device that acts as a back-up power supply unit
Uninterruptible power suppcheap true religion jeans ly, more popularly known as UPS is an electronic device that acts as a back-up power supply unit for a prescribed period of time when the electricity supply is disrupted or when the line voltage varies abnormally. UPS has gained importance as it is badly needed to provide back-up power supply to computers. People usually do not attach much importance to power protection or backup power supply till they suffer loss of valuable computer files or worse, equipment damage during electricity failure. To obtain uninterrupted power supply, you need to certain add-on items like an energy storing backup battery, an AC-DC charger and a DC-AC inverter. There are three main types of UPS power backup devices available in the market. They are known as Standby or Off-Line (SBS), which is the basic model and of the lowest grade; Line Interactive (SBS), which is the intermediate model and of the middle grade; On-line which is of the highest grade. All of them use battery backup when the input power supply fails, but under normal conditions these three units handle the power differently. Of these three basic design types, each offers more power protection than the lower grades.Standby UPS includes a transfer switch and its purpose is to switch the load to the battery / inverter should the AC power source fails. The transfer time is true religion jeans outlet usually between two to 10 minutes depending on the amount of time it takes to detect the lost utility voltage and turn on DC-AC inverter. Due to this delay, the power to the load is during this period is interrupted. The equipment's power supply should understandably have more hold up time than UPS transfer time to avoid loss of data. Generally, a power factor corrected SMPS of a personal computer has at least 10 to 20 ms hold-up time. Since the inverter operates in standby mode and starts up only when input power fails, the SPS has the highest efficiency and reliability. This is the least costly UPS and hence the most common backup type used for PCs. Line Interactive UPS under normal condition evens out and to a certain degree regulates the input AC voltage through a filter atrue religion jeans sale nd a tap-changing transformer. The bi-directional inverter/charger is always connected to the output of the UPS and consumes a portion of AC power for charging the battery. When the input power fails, the transfer switch disconnects AC input and the battery/inverter provides output power. It is said its rate of efficiency is quite high at 90 to 96 percent.Online UPS are preferred because it always delivers all or a considerable portion of the output power through its inverter even under normal line conditions. There are two main types of on-line UPS available in the market - Double
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