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Site Preparation
Uninterruptable 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.
UPS Features
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 some time after a blackout has occurred.
In addition, some UPS or UPS plus software combinations provide the following functions:
• Automatic shutdown of equipment during long power outages.
• Monitoring and logging of 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, ask 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 Amperage Requirements
To determine the size of UPS that you need, use the following procedure:
1 To find VA (Volt-Amps), 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 VA:
VA = Volts x Amperes
2 Add the VA from each piece of equipment together to find the total VA requirement.
To determine the minimum amperage requirements for your UPS, we recommend that you add 30%
to the total.
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Extreme Networks Consolidated "e" and "i" Series Hardware Installation Guide
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