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What is magnetic saturation?

Magnetic saturation is a broad concept that you must understand to be able to work the rest of the terms of the magnetism sector. Read the following article and you will learn what magnetic saturation is.

What does the saturation of the magnet mean?

Permanent magnets obtain their magnetic properties only when they are produced by the application of an external magnetic field. This external magnetic field, to which the resulting magnets are exposed, makes them align uniformly with their smaller elementary magnets. Only this change in the interior of the permanent magnets causes permanent magnetism. The more uniform the elemental magnets are, the stronger the magnetic properties will be. At some point in the magnetization process, all the small elementary magnets are aligned. In this state, the permanent magnet has maximized its magnetic forces. It is no longer possible to increase the magnetic effects of the permanent magnet. Magnetic saturation is achieved.

magnetic saturation

 

Magnets, and the application of magnetic saturation in the magnetic field.

Trying to better illustrate the phenomenon of magnetic saturation. An iron core is inserted into a coil, which can be fed by a variable voltage source with a variable current. The experimental configuration also includes a Hall probe with which the magnetic flux density B (in Tesla) can be measured on the surface of the iron core. If an electrical voltage is now applied to the coil, a current with a very specific current flows through it. As the current increases, so does the measurable magnetic flux density of the iron core. At the beginning of the experiment, when the intensity of the current is still small, doubling it leads to a proportional increase in the density of the magnetic flux, so it is also approximately doubled. If the current increases even further, however, the magnetic flux density curve flattens more and more. Very soon, a point has been reached at which, even with an additional increase in current intensity, finally an increase in magnetic flux density can no longer be measured. The BS saturation point of the iron core is reached at a magnetic flux density of approximately 1-2 Tesla. Physically formulated, the relative permeability μ r approximates value 1. The magnetic permeability μ is composed:

 

μ = μ 0 * μ r

where μ 0The magnetic field constant for vacuum. The closer magnetization comes to magnetic saturation, the more atomic spins aligned to the conductivity of the magnetic field affect it. Electrical energy can only be converted into low-loss magnetic energy if the magnetic field strength of the external magnetic field is as small as possible. Therefore, your current must be small to achieve a low loss energy conversion of electrical energy to magnetic energy. In the case of all permanent magnets, if the magnetic field strength is reduced to 0 (without its change of direction), the residual magnetism remains, the remanence.

 

When magnetic forces favor factors that can affect magnetic saturation.

The structural design of an iron core with an air space leads to a delay in its magnetic saturation. In this way, a desired effect is achieved, with the help of which the magnetic losses of the iron core can be reduced. In every transformer as a technically significant device, therefore, iron cores are provided with air voids. Transformers consist of a simplified representation of two iron cores and two coils, one with many turns, the other with fewer turns. Therefore, an AC voltage can be transformed while reducing the current. The electrical power to transmit is therefore subject to lower losses.

 

Conclusion

Especially in a technically important and frequently used device in practice, the transformer, it is important that this works as a low loss. Therefore, the effort should always go to keep the current as small as possible. Only in this way can losses be minimised by approaching saturation point.

For all your problems with permanent magnets, iron cores or transformers, you can take advantage of our experience in the complex field of magnetism. Contact us at any time.

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