Confidential and proprietary information of Extreme Networks. © 2011 Extreme Networks, Inc.
All rights reserved. DRAFT. October 20, 2011
Summit Family Switches Hardware Installation Guide
149
Uninterruptible Power Supply Requirements
An uninterruptible power supply (UPS) is a device that sits between a power supply (such as a wall
outlet) and a device (such as a switch) to prevent outages, sags, surges, and bad harmonics from
adversely affecting the performance of the device.
A UPS traditionally can perform the following functions:
●
Absorb relatively small power surges.
●
Smooth out noisy power sources.
●
Continue to provide power to equipment during line sags.
●
Provide power for a period of time after a blackout has occurred.
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 the installation will allow? (See
“UPS Transition Time” on
page 150
)
NOTE
Extreme Networks recommends that you use a UPS that provides online protection.
Calculating Volt-Amperage Requirements
To determine the size of UPS that you need:
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, Extreme Networks
recommends that you add 30% to the total.
