User's Manual

AT-9000 Gigabit Ethernet Switch Installation Guide
42
Power Supplies
The AT-9000/12POE, AT-9000/28, AT-9000/28SP, and AT-9000/52
switches have one AC power supply. The AT-9000/28POE switch has two
AC power supplies. The supplies are not field-replaceable.
Excluding PoE operation, only one power supply is active at a time in the
AT-9000/28POE switch. The second power supply operates in a
redundant state and is automatically activated by the switch if the active
power supply loses power or fails. The change-over is instantaneous,
making it transparent to the network users. Power redundancy is available
only when both AC connectors on the switch are connected to power
sources.
For PoE, however, the power supplies operate in a load-sharing manner,
with each power supply providing 185 watts, half the total PoE budget of
the switch. The maximum 370 watts power budget of PoE is only available
when both power supplies are connected to power sources.
Refer to “Technical Specifications” on page 81 for the input voltage range.
Warning
The power cord is used as a disconnection device. To de-energize
equipment, disconnect the power cord.  E3
Warning
This unit might have more than one power cord. To reduce the risk
of electric shock, disconnect all power cords before servicing the
unit.  E30