home-Internal stairs-Permanent magnets. Magnetic flux switching systems Addition of magnetic fields of permanent magnets

Permanent magnets. Magnetic flux switching systems Addition of magnetic fields of permanent magnets

To understand how to increase the strength of a magnet, you need to understand the process of magnetization. This will happen if the magnet is placed in an external magnetic field opposite side to the original one. An increase in the power of the electromagnet occurs when the current supply increases or the turns of the winding are multiplied.


You can increase the strength of a magnet using a standard set necessary equipment: glue, a set of magnets (you need permanent ones), a current source and an insulated wire. They will be needed to implement the methods of increasing the strength of a magnet, which are presented below.

Reinforcement with a more powerful magnet

This method involves using more powerful magnet to enhance the original one. To implement this, you need to place one magnet in the external magnetic field of another, which has greater power. Electromagnets are also used for the same purpose. After holding a magnet in the field of another, amplification will occur, but the specificity lies in the unpredictability of the results, since for each element such a procedure will work individually.



Strengthening by adding other magnets

It is known that every magnet has two poles, and each attracts opposite sign other magnets, but the corresponding one does not attract, only repels. How to increase the power of a magnet using glue and additional magnets. This involves adding other magnets to increase the final power. After all, the more magnets, the correspondingly there will be more power. The only thing that needs to be taken into account is the connection of magnets with like poles. In the process, they will repel each other, according to the laws of physics. But the challenge is gluing, despite the physical difficulties. It is better to use glue that is designed for gluing metals.

Curie Point Enhancement Method

In science there is the concept of the Curie point. Strengthening or weakening of a magnet can be done by heating or cooling it relative to this point itself. Thus, heating above the Curie point or strong cooling (much below it) will lead to demagnetization.

It should be noted that the properties of a magnet when heated and cooled relative to the Curie point have an abrupt property, that is, having achieved the correct temperature, its power can be increased.

Method No. 1

If the question arises of how to make a magnet stronger if its strength is regulated by electric current, then this can be done by increasing the current supplied to the winding. Here there is a proportional increase in the power of the electromagnet and the current supply. The main thing is ⸺ gradual feeding to prevent burnout.

Method No. 2

To implement this method, the number of turns must be increased, but the length must remain the same. That is, you can make one or two additional rows of wire so that the total number of turns becomes larger.

This section discusses ways to increase the strength of a magnet at home; experiments can be ordered on the MirMagnitov website.

Strengthening a regular magnet

Many questions arise when ordinary magnets cease to perform their direct functions. This often happens due to the fact that household magnets are not such magnets, because, in fact, they are magnetized metal parts that lose their properties over time. It is impossible to enhance the power of such parts or return them to their original properties.

It should be noted that it makes no sense to attach magnets to them, even more powerful ones, since when they are connected with reverse poles, the external field becomes much weaker or is completely neutralized.

This can be checked using an ordinary household mosquito curtain, which should be closed in the middle using magnets. If you attach more powerful magnets on top of weak initial magnets, then as a result the curtain will generally lose its connection properties through attraction, because the opposite poles neutralize each other’s external fields on each side.

Experiments with neodymium magnets

Neomagnet is quite popular, its composition: neodymium, boron, iron. This magnet has high power and is resistant to demagnetization.

How to strengthen neodymium? Neodymium is very susceptible to corrosion, that is, it rusts quickly, so neodymium magnets are coated with nickel to increase service life. They also resemble ceramics and are easy to break or crack.

But try to increase its power artificially there is no point, because it is a permanent magnet, it has a certain level of strength for itself. Therefore, if you need to have a more powerful neodymium, it is better to purchase it, taking into account the required strength of the new one.


Conclusion: the article discusses the topic of how to increase the strength of a magnet, including how to increase the power of a neodymium magnet. It turns out that there are several ways to increase the properties of a magnet. Because there is simply magnetized metal, the strength of which cannot be increased.

Most simple ways: using glue and other magnets (they must be glued with identical poles), as well as a more powerful one, in the external field of which the original magnet must be located.

Methods for increasing the strength of an electromagnet are considered, which consist of additional winding with wires or increasing the flow of current. The only thing that needs to be taken into account is the strength of the current flow for the safety and security of the device.

Conventional and neodymium magnets are not capable of increasing their own power.

a) General information. To create a constant magnetic field in a number of electrical apparatus permanent magnets are used, which are made of hard magnetic materials that have a wide hysteresis loop (Fig. 5.6).

The work of a permanent magnet occurs in the area from H= 0 before H = - N s. This part of the loop is called the demagnetization curve.

Let us consider the basic relationships in a permanent magnet having the shape of a toroid with one small gap b(Fig. 5.6). Due to the toroidal shape and small gap, leakage fluxes in such a magnet can be neglected. If the gap is small, then the magnetic field in it can be considered uniform.


Fig.5.6. Permanent magnet demagnetization curve

If we neglect bulging, then the induction in the gap IN & and inside the magnet IN are the same.

