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There are many technical indicators of power transformers, such as efficiency, temperature rise, volume, cost, etc. and they are related to each other.
For the Low-Frequency Power Transformer, the Exciting Current Is Better to Get as Small as Possible?
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Author: Site Editor
Publish Time: 2023-07-14
Origin: Site
The exciting current is one of the main technical indicators of the power transformer, but it is not the only indicator. There are many technical indicators of power transformers, such as efficiency, temperature rise, volume, cost, etc. and they are related to each other.
Therefore, it is inappropriate to blindly pursue a small exciting current.
For example:
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Some power transformers, the exciting curruent is very small, but the iron core loss is very large. Iron loss is the main component converted into heat energy.
Under the condition of no-load operation, the temperature rise of the transformer with large iron loss must be higher.
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For a power transformer made of the same size of iron core, in order to get the small exciting current, it needs to wind more turns.
In this case, the bigger internal resistance of the copper wire, the bigger attenuation of the working voltage, the bigger copper loss, the higher temperature rise, and the worse the efficiency. And the cost become higher and high. To lead that the price is not competitive.
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The exciting current is mainly equal to the sum of the magnetizing current and the iron loss current vector, in generally, 90% is the magnetizing current (determined by the performance of the iron core).
The designer of the power transformer should choose 80%-85% of the saturation magnetic flux as the working magnetic flux to ensure that the transformer still operates normally when the grid voltage fluctuates upward by 15%-20%.
The exciting current big or small, is determined by the characteristics of the iron core and the working magnetic flux. Except for some circuits that have extremely strict requirements on magnetic flux leakage, the exciting current is not as important as people think.
