Users Manual Part 2

Chapter 12
Cooling Fans
One or more fan modules generate an airflow to manage the temperature within the MTS cabinets.
12.1
Cooling Fans Overview
Each fan module consists of two fans. A sensor monitors the fans revolution and in the event of failure,
an alarm is generated.
NOTICE: Low power configurations of MTS LiTE and MTS 2 can optionally operate with cooling
fans.
Figure 186: MTS Fan Kit
Molex connector
Cable
12.2
Cooling Fans Theory of Operation
The MTS card cage contains fan kits which reside below the modules. The PSU supplies and controls
the three fan kits speed (max two for MTS LiTE) to reduce the noise in normal temperature
environments. The fan speed is based on the temperature of the modules. The latter require that the
Site Controller software monitors the module temperatures and controls the fans speed through the
CAN Bus.
MTS LiTE and MTS 2 offer configurations which do not need fans. The temperature range is from -30
°C to 55 °C. If the temperature range is extended to 60 °C, two fan kits for MTS LiTE or three fan kits
for MTS 2 need to be mounted. MTS 4 requires fans for all configurations. There is no need for the
fans in MTS 2 for the low power PA BTS configurations. In other configurations, three fan kits are
needed at the bottom of the card cages. There may be a reliability issue with the fans if operated below
-10 °C. At an ambient temperature below -10 °C, the fans are stopped and restarted again at -8 °C.
The fan supply ramps up to 24 V output for a few seconds in all start up situations.
6802800U74-AP
Cooling Fans
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