specific Extreme Networks equipment. The web page provides specifications for power cords in each
country so that you can purchase cords locally.
UPS (Uninterruptible Power Supply) Requirements
A UPS (uninterruptible power supply) 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
on page 25.)
Note
We recommend 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 found on a sticker on the back or bottom of your equipment.
2 Multiply the numbers together to get Volt-Amperes (VA):
VA = Volts x Amperes
3 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.
Preparing to Install
ExtremeAccess Series: Hardware Installation Guide
24
