# Relationship between size and power of annular transformer core

##### author: MagTop
03/02/2023

For the ring transformer we understand that it is composed of ring core, copper wire, insulating film, wire and other materials, so whether the iron core is related to power?Does the bigger the core, the more power it has?
The ring transformer core and power can be said to have a direct relationship between the size of the ring transformer core and the size of the power is proportional to the existence of, that is to say, the greater the power, its volume will increase.
The larger the power of the transformer, the longer the magnetic circuit of the core is required, resulting in the larger the size of the core.
Much of this has to do with the material the core is made of.
The power of annular transformer is determined by core material and cross - sectional area.
The cross-sectional area refers to the cross-sectional (rectangular) area of the core column wrapped by the winding.
After the cross-sectional area S is measured, the power P of the transformer can be estimated according to P=S2/1.5.
Where the unit of S is cm2.
For example: core cross-sectional area S=7cm2, power P=S2/1.5=7*7/1.5=33W, excluding various errors, the actual nominal power is 30W.
Usually, the iron core is made of silicon steel sheet seamless coil, the silicon steel sheet is used to make the iron core of the transformer, because the silicon steel sheet itself is a kind of magnetic material with strong magnetic conductivity, in the wire circle, it can produce a larger magnetic induction intensity to achieve the condition that the iron core becomes smaller, but this does not mean that the volume of the iron core with large power can be infinitely smaller, because the smaller the iron core, the more difficult the production process.
Because of the limitations of the manufacturing process, the core can't be as small as it wants to be.
When the power ring transformer works in AC state, it will produce power loss. Usually, we call this power loss "iron loss". The iron loss is mainly called "hysteresis loss" and "eddy current loss".
Eddy current loss and hysteresis loss are caused by the phenomenon of hysteresis in the magnetization process of the iron core, and the loss is proportional to the area surrounded by the hysteresis loop of the material.
Then, as we need more power, we must reduce this power loss by increasing the area of the core.
Therefore, if you want a large power, you need the larger the volume of the iron core, so that the removal of its iron loss, the power can reach the required value.
The power is also related to the number of turns and diameter of the wire winding.
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