Based on the total current law with closed loop integration 1231 rice. we get:


Fig.5.7. Permanent magnet shaped like a toroid

Thus, the field strength in the gap is directed opposite to the strength in the magnet body. For a direct current electromagnet having a similar shape of the magnetic circuit, without taking into account saturation, we can write: .

Comparing, you can see that in the case of a permanent magnet n. c, creating a flux in the working gap, is the product of the tension in the body of the magnet and its length with the opposite sign - Hl.

Taking advantage of the fact that

, (5.29)

, (5.30)

Where S- pole area; - conductivity of the air gap.

The equation is the equation of a straight line passing through the origin in the second quadrant at an angle a to the axis N. Taking into account the scale of induction t in and tension tn angle a is determined by the equality

Since induction and tension magnetic field in the body of a permanent magnet are connected by a demagnetization curve, then the intersection of the indicated straight line with the demagnetization curve (point A in Fig. 5.6) and determines the state of the core at a given gap.

With a closed circuit and

With growth b conductivity of the working gap and tga decrease, the induction in the working gap decreases, and the field strength inside the magnet increases.

One of important characteristics permanent magnet is the energy of the magnetic field in the working gap Wt. Considering that the field in the gap is uniform,

Substituting the value N b we get:

, (5.35)

where V M is the volume of the magnet body.

Thus, the energy in the working gap is equal to the energy inside the magnet.

Product dependency B(-N) in the induction function is shown in Fig. 5.6. Obviously, for point C, at which B(-N) reaches its maximum value, the energy in the air gap also reaches its greatest value, and from the point of view of using a permanent magnet, this point is optimal. It can be shown that point C, corresponding to the maximum of the product, is the point of intersection with the beam demagnetization curve OK, drawn through a point with coordinates and .

Let's take a closer look at the effect of the gap b by the amount of induction IN(Fig. 5.6). If the magnet was magnetized with a gap b, then after removing the external field, an induction will be established in the body of the magnet corresponding to the point A. The position of this point is determined by gap b.

Reduce the gap to the value , Then

. (5.36)

As the gap decreases, the induction in the magnet body increases, but the process of changing the induction does not follow the demagnetization curve, but along a branch of a private hysteresis loop AMD. Induction IN 1 is determined by the point of intersection of this branch with a ray drawn at an angle to the axis - N(dot D).

If we increase the gap again to the value b, then the induction will drop to the value IN, moreover, dependence V (H) will be determined by branch DNA private hysteresis loop. Typically a partial hysteresis loop AMDNA is quite narrow and is replaced by a straight one A.D. which is called direct return. The inclination to the horizontal axis (+ H) of this straight line is called the coefficient of return:

. (5.37)

The demagnetization characteristics of a material are usually not given in full, but only the saturation induction values ​​are specified. Bs, residual induction In g, coercive force N s. To calculate a magnet, it is necessary to know the entire demagnetization curve, which for most hard magnetic materials is well approximated by the formula

The demagnetization curve expressed by (5.30) can be easily plotted graphically if the B s, B r.

b) Determination of flux in the working gap for a given magnetic circuit. In a real system with a permanent magnet, the flux in the working gap differs from the flux in the neutral section (the middle of the magnet) due to the presence of leakage and bulging fluxes (Fig.).

The flow in the neutral section is equal to:

, (5.39)

where is the flow in the neutral section;

Bulging flow at the poles;

Leakage flux;

Work flow.

The scattering coefficient o is determined by the equality

If we assume that the flows are created by the same magnetic potential difference, then

. (5.41)

We find the induction in the neutral section by defining:

,

and using the demagnetization curve Fig. 5.6. The induction in the working gap is equal to:

since the flow in the working gap is several times less than the flow in the neutral section.

Very often, the magnetization of the system occurs in an unassembled state, when the conductivity of the working gap is reduced due to the absence of parts made of ferromagnetic material. In this case, the calculation is carried out using direct return. If the leakage fluxes are significant, then it is recommended to carry out the calculation in sections, just as in the case of an electromagnet.

Leakage fluxes in permanent magnets play a much larger role than in electromagnets. The fact is that the magnetic permeability of hard magnetic materials is significantly lower than that of soft magnetic materials from which systems for electromagnets are made. Leakage fluxes cause a significant drop in the magnetic potential along the permanent magnet and reduce n. s, and therefore the flow in the working gap.

The dissipation coefficient of completed systems varies within fairly wide limits. Calculation of the scattering coefficient and scattering fluxes is associated with great difficulties. Therefore, when developing a new design, it is recommended to determine the value of the dissipation coefficient on a special model in which the permanent magnet is replaced by an electromagnet. The magnetizing winding is selected in such a way as to obtain the required flux in the working gap.


