Uninterruptible power supply units
Uninterruptible power supply units, the UPS — the automatic device, some time allowing the connected equipment to work from own accumulators, at loss of electric current or at an exit of its parameters for admissible regulations. Most often the UPS is used to ensuring smooth operation of computers and computer peripherals where the saved data are very necessary. But you should not think that the UPS provides only back power supply in case of complete loss of a power supply. It also cleans and regulates loading on an input so that at the exit the consumer received so-called "net sinusoidal" current. In different conditions of the UPS carry out different tasks. Some protect from differences of tension of the electric network in house conditions, others — at large offices, the third — in the systems of bank, medical or industrial production, and the fourth cope with protection at the defense enterprises.
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UPS types
There are three types of creation of the UPS. The first — the reserve, or otherwise called off-line which is used for a power supply of personal computers or workstations of local computer networks. Practically all inexpensive low-power UPSes offered in the domestic market are constructed by such principle. At power supply exit for rated values of tension or its absence, there is an automatic switching of loading to a power supply from accumulators (using the simple inverter). UPSes of the class off-line provide reservation of a power supply in case of its complete loss. However, they are not capable to issue a net sinusoidal current at the exit. Similar UPSes are almost silent and work with the minimum heat releases.
Interactive — Line-interactive — the same, as reserve type, but is present at an input the step power conditioner, allowing to receive regulated voltage output. Main advantage linearly - the interactive UPS in comparison with a source of reserve type is that he is capable to provide a normal power supply of loading at the increased or lowered power supply network tension (the most widespread type of malfunctions in domestic power supply networks) without transition to a standalone mode.
Online — is used for a power supply of servers and workstations of local computer networks and also any other equipment imposing increased requirements to quality of network power supply. The principle of work consists in double conversion (double conversion) of a sort of current. At first input alternating voltage will be transformed to permanent, then back to alternating voltage using the inverter (inverter). Data of the UPS differ in very high heat release and noise level.
Characteristics of the UPS
In each electric unit there is a payment which is characterized by two main values: tension (it is measured in volts) and current intensity (unit of measure — ampere). Having multiplied these two indicators, it is possible to receive the actual equipment capacity which is measured in the volt-amperes (VA). Power of the majority of the UPS is expressed in volt-amperes (VA, kVA) or watts (kilowatts). UPS power for all electronics connected to it should exceed the power of the protected equipment for 10-20 percent. As for the battery life then everything depends on the UPS type and also battery capacity. Typical time of reservation of the UPS which are available today in the market at the maximum load is from 5 to 30 minutes. Installation of additional batteries increases reservation time that is extremely important for automatic closing of very complex systems.
Choice of the UPS
Depending on the power of the power source distinguish household units of uninterrupted power and industrial uninterruptible power supply units. Ordinary users, of course, will be interested in the UPS of the first type, the prices for which also differ depending on power. So, the UPS with a power around 800VA will cost about 4-6 thousand rubles, more serious models with a power around 1500 VA will cost about 12 thousand rubles. More powerful UPSes are simply not necessary and too expensive to home use. As for firms of producers, the market house UPS-ov is not so big.
When choosing "defender" of a home computer network it is worth paying attention to products of firms APC, Ippon and Powerman. Also, practically all modern UPSes can perform monitoring of input voltage, temperature and battery power using the regular software. And in the presence at the UPS of the network interface monitoring can be performed through network under the SNMP protocol. As for the choice of the UPS of the necessary power, for descriptive reasons it is worth giving an example. Power of uninterruptible power supply units is specified in volt-amperes (VA), and power in more usual in watts (W) can be learned, having increased power in volt-amperes by coefficient 0.6. The modern system unit of the computer with the power supply of 350 Watts consumes 250 W, the connected monitor of 45 more W, i.e. the final digit equals 295 W, having separated this digit into 0.6, it turns out 491VA. In other words, for such configuration minimum suitable power of the UPS — 500VA.
As a result, having an opportunity to count necessary power and proceeding from requirements of the home computer network, it is possible absolutely precisely the nobility what UPS is necessary. Today occasionally information saved on the computer is more important and more expensive than the most computer iron.
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