Juniper EX4300 Series Hardware Manual page 125

Table 47: Details of the DC Power Supplies in EX4300 Switches
Details
Operating range
To prevent electrical injury while installing or removing DC power supplies, carefully follow instructions
in "Installing a DC Power Supply in an EX4300 Switch" on page 301
from an EX4300 Switch" on page
DC Power Supply Airflow
Each power supply has its own fan and is cooled by its own internal cooling system.
Each power supply has a label AIR OUT (AFO) or AIR IN (AFI) on the faceplate of the power supply that
indicates the direction of airflow in the power supply.
Table 48 on page 115 lists the DC power supply models and the direction of airflow in them.
Table 48: Airflow Direction in DC Power Supply Models for EX4300 Switches
Model Label on Power
Supply
JPSU-550-DC- AIR OUT (AFO)
AFO-A
JPSU-550-DC-AFI- AIR IN (AFI)
A
N+0 Redundancy Configuration of DC Power Supplies
N +0 redundancy configuration, no power is reserved for resiliency regardless of number of power
In an
supplies installed in the switch.
Depending on the power supplies installed in the switch, you can determine the system power budget.
550 W DC Power Supply
–40.8 through –60 VDC
NOTE: The minimum input power required to power on the
switch is –43.5 +/– 0.5 VDC. After the switch is powered on, the
operating range is –40.8 through –60 VDC.
296.
Direction of Airflow
Front-to-back—that is, air intake to cool the chassis is through the
vents on the front panel of the chassis and hot air exhausts through
the vents on the rear panel of the chassis.
Back-to-front—that is, air intake to cool the chassis is through the
vents on the rear panel of the chassis and hot air exhausts through the
vents on the front panel of the chassis.
(Continued)
and "Removing an AC Power Supply
115