Installation guide

Summit External Power Supplies (EPS)
Summit Family Switches Hardware Installation Guide
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Two or Three EPS-600LS Modules. When the Summit X450e-48p or X250e-48p switch detects that an
EPS-C is connected and providing stable power from two or three EPS-600LS power modules, the PoE
power budget is automatically recalculated to enable 740 W of PoE power. The internal PSU is disabled
to prevent damage from excessive current demands beyond the internal PSU's capabilities.
External-to-Internal PSU Transfer
This section describes the conditions where power from an external power module either fails or is
disconnected.
Active Internal PSU with Single 600-LS Module Failure. When an EPS-C configured with a single EPS-
600LS module is connected to the Summit X450e-48p or X250e-48p switch and the EPS-600LS fails or is
disconnected, power is drawn from the internal PSU without power interruption to the PoE connected
devices.
Inactive Internal PSU with a Dual EPS-600LS Configuration and Module Failure. This section describes the
PoE behavior when an EPS-C chassis configured with two EPS-600LS modules is connected to the
Summit X450e-48p or X250e-48p switch and one or both EPS-600LS modules fail or are disconnected.
It is possible for one external power module to fail while the second power module continues to
function. If one EPS-600LS fails, the PoE power budget is automatically reduced to 370 W for the
Summit X450e-48p or X250e-48p switch. PoE port power management occurs as described in the
ExtremeXOS 12.0 Concepts Guide, Power over Ethernet section. With only a single operating power
module, the remaining EPS-600LS behaves as a redundant power module. The internal PSU is returned
to an active state to provide redundant capability.
If both external power modules fail or are disconnected, PoE power is interrupted while transferring
PoE power back to the internal PSU. The internal PSU is then limited to 370 W of PoE power. The PoE
power budget is automatically adjusted accordingly. Power management will occur as described in the
ExtremeXOS 12.0 Concepts Guide, Power over Ethernet section.
Disconnecting the EPS-C/EPS-600LS. To manually disconnect an EPS-C or to remove the EPS-600LS
modules, the recommended practice is to disconnect the EPS-600LS modules one at a time, pausing two
seconds between each EPS-600LS disconnect. This enables a graceful power transition from the external
PSUs to the internal PSU.
Example: Two active EPS-600LS modules in an EPS-C
a Unplug one EPS-600LS unit from its power source.
PoE power is automatically reduced to 370 watts and the internal PSU is enabled providing
redundant 370 watt PoE power.
b Wait at least two seconds before disconnecting the remaining EPS-600LS unit.
c Unplug the second EPS-600LS unit from its power source.
The internal PSU is already enabled and provides uninterrupted 370 watts of PoE power.
NOTE
After an EPS-600LS unit is disconnected from its power source, it may be removed from the EPS-C. See
“Removing an EPS-600LS Power Module” on page 101 for complete disconnect and removal details.
d Disconnect the EPS-C from the switch.