How to determine the poles of a magnet
Humanity became acquainted with magnets quite a long time ago: the first deposits of magnetite stone were discovered in ancient times on the territory of modern Greece, not far from the city of Magnisia. The “Stone from Magnisia” instantly intrigued the residents of the locality, because it attracted iron objects. And if in those distant times the properties of stones simply caused surprise and delight, today the capabilities of magnets are used to the fullest: depending on the type, they help organize the operation of various sensors, motors and microphones.
Understanding the intricacies of how magnets work is not so difficult: there is a lot of information, but it is quite accessible and understandable even to a schoolchild who has just begun to be interested in physics. First of all, we advise you to study the types and methods of using permanent magnets, as well as clarify how to determine the poles of magnets and electromagnets without special equipment.
A natural magnet, or magnetic iron ore as it is called today, is a substance around which a magnetic field is always present. Any piece of iron ore has a fairly strong magnetization, but the molecules of the material move in two directions, which means even a very small magnet will have a north and south pole.
If you have two pieces of iron ore in your hands, then answering the most common question “how to determine the poles of a magnet” is not at all difficult, because opposite sides are magnetized, but identical sides are repelled.
In the modern world there are several types of magnets, besides natural magnetite:
· Temporary - these are metal products that are magnetized only when they enter a magnetic field. Nails, paper clips, bars and other small things begin to attract each other and similar objects;
· Electromagnets, which humanity became familiar with in 1825, when they were invented by an engineer from England, William Sturgeon. The structure consists of an iron core on which wire is wound. A magnetic field of the required strength and polarity can be obtained only if a current is applied through it. We encounter electromagnets every day, because almost all equipment works with their help, but at the time of their invention they were not appreciated;
· Permanent, most numerous. They charge only once and form a magnetic field around themselves constantly. We have already become acquainted with a natural permanent magnet - it is natural iron ore, but there are several types of artificial magnets. The most popular are ferrite and neodymium. The latter are considered the strongest and can last more than 100 years.
The easiest way to purchase neodymium magnets: they are available in every specialized electrical equipment store. Wondering how to determine the poles of a neodymium magnet and check its performance? Modern magnets are no different from natural ones and behave exactly the same, which means they repel if the poles are the same, and attract if they are different.
The simplest and most understandable way to understand the poles is to use special devices. A compass is a quick answer to the question “how to determine the north pole of a magnet”: an arrow pointing north will definitely be attracted to the south pole of the magnet.
A modern electronic teslameter is also quite suitable, because if you bring the probe of this device to a piece of iron ore, the corresponding letter – S or N – will appear on the display.
Instead of the device, you can use an additional marked magnet: like poles will repel, and different ones, of course, will attract.
If you only have a diagram of the device, then you will definitely be interested in how to determine the poles of a magnet from a drawing. To do this, you can use the “left” hand rule, which suggests placing your left hand in such a way that the magnetic lines of force enter the palm and the four fingers coincide with the direction of the current. The thumb in this case will indicate the direction of movement of the conductor.
How to determine the south pole of a magnet if you don't have a compass at hand? Make a device from scrap materials: for example, using a needle and water or a plastic jar with powdered sugar. The needle will be magnetized and point north while lying in the water, and the powdered sugar will turn into charged dust and spin along the lines of force above the magnet. The sun will help you find out where is north and where is south, but you will need the ability to navigate the area and basic knowledge of geography.
What can be done to make an object have magnetic properties?
Answer: if you need to conduct an experiment and, for example, take a comb and small pieces of paper (the comb should magnetize the paper), rub the inflated balloon with the comb and present the comb at a short distance from the paper, then you can see the result; pieces of paper will be magnetic to the comb.
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Incorrect brush replacement
ATTENTION! A completely simple way to reduce fuel consumption has been found! Don't believe me? An auto mechanic with 15 years of experience also didn’t believe it until he tried it. And now he saves 35,000 rubles a year on gasoline! Read more"
As a rule, if the starter has not been repaired for a long time and its brushes have not been replaced, the polarity of the supplied voltage can easily be disrupted. In other words, the positive and negative positions in the starter cables have been reversed. The reason is depressurization of the line and mutual contact of wires.
Another development of events is also likely when the starting device has previously been repaired. The procedure for replacing the brushes this time was carried out incorrectly, the elements were accordingly placed in the wrong sequence. You need to test and determine where the brush with the “plus” polarity is facing. She should look directly opposite the "minus".
To determine the polarity of the brushes, simply attach them to each other. Accordingly, attraction or repulsion will help determine the correct polarity.
Incorrectly installed brushes are usually associated with the starter cover. It is placed incorrectly, which leads to polarity reversal (more on this below).
Permanent magnet starters
Strong magnets have become inexpensive to produce and have proven to be quite useful for car starters. Making a magnet and assembling a housing with magnets is much easier than winding an excitation winding, so permanent magnet starters quickly replaced outdated designs with excitation windings. Permanent magnet starters are small, light and strong enough to reliably start engines.
