How to Measure the Quality of Switching Power Transformer

Composition of switching power transformerThe main materials of switching power transformer: magnetic materials, conductor materials and insulating materials 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 system and NiZn system according to their composition and application frequency. The former has high permeability and high saturation magnetic induction, and has low loss in the medium and low frequency range. There are many shapes of magnetic cores, such as EI type, E type, EC type, etc.

Conductor material - Enamelled Wire: generally used for winding small electronic transformers, there are two kinds of enamelled wires: high strength polyester enamelled wire (QZ) and polyurethane enamelled wire (QA). According to the thickness of paint layer, it is divided into 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, insulation and electrical strength up to 60kV / mm; The insulation layer of the latter is polyurethane paint, which has strong self-adhesive and self welding performance (380 ), and can be welded directly without removing the paint film.

Pressure sensitive tape: the insulating tape has high electrical strength, convenient use and good mechanical performance. It is widely used in interlayer, group insulation and outsourcing insulation of switching transformer coils. The following requirements must be met: good viscosity, anti stripping, certain tensile strength, good insulation, good pressure resistance, flame retardant and high temperature resistance.

Skeleton material: the switch 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, fixation 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 bear the welding heat of the pins, It is required that the thermal deformation temperature of the skeleton material is higher than 200 , and the material must be flame retardant, with good processability and easy to be processed into various shapes

How to judge the quality of switching power transformer1. How to judge whether the switching power supply transformer is good or bad? Check whether there are obvious abnormalities by observing the appearance of the transformer. For example, whether the coil lead is broken, desoldered, whether the insulating material is burnt, whether the iron core fastening screw is loose, whether the silicon steel sheet is rusted, whether the winding coil is exposed, etc.2. How to judge the quality of switching power transformer and insulation test. Multimeter R 10K gear shall measure the resistance between iron core and primary, primary and secondary, iron core and secondary, electrostatic shielding layer and secondary and secondary windings respectively. The pointer of multimeter shall point to the infinity position. Otherwise, the insulation performance of the transformer is poor.

3. How to judge the quality of switching power transformer and the detection of coil on-off. Place the multimeter in R Gear 1: in the test, if the resistance value of a winding is infinite, it indicates that the winding has open circuit fault.Several detection methods of switching power transformerSeveral detection methods of switching power transformer are as follows:

1. Check whether there are obvious abnormalities by observing the appearance of the transformer. For example, whether the coil lead is broken, desoldered, whether the insulating material is burnt, whether the iron core fastening screw is loose, whether the silicon steel sheet is rusted, whether the winding coil is exposed, etc.2. Insulation test. Use the rx10k gear of the universal meter to measure the resistance values between the iron core and the primary, between the primary and each secondary, between the iron core and each secondary, between the electrostatic shielding layer and the secondary and each winding of the secondary. The pointer of the multimeter shall point to the infinity position. Otherwise, the insulation performance of the transformer is poor.3. Coil on-off detection. Put the multimeter in rx1. If the resistance value of a winding is infinite during the test, it indicates that the winding has open circuit fault.

4. Distinguish primary and secondary coils. The primary pin and secondary pin of the power transformer are generally led out from both sides, and the primary winding is mostly marked with the word 220V, while the secondary winding is marked with the rated voltage value, such as 15V, 24V, 35V, etc. Then identify according to these marks.