Table 6: Ac Pdm Delta And Wye Current Requirements - Juniper MX2020 Hardware Manual

Copyright © 2015, Juniper Networks, Inc.
AC power requirements—Table 6 on page 15
for the three–phase delta and wye power feeds.

Table 6: AC PDM Delta and Wye Current Requirements

Three–Phase
Voltage Input Feed
200 V 1
(minimum–nominal)
(line-to-line) for delta
2
(per phase)
200 V 1
(minimum–nominal)
(line-to-neutral) for
2
wye (per phase)
NOTE: This is the minimum required to provide 2.5KW per PSM. Based on
facilities guidelines, you should over-provision the MX2020 router. The two
numbers listed in the current columns reflect the distribution of phases
from the feed to PSM. For example, from one feed each phase goes to two
PSMs and from other feed each phase goes to only one PSM.
PDMs—In the DC configuration, each subsystem provides N+1 PSM 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 A or 80 A current limit. The capacity of these feeds is relayed to system software
through a switch located on the DC PDM. The MX2020 router supports two types of
three-phase power system PDMs. The three-phase delta and three-phase wye.
Individual phases are taken from three-phase feeds to individual PSMs. One AC feed
provides power to six PSMs, while the second input feed provides power to the
remaining three PSMs (supporting a total of nine PSMs).
PSMs—All AC or DC PSMs in a subsystem share the load (the nine PSMs on the top
half share the load, as well as the nine PSMs on the bottom share the load). If one PSM
fails in a redundant configuration, the remaining PSMs provide power to FRUs. In the
AC or DC configuration, up to eighteen PSMs may be required to supply power to a
fully configured router. Nine PSMs in the lower card cage supply power to the two
CB-REs (active and redundant), eight SFBs, lower ten MPCs, two lower fan trays and
one fan tray on the top half. Nine PSMs in the upper card cage supply power to the two
upper fan trays, upper ten MPCs, two CB-REs (active and redundant), eight SFBs, and
a fan tray in the lower card cage. A portion of power from each zone is reserved to
power critical FRUs. These FRUs allow the system to operate even if power to a
complete zone fails.
Cooling system—The cooling system has a total of four fan trays— two per zone—which
are controlled by the host subsystem. Each zone is made up of a set of ten MPCs, four
Chapter 2: System Overview and Architecture
shows the MX2020 current requirements
Current Delta per Current Wye per
Three-Phase PDM Three-Phase PDM
50 A –
25 A –
– 30 A
– 15 A
15