User guide

User Guide CC8-BLUES • Multi-Processing CompactPCI CPU
- 22 -
EKF Elektronik GmbH • Philipp-Reis-Str. 4 • 59065 HAMM • Germany
Tel. [phone] • Fax. [phone] • E-Mail [e-mail] • Internet http://www.ekf.de
The measuring results in the table above are based on a forced vertical airflow of 16m
3
/h around
each card slot in a fully equipped 19-inch system rack, achieved by three Papst 4312M fans
operated at 12V. Under these conditions, the CC8 heatsink delivers a thermal resistance of
about 1K/W.
What can be recommended as an optimum airflow? The table below shows the effect on the
maximum allowable ambient temperature of our PIII-850 system at the specified maximum
processor die temperature of 80
o
C. Again, the processor is stressed to its maximum power
dissipation by running kpower.exe.
Fan Type
Pabst
x 3
Vertical Airflow
around each
Card Slot
Maximum Ambient Temp. @Throttle Mode
0% 25% 50% 87.5%
4312GL/6V 4m
3
/h 20
o
C35
o
C44
o
C69
o
C
4312GL/12V 10m
3
/h 31
o
C43
o
C55
o
C73
o
C
4312M/12V 16m
3
/h 42
o
C48
o
C57
o
C74
o
C
4312-179/13.2V 27m
3
/h 43
o
C50
o
C60
o
C75
o
C
As easily can be seen, increasing the airflow above 16m
3
/h has no significant effect on the
maximum allowable ambient temperature. So ~16m
3
/h would be the optimum airflow for most
industrial systems.
Conclusion
Take care of sufficient heat exchange in your system. If appropriate, setup the Throttle Mode
feature. Both Celeron and Pentium-III processors can be reliably operated over a wide
temperature range in a suitable environment.