Composition of switch mode power supply transformer
The main materials of switching power supply transformer: magnetic materials, wire materials and insulating materials are the core of switching transformer.
Magnetic materials: The magnetic materials used in switching transformers are soft ferrites, which can be divided into two categories: MnZn series and NiZn series according to their composition and application frequency. The former has high magnetic permeability and high saturation magnetic induction, and can be used in the medium and low frequency ranges. Has lower loss. There are many shapes of magnetic cores, such as EI type, E type, EC type, etc.
Wire material - enameled wire: There are two types of enameled wire commonly used for winding small electronic transformers: high-strength polyester enameled wire (QZ) and polyurethane enameled wire (QA). According to the thickness of the paint layer, it is divided into type 1 (thin paint type) and type 2 ( There are two types (thick paint type). The insulation coating of the former is polyester paint, which has excellent heat resistance, and the insulating electric strength can reach 60kv/mm; the insulation layer of the latter is polyurethane paint, which has strong self-adhesiveness and self-propelled properties. Welding performance (380℃), can be directly welded without removing the paint film
Pressure-sensitive tape: Insulating tape has high electrical strength, is easy to use and has good mechanical properties. It is widely used in the layers of switching transformer coils, inter-group insulation and outsourcing insulation. It must meet the following requirements: good adhesion, resistance to peeling, and a certain degree of tensile strength Tensile strength, good insulation performance, good voltage resistance, flame retardant and high temperature resistance
Skeleton material: The switching transformer skeleton is different from the general transformer skeleton. In addition to serving as the insulation and support material of the coil, it also plays the role of installation, fixation and positioning of the entire transformer. Therefore, in addition to meeting the insulation requirements, the material used to make the skeleton should also Considerable tensile strength, and in order to withstand the welding heat of the pins, the thermal deformation temperature of the skeleton material is required to be higher than 200°C. The material must be flame retardant, and it should also have good processability and be easy to process into various shapes.
