An uninterruptible power supply, as well as an uninterruptible power supply, UPS, or battery / flywheel backup, is an electrical device that provides emergency power to a load in the event of a failure of the input power supply, usually utility power.
A Managed Ups Services differs from an auxiliary or emergency power system or generator standby in that it provides instant or near-instantaneous protection against incoming power interruptions with one or more connected batteries and associated electronics for low power users and generators and flywheels for high power users. Battery life for most uninterruptible power supplies is relatively short (5 to 15 minutes typically for small devices), but sufficient to allow time to connect an auxiliary power supply or to properly shutdown equipment. protected.
A UPS is not limited to protecting any particular type of equipment, but is commonly used to protect computers, data centers, telecommunications equipment, or other electrical equipment where an unexpected power outage could result in injury, death, or serious disruption. and / or loss of data. UPS units vary in size, from units designed to protect a single computer without a video monitor (rated at around 200 VA) to large units that power entire data centers ( 1 MVA), buildings ( 300 kVA) or manufacturing processes.
Different types of UPS design
There are three main categories of modern UPS systems: online, interactive online, or backup / stand-alone.
In a standby / stand-alone UPS system, the load is powered directly from the input power and the standby circuit is only activated when the utility power is disconnected. Most UPSs less than 1 kVA are line-interactive or standby, which is generally less expensive.
The Line Interactive UPS keeps the inverter online and redirects the DC battery current path from normal charge mode to supply current when power is lost.
The online UPS uses a “double conversion” method to accept AC input, rectify to DC for passage through a rechargeable battery (or battery strings), and then back to 120/240 VAC to power equipment. protected.
For large power supplies, dynamic uninterruptible power supplies are sometimes used. The synchronous motor / alternator is connected to the mains through a choke. Energy is stored in the flywheel. When the mains supply fails, the eddy current control system stores energy in the load. DUPS are sometimes combined or combined with a diesel generator [clarification needed] to form a Diesel Rotary Uninterruptible Power Supply, or DRUPS.
In recent years, a fuel cell UPS has been developed that uses hydrogen and a fuel cell as the power source, potentially allowing long run times in a small space.