Extreme Networks 12800 Series - Handbuch (Seite 55)

Meeting Power Requirements
BlackDiamond 12800 Series Switches Hardware Installation Guide 55
In addition, some UPS devices or UPS plus software combinations provide the following functions:
● Automatically shut down equipment during long power outages.
● Monitor and log power supply status.
● Display the voltage (current draw) of the equipment.
● Restart equipment after a long power outage.
● Display the voltage currently on the line.
● Provide alarms on certain error conditions.
● Provide short-circuit protection.
Selecting a UPS
To determine UPS requirements for your switch, answer these questions:
● What are the amperage requirements?
● What is the longest potential time period that the UPS would be required to supply backup power?
● Where will the UPS be installed?
● What is the maximum transition time that your installation will allow?
NOTE
Extreme Networks recommends that you use a UPS that provides online protection.
Calculating Volt-Amperage Requirements
To determine the minimum volt-amperage requirements for your UPS:
1 Locate the voltage and amperage requirements for each piece of equipment. These numbers are
usually located on a sticker on the back or bottom of your equipment. Then multiply the numbers
together to get Volt-Amperes (VA):
VA = Volts x Amperes
2 Add the VA from all the pieces of equipment together to find the total VA requirement.
To determine the minimum volt-amperage requirements for your UPS, we recommend that you add
30% to the total.
UPS Transition Time
Transition time is the time that is necessary for the UPS to transfer from utility power to full-load
battery power. For Extreme Networks products, a transition time of less than 20 milliseconds is required
for optimum performance.
DC Power Requirements
This system should be installed in a DC-I battery return configuration. In a DC-I configuration, the
battery return conductor should be connected directly to the central office power return bus, and not to
the equipment frame or the grounding means of the equipment.