Dell PowerVault 775N (Rackmount NAS Appliance) - Manual (Page 4)

Surge Protectors
Surge protectors are available in a variety of types and usually provide a level of protection commensurate with the cost of
the device. Surge protectors prevent overvoltage spikes, such as those that may occur during an electrical storm, from
entering the system through the electrical outlet. Surge protectors do not offer protection against brownouts, which occur
when the voltage drops more than 20 percent below the normal AC line voltage level.
Line Conditioners
Line conditioners go beyond the overvoltage protection of surge protectors. Line conditioners keep a system's AC power
source voltage at a fairly constant level and provide protection from brownouts of short duration. Because of this added
protection, line conditioners cost more than surge protectors—up to several hundred dollars. However, these devices cannot
protect against a complete loss of power.
Uninterruptible Power Supplies
UPS systems offer the most complete protection against variations in power because they use battery power to keep the
system running when AC power is unavailable or unusable. The battery is charged by the AC power while it is available so
that once AC power is lost, the battery can provide power to the system for a limited amount of time—from 15 minutes to an
hour or so—depending on the UPS system.
UPS systems that provide only 5 minutes of battery power allow you to conduct shutdown of the system but are not intended
to provide continued operation. Use surge protectors with all UPS systems, and ensure that the UPS systems are UL safety
approved.
Other Documents You May Need
The following documentation is included with your system:
The System Information document provides important safety and regulatory information. Warranty information might
be included within this document or as a separate document.
The Setting Up Your System document provides general instructions for setting up your system.
The User's Guide describes system features, technical specifications, and the System Setup program.
The Installation and Troubleshooting Guide describes how to install, troubleshoot, and upgrade your system.
The System Administrator's Guide provides system operation and management information.
The systems management software documentation describes the features, requirements, installation, and basic
operation of the system management software. See the software's online help for information about the alert messages
issued by the software.
Operating system documentation describes how to install (if necessary), configure, and use the operating system
software.
Documentation included with any options you purchased separately from the system, which provides information you
need to configure and install these options in your system.
You may also have the following documents.
Documentation updates are sometimes included with the system to describe changes to the system or software.
NOTE: Always read these updates before consulting any other documentation because the updates often contain
information that supersedes the information in the other documents.
The Rack Installation Guide describes how to unpack, set up, and install your system in a rack.
Technical information files—sometimes called "release notes"—may be included on the Resource CD to provide last-
minute updates about technical changes to the system or advanced technical reference material intended for