Fig.5.8. Magnetic circuit with a permanent magnet and leakage and bulging fluxes

c) Determining the size of the magnet based on the required induction in the working gap. This task is even more difficult than determining the flow with known dimensions. When choosing the dimensions of a magnetic circuit, one usually strives to ensure that the induction B 0 and tension H 0 in the neutral section corresponded to the maximum value of the product H 0 V 0 . In this case, the volume of the magnet will be minimal. The following recommendations are given for the selection of materials. If it is necessary to obtain a large induction value with large gaps, then the most suitable material is Magnico. If, with a large gap, it is necessary to create small inductions, then Alnisi can be recommended. With small working gaps and great importance induction it is advisable to use alni.

The cross section of the magnet is selected from the following considerations. The induction in the neutral section is chosen equal to At 0. Then the flow in the neutral section

,

where does the cross section of the magnet come from?

.
Induction values ​​in the working gap In p and pole area are given quantities. The most difficult thing is to determine the value of the coefficient scattering. Its value depends on the design and induction in the core. If the magnet cross-section is large, then several magnets connected in parallel are used. The length of the magnet is determined from the condition for creating the necessary n.s. in the working gap at tension in the magnet body H 0:

Where b p - the size of the working gap.

After selecting the main dimensions and designing the magnet, a verification calculation is carried out using the method described earlier.

d) Stabilization of magnet characteristics. During operation of the magnet, a decrease in the flux in the working gap of the system is observed - aging of the magnet. There are structural, mechanical and magnetic aging.

Structural aging occurs due to the fact that after hardening of the material, internal stresses arise in it, and the material acquires a heterogeneous structure. During operation, the material becomes more homogeneous, internal stresses disappear. In this case, the residual induction In t and coercivity N s are decreasing. To combat structural aging, the material is subjected to heat treatment in the form of tempering. In this case, internal stresses in the material disappear. Its characteristics become more stable. Aluminum-nickel alloys (alni, etc.) do not require structural stabilization.

Mechanical aging Occurs due to shocks and vibrations of the magnet. In order to make the magnet insensitive to mechanical stress, it is subjected to artificial aging. Before installation into the apparatus, magnet samples are subjected to the same shocks and vibrations that occur during operation.

Magnetic aging is a change in the properties of a material under the influence of external magnetic fields. A positive external field increases the induction along the direct return, and a negative external field reduces it along the demagnetization curve. In order to make the magnet more stable, it is subjected to a demagnetizing field, after which the magnet operates on the return line. Due to the lower slope of the return line, the influence of external fields is reduced. When calculating magnetic systems with permanent magnets, it is necessary to take into account that during the stabilization process the magnetic flux decreases by 10-15%.

Switching systems magnetic flux based on switching the magnetic flux relative to removable coils.
The essence of the CE devices reviewed on the Internet is that there is a magnet, for which we pay once, and there is a magnetic field of the magnet, for which no one pays money.
The question is that it is necessary to create conditions in transformers with switching magnetic fluxes under which the magnetic field becomes controllable and we direct it. interrupt. redirect like this. so that the switching energy is minimal or cost-free

In order to consider options for these systems, I decided to study and present my thoughts on new ideas.

To begin with, I wanted to look at what magnetic properties a ferromagnetic material has, etc. Magnetic materials have a coercive force.

Accordingly, the coercive force obtained by cycle, or by cycle, is considered. Designated accordingly and

The coercive force is always greater. This fact is explained by the fact that in the right half-plane of the hysteresis graph the value is greater than , by the amount:

In the left half-plane, on the contrary, it is less than , by an amount . Accordingly, in the first case the curves will be located above the curves, and in the second - below. This makes the hysteresis cycle narrower than the cycle.

Coercive force

Coercive force - (from Latin coercitio - retention), the value of magnetic field strength required for complete demagnetization of a ferro- or ferrimagnetic substance. Measured in Ampere/meter (SI system). Based on the magnitude of the coercive force, the following magnetic materials are distinguished:

Soft magnetic materials are materials with low coercive force that are magnetized to saturation and remagnetized in relatively weak magnetic fields with a strength of about 8-800 a/m. After magnetization reversal, they do not externally exhibit magnetic properties, since they consist of randomly oriented regions magnetized to saturation. An example is various steels. The more coercive force a magnet has, the more resistant it is to demagnetizing factors. Hard magnetic materials are materials with a high coercive force that are magnetized to saturation and remagnetized in relatively strong magnetic fields with a strength of thousands and tens of thousands of a/m. After magnetization, hard magnetic materials remain permanent magnets due to high values ​​of coercivity and magnetic induction. Examples are rare earth magnets NdFeB and SmCo, barium and strontium hard magnetic ferrites.

As the mass of the particle increases, the radius of curvature of the trajectory increases, and according to Newton’s first law, its inertia increases.

With increasing magnetic induction, the radius of curvature of the trajectory decreases, i.e. The centripetal acceleration of the particle increases. Consequently, under the influence of the same force, the change in particle speed will be less, and the radius of curvature of the trajectory will be greater.

As the charge of the particle increases, the Lorentz force (magnetic component) increases, and therefore the centripetal acceleration also increases.

