Composition of switching power supply transformer
The main materials of switching power supply transformers: magnetic materials, wire materials and insulating materials are the core of switching transformers.
Magnetic material: The magnetic material used in switching transformers is soft ferrite, which can be divided into two categories: MnZn system and NiZn system according to its composition and application frequency. The former has high magnetic permeability and high saturation magnetic induction. Has lower loss. There are many shapes of magnetic cores, such as EI type, E type, EC type, etc.
Conductor material-enameled wire: Enameled wires generally 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, it is divided into type 1 (thin paint type) and type 2 ( Thick paint type) Two types. The insulating coating of the former is polyester paint, which has excellent heat resistance, and the dielectric strength of the insulation can reach 60kv/mm; the insulating layer of the latter is polyurethane paint, which has strong self-adhesiveness and self-adhesiveness. Solderability (380°C), can be directly welded without removing the paint film
Pressure-sensitive tape: Insulating tape has high electric strength, is easy to use and has good mechanical properties. It is widely used in the interlayer, intergroup insulation and outsourcing insulation of switching transformer coils. It must meet the following requirements: good adhesion, anti-peeling, and certain tensile strength. Tensile strength, good insulation performance, good pressure resistance, flame retardant and high temperature resistance
Skeleton material: The switching transformer skeleton is different from the general transformer skeleton. In addition to being the insulation and support material of the coil, it also undertakes the installation, fixing and positioning of the entire transformer. Therefore, in addition to meeting the insulation requirements, the material for making the skeleton should also have At the same time, in order to withstand the soldering 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.
