Fortunately, there is a solution to almost all of the power problems that we will likely encounter, and that is the UPS or uninterruptible power supply. A UPS is typically a brick or mini-tower shaped device that connects the wall outlet to the computer. At a minimum, a UPS has a small rechargeable battery that can allow the computer user to quickly and safely shut down the computer in the event of a power failure, preventing the loss of data or damage to the computer. At its best, many UPS devices also provide protection from other power line hazards, in addition to power outages. Readily available locally, and manufactured by such companies as Belkin, Tripp Lite, Cyberpower, Powerware, APC, Energizer, and others, street prices of personal computer UPS range from about $30 for a minimal unit with a low capacity rechargeable battery, to about $200 for a unit that has numerous features and a large capacity battery. Larger, more powerful and expensive UPS are available for corporate and other power critical users.
One proviso necessary is to be sure that any UPS has the battery capacity to power your computer until it can be shut down. This ability to power computers is standardized in the industry by labeling each UPS in terms of VA and watts. All of the major UPS manufacturers websites have a calculator to determine the proper minimum capacity for your particular computer and monitor, and most UPS packages have a table with this information printed on the box. A UPS with inadequate capacity will not be able to power the computer long enough to ensure a safe shutdown.
The basic UPS, which is typically the least expensive, is referred to by some manufacturers as a Category 3 model because it provides protection for the three most common power problems, power failure, power surge or spike (sudden increases in voltage), and short-term low voltage also called power sag. This type of UPS simply provides power to the computer to enable a proper shutdown in the event of power failure, as well as some protection from power surges. Some of these UPS also have a serial or USB connector to automatically save running programs, and shut down the computer in an orderly fashion in the event of a power failure. These UPS may also provide surge protection for phone, coax, and network lines. Some of these will also filter electrical line noise. A category 3 or basic UPS should be considered as a minimum necessity for all computer users, since they typically provide protection for the most common power problems.
The mid-grade UPS is referred to by some as a Category 5, and provides all of the features of the category 3, plus the additional protection of AVR, or Automatic Voltage Regulation. The AVR adds protection from under- and overvoltage, the 4 and 5 features of a category 5 device. Undervoltage, commonly known as a brownout, occurs when line voltage drops below normal, and can last from minutes to days. Brownouts can cause physical damage to computers and other sensitive electronics. Brownouts have occurred when electrical demand exceeds capacity. Overvoltage occurs when line voltage is increased, either for short or long periods of time. Overvoltage will likely cause damage to hardware and loss of data, unless an AVR type device is utilized. A UPS with AVR provides a safe and somewhat constant voltage to the computer regardless of the voltage coming from the wall outlet. The AVR utilizes the battery of the UPS to supplement low voltage, and reduces the voltage if the voltage is too high. Many AVR systems also provide some protection from lightning damage, and many manufacturers also include some form of insurance coverage protecting from loss if connected equipment is damaged through the power line. In my house, this is the minimum level of protection I would have on my computers.
The premium UPS, sometimes referred to as Category 9, provides the maximum level of power protection, but also at a premium price. The four additional protections provided by these UPS, over the category 5 type, are strong filtering for line noise, protection from frequency variations, harmonic distortion, and transient voltages. Basically this UPS totally isolates the computer from the power line, and only provides clean power to the computer. While all of these power line threats are real and can cause damage to computer components and data, they are not as common as the other perils. This type of UPS is appropriate for mission critical equipment where cost is not an issue.
In addition to protecting our computers, there are several other uses for UPS that are not commonly considered, and the less expensive UPS are quite capable of satisfying. In the event of a power failure the base unit of our cordless phones will cease to function, and we may be incapable of satisfying our addiction to TV. Even the smallest UPS can power a cordless phone base unit for a period of time, as well as power small TVs, and recharge our cell phones. The duration that these devices can power our non-computer devices is determined by the power needs of those devices. I have a small 9 B&W TV that takes 15 watts, and could be powered by my computers 800VA UPS for several hours, while my 7 watt cordless phones can be powered for almost twice as long.
Just something to think about as we approach this season of peak power usage and hurricanes.
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