Dc Power Supply Configurations - Juniper MX480 Hardware Manual

Figure 15: High-Capacity DC Power Supply

DC Power Supply Configurations

In the DC power configuration, the MX480 router contains either two or four DC power supplies (see
Figure 14 on page 56) located at the rear of the chassis in slots PEM0 through PEM3 (left to right). You
can upgrade your DC power system from two to four power supplies.
Four power supplies provide full redundancy. If a DC power supply in a redundant configuration is removed
or fails, its redundant power supply takes over without interruption. The DC power supply in PEM2 serves
as redundant to the DC power supply in slot PEM0, and the DC power supply in PEM3 serves as redundant
to the DC power supply in slot PEM1. If only two DC power supplies are installed, they must be installed
in slots PEM0 and PEM1 or in slots PEM2 and PEM3.
Table 18 on page 57 shows the components that are powered by each DC power supply slot. It applies
to existing and high-capacity power supplies.
Table 18: Power Supply Redundancy and Power Distribution
DC Power Supply Slot
PEM0
PEM1
PEM2
PEM3
Power Supply Provides Power to the Following Components
Fan tray, DPC slots 0 and 1, and SCB slots 0 and 1
Fan tray and DPC slots 2 through 5
Fan tray, DPC slots 0 and 1, and SCB slots 0 and 1
Fan tray and DPC slots 2 through 5
57