Connecting A Dc Power Supply Directly To Dc Power Sources - Cisco Nexus 7000 Hardware Installation And Reference Manual

Connecting a DC Power Supply to DC Power Sources
With the power supply connected to the earth ground, you can connect the power supply to the DC power
source (see the

Connecting a DC Power Supply Directly to DC Power Sources

Before performing any of the following procedures, ensure that power is removed from the DC circuit.
Warning
Statement 1003
Installation of the equipment must comply with local and national electrical codes. Statement 1074
Warning
When installing or replacing the unit, the ground connection must always be made first and
Warning
disconnected last. Statement 1046
To connect a DC power supply to a DC power source, you must connect two isolated inputs from the DC
power grid to the power supply for each 3 kW of output power provided by the power supply. For the
3-kW power supply, you connect the four cables (two isolated inputs) to the power supply (use two 3-kW
power supplies to output 6 kW of power). For the 6-kW DC power supplies, the cables for two isolated
inputs are bundled into one cable with a plug that connects to the power supply (one cable and plug for
3 kW or two cables and plugs for 6 kW).
You can wire these power supplies for combined power mode, power-supply redundancy mode,
input-source redundancy mode, and full redundancy mode as follows:
•
•
•
•
Figure
Note
optional power supplies in gray.
Cisco Nexus 7000 Series Hardware Installation and Reference Guide
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"Connecting a DC Power Supply to DC Power Sources" section on page
Combined power mode uses all of the output from all of the connected power supplies. This mode
does not provide any power redundancy. You can connect all of the power supplies to the same DC
power grid as shown in Figure
Power supply redundancy uses the required number of power supplies plus one (N+1) power supply
for redundancy. This mode enables you to replace a power supply during operations. You can
connect all of the power supplies to the same DC power grid as shown in
Input source redundancy uses two power grids. Power supplies with two power cables have each
cable connected to a different power grid. Power supplies with one power cable have half of the
power supplies connected to one grid and the other half connected to the other grid. To see how these
power supplies are connected to two grids, see
Full redundancy provides both the power supply (N+1) redundancy and input source redundancy.
You configure an extra power supply and you connect all of the power supplies to two grids, as
shown in Figure 6-6.
6-3, Figure 6-4, Figure
6-3.
Figure
6-5, and Figure 6-6 show the required power supplies in black and
Chapter 6 Installing Power Supplies
Figure
6-5.
6-8).
6-4.
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