What The Tech: How do fans deal with vibra­tion and reso­nance?

Without reso­nance caused by vibra­tion, no bird could fly, and you couldn’t bounce on a tram­po­line. Reso­nance is also key for a smoothly oper­ating fan. But, unfor­tu­nately, reso­nance can also cause damage. Learn how precisely manu­fac­tured fans can handle reso­nance and vibra­tion.

Reso­nance caused by vibra­tion – that is, vibra­tion with ever-increasing ampli­tudes, can become destruc­tive. This is called a reso­nance disaster. Even fans are not immune to damage caused by reso­nance. Reso­nance is trig­gered by the fan’s own increas­ingly strong vibra­tions and is also known as sympa­thetic vibra­tion. This quickly leads to damage, such as destroyed motor bear­ings.

Although fans are precisely balanced by the manu­fac­turer, there is still a risk due to different instal­la­tion situ­a­tions. Unfor­tu­nately, these cannot be predicted or taken into account. Installing a fan in a system always creates a new vibra­tional arrange­ment with a specific struc­tural reso­nance frequency. Vibra­tion-absorbing elements are used to isolate the fan from vibra­tions in the envi­ron­ment. The FanGrid modules, which are also avail­able as a plug & play solu­tion, help mini­mize the external influ­ence.

For example, the intake and delivery sides are reli­ably sepa­rated from one another. Crit­ical speeds are avoided by program­mable blanking zones. Or even easier: inte­grated vibra­tion sensors detect crit­ical speed ranges and auto­mat­i­cally prevent them. Even so, it is essen­tial to perform a vibra­tion measure­ment after instal­la­tion and repeat this regu­larly. To do this, vibra­tions are measured in two, or prefer­ably three axes.