Magnetism, Magnetic Flux and Magnetic Materials

A small magnetic field is formed around the conductor according to the "North" and "South" poles, the direction of the magnetic field is determined by the direction of the current passing through the conductor. Magnetism plays an important role in Electrical and Electronics Engineering because without it, components such as relays, solenoids, inductors, coils,speakers, motors, generators, transformers and electricity meters would not have worked without magnetism.

Each wire coil uses the effect of electromagnetism when an electric current passes through it. But before we look at magnetism, and electromagnetism in particular, in more detail, we need to go back to our physics classes on how magnetism and magnetism work.

The Nature of Magnetism

Magnets can be found in a natural state in the form of magnetic ore. Its two main species are Magnetite, also called "iron oxide", (FE3O4) and Lodestone, also called the "pioneer stone". If these two natural magnets hang on a piece of rope, the Earth's magnetic field will always take a position aligned to point north.

A good example of this effect is the hand of the compass. In most practical applications, these naturally occurring magnets can be ignored, since their magnetism is very low, and today man-made artificial magnets can be produced in many different shapes, sizes and magnetic forces.

Basically there are two forms of magnetism, "Permanent Magnets" and "Temporary Magnets", which vary depending on the type of application used. There are many different types of materials to make magnets, such as iron, nickel, nickel alloys, chromium and cobalt, and some of these elements, such as nickel and cobalt, show very weak magnetic amounts on their own in their natural state.

However, when mixed with or "alloyed" with other materials such as iron or aluminum peroxide, they become very powerful magnets that produce unusual names such as "alcomax", "hycomax", "alni" and "alnico".

The non-magnetic material has its molecular structure in the form of loose magnetic chains or separate small magnets loosely arranged in a random order. The overall effect of such an arrangement results in zero or very weak magnetism, since this haphazard arrangement of each molecular magnet tends to neutralize its neighbor.

When the material is magnetized, this random order of molecules changes, and small unaligned and random molecular magnets are "sorted" to form a series of magnetic arrangements. The idea of molecular alignment of ferromagnetic materials is known as the Weber Theory and is shown below.

Magnetic Molecule Alignment of a Piece of Iron and a Magnet

Magnetic Molecule Alignment of a Piece of Iron and a Magnet

Weber's theory is based on the fact that all atoms have magnetic properties due to the rotational motion of atomic electrons. Atom groups combine so that their magnetic fields all rotate in the same direction. Magnetic materials consist of small groups of magnets around atoms at the molecular level, and a magnetized material, most of its small magnets are sorted in one direction to form an arctic in only one direction and a south pole in the other. .

Similarly, a material that looks at small molecular magnets in all directions will neutralize its molecular magnets by its neighboring magnet, thereby neutralizing any magnetic effect. These areas of molecular magnets are called "domains".

Any magnetic material will produce a magnetic field that depends on the degree of alignment of the magnetic fields in the material created by the orbit and rotating electrons. This degree of alignment, magnetization, can be determined by an amount known as M.

In an uncontested material, M = 0, but after the magnetic field is removed, some areas remain aligned on the small regions in the material. The effect of applying a magnetizing force to the material is to align some areas to produce a non-zero magnetization value.

After the magnetism force is removed, the magnetism in the material either remains or decreases rapidly, depending on the magnetic material used. The ability to maintain the magnetism of a material is called permanence. The materials that should protect their magnetism will have quite high permanence.

Magnetic Flux

All magnets, regardless of their shape, have two regions called magnetic poles, and magnetism both inside and around the magnetic circuit forms a certain chain of organized and balanced invisible flux lines around them. These flux lines are collectively called the magnet's "magnetic field". The shape of this magnetic field is denser in some parts than in others, and the area where the magnet has the greatest magnetism is called "poles". A magnet has a pole at both ends.

These flux lines (called vector fields) are invisible to the naked eye, but they can be visually visible to track them using iron fillings sprinkled on a piece of paper or a small compass. Magnetic poles are always found in pairs, the magnet always has a region called the North Pole, and it always has an opposite region called the South Pole.

