As more and more computers find their way into homes and offices, so does the chance of damaged equipment. American Power Conversion (APC) is a leader in the effort to make the world safe for your computers and peripherals. Himanshu Patel of APC came to the December General Meeting of the Danbury Area Computer Society to tell us how power can be dangerous to our computers and show us how APC's products can protect them.
Unfortunately, Himanshu was unable to show us anything. He had two LCD projection display panels but neither was working. In addition, his notebook computer could not synchronize with the DACS LCD panel. Undaunted, Himanshu decided to wing it, launching into his presentation without the aid of his multimedia presentation slides. He explained the dangers presented by the very power the computer needs to run. That same power can severely damage or even destroy equipment. All of the information in Himanshu's presentation, and this article, can be found at APC's Web site, which is www.apcc.com.
Sags, also known as brownouts, are short-term decreases in voltage levels and the most common power problem. They are usually caused by the startup power demands of many electrical devices (including motors, compressors, elevators, and shop tools). Electric companies use sags to cope with extraordinary power demands. In a procedure known as "rolling brownouts," the utility will systematically lower voltage levels in certain areas for hours or days at a time. Hot summer days, when air conditioning requirements are at their peak, will often prompt these brownouts. A sag can "starve" a computer of the power it needs to function and cause frozen keyboards and unexpected system crashes, both of which result in lost or corrupted data. Sags also reduce the efficiency and life span of electrical equipment, particularly motors.
Blackouts, which are a total loss of power, are caused by excessive demand on the power grid, lightning storms, ice on power lines, car accidents, back hoes, earthquakes, and other catastrophes. If a blackout occurs while your computer is on, current work in RAM or cache is lost. The hard drive File Allocation Table (FAT) may also be lost, which results in total loss of data stored on drive.
A spike, also referred to as an impulse, is an instantaneous, dramatic increase in voltage. Like the force of a tidal wave, a spike can enter electronic equipment through AC, network, serial, or phone lines and damage or completely destroy components. Spikes are typically caused by a nearby lightning strike but can also occur when utility power comes back on line after having been knocked out in a storm or as the result of a car accident. Catastrophic damage can occur to hardware and data may be lost.
Surges are short-term increases in voltage, typically lasting at least a fraction of a second. Surges result from the presence of high-powered electrical motors, such as air-conditioners and household appliances in the vicinity. When this equipment is switched off, the extra voltage is dissipated through the power line. Computers and similar sensitive electronic devices are designed to receive power within a certain voltage range. Anything outside of expected peak and average voltage levels will stress delicate components and cause premature failure.
Electrical noise, more technically referred to as Electromagnetic Interference (EMI) or Radio Frequency Interference (RFI), disrupts the smooth sine wave one expects from utility power. Electrical noise is caused by many factors and phenomena, including lightning, load switching, generators, radio transmitters, and industrial equipment. It may be intermittent or chronic. Noise introduces glitches and errors into executable programs and data files. Below are some figures from APC's Web site, dealing with the cause of computer problems. The source for the information is Contingency Planning. As you can see, power problems are the main culprit.
Now that we know what the dangers are and what they can do, what can be done? APC has a wide array of power protection products available. They range from surge-suppressing power strips to uninterruptable power supplies (UPS) that can protect an entire data center. Simply put, a UPS is multiple outlet surge suppresser with a big battery. In the event of a spike, surge, or sag, the equipment is protected from harm. In the event of a blackout, the battery kicks in and allows you time to shut down your computer in an orderly fashion to prevent data loss.
Himanshu showed us a blackened piece of melted plastic and metal that hung from an electrical cord, which he had received at his office earlier that day. He said it was a UPS that had been plugged into an electrical system that had suffered a major power spike. All the computer equipment plugged into the UPS was completely unharmed. The UPS did what it was supposed to do: It sacrificed itself and absorbed the massive spike. The only damage that extended beyond the UPS was a stain on the carpeting caused by the melting plastic of the case. This display elicited a strong reaction from the audience and drove home the reason that protection for computers is so important. Himanshu was happy to point out that APC replace the damaged UPS free of charge and that any equipment plugged into the APC UPS would have been covered for damages up to $25,000.
|WALLY DAVID is a member of DACS' board of directors and is also a regular contributor to dacs.doc. He is the network administrator for the National Shooting Sports Foundation, a nonprofit trade association for the gun industry. Wally can be reached via E-mail at email@example.com.|