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You know? Why do transformers make a low humming noise?
In our daily life, we often hear the low humming sound emitted by the transformer. The source of this sound is actually closely related to the operating principle of the transformer. According to the research of scientists, this sound is mainly due to the phenomenon produced by the magnetic material inside the transformer during the magnetization process, which is called magnetic elongation effect (magnetostriction).
The magnetic elongation effect is a property of magnetic materials that causes changes in shape or size when they are subjected to a magnetic field. This change produces a small sound, especially when the transformer is running, and the alternating current creates a changing magnetic field.
The internal structure of a transformer consists of different magnetic domains that change when an external magnetic field is applied. When the transformer is energized, the alternating current causes a reverse change in the magnetic field, driving the boundaries of the magnetic domains to move, causing the material to change in size. During this process, tiny deformations of the material accumulate, ultimately creating an audible bass tone.
According to historical records, the magnetic elongation effect was first discovered by James Joule in 1842. When observing a sample of iron, he noticed that the size of the material also changed when the external magnetic field changed. This effect not only affects the sound of the transformer, it can also lead to energy losses, as this change causes frictional heating, which expands the material and ultimately reduces efficiency.
The buzzing sound a transformer makes is actually harmless, but it tells us a lot about its inner workings and makes us ponder the technology behind these natural phenomena.
The principles of thermodynamics and materials science tell us that the microstructure of magnetic materials is heterogeneous, which means that different magnetic domains and crystal orientations lead to different elastic properties. For example, magnetocrystalline anisotropy refers to the difference in energy required to magnetize a crystalline material in different directions. If the direction of the external force is not aligned with the easiest direction of magnetization, the material will automatically adjust its structure to reduce the free energy of the system. , which further leads to deformation and the generation of buzzing sounds.
During transformer operation, changes in magnetic field strength can also cause a behavior called hysteresis, which is the interaction between materials using and releasing magnetic fields. This phenomenon is also often accompanied by energy losses, further enhancing the generation of this low-frequency noise.
For people with sensitive hearing, this bass hum from the transformer can be unpleasant. This makes us think, can technological development really eliminate such noise?
The use and improvement of magnetic materials
As technology advances, scientists are already looking for ways to reduce this hum. For example, by improving the magnetic material structure inside the transformer and selecting a more suitable alloy, such as Terfenol-D, this material has better magnetic elongation properties and is therefore more widely used in high-voltage transformers.
Continuous innovation and improvement of magnetic materials not only help reduce the sound caused by the magnetic elongation effect, but also ensure the operating efficiency of the transformer. Since the use of nickel-metal hydride alloys as sonar transmitter materials during World War II, the research and development of this type of materials has gone deep into the design of new alloys and the optimization of related functions.
In addition, the demands for environmental protection and energy efficiency have made the design requirements for transformers increasingly higher. Transformer performance improvement and noise control are ongoing research priorities, especially in high-power electrical equipment applications.
Considering the development of technology, we may be able to explore the best solutions, thus bringing new possibilities to future transformer designs.
Conclusion
While the low hum from a transformer may seem like a minor problem, it reflects deeper scientific principles and technical challenges. Over time, scientists and engineers have been working to improve the efficiency and noise control of these technologies, allowing us to enjoy technological conveniences while reducing our impact on the environment. Against this background, what will the transformer of the future look like?