Magnetic fields are always visually shown as force lines that give a certain pole at both ends of the material, where the flux lines are denser and denser. Lines that create a magnetic field that indicates direction and intensity are called Force Lines or, more commonly, "Magnetic Flux", and are given the Greek symbol Phi ( Φ), as shown below.

Force Lines From the Magnetic Field of Rod Magnets

As shown above, the magnetic field is strongest near the poles of the magnet, if the flux lines are more closely spaced. The general direction of magnetic flux flow is between the North (N) and the South (S) pole. In addition, these magnetic lines form closed loops that exit the north pole of the magnet and enter from the south pole. Magnetic poles are always even.

However, magnetic flux does not actually flow from the north to the south pole or flow anywhere in this regard. Because magnetic flux is a static region around a magnet where magnetic force exists. In other words, the magnetic flux does not flow or move, it is only there and is not affected by gravity. When drawing strength lines, some important facts emerge:

  • The lines of strength never intersect.
  • Force lines ARE CONTINUOUS.
  • Force lines always create separate CLOSED LOOPS around the magnet.
  • The force lines have a definite NORTH-to-south DIRECTION.
  • The force lines that are close to each other indicate a STRONG magnetic field.
  • The force lines, which are further apart, indicate a WEAK magnetic field.

Magnetic forces pull and push like electrical forces, and when the two force lines are close together, the interaction between the two magnetic fields causes one of two things to occur:

  1. – Pushes each other when the neighboring poles are the same (north-north or south-south).
  2. – Attracts each other when the neighboring poles are not the same (north-south or south-north).
    This effect is easily remembered with the famous phrase "opposites attract", and this interaction of magnetic fields can be easily demonstrated using iron fillers to show the force lines around a magnet. The effect of various polar combinations on their magnetic fields, such as similar poles pushing each other and different poles attracting each other, can be seen below.

Magnetic Field of Similar and Different Poles

When magnetic field lines are drawn with a compass, it will be seen that the force lines are produced to give a certain pole at both ends of the magnet, which is separated from the north pole and re-entered. The South Pole. Magnetism can be destroyed by heating or hammering magnetic material, but it cannot be destroyed or isolated simply by dividing the magnet into two parts.

So if you take a normal stick magnet and cut it in half, you don't have two halves of a magnet, instead each broken piece somehow has its own North Pole and a South pole. If you take one of these parts and cut them in half again, each of the smaller pieces will have an Arctic and a South pole, etc. No matter how small the parts of the magnet get, each piece will still have an Arctic and a South pole,

So in order to benefit from magnetism in electrical or electronic calculations, we need to define what are the various aspects of magnetism.

The Magnitude of Magnetism

We now know that magnetic flux around the force lines, or more commonly a magnetic material, was given the Greek symbol Phi (Φ), whose flux unit was Weber (Wb) after Wilhelm Eduard Weber. However, the number of force lines in a particular unit area is called "Flux Density", and since the flux ( Φ ) ( Wb ) and area ( A ) are measured in square meters ( m2 ), the flux density is therefore indicated by webers/meter2 or ( Wb/m2 ) and symbol B.

However, when talking about flux density in magnetism, the flux density is given tesla's unit after Nikola Tesla, so a Wb/m2 is equal to a Tesla, 1Wb/m2 = 1T. Flux density is proportional to the force lines and inversely proportional to the area, so we can define flux density as follows:

Magnetic Flux Density

Magnetic Flux Density

The symbol of magnetic flux density is B, and the unit of magnetic flux density is Tesla, T.

Example of Magnetism

The amount of flux present in a round magnetic rod was measured at 0.013 weber. If the diameter of the material is 12 cm, calculate the flux density.

The cross-sectional area of magnetic material in m2 is given as follows:

Magnetic flux is given as 0.013 weber, so the flux density can be calculated as follows:

Thus, the flux density is calculated as 1.15 Tesla.

When dealing with magnetism in electrical circuits, it should be remembered that a Tesla has the density of a magnetic field and is exposed to a Newton meter-long force on a conductor that carries 1 amp at right angles to the magnetic field. In our next article, we will enter the topic of electromagnetism.