Power problems are the great killer of computer equipment, and often data as
well. These problems include static, noise, spikes and ground faults.
Because electric power is so "normal", and because it does its work silently,
(and often slowly), it is rarely suspected.
What are the Problems - And why should You be ConcernedThe electric power system, originally designed to power light bulbs, is quite an engineering miracle, but it is engineering on a very large scale. Insignificant events on power grid scale can be disasterous to computers and other electronic equipment. Here is a list of common problems, any of which can destroy your computer equipment:
PC Power Supplies - A Hidden TroublemakerThe PC power supply itself (generally a silver metal box inside the computer) provides a degree of protection, depending on its quality. The power supply may have some spike protection and EMI filtering built in. Its job is to provide specific and very steady voltages to the computer circuitry even though the line power may fluctuate. How much fluctuation it can take depends on its quality.
We have seen many cases, especially in "cheap clone" computers, where problems of instability and freezing were due to a poor quality power supply, not the mother board or CPU. Ironically, this is a component almost never suspected when such problems occur.
UL approved power supplies (Backwards UR symbol) are generally of
considerably higher quality than those with no certification, but cost $5 to
Surge Supressors - The Good, the Bad and the FlamibleOver 80% of the "surge supressors" sold are of value only as switched plug strips, providing no meaningful protection. Some actually catch on fire if exposed to serious overvoltages (PC magazines have had to halt testing of some models because it was too dangerous).
Good surge supressors contain large capacitors and iron core coils as well as adequately sized surge diodes. These provide protection also against EMI (ElectroMagnetic Interference) and FLES (Fast Leading Edge Spikes) cheaper units simply pass through. Be prepared to pay $40 to over $100 for effective devices.
Especially if you live in a high lightning strike area also put protection on the telephone line to your modem. Your computer can be killed through this route also. Many surge devices include telephone line protection as well as power line protection.
Studies by the copy machine industry have shown copiers protected by a high quality surge/noise/spike protection device required less than 1/3rd as many service calls as those without adequate protection. The ratio is probably even steeper for computing devices, but since degradation happens over time most owners are entirely unaware of the damage until their equipment starts flaking out.
Don't be impressed by claims from some surge device manufacturers they will
pay for any damage to your equipment if it is protected by one of their
devices. It's ridiculously difficult, sometimes impossible to get them to pay off.
Network Protection Devices - For Ground Fault and StaticProblems from EMI (ElectroMagnetic Interference), static electricity, ground faults and multiple building grounds can arise whenever computing devices are connected by long cables. This applies both to network cables and serial cables (for terminals and pritners). Industrial buildings are particularly prone to grounding problems as their electrical systems have often been modified, sometimes incorrectly.
We had one client where, after they added an additional workstation, chips on their network cards would physically split open every 5 to 7 days. We had another client where chips were blown entirely off the network cards.
Surge and static drain devices are made to protect all varieties of serial
and network cabling from problems of this kind. Contact
Automation Access for pricing on devices that
will fit your network needs.
Line Conditioners - Keeping the Voltge steadyIn some locations, power is so unstable a Line Conditioner is required to keep line voltages within a range the computer power supply can handle. Tripp Lite seems to have almost a monopoly on these devices, with electronic models also including effective surge/noise/spike protection. We still see massive "autotransformers" in some installations but these are expensive and hard to find now. (Index)
Uninterruptible Power - Time for an orderly shutdownA UPS (Uninterruptible Power Supply) is not an option for network servers or multiuser hosts, it is a necessity. Serious corruption of disk systems and databases can result from "unscheduled shutdowns" resulting in partial or total data loss.
Uninterruptible Power Supplies provide power from batteries for a sufficient time for your system to be shut down in an orderly manner. Properly sized, they will keep your server or host up for 10 to 20 minutes. Decent UPS units come with software that will do an unattended shutdown of your system.
In a critical installation, the UPS provides battery power sufficient to hold the computers up until the diesel generator sets can fire up and come on line. High end units are also SNMP (Simple Network Management Protocol) enabled so their status and condition can be monitored over the Internet.
Uninterruptible Power Supplies come in two varieties. "Standby" units switch your system to battery power when the line voltage falls below a certain threshold. "On-Line" units keep your system on battery power all the time, but the batteries are being recharged at the same rate power is drawn (except when there is a power failure). On-Line units are essential in situations where the power fluctuates greatly, as they provide a steady voltage output at all times. Standby units provide normal line voltage except when there is a power failure. Reputable UPS units also provide surge/spike/noise protection.
UPS units are rated in VA (Volt Amperes). A VA is similar to a Watt, but
more complicated. UPS units are available from about 250 VA (nearly useless)
to many kiloVAs. A modest PC server should generally have a unit providing
750 VA or so.
Some UPS units provide power analysis outputs and have software available
to display the record of power condition on your computer screen.
©:Andrew Grygus - Automation Access -
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