This is what magnets for the starter look like. They are very similar, but in fact they are different.
Very similar magnets, but different, they should be of two types - South - North and North - South.
In the starter housing, the magnets are arranged in a strictly defined manner. If the magnets are incorrectly selected (during repairs), the starter may not spin at all. If the magnets are not positioned correctly, the starter will spin the wrong way.
The picture quite conventionally shows that the magnetic system for rotating the armature in the other direction is turned 90 degrees.
Magnets problem
The largest Russian retailer Magnit will one of these days begin supplying fruits from Turkey, said Sergei Galitsky, general director and main owner of Magnit. According to him, Magnit expects its competitiveness to increase after the start of supplies of Turkish products. We, as a large company, have never done such things, and now that we purchase directly, we become more competitive with those people who were involved in gray schemes. We suffered when we saw that gray imports entered the country in one way or another,” he explained.
Magnit and Bakhetle index: has the “Japanese disease” come to trade?
And after filing an application to the court, a bag of cartridges for a Kalashnikov assault rifle was found in the trunk of the trade union activist. On the eve of the presidential election, every news item talked about government attention to the working class. During the May Day holidays, the unity of workers and heads of state must continue. FNPR is going to invite the president and prime minister to a march in Moscow. In real life, which does not appear on television, an employee trying to defend his labor rights finds himself face to face with a powerful corporation. And they were fired. The court declared the dismissal illegal.
Installment card "Magnit"
Due to the asymmetry of the Earth's magnetic field, the magnetic poles are not antipodal points. The location of the magnetic north pole is not the same as the geographic north pole. Since about the beginning of the 17th century, the pole has been located under pack ice within the boundaries of what is now the Canadian Arctic. This leads to the fact that the compass needle does not point north exactly, but only approximately. Since the second half of the 20th century, the pole has been moving quite quickly towards Taimyr. In a year, the speed of movement of the north magnetic pole was 64 kilometers per year [7].
The location of the south magnetic pole is not the same as the geographic south pole. It currently lies on the edge of Antarctica. As noted above, the difference between the geographic north magnetic pole and the earth's north pole is negligible.
Therefore, with a certain error, we can say that the compass with the blue part of the arrow points to the north, implying both the geographic north magnetic pole and the north pole of the Earth. Geomagnetic poles are the points where the axis of the magnetic dipole, which is the main component of the multipole decomposition of the Earth's magnetic field, intersects the Earth's surface.
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North magnetic pole [1] [2]. South magnetic pole [4] [2].
Near Voronezh, the Magnit warehouse is burning all night; the fire area is 42 thousand square meters. meters
RU - A small private business originally from x, with headquarters a thousand kilometers from Moscow, which managed to grow into one of the largest companies in Russia and become an exemplary story in the eyes of investors, including foreign ones. And all this time the company was managed by its founder. This chapter in the history of Magnit ended in a year whose main event was the change of shareholders of the retailer. A few years earlier, Magnit left the pedestal in Russian retail, losing first place in revenue to its arch-competitor X5 Retail Group of the Pyaterochka, Perekrestok, and Karusel chains.
Where is the plus and minus of a magnet?
Magnet polarity detector
Author: multihobbyt Published 03/25/2015 Created using KotoEd.
If we take it out of the cooler and add a battery, two LEDs and one resistor to it, we get a device like this:
In the cooler, this microcircuit runs on 12V. I was able to power it without any problems from a 3-volt battery taken from a burnt-out old motherboard along with a socket for it. The LEDs and buttons were also taken from some kind of computer gadget.
It works like this: When you press any of the buttons (the right one is fixed and allows you to turn on the device with one click until this button is pressed to turn it off, the left one is not fixed and turns on the device only while your finger is on it) one of the LEDs will light up. When When you bring the magnet close to the microcircuit, the LED that indicates the applied pole will light up. For the north (N) I used a blue LED, for the south (S) a red LED. Additional contacts are installed on the printed circuit board to allow signals to be picked up by another device.
At the request of one of the readers, I add a diagram in graphic format.
In the archive there is a diagram in Spl and a printed circuit board in SL6
Polarity of magnets in starter
Last week in the morning, in slushy weather (the law of meanness works!) the car refused to start, without preliminary “whims” the starter simply stopped working. When you turn the key, the retractor clicks and that’s it, then silence. Setting myself up in a positive mood, while cursing the rain, the piercing wind and the temperature near zero, I began to unscrew the starter. I’ll skip the procedure for removing the starter; there’s nothing more natural there, except for the fact that it was necessary to remove the engine protection and, using a chisel, “unscrew” the lower nut securing the starter while lying under the car. I'll reveal a terrible secret
: with the hood raised, the rain pours freely onto your face, and its taste, as Comrade Raikin used to say, is “special.” With the taste of butter and antifreeze. And with the hood closed you can't see anything
