M40E Router Power Supplies - Juniper JUNOS - NETWORK OPERATION GUIDE REV1 Network Operation Manual

JUNOS Internet Software Network Operations Guide: Hardware

M40e Router Power Supplies

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Understanding Power Supplies
The M40e router uses either AC or DC power. Two load-sharing, pass-through power
supplies are located at the bottom rear of the chassis. Figure 90 shows the M40e
router power supplies and where they are installed in the chassis.
When the power supplies are installed and operational, they automatically share the
electrical load. If a power supply stops functioning for any reason, the remaining
power supplies instantly begin providing all the power the router needs for normal
functioning, and can provide full power indefinitely.
Mixing AC and DC power supplies is not supported and prevents the router
NOTE:
from booting. If two power supplies are installed, they must be either both AC or
both DC.
! A circuit breaker box must be installed on a DC-powered router, while a circuit
breaker is incorporated into each AC power supply. Converting the router from
AC to DC power or vice versa involves removing or installing the circuit
breaker box. Only authorized service personnel should perform the
conversion; this manual does not include instructions.
! When two power supplies are installed, at least one Routing Engine and one
FPC must also be installed for both power supplies to power on. In the
absence of this minimum load, only one power supply starts. (The router
powers on and operates correctly with one power supply, but without the
redundancy benefit of having a second power supply installed.)