Vega Customer Applications Manual
Section 5 - Fans and Cooling
Rev. A3: October 2003
Page 20 of 48
Section 5 - Fans and Cooling
Installation for best Airflow.
The exceptional power densities of Vega are achieved by careful thermal design and forced air cooling from an integral
fan. Airflow can be forward in which case air is drawn in at the fan end and exhausted from the module or reverse in
which air is drawn in at the module end and exhausted via the fan end. In the specification "Ambient air temperature" is
taken to be the air entering the fan (forward) or entering the module end (reverse).
Best performance is achieved using forward flow air. Forward or reverse airflow must be specified at time of purchase.
The available output power is de-rated for reverse air applications. Contact Technical sales to discuss carefully any
reverse air requirements to ensure adequate cooling is maintained or the correct de-rating of output power is adhered
to.
In both forward and reverse flow, adequate cooling can only be maintained by ensuring that obstructions to airflow are
kept 50mm
from the fan end and 50mm
from the module end of the power supply where air is drawn in / exhausted.
Always design a system so that the coolest possible air is routed to the intake of the power supply. Try and avoid
using "re-circulated air" by having highly enclosed boxes with the exhaust in the box itself. A clear flow path from an
intake of the coolest available air (ie outside of an installation box), through power supply and exhausted back out into
the same air is always best. Where Vega is used in a fully enclosed box with re-circulating air it is important to ensure
that the air temperature being drawn into the Vega itself is sufficiently cool.
Audible noise from the Fans.
Measurements have been taken with a background noise level of approximately 38dB. All measurements were taken
at a distance of 1m from the fan grill, with the fan end closest to the noise meter.
Results
Fan option
nomenclature
Air Direction
Fan Type
Typ fan
Voltage
Audible Noise
(dB @ 1m)
Forward
Papst 612NHH
12.5V
55.0
F
Forward
Sanyo 109R0614E402
14V
57.0
Forward
Papst 612
12.2V
49.1
Q
Forward
Papst 612NH
12.4V
49.7
Reverse
Sanyo 109R0614E402
14V
61.0
R
Reverse
Papst 612NHH
12.5V
60.3
Reverse
Papst 612
12.2V
56.4
P
Reverse
Papst 612NH
12.4V
53.2
Restricting the air intake by placing (for example) another grill in front of the fan can cause a "chopping" effect created
by non-planar flow of the air into the fan which may increase the audible noise as well as reduce airflow.
