Industrial uninterruptible power supply also known as UPS protects electrical loads from mains failure. Also it protects them from spikes or noise that can come through power distribution. Types are online ups with double conversion, offline, line interactive uninterruptible power supply and then there are also hybrids with so-called on demand double conversion
In last years industrial uninterruptible power supply has become very important part of infrastructures and industries where they can’t afford loss of power.
So it is used to help protect from power electricity lost in places such as data centers, telecommunication facilities, places with computer servers, hospitals, factories, supermarket, airports, basically it can be found anywhere. Industrial uninterruptible power supply is usually used in conjunction with diesel generators. Where ups is used in first minutes of power failure. And this is just enough time for diesel generator to start. After diesel is fully running it takes over the load. Generator is usually configured with delay when switching back loads to ups, just in case there are shorter interruptions.
Power ranges of Industrial uninterruptible power supply are from very small 300 – 800 VA (used mostly for personal computers) up to high-powered industrial Uninterruptible power supply which can be up to 1000kVA. Of course it always possible to put more devices into parallel, thus making them even stronger. They upper size is limited by technology, mostly by peak current through thyristors. Thyristors and capacitors represent also the most expensive part (besides batteries) of ups.
Online double conversion uninterruptible power supply are the most used ups devices. It has pure sine wave which is in fact better sine wave then delivered through power distribution. Beocouse of this in the event of power outage the transfer of load is without interruption from normal mode to battery mode. The power efficiency can be between 92 to 97% and of course smaller if compared to offline or line interactive ups, but when working with expensive and sensitive loads its absolutely crucial to protect them not only from power outage but also from al sort of noises and spike that can come through mains power supply distribution.
Offline ups are sort of cheaper variant, it cheap to made, and when in normal mode it uses almost no power, that’s why it have very high power efficiency (or own consumption). But it doesn’t protect ups from noises or smaller changes in main voltages. Also the transfer time from normal mode to batter mode is to big for sensitive electronic components. Line interactive ups on other hand is something in between online and offline ups. because it has transformer its resilient to changes in output voltage, but still it doesn’t full protect loads like online uninterruptible power supply does.
Typical autonomy battery time is usually from 8-15 minutes, but in any ups over 1 kVA that can be usually increases by adding more batteries, modules or more battery cabinets. In most cases batteries are 12 V or 6 V. So 3 or 6 cell batteries, where each cell is 2 V. Battery capacity is from 5 Ah to over 100 Ah. Batteries used must be deep cycle batteries. Normal batteries last from 3 to 5 years, while long life batteries could last up to 10 years. All depends on environment which should be too hot. It should between 15 to 22 degrees celsius.
Uninterruptible power supply can have 1 phase or 3 phase input, same goes for output. Larger ups devices usually have communication card, so its possible to monitor device over lan or over internet. It is also possible to configure remote shutdowns. So for example if ups is used in data center its possible to configure loads – computers to shut down when time on battery reaches some critical value.
Typical components of industrial uninterruptible power supply are rectifier, inverter, batteries and battery charger. Rectifier transform ac mains to dc power, inverter convert this dc power back to ac power, while it can also convert dc battery power to ac power. Of course for converting low voltage battery power there is a part called booster that boost voltage to higher value which is more suitable for transforming from dc to ac. Important parts are also electronic bypass and manual bypass. When there are overload ups will switch to electronic bypass for its protection. Loads wont be disturbed in this case. Manual bypass is used for maintainance purposes in last case of course loads aren’t protected anymore. In cases where there is needed ultra stability more industrial uninterruptible power supply can be put into parallel for bigger security or just to increase overall power.
The most known industrial uninterruptible power supply brands are Apc, Socomec, Eaton, Cyber power, Liebert and GE Digital energy
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