Juniper EX4300 Series

Table 47: Details of the DC Power Supplies in EX4300 Switches (Connued)
Details 550 W DC Power Supply
Operang range –40.8 through –60 VDC
NOTE: The minimum input power required to power on the
switch is –43.5 +/– 0.5 VDC. Aer the switch is powered on, the
operang range is –40.8 through –60 VDC.
To prevent electrical injury while installing or removing DC power supplies, carefully follow instrucons
in "Installing a DC Power Supply in an EX4300 Switch" on page 301 and "Removing an AC Power Supply
from an EX4300 Switch" on page 296.
DC Power Supply Airow
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 direcon of airow in the power supply.
Table 48 on page 115 lists the DC power supply models and the direcon of airow in them.
Table 48:
Airow Direcon in DC Power Supply Models for EX4300 Switches
Model Label on Power
Supply
Direcon of Airow
JPSU-550-DC-
AFO-A
AIR OUT (AFO) 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.
JPSU-550-DC-AFI-
A
AIR IN (AFI) 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.
N+0 Redundancy Conguraon of DC Power Supplies
In an
N +0 redundancy conguraon, no power is reserved for resiliency regardless of number of power
supplies installed in the switch.
Depending on the power supplies installed in the switch, you can determine the system power budget.
115