How Magnetic Regulators Noise Cancellation

The main reason for the noise of the magnetic regulator core is that under the action of the alternating magnetic field, the size of the silicon steel sheet will change slightly. Since the change period of magnetostriction is half the cycle of the power frequency, the transformer body caused by magnetostriction The vibration of the silicon steel sheet is 2 times the power frequency as the fundamental frequency, so the vibration of the silicon steel sheet is mainly caused by the magnetostrictive properties of the ferromagnetic material.

The magnetostriction rate is related to the material of the silicon steel sheet. The higher the magnetostriction rate, the greater the noise. When the magnetic field strength is the same, the magnetostriction of the silicon steel sheet with good material is also small, so the noise is also small. The stretching ratio is also related to the strength of the magnetic field, the stronger the magnetic field, the greater the noise.

The magnetostriction rate is also related to whether the surface of the silicon steel sheet can be painted and annealed. Since the coating has adhesion to the silicon steel sheet, the deformation of the silicon steel sheet can be avoided. The silicon steel sheet annealed under the same magnetic field strength is magnetostrictive than the unannealed silicon steel sheet. The stretching is much smaller, which is due to the selective annealing process, which can reduce the magnetostriction exponentially.

The no-load noise of the transformer is not only related to its own material, but also related to the condition of the joints.