Why does the magnet release heat when it is energized, and what is the principle of the electromagne

Only the electromagnet can be energized, and only when the electromagnet is connected to alternating current will it generate heat (or direct current). This is due to the hysteresis loss and eddy current loss that occur when the core of the electromagnet is working, and the hysteresis loss and eddy current loss are collectively referred to as the core loss.

The material that makes up the core of the electromagnet is a ferromagnetic material, which has three characteristics: 1. High permeability; 2. Magnetic saturation; 3. Hysteresis and remanence. The hysteresis loss in the core loss is caused by the hysteresis and remanence of the ferromagnetic material.

Because the alternating current needs to produce alternating magnetic flux in the core, and the ferromagnetic material has hysteresis, the alternating magnetic flux has to overcome the hysteresis and remanence phenomena, and to overcome the hysteresis and remanence phenomena, it is necessary to lose energy and convert it into heat.

Ferromagnetic materials are usually made of iron, nickel, cobalt and their alloys in order to ensure high permeability. When the alternating magnetic flux passes through the ferromagnetic material, according to the law of electromagnetic induction, the ferromagnetic material will also induce electromotive force and generate an electric current, and the current flows in the core section according to the path of concentric circles, this current is called eddy current. Since the ferromagnetic material material itself has electrical resistance, it will also incur losses when the current flows through, which is called eddy current loss.

In order to reduce eddy current losses, usually the core is made of sheet silicon steel plate to increase its resistance, thereby reducing eddy currents and ultimately reducing eddy current losses.

Why does the magnet release heat when it is energized, just because you use it as a resistor!

The question of magnet energizing is not accurate? Not good.

The principle of electromagnet preheating is that before the electromagnet is energized, the coil of the electromagnet spontaneously generates a magnetic field, so that the molecules or ions inside the material move in an orderly manner, so as to achieve the effect of heating. In this way, when the current is passed into the coil, the resistance in the coil is reduced and the magnetic field can be established more quickly. This can increase the magnetic force and efficiency of the electromagnet, improving its suction and stability.

In addition, preheating can also reduce the heat loss of the solenoid coil and prolong the life of the solenoid. Therefore, preheating is very important when the electromagnet needs to be used for a long time or the requirements for the use of the electromagnet are relatively high.

In an electromagnet, when an electric current passes through the coil, a magnetic field is formed around the coil. This magnetic field can attract metallic objects around it to the electromagnet. The principle of electromagnet preheating is that before the electromagnet is energized, the coil of the electromagnet spontaneously generates a magnetic field, so that the molecules or ions inside the material move in an orderly manner, so as to achieve the effect of heating.

In this way, when the current is passed into the coil, the resistance in the coil is lowered and the magnetic field can be established more quickly. This can increase the magnetic force and efficiency of the electromagnet, improving its suction and stability. In addition, preheating can also reduce the heat loss of the solenoid coil and prolong the life of the solenoid.

Therefore, when the electromagnet needs to be used for a long time or the requirements for the use of the electromagnet are relatively high, the tremor preheating is very important.

Doing your homework.

Summary. Wrap the electromagnet with a damp rag. A device that generates electromagnetism by energizing.

A conductive winding that matches its power is wound around the outside of the core, and the coil that is emung with current is magnetic like a magnet, and it is also called an electromagnet. It is usually made into a bar or hoof shape to make the core more easily magnetized. In order to degauss the electromagnet immediately when the electromagnet is deenergized, it is often made of soft iron or silicon steel materials with fast demagnetization.

Such an electromagnet is magnetic when energized, and the magnetism disappears when the power is off. Electromagnets have an extremely wide range of applications in daily life, and the power of generators has been greatly improved due to its invention.

What is the reason for the weakening of the magnetic properties of the core of the electromagnet when heated?

Wrap the electromagnet with a damp rag. A device that generates electromagnetism by energizing. A conductive winding that matches its power is wound around the outside of the core, and the coil that is emung with current is magnetic like a magnet, and it is also called an electromagnet.

