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This chapter describes the power and cooling requirements for the Cisco CRS Series 16-Slot Line Card Chassis Enhanced. It contains the following sections:
The chassis power system provides power to chassis components and is made up of two power shelves that contain power modules. Each power shelf is connected to a separate and independent power source. Input power enters the power shelves and is processed by the power modules before being distributed to the components in the chassis. At the shelf level, the power system provides 2N redundancy; the PMs themselves provide load-share redundancy. The power system also includes SNMP MIBS and XML support.
The line card chassis can be either DC or AC powered. The AC power system requires single-phase AC input power to the power shelves. If you have 3-phase AC Delta or AC Wye at your equipment, a Cisco CRS 3-Phase AC Power Distribution Unit(PDU) will be required to convert 3-phase AC input power to single-phase AC input power for the power shelf.
Note | In an AC power system, PDU refers to the Cisco CRS 3-Phase AC Power Distribution Unit which is required to convert 3-phase AC-Wye or AC-Delta input power to single-phase AC input power for the AC power shelf. For further information and installation instructions, see http://www.cisco.com/en/US/docs/routers/crs/crs1/mux_box/installation/quick_start/guide/crs_pdu_qs.html Cisco CRS 3-Phase AC Power Distribution Unit Installation Guide. |
Maximum input power requirements for the Cisco CRS 16-Slot Line Card Chassis Enhanced router are as follows:
Note | If you have a Cisco CRS 3-Phase AC PDU installed, six AC PMs are required to be installed in each AC power shelf to maintain a balanced 3-phase power load. |
Note | These power requirements are for a fully loaded Cisco CRS 16-Slot Line Card Chassis Enhanced router with sixteen PLIMs. A chassis with fewer PLIMs uses slightly less power. However, it is a good idea to allocate this much power for each chassis to ensure that enough power is available for future system expansion. |
See the Cisco CRS Carrier Routing System 16-Slot Line Card Chassis Enhanced Router System Description for detailed information about how each power system operates and distributes power to the components in the chassis.
This section describes the power and grounding requirements you must consider when planning the site facilities for the line card chassis. In addition, see the DC Power System section or the AC Power System section for additional power requirements.
Note | A certified electrician should review the information in these sections to ensure that the installation site meets these requirements. For larger system configurations, consult a facilities electrical expert to understand the load that the routing system may put on the facility power plant. |
General power and grounding requirements are:
Note | Be sure to review the safety warnings in Regulatory Compliance and Safety Information for the Cisco CRS Carrier Routing System before attempting to install the routing system. |
The router chassis has two safety earth ground connections. The chassis allows you to connect the central office ground system to the bonding and grounding receptacles on the router chassis. Threaded ground inserts are located on top of the chassis rear (MSC) side panel to the right of the lower power shelf. There are also two sets of grounding studs located at the bottom of the rear (MSC) side of the chassis. The following figure shows the NEBS and grounding points at the top on the rear (MSC) side of the chassis. This grounding point is also referred to as the network equipment building system (NEBS) bonding and grounding point.
Note | These bonding and grounding receptacles are provided to satisfy the Telcordia NEBS requirements for bonding and grounding connections. |
1 |
Two Torx security screws |
Note | The two bolts below the NEBS bonding and grounding points at the top of the chassis are required for proper bonding and grounding of the chassis and should not be removed. |
The following figure shows the grounding points located at the bottom of the rear (MSC) side of the chassis.
To connect the chassis to a ground connection, you must have the following:
Note | The DC return of this system should remain isolated from the system frame and chassis (DC-I: Isolated DC Return). |
Each DC powered chassis contains two DC power shelves for 2N redundancy. The power shelves contain the input power connectors. Each shelf can contain up to eight DC PMs. The power shelves and DC PMs are field replaceable.
Observe the following guidelines for DC-powered chassis. In addition, be sure to review the requirements in the General Power and Grounding Requirements section.
The following table lists the DC input current and voltage specifications.
Nominal input voltage |
–48 VDC North America–60 VDC European Community(range: –40 VDC to –72 VDC) |
Input line current |
50 A maximum at –48 VDC40 A maximum at –60 VDC60 A maximum at -40 VDC |
Each DC power shelf contains eight pairs of double-stud terminals, covered by a plastic terminal block cover. To provide 2N power redundancy, one power shelf should be connected to the central office “A” power bus and the other power shelf should be connected to the “B” power bus.
The requirements for the DC input power connections are as follows:
Caution | A certified electrician must select the appropriate DC input power cable based on standard electrical practices, such as derating factors, wiring type, operating temperatures, and so on. The electrician must verify that the cable complies with the National Electrical Code (NEC) and local codes and any guidelines in effect at the installation site. At minimum, DC input power cables must be 6-AWG or heavier and rated for 90°C (194°F) temperature or higher. |
The following figure shows the DC input power cables connected to the DC power shelf terminal studs.
