Power Failure Safeguards
In all electrical systems power interruptions occur, sometimes resulting in a power failure. Temporary failures in electrical powered systems result from normal surges and spikes occurring during electrical generation and transmission, from environmental occurrences such as storms and lightning, and other reasons. The power surges and spikes associated with frequently occurring temporary power glitches as well as complete losses of power can result in conditions that exceed the design ratings for the sensitive components found in commonly used electrical equipment. This is of particular concern to those using computers and associated peripherals. Many of the sensitive electronic components found in computers and related equipment can be damaged by power surges or by sudden power losses that prevent them from shutting down properly as happens during a power failure.
In order to reduce the possibility of damage to sensitive computer electronic components and loss of important data, it is necessary to provide a safeguard that will provide consistent and uninterrupted power supply. Most people are familiar with the use of surge protectors to protect sensitive electrical equipment from sudden surges or spikes. Another piece of equipment that is useful for managing a power failure is the uninterruptible power supply (UPS). These devices by design keep power supplied to electrical equipment even if the normal source of electricity is compromised by interruption or loss of power. For home and office, stand-alone computer applications this can be addressed effectively with one of the basic, relatively inexpensive UPS device commonly available.
UPS devices, which use rechargeable battery backups, safeguards the steady supply of required power. One component in UPS devices convert incoming alternating current to the direct current needed to keep the backup batteries charged. Another component acts to convert the direct current stored in the batteries to the alternating current required by electronic equipment in the event the regular source of power is interrupted. The system produces a constant power source for electrical equipment when the normal power source stops providing electricity. UPS devices only provide power for a few minutes, but that is usually long enough to get past the common power fluctuations or short interruptions. Even if the power remains off for a longer period than the battery life of the device, there is still the chance to affect an orderly shutdown to avoid equipment incurring the stress of hard power cycles and loss of important data.
There are three common types of UPS devices to choose from to protect computers and other sensitive electronic equipment:
- The first type, standby power supply (SPS) provide power derived directly from the usual power source until power fails. After a power failure the battery power switches on to resume the supply of power. Batteries charge when required when normal power is available. This type is sometimes called an “offline” UPS.
- The second type, Ferroresonant UPS systems, utilize a transformer to maintain a constant output voltage even with a fluctuating input voltage or power interruption and provides good protection against line noise.
- The last type, often termed “online” UPS systems, use an inverter to provide a constant, dependable power supply. Consequently there is no switchover time which makes this type of device the most seamless and the best protection available from power interruptions. The cost of a UPS system depends on the type chosen and decisions about which type is best are based on the specifics of the intended application.
Power disruptions are common for the reasons discussed. Use of uninterrupted power supplies makes good sense to protect computers and other sensitive electronics from damage and to avoid data loss when a power failure occurs.
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