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Most forms of uninterruptible power supply (UPS) can be either powered by battery or flywheel energy. These are ready for immediate use at the instant that the mains electricity fails, but the relatively small and finite amount of stored energy they contain makes them suitable for short periods of use, typically in the order of a few dozen minutes to a couple of hours depending on the actual load.
The run-time for a battery-operated UPS depends on the type and size of batteries and rate of discharge, and the efficiency of the inverter. The total capacity of a lead–acid battery is a function of the rate at which it is discharged, which is described as Peukert's law. Manufacturers supply run-time rating in minutes for packaged UPS systems.
Backup batteries range from small single cells to retain clock time and date in computers, up to large battery room facilities that power uninterruptible power supply systems for large data centers. Small backup batteries may be primary cells ; rechargeable backup batteries are kept charged by the prime power supply.
An example is a server chassis that has three power supplies; the system may be set to 2+1 redundancy so that the blades can enjoy the power of two PSUs and have one available to give redundancy if one fails. It is also common to mix live (hot) redundancy where UPSes are online, and cold standby redundancy where they are offline until needed.
The Smart-UPS is a series of enterprise-level uninterruptible power supplies (UPS) made by American Power Conversion (APC). [1] Most of the units have a SmartSlot (with the exception of SC and SMC series) which accepts an optional interface card providing features ranging from network connectivity to temperature and humidity monitoring. [ 2 ]
The PUE metric has several important benefits. First, the calculation can be repeated over time, allowing a company to view their efficiency changes historically, or during time-limited events like seasonal changes. Second, companies can gauge how more efficient practices (such as powering down idle hardware) affect their overall usage.
In engineering and systems theory, redundancy is the intentional duplication of critical components or functions of a system with the goal of increasing reliability of the system, usually in the form of a backup or fail-safe, or to improve actual system performance, such as in the case of GNSS receivers, or multi-threaded computer processing.
NASA G2 flywheel. Flywheel energy storage (FES) works by accelerating a rotor to a very high speed and maintaining the energy in the system as rotational energy.When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of conservation of energy; adding energy to the system correspondingly results in an increase in the speed of the ...