Uninterruptible power supply (UPS) is a type of power supply system that contains a battery to maintain power to provide power to electronics in the event of a power surge or outage.
Typically UPS power keeps a personal computer (PC) running for several minutes after a power outage, enabling you to save data that is in memory and shut down the computer gracefully. Many uninterruptible power supplies now offer a software component that enables you to automate backup and shut down procedures in case there’s a power failure while you’re away from the computer.
An uninterruptible power supply system generally offers multiple outlets, allowing you to maintain battery back-up power to more than one device and will also include additional outlets for surge protection.
Types of UPS
There are two basic types of UPS systems: the standby power system (SPS) and on-line UPS system. The standby UPS is the most common type of UPS used for desktop computers and other individual electronic devices. The line interactive UPS is more commonly used in small business and server situations.
Standby Power System (SPS)
The standby power system monitors the power line and switches to battery power as soon as it detects a problem. The switch to battery, however, can require several milliseconds, during which time the computer is not receiving any power.
Image Description: The standby UPS, produced by Schneider Electric’s Data Center Science Center
On-Line UPS System
An on-line UPS avoids these momentary power lapses by constantly providing power from its own inverter, even when the power line is functioning properly. In general, on-line UPSs are much more expensive than SPSs.