In recent years, it has been increasingly used in residential and public large transformers, which has put forward certain requirements for the noise of large transformers and small and medium-sized transformers. The noise of transformers is increasingly attracting people's attention. How to reduce the noise of transformers has become an urgent issue in transformer manufacturing.

Reasons for Transformer Noise

The audible noise of transformers is caused by the electromagnetic force of the center of magneto elastic deformation and winding, as well as the oil tank and magnetic shielding. In the past, it was assumed that the noise generated by the magnetic field caused by the longitudinal oscillation at the center was the primary component of transformer noise. The amplitude of oscillation is related to the magnetic flux density and magnetic energy of the central data, rather than the load current.

Specifically, there are three sources of transformer noise: one is the center, the second is the winding, and the third is the cooling system, which is the sum of noise caused by no-load and load and the cooling system. The central cause of noise is the magnetic induced elasticity of the center of the silicon steel sheet, which undergoes small changes under the action of an alternating magnetic field. The magnetic induced elasticity causes a change in the excitation frequency of the central periodic oscillation. The reason for coil oscillation is that current generates electromagnetic force in the coil, and the leakage of magnetic field can cause structural oscillation. Electromagnetic force (and oscillation fluctuations) is proportional to the square component of current, while emitted power is proportional to the square component of oscillation fluctuations. Therefore, there is a clear correlation between the emitted sound power and the load current.

Factors affecting transformer noise

The primary reason for the occurrence of noise in the center is that the scale of the silicon steel plate has undergone slight changes under the influence of an alternating magnetic field. The oscillation of silicon steel sheets is primarily caused by the magneto elastic properties of ferromagnetic materials, as the magneto elasticity changes the frequency of the half cycle power supply and causes the oscillation of the transformer. The power supply frequency is twice the reference frequency.

The data of magneto elasticity and silicon steel plate. The greater the magneto elasticity, the greater the noise. When the strength of the magnetic field is the same, it is also very small, so the noise is very small.

Magnetoelasticity is also related to the strength of the magnetic field, the stronger the magnetic field.

Magnetoelasticity is also related to the annealing of coatings and silicon steel sheets, as the coatings adhere to the silicon steel sheets and prevent deformation. The magnetic field strength of annealed silicon steel sheets is much smaller than that of annealed silicon steel sheets, because choosing a better annealing process can reduce the exponential growth of magnetoelasticity.

Article source: Transformer silicon steel sheethttp://www.cheungshun.com/