It is usually made into a bar or hoof shape to make the core more easily magnetized. In order to degauss the electromagnet immediately when the electromagnet is deenergized, it is often made of soft iron or silicon steel materials with fast demagnetization. Such an electromagnet is magnetic when energized, and the magnetism disappears when the power is off.

Electromagnets have an extremely wide range of applications in daily life, and the power of generators has been greatly improved due to its invention.

The reason why the magnetism of the electromagnet weakens after heating.

Because the magnetic molecules become active and accelerate their motion after heating, the arrangement of the magnetic molecules is disrupted (that is, demagnetization in physics), so the magnetism is weakened.

First, the cause of fever.

1. When the voltage is constant, the resistance is too small.

The relationship between resistance, voltage, and current is: u=ri. When the voltage is constant, the smaller the resistance, the greater the current.

The greater the current passing through the unit cross-section, the greater the heat generated by the enameled wire. The more hot the coil, the higher the resistance will be, and the less current will pass through. As a result, the suction power of the electromagnet decreases.

It will come back when it gets cold.

Magnetic potential f=ni, the product of the current and the number of turns (a).

Magnetic field strength h=(a m).

Permeability = Magnetic flux =

Magnetoresistance rm=

Eddy currents are formed on the iron core, and the eddy currents generate heat.

The number of turns of the coil is too small, and the current is too large, so there is a lot of heat generated on the wire resistance. It is recommended to increase the number of turns while decreasing the voltage. With a single magnetic field that you did, the strength will decrease because the current has been reduced.

12 volts] car battery is sufficient, but if the number of turns is too low, the battery may be damaged.

What a vortex flow, nonsense. Where does direct current come from?

The strength of the magnetic field is proportional to the current and the number of turns. The current is inversely proportional to the length of the wire. In other words, increasing the number of turns reduces the current, but the magnetic field does not. But increasing the number of laps will increase the volume, and you need to find a balance.

In addition, screws are not a good material for making electromagnets. In amateur conditions, the E-core of the transformer is recommended. That effect is much better than screws. The coil is wound around the middle iron of the E, and the E-shaped opening is where the magnet is strongest.

If I'm not mistaken, eddy currents are a phenomenon peculiar to the magnetic field of alternating current coils, right? And what people use at home is a smooth battery direct current. I think that the number of coils is too small, and the coil heats up, which causes the core to heat up, because the core volume is relatively large and the heat dissipation surface is relatively small, so I feel that the coil is not hot at the core.

After winding, you can use a multimeter to measure the resistance (about only 0.).A few euros bar).

It is recommended that you use a finer enameled wire winding, and the number of turns should not be less than 500 turns. If it is still hot, you can add a current limiting resistor. If the battery is 10ah

It is best not to discharge more than 1 current.

f=kni/d

f is the suction, n is the number of turns, i is the current, d is the gap of the magnetically closed loop, k is the constant.

Heat generation is.

Current vortex. This is inevitable. That's a good idea.

If you put that.

and insulated from each other.

In this way, the feeling of heat in the coming year will be smaller.

The electromagnet is actually like a resistor, the resistance will lose electrical energy, convert the electrical energy into heat energy dissipation, if the electromagnet is energized for a long time, it will also cause serious heating, will burn the built-in coil, so under normal circumstances, it is not able to be energized for a long time.

If the conductor used in the electromagnet is designed with a large current density, a large permeability and reluctance of the core material, and a large electromagnet loss, it is difficult to withstand continuous long-term energizing work.

However, if there are special requirements for customers, they will also be specially made to be energized for a long time, and they will be designed according to the length of energizing time required by customers during the design, so that the heating and heating of the coil and iron core are within the safe range when the electromagnet works normally and continuously.

According to the power formula.

p=u²/r

We can know that when the resistance is higher, the power is less. When the electromagnet heats up, it will cause its own resistance to become larger, so that the output power will become smaller, so it is better to avoid long-term power-on when using the electromagnet.

The magnet we know is not actually invented by humans, but a natural magnetite discovered by the ancient Greeks and Chinese. What happens if you power the magnet?