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Power Problems —Back to Index

All computer users should consider using devices that protect the power used in their computer systems. There are several types of power problems which can destroy part or all of a computer system.

• Power surges are an increase in the voltage that powers your electrical equipment. Surges often go unnoticed, often lasting less than a second, but they are quite destructive. Surges can be produced from a variety of sources. Your electric company's power systems are often pushed beyond their capacity, and this can result in unstable, unreliable power. They can be caused by your neighbor starting up an electrical motor or happen when the office on the floor below you blows a fuse. The danger of power surges to computer systems is that they can "surge" through the equipment, causing damage to the power supply, hard disk, memory, modem and video - anything that is a part of the system.
• A good device to use to protect your computer equipment against power surges is a surge suppressor. No surge suppressor is able to survive a direct lightning strike, no matter what the manufacturer of the equipment you are considering says to the contrary. However, your surge suppressor should take the hit - and may be damaged in the process - but your equipment should stay protected. Which would you rather replace, a $60 surge supressor or $1,500 system? When purchasing a surge suppressor, you should look for a system that comes with insurance covering all your connected equipment - even against direct lightning strikes!
• The term line noise refers to the random (and normal) fluctuations of electrical impulses that are carried along with standard electrical current. Where does this "noise" come from? Turning on the flourescent light overhead can cause a fluctuation in the power in your electric lines. Turning on a laser printer can also. Even a lightning storm can add line noise into your computer system. Ever notice the "snow" on your TV when you turn on a microwave oven or hair-dryer? That's line noise being sent back into your electrical system and up into your TV.
• Line noise isn't usually as destructive as a surge, but it can introduce errors into programs and files and hard drive components can be damaged. To protect against line noise, use a surge suppressor, a line conditioner or a UPS that has special noise filters that remove line noise to protect against line noise.
• In the middle of the hottest summer day, when everyone in the neighbourhood has turned on their air conditioner, you may have see your lights dim. This is called a brownout or voltage sag. Undervoltages are often followed by overvoltages - spikes (a lot like surges) - which can also damage computer components and data. Electronic devices need to receive a steady voltage in order to operate correctly.
• Brownouts place undue strain on power supplies and other internal components, forcing them to work harder in order to function. They can destroy electrical components and cause data glitches and hardware failure. Overvoltages burn out power supplies and can cause damage to other electronic hardware. Extended overvoltages can even cause fires as electronics "fry" in the extra electricity. If you live in an area with problems like brownouts, a UPS system offers the best protection for your equipment.
• Finally, there are complete power failures, also known as blackouts, and they can happen at any time. Some are caused by stormy weather, others by someone trimming their trees and accidentally cutting through a power line. Any temporary, or not so temporary, interruption in the flow of electricity will result in a power failure which can cause hardware damage and data loss. Worst of all, they can cause you to lose hours of work when your system shuts down without warning. Power failures can even damage hard drives resulting in loss of all data on a system. If you are concerned about loss of data due to power failures, a UPS is the equipment you need to get.

Surge Suppressors —Back to Index

• A surge suppressor can look like a long, narrow rectangle or semi-circle with several grounded power plugs(three pronged), and should have an on-off switch and a grounded power cord that plugs into an electrical wall socket. When you examine manufacturers' packaging, compare several statistics:
• Joule Ratings Joules are a way of measuring energy and the Joule ratings measure a suppressor's ability to absorb surges. For a point of reference, 200 joules provide basic protection, 400 joules provide good protection and anything with over 600 joules is better. Some manufacturers will also indicate that they put in additional circuitry to provide additional protection.
• Surge Amp Ratings - Look at the back of your computer and monitor (or in the equipment manuals). Here you should find an indication of how many amps or volt amps or watts your equipment "pulls" or requires. A volt is a unit of electromotive force and an ampere (also know as an amp) is a unit of electric current. Watt is another unit of electric currrent. If your equipment lists "watts", you can convert this to amps by multiplying by a constant of 1.4. That is to say, watts x 1.4 = Voltage Amps. Tally up the number of amps used by the equipment you plan to plug into the surge suppressor. Try to find a suppressor that offers at least that number of amps. Let's say your computer pulled 10 watts, your monitor pulled 1 amp and your modem pulled 1/2 amp. You would add: (10w x 1.4) + 1a + 1/2 a. You would need the surge suppressor to have a minimum rating of 15.5 amps. It doesn't hurt to get one with a higher rating.
• UL 1449 Voltage Let-through Ratings - Try to find a suppressor that has been tested by Underwriter Laboratories (UL). UL rates suppressors according to the amount of voltage they allow to pass through to your equipment. The lower the let-through voltage, the better the surge suppressor is. UL established the 330 volt let-through as the benchmark. While getting a suppressor with a higher JOULE or AMP rating can be worthwhile, any let-through rating lower than 330 volts is not necessarily useful, and can possibily overwork the suppressor and cause it to fail.

Uninterruptable Power Supply —Back to Index

UPS stands for Uninterruptable Power Supply. UPSs are devices which monitor the power levels in the electric line feeding power to your equipment. If your power goes off, then, the UPS will detect this and switch over to battery power. You should also hear a loud beep and see a light flashing on the UPS to indicate there was a problem with the AC current. Depending on the size of battery, and whether you have purshased an appropriately sized UPS for the equipment plugged in, you can get from several minutes to several hours of power. This can give you the opportunity to save any open files and then shutdown your applications and computer equipment in a normal fashion.

UPS units come in three basic types:

1. Standby: (also known as off-line) Power comes directly from the A/C outlet into the UPS (and then into your equipment) until there is a brownout (voltage sag) or blackout. The UPS has a mechanism that detects the power failure and turns the battery on, such that your equipment continues to be supplied with power. The UPS batteries are charged by electrical current, and will recharge themselves after electrical current returns. Like surge suppressors, UPSs also provide protection from voltage spikes and surges. Standby units are the least expensive type of UPS unit.
2. Line-interactive: Line-interactive UPSs provide protection from spikes and surges, and, like standby units, detect brownouts and blackouts. In addition to providing battery backup, they also detect and correct for line noise.
3. On-line: On-line UPSs are the most expensive type of power backup, but also provide the best protection. These units take the incoming electrical current (A/C), converts it to battery power (D/C), then conditions the power to eliminate line noise, voltage sags (brownouts), or power surges. It then re-converts the power back to A/C and feeds that conditioned power to your equipment.

When purchasing a UPS, be sure to account for all equipment that will be plugged into the unit and the total number of amps that equipment will pull. To be on the safe side, get a UPS that exceeds your needs. Never underestimate the size. UPS sizes are typically based on volt amps (VA). VA is determined by the following formulas:

• Amps x 120 ( American/Canadian equipment) = volt amps
• Amps x 220 ( some international equipment) = volt amps
• Watts x 1.4 = volt amps

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