What are the main reasons for the increase in no-load loss and current of transformers?

The no-load current of transformers is determined by impedance. If the performance and quality of silicon steel sheets are poor, or if the manufacturing process of the iron core is poor, the laminations are uneven, the joints are too large, and the clamping force is too small or too large, it will cause the no-load current to increase. Another situation is that the design has too few coil turns or the cross-sectional area of the iron core is too small, resulting in high magnetic flux density and increased no-load current. Generally speaking, the no-load current of low-frequency transformers is between 3% and 10%, depending on the type of transformer made of different materials.

After a period of use, the no-load current of the transformer increases, and it is necessary to check for winding short circuits or control feedback circuit short circuits. Whether it is a control transformer, Autotransformer or isolation transformer, it is composed of silicon steel sheet, primary winding, secondary winding, insulating paint, etc. All transformers will have no-load loss and increase of no-load current. What are the main reasons for the increase in no-load loss and current of transformers? Let’s analyze together:

1. Poor insulation effect between silicon steel sheets

2. Short circuit between certain silicon steel sheets in the magnetic circuit

3. Loose silicon steel sheets in the magnetic circuit result in air gaps, increasing magnetic resistance

4. Insulation damage to core bolts or pressure plates, upper yoke iron, and other parts, resulting in short circuits

5. The number of turns in each parallel branch is different

6. The coil has a short circuit between turns or parallel branches

7. Incorrect acquisition of winding ampere turns

So in the production process of transformers, raw materials determine the quality of the product, but at the same time, each process link is also extremely important.

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