Download [PDF] 2.1 MB - ebm-papst UK
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CENTRIFUGAL COMPACT FAN<br />
70 25<br />
Figure 2: Aerodynamic power data of the<br />
fan unit<br />
Pressure increase D pf [Pa]<br />
Static efficiency [%]<br />
LEGEND<br />
characteristic curve of air<br />
performance<br />
static efficiency including motor and<br />
control electronics<br />
system resistance curve of the<br />
cooling application<br />
0 0<br />
0 50<br />
Volumetric flow rate [m 3 /h]<br />
To achieve a higher level of efficiency, the gap<br />
between the rotating and static components must<br />
be kept as small as possible. However, if the gap<br />
is too small, there is a danger of the refrigerating<br />
unit freezing, which is why a minimum gap size<br />
must be adhered to. The smaller the distance between<br />
the casing tab and the impeller, the more<br />
audible the aeroacoustic interactions of both<br />
components. These contradictory requirements<br />
mean that compromises have to be made and the<br />
compromises needed for good acoustics were determined<br />
in experiments using prototypes.<br />
Authors are engineer Michael Schmitz, Head of Central<br />
Research and Development at <strong>ebm</strong>-<strong>papst</strong> St. Georgen and<br />
F. Cifrodelli, M. Malisi, R. Pradel as well as A. Feinauer from<br />
BSH Bosch and Siemens Hausgeräte GmbH<br />
You would like more information on this topic Please address<br />
your question to: Michael.Schmitz@de.<strong>ebm</strong><strong>papst</strong>.com<br />
techmag 02°2013<br />
19