Dry-type transformers are widely used in local lighting, high-rise buildings, airports, wharf CNC machinery and equipment and other places. In simple terms, dry-type transformers refer to transformers whose iron cores and windings are not immersed in insulating oil. Cooling methods are divided into natural air cooling (AN) and forced air cooling (AF). In the process of natural air cooling, the transformer can run continuously at the rated capacity for a long time. When forced air cooling, the output capacity of the transformer can be increased by 50%. It is suitable for intermittent overload operation or emergency overload operation; due to the large increase in load loss and impedance voltage during overload, it is in a non-economic operation state, and it is not suitable to maintain continuous overload operation for a long time. structure type: It is mainly composed of an iron core made of silicon steel sheets and an epoxy resin cast coil. Insulating cylinders are placed between the high and low voltage coils to increase electrical insulation, and the coils are supported and restrained by spacers. Fasteners with overlapping portions have anti-loosening properties. Construction performance: (1) Solid insulation encapsulated winding ⑵ not encapsulated winding Winding: Among the two windings, the higher voltage is the high-voltage winding, and the lower voltage is the low-voltage winding. From the perspective of the relative position of the high and low voltage windings, the high voltage can be divided into concentric and overlapping types. The concentric winding is simple and easy to manufacture, and this structure is adopted. Overlapped, mainly used for special transformers. Structure: Because dry-type transformers have the advantages of strong short-circuit resistance, low maintenance workload, high operating efficiency, small size, and low noise, they are often used in places with high performance requirements such as fire and explosion protection. 1. Safe, fireproof and pollution-free, and can be operated directly in the load center; 2. Adopt domestic advanced technology, high mechanical strength, strong short-circuit resistance, small partial discharge, good thermal stability, high reliability and long service life; 3. Low loss, low noise, obvious energy saving effect, maintenance-free; 4. Good heat dissipation performance, strong overload capacity, can increase capacity operation when forced air cooling; 5. Good moisture resistance, suitable for operation in harsh environments such as high humidity; 6. Dry-type transformers can be equipped with a complete temperature detection and protection system. The intelligent signal temperature control system can automatically detect and display the respective working temperatures of the three-phase windings, automatically start and stop the fan, and have functions such as alarming and tripping. 7. Small size, light weight, less space occupation and low installation cost. iron core dry-type transformer dry-type transformer High-quality cold-rolled oriented silicon steel sheet is used, and the iron core silicon steel sheet adopts a 45-degree full oblique joint, so that the magnetic flux passes along the seam direction of the silicon steel sheet. winding form (1) winding; Epoxy resin is added with quartz sand for filling and pouring; (3) Glass fiber reinforced epoxy resin casting (ie thin thermal insulation structure); ⑷Multi-strand glass fiber impregnated epoxy resin winding type (generally use 3, because it can effectively prevent the casting resin from cracking and improve the reliability of the equipment). High voltage winding Generally, a multi-layer cylindrical or multi-layer segmented structure is used.
