In the manufacture of transformer, lamination is an important manufacturing link that determines the production quality of transformer, and its technological level determines the quality of the core. Its body is made of electrical magnetic silicon steel sheets stacked, requirements: clean surface, accurate positioning, and uniform compaction between sheets.

Before the transformer lamination, it is necessary to check the incoming materials of the silicon steel sheet to ensure that the surface is clean and pollution-free as much as possible, and the performance is accurate and consistent. The test instruments include: on-line thickness gauge, loss gauge, coating insulation test, pinhole tester, etc. The items tested are: surface quality of silicon steel sheet, unit loss, material thickness, coating insulation, etc.

In the lamination process, the positioning accuracy of each silicon steel sheet is the premise of ensuring the consistency of each parameter. During the lamination process, the lamination should be carried out in strict accordance with the drawing standards. Attention should be paid to: window height error, window width error, diagonal line, iron core up and down, window width error, error between diagonal line and iron core center line. Reducing the positioning error can minimize the impact of shearing stress on the silicon steel sheet and ensure the performance of the finished iron core. Most of the lamination is completed in the manual assembly state, there will be a certain gap between the core lamination, which also has a certain impact on the transformer performance, mainly resulting in the following results.

First of all, it affects the magnetic flux density: the gap between the sheets causes an uneven distribution of the magnetic flux density, which affects the change of the magnetic field. When the magnetic flux density is too high, it may lead to magnetic saturation and reduce the output voltage of the transformer. When the magnetic flux density is too low, it may not meet the working requirements of the equipment. Secondly, there is loss: the magnetic flux density at the gap is higher, resulting in more hysteresis loss and eddy current loss. The efficiency of the transformer is reduced, the operating temperature is increased, and the life of the equipment is affected. There is also the cause of noise: the gap in the core will aggravate the air vibration caused by the magnetic field change, resulting in abnormal noise generation, which will interfere with the operation of the equipment.

In addition, after the lamination is completed, the surface pretreatment and coating material can be carried out according to the actual functional needs to improve the overall beauty and corrosion resistance of the transformer. Protect the core from dust, moisture, rain, snow, salt spray and other environmental factors.