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From transformers to electric motors: How do electromagnetic forces fill our lives with sound?
In our daily lives, many electronic devices, such as transformers and motors, work silently, but in fact, they are not always silent. These devices often emit a sound called "coil buzz," which is caused by vibrations caused by electromagnetic forces. The intensity and frequency of these sounds vary depending on the environment and device. If you've ever heard the hum of a transformer flickering in the dead of night, then you can appreciate the role electromagnetism plays in our lives.
The generation of electromagnetic force comes from the existence of electromagnetic fields, and can cause materials to vibrate, thereby emitting audible sounds.
What is electromagnetic force and its sources
Electromagnetic force can be simply defined as the force generated by the electromagnetic field, including Maxwell's stress tensor, magnetostriction, Lorentz force and other forms. When these forces are applied to conductors or other materials, they can cause vibrations. The frequency range of sound is between 20 Hz and 20 kHz, which means that some low-frequency or high-frequency electromagnetic noise may escape into our ears. .
Electromagnetic noise in electric motors
In electric motors, electromagnetic torque is generated due to the action of electromagnetic force. These torques can affect the operation of the rotor and stator and even turn them over. When the rotor is running, unstable torque changes produce wobbling and noise, which is called "torque pulsation." Not only does this affect the performance of your device, it can also become a source of sound that shouldn't be ignored.
In transformers and other electrical equipment, sound is produced through a variety of pathways, including the effect of the Lorentz force on the windings.
Noise in passive components
In addition to electric motors, many static devices such as inductors and transformers also produce noise when operating. In transformers, when the load changes, Lorentz force, Maxwell force and magnetostriction will provide assistance for the generation of sound; in capacitors, unstable voltage and current waveforms can also cause sound, which makes some capacitors Known as the "singing capacitor".
Methods to reduce electromagnetic noise
Faced with the increasing electromagnetic noise problem, the industry has also developed a variety of suppression techniques. Motor damping technology, such as reducing electromagnetic energy or structural reaction, has become an effective means of reducing sound. In addition, choosing the appropriate winding design and slot-pole combination, as well as adding damping, can also effectively reduce the potential for noise generation.
With the right design and technology, electromagnetic noise from many devices can be effectively controlled, further improving our quality of life and comfort.
The impact of sound on life
While electromagnetic forces and associated noise may seem like a minor thing on a technical level, in real life they cause problems for many people. Many people choose to use silent devices at home to avoid annoying noise from interfering with their daily lives. Therefore, how to balance the operating efficiency of power equipment and minimize the impact of sound has become a challenge that manufacturers and consumers need to face together.
Future exploration and thinking
With the advancement of technology, quieter devices will become an important trend in the future. Manufacturers must not only focus on how their products perform, but also delve into how to operate them efficiently and quietly. Can the sound caused by electromagnetic force become a part of our lives and no longer a trouble?
