The transformer is humming: what it depends on, the reasons and how to eliminate them

When the transformer operates, a characteristic humming sound appears. This is a normal phenomenon due to the appearance of magnetostriction. The physical phenomenon has minimal impact on household appliances. If this type of transformer hums, the system may not be functioning properly. This will need to be sorted out. If a characteristic sound is detected in the power supply, amplifier or similar devices, it is necessary to find the cause and eliminate it. What to do in this case will be discussed further.

About the operating principle of the transformer

During operation, the transformer transforms the characteristics of electric current or voltage, increasing or decreasing the specified parameters, depending on the conditions required by the consumer.

The device consists of the following components:

core;
primary winding;
secondary winding.

Principle of operation of a transformer
The core is made up of individual plates formed into a package. When current flows through the primary circuit, a magnetic field is formed, which excites current in the secondary winding.

What to do if your heat meter is broken

When you pay your next utility bill, you suddenly receive an amount that is slightly more than what you paid last month. When you make a verbal complaint, they will explain to you that you have to pay more because the meter is broken. Before paying an unfairly inflated payment, you should write a written request to clarify the situation and ask for a full recalculation of the payment.

Once you receive a response, you either challenge the decision or pay the bills. An excellent option would be if other apartment owners also come with a written appeal, so the proceedings will end in your favor.

This article described in detail what should be done if the device buzzes loudly, and also touched upon the topic of how to pay if the heat meter is faulty. We hope our advice will be useful in life. We wish you success!

Many consumers are faced with the fact that the electric meter begins to hum and crackle. The hum can be uniform, or intensify, accompanied by a crackling sound, when one or another electrical appliance is turned on. Let's consider the reasons for such a malfunction of the meter, and how to act in such a situation.

Main causes of hum

Magnetostriction is the effect of changing the size of a body that allows charged particles to pass through it. This is typical for magnetic field sensitive materials used to make the core.

As a result of this effect, the process of functioning of the device is accompanied by sound waves of a certain frequency - buzzing.

In addition to magnetostriction, the causes of noise can be:

working oil pumps
fans of cooling systems of powerful transformers,
eddy currents (Foucault currents) are called electric currents that arise due to electromagnetic induction in a conducting medium when the magnetic flux penetrating it changes. Eddy currents generate their own magnetic fluxes, which, according to Lenz's rule, counteract the magnetic flux of the coil and weaken it,

Electrodynamic forces in the windings and electromechanical devices that regulate voltage under load also create noise.

How to get rid of sound?

You can get rid of extraneous hum in your speakers yourself. Let's consider what to do for this.

Computer settings

Incorrect settings used when configuring Windows OS (a common operating system installed on most computers) often cause humming noise in the speakers.

To fix problems, you need to perform a number of steps.

Open Control Panel. You can find the required item in the Start menu.
Click on the "Hardware and Sound" section. There will be a subsection called "Sounds".
Select the audio playback device marked with a green checkmark.
Right-click on it and then click on the “Properties” line.
The “Levels” tab will appear in the window that opens.
In the Realtek settings, under the first line, additional sources will be displayed that need to be reduced to the minimum level.
Next you need to open the tab called “Improvements”. Opposite the Loudness parameter there should be a checkmark confirming that it is enabled. This option may be called differently in different versions of the operating system, such as “Volume Leveling.”
After making new settings, you should check the sound.

Driver problem

Software is an important component of equipment operation. In some cases, the problem can be completely corrected by a simple software update. Some operating systems independently notify the user that the driver needs to be updated and perform this procedure automatically.

Otherwise, you can find the program you need on the Internet. They are in the public domain.

Afterwards you need to make the necessary settings.

The procedure begins by opening the “Control Panel”.
The next item is “Equipment and Sound”.
Find the subsection that is responsible for the sound driver settings. In most cases it is called "Realtek HD Manager".
Open this item and carefully evaluate the menu. When changing parameters, evaluate the result. You can turn some audio filters on or off, and change the volume.

Factors affecting hum level

A humming sound occurs if the unit operates in certain modes. During one cycle of operation of the transformer, tension and compression of the core occurs twice. If the mains frequency is standard with alternating current (50 Hz), the device begins to hum.

Also read: Where does zero come from in a transformer?

The frequency of sound is twice that of electric current.

The strength of the transformer hum is determined by the following factors:

Degree of workload;
Overall dimensions of the constituent elements;
Physical characteristics, material used to manufacture the magnetic core.

