Dari Electric recommends for you
High-voltage test transformers are basic test equipment used by power plants, power supply bureaus, and scientific research institutions for AC withstand voltage tests. They meet the standards of the National Quality Supervision Bureau and are used for insulation strength tests under specified voltages on various electrical products, components, and insulating materials, to assess the insulation level of products, detect insulation defects in test objects, and measure the ability to withstand overvoltages.
Currently, the quality of high-voltage test transformers on the market is mainly determined by silicon steel sheets, high-voltage bushings, insulating materials, manufacturing processes, and electrical components in the control section. Among these, the quality of silicon steel sheets, high-voltage bushings, insulating materials, and electrical components is the most important. Silicon steel sheets should be high-grade non-oriented silicon steel; high-voltage bushings can be made of nylon, epoxy resin, or silicone rubber, with silicone rubber being the best quality. The prices of test transformers on the market vary greatly. Some manufacturers, in pursuit of maximum profit, use a large amount of inferior materials, harming the interests of users.
1. Using scrap silicon steel sheets. This material can be purchased on the market for 5,000-8,000 yuan per ton, while the genuine material costs about 36,000 yuan per ton, a difference of 5-7 times.
2. Using counterfeit and inferior electrical materials and components, with a price difference of 3-6 times.
3. The price difference between nylon and silicone rubber high-voltage bushings is 2 times.
4. Not using high-quality paper for insulation materials but substituting with other materials.
5. Cutting corners in the manufacturing process.
How to judge the quality of a high-voltage test transformer when purchasing?
1. First, you can go to the manufacturer and ask to see the materials and semi-finished products. You can also choose any transformer at the factory and ask to open it immediately to check whether scrap silicon steel sheets are used. If the manufacturer hesitates or refuses for various reasons, it indicates that they definitely use scrap silicon steel sheets.
2. Secondly, shake the high-voltage test transformer vigorously in all directions as much as possible, then open the transformer oil valve and pour out some transformer oil to see if it has turned red or become turbid. If the oil is red or turbid, it indicates that the manufacturer definitely uses scrap silicon steel sheets, which have a lot of rust attached. No matter how they are treated, the rust cannot be completely removed. After the rusty scrap silicon steel sheets are processed into transformer core iron and immersed in transformer oil, the rust scatters into the oil after repeated washing, turning it red. This phenomenon is especially obvious after long-distance transportation. The rust in the oil poses a serious hidden danger to the transformer's insulation, and the service life of such a transformer will definitely not be long.
3. Thirdly, you can also ask the manufacturer to conduct a power-on test. If the no-load current is unqualified, it indicates problems with both the materials and the manufacturing process. However, without long-distance transportation, the silicon steel sheets may not be visibly defective. The quality of silicon steel sheets can be distinguished using the two methods mentioned above.
4. Check the material used for the high-voltage bushing.
5. Check the electrical components.
Note: The above information and technical parameters are compiled and released by Yangzhou Dari Electric Co., Ltd.
