Mx2020 Dc Power Distribution; Figure 152: Typical Dc Source Cabling To The Router - Juniper MX2020 Hardware Manual

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MX2020 DC Power Distribution

Copyright © 2013, Juniper Networks, Inc.
Appendix D: Power Guidelines, Requirements, and Specifications for the MX2020 Router
current specified above or each DC power supply rated for at least 125% of the continuous
current that the system draws at –48 VDC.
MX2020 DC Power Distribution Module Description on page 49
MX2020 DC Power Electrical Safety Guidelines on page 342
MX2020 DC Power Subsystem Electrical Specifications on page 357
Most sites distribute DC power through a main conduit that leads to frame-mounting DC
power distribution panels, one of which might be located at a location near the rack that
houses the router. A pair of cables (one input and one return) connects each set of PDM
input terminal studs to the power distribution panel. Each DC power subsystem is feed
redundant. The PSMs can be connected to two separate feeds from different sources
that are used for feed redundancy. There are two PDMs per power subsystem each
capable of carrying nine feeds each. Each feed is connected from one source to one PDM
and feeds from the other source to the second PDM of the DC power subsystem. This
configuration provides the commonly deployed A/B feed redundancy for the system. If
both DC feeds are available, operating power will be drawn from the feed with higher
voltage.
Figure 152 on page 359 shows a typical DC source cabling arrangement.

Figure 152: Typical DC Source Cabling to the Router

Chassis
grounding
points
-48V
RTN ,60A
RTN
,60A -48V RTN
RTN -48V ,60A
,60A RTN
-48V -48V
RTN
60A
DC power supply on MX2020
The DC PDMs in slots
PDM0
feeds derived from feed A , or feed
feed redundancy for the system to balance the power draw.
A/B
Central office
secondary DC
power distribution
Ground
window
Batteries
Power plant and batteries in same building
Central
office ground
, , , and can be powered by dedicated power
PDM2 PDM1 PDM3
B . This configuration provides the commonly deployed
Rectifiers AC
Plant
controls
359