When the speed of motion of a particle changes, the radius of curvature of its trajectory changes, and the centripetal acceleration changes, which follows from the laws of mechanics.

If a particle flies into a uniform magnetic field by induction IN at an angle other than 90°, then the horizontal component of the velocity does not change, but the vertical component under the influence of the Lorentz force acquires centripetal acceleration, and the particle will describe a circle in a plane perpendicular to the vector of magnetic induction and velocity. Due to the simultaneous movement along the direction of the induction vector, the particle describes a helical line, and will return to the original horizontal at regular intervals, i.e. cross it at equal distances.

The braking interaction of magnetic fields is called Foucault currents

As soon as the circuit in the inductor is closed, two counter-directed currents begin to act around the conductor. According to Lenz’s law, positive charges The electrogas (ether) begins its screw motion, activating the atoms through which an electrical connection is established. Hence it is impossible to explain the presence of magnetic action and reaction.

By this I explain the inhibition of the exciting magnetic field and the opposition to it in a closed circuit, the braking effect in the electric generator (mechanical braking or the resistance of the rotor of the electric generator to the mechanically applied force and the resistance (braking) of the Foucault current to the falling neodymium magnet falling in the copper tube.

A little about magnetic motors

The principle of switching magnetic fluxes is also applied here.
But it’s easier to move on to drawings.

How this system should work.

The middle coil is removable and operates on a relatively wide pulse length, which is created by the passage of magnetic fluxes from the magnets shown in the diagram.
The pulse length is determined by the inductance of the coil and the load resistance.
Once the time has elapsed and the core becomes magnetized, the core itself must be interrupted, demagnetized, or remagnetized. to continue working with the load.


There are two main types of magnets: permanent and electromagnets. You can determine what a permanent magnet is based on its main properties. Permanent magnet got its name because its magnetism is always “on”. It generates its own magnetic field, unlike an electromagnet, which is made of wire wrapped around an iron core and requires current to flow to create a magnetic field.

History of the study of magnetic properties

Centuries ago, people discovered that some types rocks have original features: attracted to iron objects. Mention of magnetite is found in ancient historical chronicles: more than two thousand years ago in European and much earlier in East Asian ones. At first it was regarded as a curious object.

Later, magnetite was used for navigation, finding that it tends to occupy a certain position when given the freedom to rotate. Scientific research carried out by P. Peregrine in the 13th century, showed that steel could acquire these characteristics after being rubbed with magnetite.

Magnetized objects had two poles: “north” and “south,” relative to the Earth’s magnetic field. As Peregrine discovered, isolating one of the poles was not possible by cutting a fragment of magnetite in two - each individual fragment ended up with its own pair of poles.

In accordance with today's concepts, the magnetic field of permanent magnets is the resulting orientation of electrons in a single direction. Only some types of materials interact with magnetic fields; a much smaller number of them are capable of maintaining a constant magnetic field.

Properties of permanent magnets

The main properties of permanent magnets and the field they create are:

  • the existence of two poles;
  • opposite poles attract, and like poles repel (like positive and negative charges);
  • magnetic force imperceptibly spreads in space and passes through objects (paper, wood);
  • An increase in MF intensity is observed near the poles.

Permanent magnets support the MP without external assistance. Depending on their magnetic properties, materials are divided into main types:

  • ferromagnets – easily magnetized;
  • paramagnetic materials – are magnetized with great difficulty;
  • Diamagnets - tend to reflect external magnetic fields by magnetizing in the opposite direction.

Important! Soft magnetic materials such as steel conduct magnetism when attached to a magnet, but this stops when it is removed. Permanent magnets are made from hard magnetic materials.

How does a permanent magnet work?

His work deals with atomic structure. All ferromagnets create a natural, albeit weak, magnetic field, thanks to the electrons surrounding the nuclei of atoms. These groups of atoms are able to orient themselves in the same direction and are called magnetic domains. Each domain has two poles: north and south. When a ferromagnetic material is not magnetized, its regions are oriented in random directions, and their magnetic fields cancel each other out.

To create permanent magnets, ferromagnets are heated at very high temperatures and exposed to strong external magnetic fields. This leads to the fact that individual magnetic domains inside the material begin to orient themselves in the direction of the external magnetic field until all domains are aligned, reaching the point of magnetic saturation. The material is then cooled and the aligned domains are locked into position. Once the external MF is removed, hard magnetic materials will retain most of their domains, creating a permanent magnet.

Characteristics of permanent magnet

  1. Magnetic force is characterized by residual magnetic induction. Designated Br. This is the force that remains after the disappearance of the external MP. Measured in tests (T) or gauss (G);
  2. Coercivity or resistance to demagnetization - Ns. Measured in A/m. Shows what the external MF intensity should be in order to demagnetize the material;
  3. Maximum energy – BHmax. Calculated by multiplying the remanent magnetic force Br and coercivity Hc. Measured in MGSE (megaussersted);
  4. Temperature coefficient of residual magnetic force – Тс of Br. Characterizes the dependence of Br on the temperature value;
  5. Tmax – highest value temperature at which permanent magnets lose their properties with the possibility of reverse recovery;
  6. Tcur is the highest temperature value at which the magnetic material irreversibly loses its properties. This indicator is called the Curie temperature.

