Uninterruptible Power Supply (UPS)
What is a UPS? Uninterruptible power supply (UPS) is an electrical device that provides emergency power to a load when the primary power source defaults or fails. In industrial applications, a UPS is used to safeguard computers, data centres, and telecommunication equipment from unexpected power disruptions which could potentially cause injury or death, severe business fluctuations, or data loss. An industrial UPS provides emergency power to a load when the input power source or mains power fails. It differs from an auxiliary or emergency power system or standby generator in that it will provide near-instantaneous protection from input power interruptions, by supplying energy stored in batteries, supercapacitors, or flywheels. What is power conversion? UPS systems provide reliable, ‘clean’ power by performing a double power conversion. They take in AC power from the main power source, rectify it to DC to perform filtering and to charge the UPS battery, then convert the power back to AC.
Major OEM UPS
What size UPS do you need?
UPSs are given a power rating in volt-amperes (VA) that range from 300 VA to 5,000 kVA. This rating represents the maximum load that a UPS can support, but it shouldn’t match exactly the power load you have. To allow room for growth, the best practice is to choose a UPS with a VA rating that is 1.2x the total load you need it to support. If your UPS will be supporting motors, variable-speed drives, medical imaging devices or laser printers, add more VA capacity to your requirements to account for the high power inrush that occurs when those devices startup.
Companies that are anticipating rapid growth should use a higher multiplier than 1.2x. Newer server hardware tends to have higher power requirements than older models, so factoring in additional VA will account for adding more and newer equipment.
Do you know the difference between VA versus watts?
What are the different types of Uninterruptible Power Supply?
UPS systems are grouped by topology, which refers to how the UPS and utility power work together. This translates to the level of efficiency and reliability you can expect from your power source. There are five main types of UPS topologies:
Standby UPSs allow equipment to run off utility power until the UPS detects a problem, at which point it switches to battery power to protect against sags, surges or outages. This topology is best suited for applications requiring simple backup or with less sensitive equipment, such as small office/home office and point-of-sale equipment.
Line-interactive UPSs actively regulate voltage either by boosting or decreasing utility power as necessary before allowing it to pass to the protected equipment or by resorting to battery power. Line-interactive models are ideal for applications where protection from power anomalies is required, but the utility power is relatively clean. Main distribution frame (MDF) and intermediate distribution frame (IDF) communication closets, non-centralized server and network rooms, and general IT enclosures are ideally suited for this topology.
Online UPSs provide the highest level of protection by isolating equipment from raw utility power—converting power from AC to DC and back to AC. Unlike other topologies, this double conversion method provides zero transfer time to battery for sensitive equipment since the electricity is already coming from the UPS. The online, double conversion UPS topology is best applied to mission-critical equipment and locations where utility power is poor or highly unreliable.
Ferroresonant UPSs operate similarly to line-interactive UPSs with the exception that a ferroresonant transformer is used to condition the output and hold energy long enough to cover the time between switching from line power to battery power which effectively means a no-break transfer. Many ferroresonant UPSs are 82-88 percent efficient and offer excellent isolation. Although no longer the dominant type of UPS, these robust units are still used in industrial settings such as the oil and gas, petrochemical, chemical, utility and heavy industry markets.
Multi-mode UPSs are considered the best choice for companies looking to achieve an optimal balance of efficiency and protection. The two modes within these UPSs are a high-efficiency, eco-mode and a premium power protection mode. The UPS can switch between these two modes automatically when it detects problems in the utility power. This functionality can save a significant amount in operating expenses.
