Uninterruptable Power Supply (UPS)

UPS topologies are defined by how power moves through the unit:

Online (Double Conversion) UPS—Online UPS systems, such as the Vertiv™ Liebert® GXT5 or APS, deliver continuous high-quality AC power to equipment with no break in output when transferring to battery. AC input power is converted to DC, then back to AC, supplying the load with continuous pure sinewave output. This provides power conditioning, zero transfer time to battery, tight output voltage regulation and better transient suppression than line-interactive units. Because these systems are more complex, they typically cost more than their Line Interactive counterparts. They are well suited for all IT applications, but really shine in applications with poor quality input power or highly sensitive loads.

Line Interactive UPS— A Line Interactive UPS, such as the Vertiv™ Liebert® PSI5, interacts with the incoming power by filtering noise, providing surge protection, and adjusting the voltage when necessary. Using a simple and highly reliable design, the line interactive UPS can handle most power issues in online mode. It will switch to battery when needed which results in a 4-6 millisecond break in power during the transfer. This break in power is called the “transfer time”. Typical IT loads have no issues with this duration and the transfer to battery will appear seamless. This technology is particularly effective in areas where outages are rare, but power fluctuations are common. They are a great cost-effective choice for most IT applications

Standby (offline) UPS—A standby UPS, such as the Vertiv™ Liebert® PST5, is a cost-effective choice for basic power protection. They provide basic filtering and surge protection. In the event of an over voltage, brown out, or black out situation they will switch to battery power until the event resolves. This results in a 6-8 millisecond transfer time, which is typically well tolerated by computer loads. Due to their basic design these units are smaller and less expensive that other types of UPS units, allowing the user to have backup power wherever they need it. They are a good choice for home applications such as desktop PC’s and modems, or business applications such as POS terminals and electronic sign controllers.