Dell PowerEdge 1400 User Manual

Also see for PowerEdge 1400: Update Manual

1-6 User’s Guiderequire you to load software files called device drivers into system memorybefore they will work.These software drivers help the computer recognize the external device anddirect its operation. Dell recommends that you attach external devices only while the computer isturned off unless you are instructed otherwise in the documentation for the par-ticular device. Then turn the computer on before turning on any external devicesunless the documentation for the device specifies other wise. (If the computerdoes not seem to recognize the device, try turning on the device before turningon the computer.) * ( ! + ," - ( " " ) " ! ( ) ' A number of devices are available that protect your system against power problemssuch as power surges, transients, and power failures. The following subsectionsdescribe some of these devices. Surge protectors are available in a variety of types and usually provide a level of pro-tection commensurate with the cost of the device. Surge protectors prevent voltagespikes, such as those caused during an electrical storm, from entering a systemthrough the electrical outlet. Surge protectors, however, do not offer protectionagainst brownouts, which occur when the voltage drops more than 20 percent belowthe normal AC line voltage level. Line conditioners go beyond the overvoltage protection of surge protectors. Line con-ditioners keep a system's AC power source voltage at a fairly constant level and,therefore, can handle brownouts. Because of this added protection, line conditionerscost more than surge protectors—up to several hundred dollars. However, thesedevices cannot protect against a complete loss of power. Uninterruptible power supply (UPS) systems offer the most complete protectionagainst variations in power because they use battery power to keep the system runningwhen AC power is lost. The battery is charged by the AC power while it is available, soonce AC power is lost, the battery can provide power to the system for a limited amountof time—from 15 minutes to an hour or so—depending on the UPS system.