Compact fans for AC and DC [PDF] - ebm-papst

Fan installationInformation on installationWhen a fan is operated for the first time in an application, the user mayhave noticed that the flow rate in the device was lower than expected.What is the reason for this?• The values stated in this catalogue were determined under optimum,constant and comparable measurement conditions.BaffleMultidirectional intake,laminar currentsUnidirectional exhaust,turbulent• Ideal mounting conditions under which free air intake and exhaustare present are seldom feasible in practice. Quite frequently the fansmust be mounted in close proximity to other components or cabinetpanels. As a consequence, the intake and exhaust currents may berestricted, causing the air flow to diminish and the noise level toincrease. Fans are particularly sensitive to obstructions which arepositioned directly in front of the output cross section as they oftencause an increase in tonal noise.Our advice: The distance between the fan and adjacent componentsshould be at least equal to the installation depth of the fan.Intake or exhaust side installationUnder ideal conditions, the operating point isrepresented as the intersection between thefan and loss curves, regardless of whether thefan is positioned at the air intake or exhaustside of the device. In addition to ensuring therequired flow rate, several additional aspectsmust be considered for determining an appropriatefan concept.The intake air currents of a fan are mainlylaminar, comprising nearly the entire suctionarea. By contrast, the exhaust air of a fan isgenerally turbulent, while it flows on a preferreddirection, e.g. axial for an axial fan. Theturbulences of the exhaust intensify the heattransfer from components within the air currents,so that mounting the fan at the airintake side of the device is recommended forcooling and heating. Mounting the fan at thedevice intake is also advantageous becausethe fan will not be subjected to the dissipatedheat of the device. Therefore, it operates atlow ambient temperatures and has a higherlife expectancy.Accident preventionThe turning rotor and the high speeds thatare sometimes involved mean that our fanproducts carry an inherent risk of injury.They may only be operated after correctinstallation and with suitable protectivefacilities (e.g. with a guard grille). Moreinformation can be found in the internet at:www.ebmpapst.com/safety14