It has probably happened to you. The lights go out, the picture on your computer screen collapses into a bright white streak, then goes blank. The machine goes off. A power failure has just zapped hours of work and you think: There must be a way to avoid this.
Fortunately, there is. For $100 to $300, users can buy an uninterruptible power supply, or UPS. Unlike surge protectors, which guard only against electrical spikes, a UPS can deal with brownouts and blackouts. A battery inside the UPS keeps the juice flowing for five or 10 minutes after a power failure, so users can save their work and shut down their machines.
If your area has frequent power outages, or you like the idea of extra power protection, a UPS may be for you. Once used only to protect large-scale computers, the UPS has come down in price and gone up in sophistication, making it much more attractive to the small-office and home-office user. Users can pick from several kinds of uninterruptible power supplies.
For the past several months, I've protected my Pentium machine with a nifty model called the UPStart. It's a $179 standby unit, the least expensive kind of UPS. In three months of operation, the UPStart has performed flawlessly, handling several electricity glitches, including a power failure two hours after I had installed it!
I had no trouble when the unit switched to battery power, even though a standby UPS has a slight delay between the electricity going off and the battery coming on. The delay is so small that most electronic equipment doesn't even notice it. SL Waber, the Mt. Laurel, N.J., company that makes the UPStart, claims the delay lasts less than 4/1000ths of a second.
Other kinds of UPS units have little or no delay, because they're constantly running. On-line units are typically used for larger computer systems (where the bulk of UPS units are used). Manufacturers also sell a less expensive alternative called the line-interactive UPS. Because these units are always running, they can more quickly react to outages and, in many cases, regulate the voltage during regular operation so that computers get predictable power.
American Power Conversion, a large UPS company, just came out with a line-interactive model called the Back-UPS Office. It looks like a surge protector but works like a UPS. At $169, it is aimed squarely at the small-office, home-office market.
I like the UPStart, however, because of the extras it offers. It is a power center, which means that with the touch of one button, users can turn on their computer, monitor, printer, and two other devices. The unit is designed to sit under the computer monitor, so the master switch, as well as separate buttons controlling each device, are at the user's fingertips. The UPStart also includes software that allows the machine to turn itself off automatically if a power failure occurs.
Not all users need a UPS. "It's very, very difficult to justify this for the home on an economic basis," says Bill Howe, research manager for E Source Inc., a Boulder, Colo., information service on energy efficiency issues. A computer system with a UPS also draws some 10 percent to 20 percent more power than a system without a UPS. Users whose machines are on all day would see a small but noticeable boost in their electric bills.
Most users are probably better off backing up their data often, he says, which will make power failures much less costly in terms of lost work. Another alternative: get a portable computer, which can automatically switch to its own battery power.
Still, the UPS offers peace of mind - just the thing for those moments when the lights go off.
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