How to Distinguish Genuine High-Voltage Test Transformers from Counterfeits
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High-voltage test transformer is a basic test equipment used by power plants, power supply bureaus, and scientific research institutions for AC withstand voltage tests. It has passed the standards of the National Quality Supervision Bureau and is used for insulation strength tests at specified voltages on various electrical products, electrical components, and insulating materials. It assesses the insulation level of products, detects insulation defects in test objects, and measures overvoltage capability.
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 part. Among these, the quality of silicon steel sheets, high-voltage bushings, insulating materials, and electrical components is most important. Silicon steel sheets are high-silicon non-oriented silicon steel sheets; 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 vast number of users.
1. Using waste silicon steel sheets. This material can be purchased on the market for 5,000-8,000 yuan per ton, while genuine material costs about 36,000 yuan per ton, a price difference of 5-7 times.
2. Electrical materials and components use counterfeit and inferior products, with a price difference of 3-6 times.
3. The price difference between nylon and silicone rubber high-voltage bushings is 2 times.
4. Insulating materials do not use high-quality paper but are replaced by 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 randomly select a transformer and ask to open it immediately to check whether waste silicon steel sheets are used. If the manufacturer hesitates or refuses for various reasons, it indicates that they are definitely using waste silicon steel sheets.
2. Secondly, shake the high-voltage test transformer vigorously in all directions repeatedly, then open the transformer oil valve and drain some transformer oil to see if the oil has turned red or turbid. If the transformer oil appears red or turbid, it indicates that the manufacturer is definitely using waste silicon steel sheets. Waste silicon steel sheets have a large amount of rust attached, which cannot be completely removed no matter how they are treated. After processing into transformer core iron, the rust-laden waste silicon steel sheets are immersed in transformer oil. After repeated washing by the oil, the rust scatters in the oil, turning it red. This phenomenon is especially obvious after long-distance transportation. The rust in the oil poses serious risks to the transformer's insulation, and the transformer's service life will definitely be short.
3. Third, you can also ask the manufacturer to conduct a power-on test. If the no-load current is unqualified, it indicates problems with the materials and manufacturing process. However, without long-distance transportation, the silicon steel sheets may not be easily identified. The quality of silicon steel sheets can be distinguished using the two methods above.
4. Check the material of the high-voltage bushing.
5. Check the electrical components.
Note: The above information and technical parameters are compiled and released by Yangzhou Dare Electric Co., Ltd.
