Designers developing energy facilities pay close attention to reducing the significance or completely eliminating the unfavorable factors that accompany the operation of such devices. And yet, some of the negative effects cannot be completely eliminated. One of them is the noise and hum of transformers.
The principle of operation of the transformer
A transformer is a technical device that transfers electrical energy from a stationary coil to another coil of the same type, which is not connected to the first in an electrical way. Energy is transmitted through a magnetic flux connecting the windings and continuously changing its direction and magnitude ("Elementary electrical engineering for radio amateurs", AD Batrakov, 1950).
When an alternating current flows through the primary coil, it creates a magnetic field. Powerful lines of force of this field penetrate not only the first, but also the second winding of the transformer. The lines are securely closed around the conductors, which become magnetically rather than electrically connected.
The degree of connection between the two coils is determined by the distance between them.
When the ends of the secondary coil are connected to a consumer of electricity, an electric current is generated in the circuit, and the device included in the circuit receives energy. Due to the difference in the number of turns of the primary and secondary coils, any required voltage can be obtained at the output. This is considered the main useful property of any transformer.
Why does the transformer make noise
High-power power current transformers are one source of harmful noise that can often be felt in industrial environments. The noise that resembles a hum is most often caused by strong vibration of the active elements of the device, which are amplified by resonance phenomena.
Why does vibration occur? In most cases, it is due to a phenomenon called magnetostriction. This effect is a kind of deformation of the crystal lattice that makes up the magnetic material. Magnetostriction occurs during the magnetization of structural elements, during which induction increases, causing the material crystals to shift.
The crystals start to rotate, as a result of which the linear dimensions of the metal change with high periodicity. It is this phenomenon that leads to vibration and noise.
Another reason for the buzzing of the transformer is the manifestation of magnetic forces. This effect is especially pronounced at the joints of the device elements. Individual sheets of the transformer core are bent by these transverse forces, generating a sound wave and increasing the magnetostrictive effect. The transformer begins to hum intensely.
The noise level of transformers directly depends on their size and weight. The length of the rod of the magnetic system, as well as the quality of the steel, can affect the sound strength. The entry of the system into resonance or damage to the coil turns can significantly increase the noise of the operating transformer.