Individual magnet characteristics change depending on temperature. At different meanings temperature different types magnetic materials work differently.

Important! All permanent magnets lose a percentage of magnetism as the temperature rises, but with at different speeds depending on their type.

Types of permanent magnets

There are five types of permanent magnets, each of which is manufactured differently using materials with different properties:

  • alnico;
  • ferrites;
  • rare earth SmCo based on cobalt and samarium;
  • neodymium;
  • polymer.

Alnico

These are permanent magnets consisting primarily of a combination of aluminum, nickel and cobalt, but may also include copper, iron and titanium. Due to the properties of alnico magnets, they can operate at the highest temperatures while retaining their magnetism, but they demagnetize more easily than ferrite or rare earth SmCo. They were the first mass-produced permanent magnets, replacing magnetized metals and expensive electromagnets.

Application:

  • electric motors;
  • heat treatment;
  • bearings;
  • aerospace vehicles;
  • military equipment;
  • high temperature loading and unloading equipment;
  • microphones.

Ferrites

To make ferrite magnets, also known as ceramic, strontium carbonate and iron oxide are used in a ratio of 10/90. Both materials are abundant and economically available.

Due to their low production costs, resistance to heat (up to 250°C) and corrosion, ferrite magnets are one of the most popular magnets for everyday use. They have greater internal coercivity than alnico, but less magnetic strength than their neodymium counterparts.

Application:

  • sound speakers;
  • security systems;
  • large plate magnets for removing iron contamination from process lines;
  • electric motors and generators;
  • medical instruments;
  • lifting magnets;
  • marine search magnets;
  • devices based on the operation of eddy currents;
  • switches and relays;
  • brakes

Rare Earth SmCo Magnets

Cobalt and samarium magnets operate over a wide temperature range, have high temperature coefficients and high corrosion resistance. This type retains magnetic properties even at temperatures below absolute zero, making them popular for use in cryogenic applications.

Application:

  • turbo technology;
  • pump couplings;
  • wet environments;
  • high temperature devices;
  • miniature electric racing cars;
  • radio-electronic devices for operation in critical conditions.

Neodymium magnets

The strongest existing magnets, consisting of an alloy of neodymium, iron and boron. Thanks to their enormous power, even miniature magnets are effective. This provides versatility of use. Each person is constantly near one of the neodymium magnets. They are, for example, in a smartphone. The manufacture of electric motors, medical equipment, and radio electronics rely on ultra-strong neodymium magnets. Due to their ultra-strength, enormous magnetic force and resistance to demagnetization, samples up to 1 mm are possible.

Application:

  • hard disks;
  • sound-reproducing devices – microphones, acoustic sensors, headphones, loudspeakers;
  • prostheses;
  • magnetically coupled pumps;
  • door closers;
  • engines and generators;
  • locks on jewelry;
  • MRI scanners;
  • magnetic therapy;
  • ABS sensors in cars;
  • lifting equipment;
  • magnetic separators;
  • reed switches, etc.

Flexible magnets contain magnetic particles inside a polymer binder. Used for unique devices where installation of solid analogues is impossible.

Application:

  • display advertising – quick fixation and quick removal at exhibitions and events;
  • signs Vehicle, educational school panels, company logos;
  • toys, puzzles and games;
  • masking surfaces for painting;
  • calendars and magnetic bookmarks;
  • window and door seals.

Most permanent magnets are fragile and should not be used as structural elements. They are made in standard forms: rings, rods, disks, and individual: trapezoids, arcs, etc. Neodymium magnets, due to their high iron content, are susceptible to corrosion, so they are coated with nickel, stainless steel, Teflon, titanium, rubber and other materials.

Video

Now I’ll explain: It’s just such a thing in life that you can’t do it too much, but you really want to (it’s just creepy)… But the point here is the following. Some kind of fate hangs over the “regulars”, an aura of mystery and reticence. All physicists (both men and women are different) are completely clueless about permanent magnets (tested repeatedly, personally), and this is probably because all physics textbooks avoid this issue. Electromagnetism - yes, that's it, please, but not a word about constants...

Let's see what can be squeezed out of the smartest book “I.V. Savelyev. General physics course. Volume 2. Electricity and Magnetism,” - you’ll hardly be able to dig up anything cooler than this waste paper. So, in 1820, a certain guy named Ørsted started an experiment with a conductor and a compass needle standing next to him. Letting go electricity by conductor in different directions, he made sure that the arrow was clearly oriented towards something clear. From experience, the cormorant concluded that the magnetic field is directional. At a later time, they found out (I wonder how?) that a magnetic field, unlike an electric field, has no effect on a charge at rest. Force occurs only when the charge moves (take note). Moving charges (currents) change the properties of the space surrounding them and create a magnetic field in it. That is, it follows that the magnetic field is generated by moving charges.

