high-frequency winding wire. In large and medium-sized winding wires, when the heat resistance grade is high and the mechanical strength is large, glass wire wrapped wire is also selected, and appropriate adhesive paint is matched during manufacturing.
 
In the winding wire, paper wrapped wire still occupies an appropriate position, and electrical wire is mainly used in oil immersed transformer. At this time, the oil paper insulation has excellent dielectric function, low price and long service life. In recent years, the sensitive comparison is film winding, mainly polyester film and polyimide film winding.