With the increase of electricity consumption, we can see the existence of transformers everywhere. Although the power system in our country is constantly improving, transformers will inevitably exist a certain amount of noise, to a certain extent, affecting people's lives. So, what is the cause of transformer noise?

Noise emitted by transformers is generally caused by magnetostrictive deformation of iron core and electromagnetic force in winding, oil tank and magnetic shield. In the past, it has been thought that the noise produced by magnetic field induced core lamination along the longitudinal vibration is an important component of transformer noise. The amplitude of the vibration is related to the magnetic flux density in the core laminate and the magnetic properties of the core material, but not to the load current. Actually not, because the power transformer noise has three sources, one is the core, the second is the winding, the third is the cooler, that is, no-load, load and cooling system caused by the noise combined.

The noise produced by the core is mainly caused by the slight change of magnetostriction, which makes the core vibrate periodically with the change of excitation frequency.

The reason for the vibration of the winding is the electromagnetic force generated by the current in the winding, and the leakage magnetic field can also make the structure vibrate. The electromagnetic force (and the amplitude of vibration) is proportional to the square of the current, and the acoustic power emitted is proportional to the square of the amplitude of vibration. Therefore, the sound power emitted is very clearly related to the load current.