You see, we are deviating further and further into electricity. After all, nothing moves in a magnet and no current flows in it. Here's what Ampere said about this: he suggested that circular currents (molecular currents) circulate in the molecules of a substance. Each such current has a magnetic moment and creates a magnetic field in the surrounding space. In the absence of an external field, molecular currents are randomly oriented, causing the resulting field to be zero (cool, right?). But this is not enough: Due to the chaotic orientation of the magnetic moments of individual molecules, the total magnetic moment of the body is also zero. - Do you feel how the heresy is getting stronger and stronger? ? Under the influence of a field, the magnetic moments of molecules acquire a predominant orientation in one direction, as a result of which the magnet is magnetized - its total magnetic moment becomes non-zero. In this case, the magnetic fields of individual molecular currents no longer compensate each other and a field arises. Hooray!

Well, what's it like?! - It turns out that the magnetic material is magnetized all the time (!), only chaotically. That is, if we start dividing a large piece into smaller ones, and getting to the micro-to-micro bits, we will get normally working magnets (magnetized) without any magnetization!!! - That's nonsense.

A little information for general development: The magnetization of a magnet is characterized by the magnetic moment per unit volume. This quantity is called magnetization and is designated by the letter “J”.

Let's continue our dive. A little from electricity: Do you know that the lines of magnetic induction of the direct current field are a system of concentric circles surrounding the wire? No? - Now know, but don't believe. To put it simply, imagine an umbrella. The handle of the umbrella is the direction of the current, but the edge of the umbrella itself (for example), i.e. a circle is, like, a line of magnetic induction. Moreover, such a line begins from thin air, and ends, of course, also nowhere! -Can you physically imagine this nonsense? Three men signed up for this case: it’s called the Bio-Savart-Laplace law. The whole confusion comes from the fact that somewhere the very essence of the field was incorrectly presented - why it appears, what it is, in fact, where it begins, where and how it spreads.

Even in absolute simple things they (these evil physicists) are fooling everyone’s heads: The direction of the magnetic field is characterized by vector quantity(“B” is measured in tesla). It would be logical, by analogy with the electric field strength “E”, to call “B” the magnetic field strength (like, they have similar functions). However (attention!) the main force characteristic of the magnetic field was called magnetic induction... But even this seemed not enough to them, and in order to completely confuse everything, the name “magnetic field strength” was assigned to the auxiliary quantity “H”, similar auxiliary characteristic"D" electric field. What's it like...

Further figuring out the Lorentz force, they come to the conclusion that the magnetic force is weaker than the Coulomb force by a factor equal to the square of the ratio of the charge speed to the speed of light (i.e., the magnetic component of the force is less than the electrical component). Thus attributing a relativistic effect to magnetic interactions!!! For very little ones, I’ll explain: Uncle Einstein lived at the beginning of the century and he came up with the theory of relativity, linking all processes to the speed of light (pure nonsense). That is, if you accelerate to the speed of light, then time will stop, and if you exceed it, then it will go backwards... Everyone has long understood that this was just a world joke by the joker Einstein, and that all this, to put it mildly, is not true. Now they have also chained magnets with their properties to this crap - why are they doing this?...

Another little information: Mr. Ampere came up with a wonderful formula, and it turned out that if you bring a wire, or some piece of iron, to a magnet, the magnet will not attract the wire, but the charges that move along the conductor. They called it pathetically: “Ampere’s Law”! They didn’t take into account that if the conductor is not connected to the battery and no current flows through it, then it still sticks to the magnet. They came up with such an excuse that, they say, the charges are still there, they just move chaotically. These are the ones that stick to the magnet. I wonder where the EMF comes from in microvolumes in order to chaotically swing these charges. It's just a perpetual motion machine! And we don’t heat anything, we don’t pump it with energy... Or here’s another joke: For example, aluminum is also a metal, but for some reason it doesn’t have chaotic charges. Well, aluminum DOES NOT STICK to a magnet!!! ...or is it made of wood...

Oh yes! I haven’t yet told you how the magnetic induction vector is directed (you need to know this). So, remembering our umbrella, imagine that we ran a current around the circumference (edge ​​of the umbrella). As a result of this simple operation, the vector is directed by our thought towards the handle exactly in the center of the stick. If the current-carrying conductor has irregular shapes, then everything is lost—simplicity evaporates. An additional vector appears called the dipole magnetic moment (in the case of the umbrella it is also there, it is simply directed in the same direction as the magnetic induction vector). A terrible confusion begins in the formulas - all sorts of contour integrals, sines-cosines, etc. - Whoever needs it can ask himself. And it’s also worth mentioning that the current must be applied according to the rule of the right gimlet, i.e. clockwise, then the vector will be away from us. This is related to the concept of a positive normal. Okay, let's move on...

