Cabletron Systems Environmental Module TM 9C300-1 - Manual (Page 15)

3-3
Monitoring Functions
Fan Speed
The 9C300-1 Environmental Module adjusts the speed of the system cooling fans
(Figure 3-3) based on the external ambient temperature. Fan speed increases as
ambient temperature rises to ensure adequate cooling for the system. Conversely,
fan speed decreases as ambient temperature decreases. In the event the ambient
temperature sensor, or the Environmental Module itself, fails, fan speed defaults
to maximum speed to ensure adequate cooling.
The ability to control fan speed is useful for two reasons:
• To increase the cooling level of the MMAC-Plus system to accommodate
changing operating environments.
• To prolong fan life and limit audible noise when full fan speed is not necessary
for cooling.
Figure 3-3. The 9C300-1 Environmental Module and Fan Tray
Fan Tray Side View
Fan Tray Top View
System Cooling Fans
Front panel