Figure 2: Dc Power Subsystem Feed Redundancy; Figure 3: Power Distribution From Three-Phase Feed Delta Pdm To The Ac; Psms - Juniper MX2020 Hardware Manual

Copyright © 2013, Juniper Networks, Inc.

Figure 2: DC Power Subsystem Feed Redundancy

PDM 1
(feed B)
PSM PSM
0 1
PDM 0
(feed A)
Each PSM has a set of two DIP switches located on the faceplate. These DIP switches
are used to indicate whether a user wants to connect one feed to the power subsystem,
two feeds, or none. These DIP switches provide critical information to the power
management subsystem to help generate alarms in case of a feed failure or a wrong
connection. Each PDM has an LED per feed indicating whether the feed is active or not,
or whether the feed is connected properly. See
Description" on page 51.
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). See Figure 3 on page 7

Figure 3: Power Distribution from Three-Phase Feed Delta PDM to the AC

PSMs

AC PS_0 AC PS_3
2800W 2800W
input
A1
B1
C1
PSM
8
"MX2020 DC Power Supply Module
and Figure 4 on page
AC PS_1 AC PS_4
2800W 2800W
input input input
AC PS_2
2800W
input
AC PS_5
2800W
input
Chapter 1: MX2020 Router Description
8.
AC PS_6 AC PS_7
2800W 2800W
input input
AC PS_8
2800W
input
A2
B2
C2
7