Uninterruptible Power Supply Buying Guide

An Uninterruptible Power Supply or UPS for short is a power protection device with a battery supply that provides AC power when the mains fail or fluctuate, and some degree of power quality control when mains or other alternating current (AC) supply is present. The UPS can also be integrated with a surge protector. The basic configuration of a typical uninterruptible power supply is comprised at a minimum of a lead acid battery, a battery charger, and an inverter for AC applications.

Standby or Offline

Uninterruptible Power Supplies fall into two categories: the first (and most common) type is known as a Standby, or Offline, UPS. Under normal circumstances, a Standby UPS acts as a sort of electrical middleman: it plugs into a wall socket, and distributes the AC power from that outlet to the other electronic devices that are plugged into it. Besides distributing power, UPS units generally provide surge protection, but it’s not until the power fails that an Uninterruptible Power Supply really swings into action. As soon as a downward fluctuation or failure in electrical current is sensed, the Standby UPS’s AC inverter instantly switches on to convert DC power from its battery into an AC current, which furnishes the devices connected to the UPS with an alternate power supply.

Continuous or Online

The second (and generally more expensive), specialized type of Uninterruptible Power Supply is referred to as a Continuous, or Online, UPS. A Continuous UPS’s functions are much more complex than those of a Standby UPS. Instead of distributing AC power from a wall plug the way a Standby UPS does, a Continuous unit runs the electronic devices that it’s powering on electricity from its battery, and that battery is, in turn, constantly recharged. The fact that a Continuous UPS doesn’t need to make the switch into battery mode means that there’s no switchover delay if the AC mains fail. For this reason, Continuous UPSs are primarily used when dealing with critical data or extremely sensitive components (mission critical or enterprise). The on-line version of the uninterruptible power supply is continuously connected to the protected device and ensures not only that data is saved during a power failure, but also makes sure that the electrical power hooked up to the device is clean and without spikes,surges, or brownouts. An uninterruptible power supply is the only way to make sure your computer and peripherals receive the right quantity of clean consistent power. As far as other advantages, a good UPS includes a surge protector, so you get all the advantages of a surge protector with the added protection of uninterruptible power for a few extra bucks. Because of this conditioning of the electrical power, the on-line UPS is also called a power conditioner or sometimes a line conditioner.

Conclusion

The Off-line UPS designs leave your equipment connected directly to the utility power, with minimal power and surge protection. This is not the best choice, but does give you some protection (depending on the UPS selected), and backup power in the event of an power outage.

The On-line UPS provides an electronic layer of insulation from power quality problems, and is the most desirable type of power backup and protection for all your electronic equipment. Take a look at an uninterruptible power supply selection online.