The hum may occur due to the following design features of the transformer:

the effect of magnetic flux tends to move the windings of the device relative to the magnetic core. If the coil is not wound tightly enough, vibration occurs due to the loose fit of the turns with a corresponding hum (the black arrow shows the coil);
If the core plates are poorly fitted, gaps appear between them. During operation, the vibration of the plates is accompanied by a characteristic metallic ringing, turning into a buzzing sound (the red arrow shows the core plates);
if the copper wires of the windings are defective or damaged, the coil may spark, with popping noises with each spark. Powerful discharges are characterized by a more intense sound;
The individual parts in the device are not sufficiently secured, resulting in vibration and noise.

A strong hum is typical of power transformers used in industrial production. But if the operation of a low-power household appliance begins to be accompanied by a significant hum, this is a reason to carry out diagnostics in order to identify and eliminate the malfunction.

Why is it buzzing too much?

If the device - an experimental type or built into some other device - previously worked silently - good, it is working. But when it starts humming excessively or making a strange whistling sound, this is abnormal. We need to look for the reason why such changes occurred. To install it, some electrical knowledge is required, a minimum of tools and skills in their use.

The reason for the strong hum may be that the plates from which the core is made could have come apart. When the transformer is of the armored type, they are simply tightened with a metal clamp. But, if, in addition to increased buzzing, there is heating of the device, then this is one of the characteristic manifestations of an interturn short circuit. To check, perform the following manipulations:

When the only tool you need is a multimeter, it is difficult to find out whether there is a short circuit (short circuit). A thorough examination helps in this situation. Indicators of a short circuit are signs of burning, melting or darkening of the insulation, as well as the characteristic smell of burnt plastic.
If there are no signs of a short circuit, then they look for the passport information of the power device and test it with a multimeter. To do this, the measuring device is set to the “megaohmmeter” (megger) position.
When the values from the data in the passport are recorded with a difference of 50% or more, this is a clear indicator of an interturn short circuit. But if the error is small, then everything is fine.

On a note!
You can check the condition of a transformer power device using other methods, but this requires more complex measuring instruments and conditions close to laboratory ones.

When a power transformer makes a powerful hum at a substation or power plant, this is a sign that it is in good condition and operating in standard mode. But when a device in some household appliance that previously worked inaudibly begins to make noise, this is an indicator of a breakdown. The malfunction must be eliminated, first finding out the specific cause. To identify and eliminate a transformer malfunction, you must have some electrical knowledge, experience working with measuring instruments, and also follow safety precautions.

Transformer testing and troubleshooting

Diagnostics will help identify the cause of the problem and eliminate the malfunction. Interturn closure is determined by external inspection. If damage to the insulating layer and dark marks on the winding are observed, this indicates the specified problem.

In this case, the device needs to rewind the coils.

If the external examination does not produce results, a more in-depth study will be required.

If you have a multimeter, you can do the following:

In megohmmeter mode, insulation resistance measurements are taken and compared with the standard values given in the reference literature. If the actual value exceeds the nominal value by more than 50 percent, this indicates the presence of an interturn short circuit;
A similar measurement is carried out for a technically sound device. A discrepancy of more than 20 percent indicates a malfunction.

Rewind

If the user of the power device did the rewinding himself, there is a high probability of a hum. There may be several reasons for this:

The magnetic core is assembled or adjusted incorrectly. Trouble often arises when rewinding a W-like core.
The reel is not secured well.
The winding is not wound tightly. You can soak it in paraffin.
The turns were calculated incorrectly. In this case, not only noise is determined, but also heating. The calculation will need to be done again to eliminate any errors made.

Interesting video: Rewinding a transformer with your own hands

To perform rewinding correctly, it is recommended to contact a professional. If the user wants to learn how to perform such an action independently, it is necessary to consider the intricacies of this process.

Rewinding of Sh-like core

The hum after rewinding is determined precisely in the Sh-like type of magnetic circuit. During the operation, it is necessary to minimize eddy current losses. On one side, each plate is insulated with varnish. After rewinding, each part is placed on the core in turn.

When half the work is done, you need to insert two plates on one side of the core. They don't need to be pushed in all the way. The assembly then continues. When the magnetic circuit is approximately 2/3 assembled, it is necessary to install more W-like plates in the remaining parts. The remaining elements must be installed between the two parts extended in the center. They are carefully hammered in with a mallet. The plates should not bend. To complete the assembly, you will need to insert the end structural elements.

Magnetostriction effect

Since the field is variable, the core plates begin to compress and stretch in time with it. This process is called magnetostriction. Such movements are made with a high frequency of 100 Hz, with a current frequency of 50 Hz, vibration is emitted into space, which has an audio range and is distinguishable by the human ear. In addition to the standard frequency, alternating current contains higher frequency harmonics. There are more of them, the more the transformer is loaded, and this, in turn, is a sharper and more audible vibration. That's why the transformer hums.