Noise, shaking - phenomena unpleasant to man. Annoying their constant presence. Vibration isolators for fans eliminate negativity, both emotional and completely objective. Vibrations are not harmless processes.
Where do the
fan vibrations come from? Working fans do not have an efficiency of 100%.Since energy is spent on side effects:
- heating of rubbing surfaces;
- knocks, backlashes;
- acoustic noise.
Noise does not occur independently. They are a consequence of the vibrations of the fan, generating sound vibrations perceived by the human ear. Not all phenomena occur due to knocks, backlash and other defects of a mechanical nature. For example, the wire in the transmission line can vibrate. This happens when an electric current interacts with the Earth’s magnetic field. As a result, the wire vibrates at a frequency of 50 Hz and emits a low buzzing sound corresponding to the note salt.
The rotating blades in the fan will certainly cause shaking. Moving in a circle, the material is influenced by centrifugal force. Despite the name, seemingly meaning movement inside, the molecules of the substance tend to break out. As long as the part is strictly symmetrical, the fan runs silently and does not create vibrations. But it is necessary to outweigh a fraction of a gram, and beats arise with the frequency of rotation of the blades. This is how the fan vibration is born.
This immediately responds with a sinusoidal-type load transmitted to the supporting structures. The process described is called fan vibration. Shaking parts transmit air movement, in addition there is acoustic noise. It is shown that vibrations are accompanied by acoustic phenomena. An exception is the case when the latter are intentionally extinguished by means of sound protection.
In order to assess how great the vibration is, there are special quantities and methods for estimating them. Special standards have been developed that regulate noise and vibration levels. Including, and from household fans.
According to human physiology, there are ranges of especially dangerous vibration frequencies. On them measurements are taken and restrictions are raised. The level depends on the location of the observed vibration. The rustle of foliage in the woods in a quiet room will seem like a roar. It is clear that in a factory where workers work, permissible vibrations are more important than in an apartment.
The following concepts were introduced to quantify the oscillations:
- Vibration Acceleration.
- Vibration Speed.
Imagine the end of the board, which oscillates in a vertical plane. That goes down, then goes up. The speed of movement of the oscillating edge, and will be vibration velocity, amplitude - vibration displacement, finally, vibration acceleration characterizes the change in speed at each point of movement.
Optionally, the speed varies sinusoidally or is uniform. Therefore, we introduced the concept of vibration acceleration. Exclusively taken together, these parameters accurately characterize the vibration. For an ordinary room in a residential building, regarding vibration acceleration, it looks like this:
- 2 Hz - 74 dB.
- 4 Hz - 75 dB.
- 8 Hz - 77 dB.
- 16 Hz - 83 dB.
- 31.5 Hz - 89 dB.
- 63 Hz - 95 dB.
The regulations on fan vibration are closely intertwined with legislation. All vibration levels are for a period of time from 7 to 23 hours. The vibration of the fan goes into acoustic oscillation, and "making noise after eleven is prohibited."