The chassis power system provides the necessary power for chassis components. Site power configurations may differ, depending on the input source available, i.e. single-phase AC, AC Delta or AC Wye.
Each AC powered chassis contains two AC power shelves for 2N redundancy. The power shelves contain the input power connectors. Each shelf can contain up to six AC PMs. The power shelves and AC PMs are field replaceable.
The following figure shows the rear side of the AC power shelf.
In addition to the requirements in the General Power and Grounding Requirements section, AC input power requirements are as follows:
Note | If you have a Cisco CRS 3-Phase AC PDU installed, six AC PMs are required to be installed in each AC power shelf to maintain a balanced 3-phase power load. |
For detailed AC power specifications, see the Line Card Chassis Specifications section.
The AC power shelf is shipped with AC power cords. Each AC power shelf accepts up to six power cords. Each power cord is 4.25 m in length and different plug types (pre-attached) are available, depending on the locale. AC cords are available for the following locales:
The following table lists the single-phase AC-input cord power options and Cisco product numbers for the Cisco CRS 16-Slot Line Card Chassis Enhanced router with an AC power shelf installed. The table also references power cord illustrations.
Locale |
Cisco Product Number |
Plug Rating |
Reference Illustration |
---|---|---|---|
North America |
CRS-AC-CAB-NA(=) |
20 A/250 VAC |
|
Europe |
CRS-AC-CAB-EU(=) |
16 A/250 VAC |
|
United Kingdom |
CRS-AC-CAB-UK(=) |
13 A/250 VAC |
|
Italy |
CRS-AC-CAB-IT(=) |
16 A/250 VAC |
|
Australia |
CRS-AC-CAB-AU(=) |
15 A/250 VAC |
Note | The BS-1363 standard rates cord sets up to a maximum of 13 A, 250 VAC for the C-21 plug. Therefore, the building circuit breaker must be 13 A maximum. Installation of the Cisco CRS 16-Slot Line Card Chassis Enhanced router must follow national and local electrical codes. |
Note | The AS 3112 standard rates cord sets up to a maximum of 15 A, 250 VAC for the C-21 plug. Therefore the building circuit breaker must be 15 A maximum. Installation of the Cisco CRS 16-Slot Line Card Chassis Enhanced router must follow national and local electrical codes. |
If you have 3-phase AC Delta or AC Wye input power at your equipment, a Cisco CRS 3-Phase AC PDU will be required to convert 3-phase AC Delta or AC Wye input power to single-phase AC input power that connects directly to the rear of the AC power shelf. The Cisco CRS 3-Phase AC PDU includes either an AC Delta or AC Wye power interface, and has power input and power output cords entering and exiting the box.
There are two versions of the Cisco CRS 3-Phase AC PDU for the Cisco CRS 16-Slot Line Card Chassis Enhanced router available:
In addition to the requirements in the General Power and Grounding Requirements section, AC input power requirements are as follows:
For detailed Cisco CRS 3-Phase AC PDU AC power specifications, see the Cisco CRS 3-Phase AC Power Distribution Unit Installation Guide.
The airflow through the Cisco CRS 16-Slot Line Card Chassis Enhanced router is controlled by a push-pull configuration. As shown in the following figure, ambient air flows in at the bottom front of the Cisco CRS 16-Slot Line Card Chassis Enhanced router and up through the card cages until it exhausts at the top rear. The bottom fan tray pulls ambient air in from the bottom front of the chassis; the top fan tray pushes warm air out the back of the chassis. The power modules in the power shelves have their own self-contained cooling fans.
A replaceable air filter is positioned above the lower fan tray. How often the air filter should be replaced depends on the facility environment. In a dirty environment, or when you start getting frequent temperature alarms, you should always check the intake grills for debris and the air filter to see if it needs replacement.
Before removing the air filter for replacement, you should have a spare filter on hand; follow the air filter replacement procedure in the Cisco CRS Carrier Routing System 16-Slot Line Card Chassis Enhanced Installation Guide
1 |
Front (PLIM) side of chassis |
6 |
Power shelves (two installed) |
2 |
Air intake |
7 |
Air exhaust |
3 |
Lower fan tray |
8 |
Upper card cage |
4 |
Air filter |
9 |
Lower card cage |
5 |
Upper fan tray |
10 |
Rear (MSC) side of chassis |
The Cisco CRS 16-Slot Line Card Chassis Enhanced router has a maximum airflow of 2,700 cubic feet (76,455 liters) per minute.