Comrade Gauss thought a little and decided that the absence of magnetic charges in nature (in fact, Dirac suggested that they exist, but they have not yet been discovered) leads to the fact that the lines of the vector “B” have neither a beginning nor an end. Therefore, the number of intersections that occur when lines “B” leave a volume bounded by a certain surface “S” is always equal to the number of intersections that occur when lines enter this volume. Consequently, the flux of the magnetic induction vector through any closed surface is zero. Let us now interpret everything into normal Russian: Any surface, as is easy to imagine, ends somewhere, and therefore is closed. " Equal to zero- this means that it is not there. We draw a simple conclusion: “There is never any flow anywhere”!!! - Really cool! (In reality, this only means that the flow is uniform). I think that we should stop here, since what follows is SUCH rubbish and depth that... Things like divergence, rotor, vector potential are globally complex and even this mega-work is not fully understood.

Now a little about the shape of the magnetic field in current-carrying conductors (as a basis for our further conversation). This topic can be much more vague than we are used to thinking. I have already written about a straight conductor - a field in the shape of a thin cylinder along the conductor. If you wind a coil on a cylindrical piece of cardboard and apply current, then the field of such a design (and it is cleverly called a solenoid) will be the same as that of a similar cylindrical magnet, i.e. the lines come out from the end of the magnet (or the supposed cylinder) and enter the other end, forming a kind of ellipses in space. The longer the coil or magnet, the flatter and more elongated the ellipses. The voltage ring has a cool field: namely, in the shape of a torus (imagine the field of a straight conductor rolled into a ball). It’s generally a joke with a toroid (it’s now a solenoid rolled into a donut) - it has no magnetic induction outside of itself (!). If you take an infinitely long solenoid, then the same garbage. Only we know that nothing is infinite, that’s why the solenoid splashes and gushes from the ends; it kind of gushes;))). And also, the field is uniform inside the solenoid and toroid. Wow.

Well, what else is useful to know? - The conditions at the boundary of two magnets look exactly like a beam of light at the boundary of two media (it is refracted and changes its direction), only we do not have a beam, but a vector of magnetic induction and different magnetic permeability (not optical) of our magnets (mediums). Or here’s another thing: we have a core and a coil on it (an electromagnet, like), where do you think the magnetic induction lines hang out? - They are mainly concentrated inside the core, because its magnetic permeability is amazing, and they are also tightly packed into air gap between the core and the coil. But there’s not a damn thing in the winding itself. Therefore, you will not magnetize anything with the side surface of the coil, but only with the core.

Hey, are you still awake? No? Then let's continue. It turns out that all materials in nature are divided not into two classes: magnetic and non-magnetic, but into three (depending on the sign and magnitude of magnetic susceptibility): 1. Diamagnets, in which it is small and negative in value (in short, practically zero, and you will never be able to magnetize them), 2. Paramagnets, in which it is also small but positive (also near zero; you can magnetize it a little, but you still won’t feel it, so never mind), 3. Ferromagnets, in which it is positive and reaches simply gigantic values ​​(1010 times more than for paramagnetic materials!), in addition, for ferromagnetic materials, the susceptibility is a function of the magnetic field strength. In fact, there is another type of substance - these are dielectrics, they have completely opposite properties and are not interesting to us.

We are, of course, interested in ferromagnets, which are so called because of the inclusions of iron (ferrum). Iron can be replaced with chemicals of similar properties. elements: nickel, cobalt, gadolinium, their alloys and compounds, as well as some alloys and compounds of manganese and chromium. This whole thing with magnetization only works if the substance is in a crystalline state. (Magnetization remains due to an effect called the “Hysteresis Loop” - well, you all already know that). It is interesting to know that there is a certain “Curie temperature”, and it is not some certain temperature, and each material has its own value, above which all ferromagnetic properties disappear. It’s absolutely amazing to know that there are substances of the fifth group, called antiferromagnets (erbium, dispositium, alloys of manganese and COPPER!!!). These special materials have another temperature: the “antiferromagnetic Curie point” or “Néel point”, below which the stable properties of this class also disappear. (Above the upper point, the substance behaves like a paramagnet, and at temperatures below the lower Néel point, it becomes ferromagnetic).

Why am I telling all this so calmly? - Please note that I never said that chemistry is an incorrect science (only physics) - but this is pure chemistry. Imagine: you take copper, cool it down, magnetize it, and you have a magnet in your hands (in your mittens? But copper is not magnetic!!! - Really, cool.

We may also need a couple of purely electromagnetic things from this book, to create an alternator, for example. Phenomenon number 1: In 1831, Faraday discovered that in a closed conducting circuit, when the flux of magnetic induction changes through the surface bounded by this circuit, an electric current arises. This phenomenon is called electromagnetic induction, and the resulting current is inductive. And now the most important thing: Size induced emf does not depend on the way the magnetic flux changes, and is determined only by the rate of flux change! - The thought matures: The faster the rotor with the curtains rotates, the greater the value the induced EMF reaches, and the greater the voltage removed from the secondary circuit of the alternator (from the coils). True, Uncle Lenz spoiled us with his “Lenz Rule”: the induced current is always directed so as to counteract the cause that causes it. Later I will explain how this matter is handled in an alternator (and in other models as well).

