Juniper MX2020 Hardware Manual page 66

MX2020 3D Universal Edge Router Hardware Guide
40
DC power subsystem—The MX2020 DC power system is made up of two subsystems.
Each subsystem provides power to ten line card slots, one local fan tray and critical
FRUs. These critical FRUs consist of two CB-REs, eight SFBs located in the center of
the chassis, and two fan trays (one for each zone). Specifically, each power subsystem
has enough power delivery capacity to power ten line card slots, three fan trays, two
CB-REs, and eight SFBs. There are nine DC power supply modules (PSMs), and two
DC power distribution modules (PDMs) in each subsystem. This means, if one power
subsystem stops functioning for any reason, only the MPCs will stop functioning, but
the router will continue functioning.
DC power distribution modules (PDMs)— In the DC configuration, each subsystem
provides N+1 power supply module redundancy along with N+N feed redundancy. The
power feeds from different sources need to be connected to different PDMs. If feeds
that connect to one PDM fail in a redundant configuration, the other feed kicks in to
provide full power. A total of four PDMs can be installed into a router. Each DC PDM
operates with up to nine separate feeds of either 60-amp or 80-amp current limit .
The capacity of these feeds is relayed to system software through a switch located
on the DC PDM.
DC power supply modules (PSMs)—The DC PSMs are hot-removable and
hot-insertable. Each PSM is cooled by the air inlets on the PDMs. The DC PSMs are a
dual redundant feed (
INP0
feeds from different sources that are used to provide feed redundancy when both input
feeds are present, power will be drawn from the feed supplying higher DC voltage.
These feeds are set by the input mode DIP switch located on the DC PSM (see
DC Power Supply Module Description" on page
subsystem capable of carrying nine feeds each. Connect feeds from one source to one
PDM and feeds from the other source to the second PDM of the power subsystem.
Each DC PSM is capable of delivering 2500 W of power if 80A feeds are connected.
AC power subsystem—The MX2020 supports connection of a three-phase AC power
system. There are two types of three-phase power systems: the three–phase delta
and three-phase wye. The AC power going to the PSMs is split into three individual
phases—each PSM works on a single phase. This means the power system works
independent of the kind of AC feed is connected. The user can connect one or two
feeds, depending on the power system configuration (number of PSMs, redundancy,
etc.). Each phase from each of the two feeds is distributed among one or two PSMs
(one feed has each phase going to two PSMs, and the other feed has each phase going
to a single PSM).
AC power distribution modules (PDMs)—The MX2020 supports connection of a
three-phase AC power system. There are two types of three-phase power systems.
The three-phase Delta and three-phase Wye. The AC power going to the PSMs is split
into three individual phases (Wye) or pair of phases (Delta). This means the power
system works independent of the kind of AC feed is connected. Each PDM requires
two feeds connected—both are three-phase. Each phase from each of the two feeds
is distributed among one or two PSMs (one feed has each phase going to two PSMs,
and the other feed has each phase going to a single PSM).
AC power supply modules (PSMs)—The AC PSMs are hot-removable and
hot-insertable. Each PSM is cooled by the air inlets on the PDMs. The AC PSMs have
and ). Each DC PSM can be connected to two separate
INP1
51). There are two PDMs per power
Copyright © 2013, Juniper Networks, Inc.
"MX2020