Allied Telesis AT-RPS3000 - Manual (Page 37)

AT-RPS3000 Redundant Power Supply Installation Guide
37
PoE+ Switches The PoE+ switches do not come with power supplies. You must purchase
them separately and install them as part of the switch’s installation
procedure.
The only way to determine which power module is appropriate for a PoE+
switch is to determine the amount of power the powered devices
connected to the switch will require. The powered requirements of the
devices can be found in their documentation.
If the power requirements of the power devices of the switch are below
480 watts, you may use the AT-PWR800 Module. If you want PoE+
redundancy, you would also install an AT-PWR800 Module in the
AT-RPS3000 Chassis.
Figure 21. Two AT-PWR800 Modules Providing Up to 480 Watts, with Full
Redundancy
If the total power requirements of the devices on a PoE+ switch are
greater than 480 watts, you have two possible solutions to providing the
necessary power. If the power requirement is between 480 and 960 watts,
you could use the load-sharing property of two AT-PWR800 Modules to
provide up to 960 watts, as shown in Figure 22 on page 38. The drawback
to this approach is that PoE+ redundancy extends only to 480 watts, the
power supplied by a single power module. If one of the power supplies
were to stop functioning, the switch would have to deny power to some
powered devices.
For example, if the powered devices on the AT-x610-24Ts/X-POE+ Switch
required 550 watts, the two AT-PWR800 Modules would each provide half,
or 275 watts, of the power requirements of the devices. If power is lost on
one of the power supplies, the remaining power module will supply up to
480 watts of power to the switch, which, being short 70 watts, will have to
deny power to some of the devices.
B
B
1
2
3
4
SYSTEM
PoE+ / SYSTEM PoE+ / SYSTEM
SYSTEM
MODULE B MODULE A
A
A
A T -PWR
8 00
DC OUT
FAULT
100-240 VAC~12A MAX
AT-PNL800/1200
PO WER SUPPL
Y
RPS
READY
RPS INPUT
12V/21A MAX
WARNING
This unit may have more than one power input. To reduce the risk of
electric shock, disconnect both A/C and RPS inputs before servicing
unit.
AT
-P
W R 8 00
2142
DC OUT
FAULT
100-240 VAC~12A MAX
AT-x610-24Ts/X-POE+
AT-RPS3000 Chassis
Switch with powered devices
AT-PWR800 Module
AT-PWR800 Module
requiring up to 480 watts