Phenomenon number 2: Induction currents can also be excited in solid massive conductors. In this case, they are called Foucault currents or eddy currents. Electrical resistance there is little massive conductor, so Foucault currents can reach very great strength. In accordance with Lenz's rule, Foucault currents choose such paths and directions inside the conductor so that their action can resist the cause that causes them as strongly as possible. Therefore, good conductors moving in a strong magnet field experience strong inhibition due to the interaction of Foucault currents with the magnetic field. This needs to be known and taken into account. For example, in an alternator, if done according to the generally accepted incorrect scheme, then Foucault currents arise in the moving curtains, and, of course, slow down the process. As far as I understand, no one thought about this at all. (Note: The only exception is unipolar induction, discovered by Faraday and improved by Tesla, which does not produce harmful influence self-induction).

Phenomenon number 3: An electric current flowing in any circuit creates a magnetic flux that penetrates this circuit. When the current changes, the magnetic flux also changes, as a result of which an emf is induced in the circuit. This phenomenon is called self-induction. In the article about alternators I will also talk about this phenomenon.

By the way, about Foucault currents. You can do one cool experiment. Easy as hell. Take a large, thick (at least 2 mm thick) copper or aluminum sheet and place it at an angle to the floor. Let a “strong” permanent magnet slide freely down its inclined surface. And... Strange!!! The permanent magnet seems to be attracted to the sheet and slides noticeably slower than, for example, along wooden surface. Why? Like, a “specialist” will immediately answer: “In a sheet conductor, when a magnet moves, eddy electric currents (Foucault currents) arise, which prevent changes in the magnetic field, and, therefore, prevent the movement of a permanent magnet along the surface of the conductor.” But let's think about it! Eddy electric current is the vortex movement of conduction electrons. What prevents the free movement of a vortex of conduction electrons along the surface of a conductor? Inert mass of conduction electrons? Energy loss when electrons collide with the crystal lattice of a conductor? No, this is not observed, and generally cannot be. So what's stopping you free movement eddy currents along the conductor? Do not know? And no one can answer, because all physics is nonsense.

Now a couple of interesting thoughts about the essence of permanent magnets. In Howard R. Johnson's machine, or rather in the patent documentation for it, this is the idea expressed: “This invention relates to a method of using the spins of unpaired electrons in a ferromagnet and other materials that are sources of magnetic fields to produce power without the flow of electrons, like this occurs in ordinary electrical conductors, and to permanent magnet motors for use this method when creating a power source. In the practice of the present invention, the spins of the unpaired electrons contained within the permanent magnets are used to create a source of motive power solely through the superconducting characteristics of the permanent magnets and the magnetic flux created by the magnets, which is controlled and concentrated so as to orient the magnetic forces for constant production useful work, such as the displacement of the rotor relative to the stator." Note that Johnson writes in his patent about a permanent magnet as a system with “superconducting characteristics”! Electron currents in a permanent magnet are a manifestation of real superconductivity, which does not require a conductor cooling system to ensure zero resistance. Moreover, the "resistance" must be negative in order for the magnet to maintain and renew its magnetized state.

What, do you think you know everything about the “regulars”? Here's a simple question: - What does the picture look like? power lines a simple ferromagnetic ring (a magnet from a regular speaker)? For some reason, everyone exclusively believes that it’s the same as with any ring conductor (and, of course, it’s not depicted in any of the books). And this is where you are wrong!

In fact (see picture) in the area adjacent to the hole of the ring, something incomprehensible is happening to the lines. Instead of continuously piercing it, they diverge, outlining a figure reminiscent of a tightly stuffed bag. It has, as it were, two ties - at the top and at the bottom (special points 1 and 2) - the magnetic field in them changes direction.

You can do a cool experiment (like, normally inexplicable;) - let’s bring it from below to ferrite ring steel ball, and to its lower part metal nut. She will immediately be attracted to him (Fig. a). Everything is clear here - the ball, once in the magnetic field of the ring, became a magnet. Next, we will introduce the ball from bottom to top into the ring. Here the nut will fall off and fall on the table (Fig. b). Here it is, the lowest special point! The direction of the field in it changed, the ball began to remagnetize and stopped attracting the nut. By raising the ball above the special point, the nut can again be magnetized to it (Fig. c). This joke with magnetic lines M.F. was the first to discover Ostrikov.

P.S.: And in conclusion, I will try to more clearly formulate my position in relation to modern physics. I'm not against experimental data. If you bring a magnet and it attracts a piece of iron, it means it has attracted it. If the magnetic flux induces an EMF, it means it induces. You can't argue with that. But (!) these are the conclusions that scientists make... their explanations of these and other processes are sometimes simply ridiculous (to put it mildly). And not sometimes, but often. Almost always…

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