Posted by Circuits Arena on Tuesday, 6 January 2015
Uninterruptable Power Supply is the artlcle explaining Uninterruptible Power Supply Systems: Most people take the mains ac provide as a right and use it nearly nonchalantly while not giving t...
Uninterruptible Power Supply Systems:
Most people take the mains ac provide as a right and use it nearly nonchalantly while not giving the slightest thought to its inherent shortcomings and therefore the danger display to classy and sensitive electronic instruments/equipments. For standard menage appliances like incandencent lamps, tubes, fans, TV and electric refrigerator, the mains ac provide doesn't build a lot of distinction, however once used for computers, medical equipments and telecommunica¬tion systems, a clean, stable interruption free power provide is of the utmost importance. Of the myriad of devices, processes and systems that have confidence ac power, computers area unit most likely the foremost sensitive to power disturbances and failures. Interruptions in power provide might cause the contents of a memory to be lost or corrupted, the complete system to malfunction or fail, or perhaps form of parts failures to occur, all of that not solely lead to inconvenience however conjointly loss of cash.
Online UPS
In case of On-line UPS, the battery operated electrical converter works unceasingly whether or not the mains offer is gift or not. Triac T1 is on for all the days whereas Triac T2 has been provided to bypass the UPS electrical converter, only if a fault develops within the UPS electrical converter. once the mains offer fails, the UPS provides power solely till the batteries get discharged. However, once the mains power resumes, the batteries can get charged once more. The change times of those provides is taken into account to be zero. sometimes sealed maintenance free batteries ar used and also the time period of the electrical converter is low (approximately ten to thirty minutes).
There area unit 3 distinct sorts of uninterrupted power provides, namely, (£) on-line UPS (ii) off-line UPS, and (Hi) electronic generators. within the on-line UPS, whether or not the mains power is on or off, the battery operated electrical converter is on all the time and provides the ac output voltage. once the mains power offer burst, the UPS are on solely till the battery gets discharged. once the most power resumes, the battery can get charged once more. In off-line UPS and electronic generators, ther electrical converter is off once the mains power is gift and also the output voltage derived directly from the mains is that the same because the mains offer voltage. The electrical converter activates only the mains offer burst.
The block diagrams of on-line UPS, off-line UPS and electronic generators area unit given in figs
The ever increasing importance of computers in trade and commerce can increase the necessity for quality, high stability and interruption free power provides.
A clean ac power supply is that the basic to the operation of most sensitive electronic instrumentation, and lots of new and complicated circuits area unit designed to beat the consequences of disturbances commonly found within the mains ac offer.
In order to guard a sensitive system from power losses and blackouts, an alternate power supply is needed which will switch into operation right away once disruption happens. associate interruptible power offer (UPS) is simply such an alternate supply. A UPS usually consists of a rectifier, device, battery bank and electrical converter circuit that converts the industrial ac input into dc appropriate for input to the battery bank and also the electrical converter. The rectifier ought to have its input protected and will be capable of activity power to the electrical converter once the industrial offer is either slightly below the conventional voltage or slightly higher than.
Offline UPS
In the case of Off-Line UPS, the electrical converter is off once the mains power is on and therefore the output voltage springs directly from the mains. The electrical converter activates only the mains offer fails. Its change time is a smaller amount than five ms. These UPS ar typically used with PCs or computers or different appliances wherever alittle period (5 ms or less) interruption in power offer may be tolerated. Usually, sealed batteries or lead-acid batteries ar used. The time period of those provides is additionally low (about ten to thirty minutes).
