Requirements for Redundant Power

If a DC supply in a PCM fails, the system boards will continue to be powered and cooled by the other power supplies if sufficient redundancy (an additional power supply) is present.

For example, if an Enterprise 3500 system needs a minimum of two PCMs and three are present, then the system has redundancy. See Table 7-3.

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Note -

The presence of an additional (extra) PCM in the system provides redundancy and allows hot-plug of PCMs.

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Table 7-3 Minimum and Redundant Working Power Supplies Required to Power Active Boards

	Enterprise 3500 System
Number of Boards	Minimum Number of Working PCMs	Redundant Working PCMs (Hot-Pluggable)
1-2	1	2
3-4	2	3
5	3	No redundancy

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Note -

When all five board slots are populated, there is no redundancy because of the two PCMs per board rule.

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Failed power supplies must be replaced as soon as practical. Otherwise, the Enterprise 3500 system will lose its redundancy and result in an outage at the next PCM failure.