Composition of switching power supply transformer
The main materials of switching power transformer: magnetic material, wire material and insulation material are the core of switching power transformer.
Magnetic materials: The magnetic materials used in switching transformers are soft ferrite, which can be divided into MnZn series and NiZn series according to their composition and application frequency. The former has high permeability and high saturation magnetic induction, and low loss in the middle and low frequency range. There are many shapes of magnetic cores, such as EI type, E type and EC type.
Wire material-enameled wire: Generally, enameled wires used for winding small electronic transformers include high-strength polyester enameled wire (QZ) and polyurethane enameled wire (QA). According to the thickness of the paint layer, they can be divided into two types: type 1 (thin paint type) and type 2 (thick paint type). The insulation coating of the former is polyester paint, which has superior heat resistance, and the insulation resistance can reach 60kv/mm; The insulating layer of the latter is polyurethane paint, which has strong self-adhesion and self-welding performance (380℃), and can be directly welded without removing the paint film.
Pressure-sensitive adhesive tape: insulating tape has high electrical strength, convenient use and good mechanical properties, and is widely used in interlayer insulation, inter-group insulation and external insulation of switching transformer coils. It must meet the following requirements: good adhesion, anti-peeling, certain tensile strength, good insulation performance, good pressure resistance, flame retardancy and high temperature resistance.
Skeleton material: The skeleton of switching transformer is different from the general transformer skeleton, which not only serves as insulation and support material for the coil, but also plays the role of installation, fixing and positioning of the whole transformer. Therefore, the material for making the skeleton should not only meet the insulation requirements, but also have considerable tensile strength. At the same time, in order to withstand the welding heat of the pin, the thermal deformation temperature of the skeleton material is required to be higher than 200℃, and the material must be flame retardant, and it should also be good in processability and easy to be processed into various shapes.
