Type
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Standby. The simplest type of UPS, familiar to most ordinary users. Its main purpose is the ability to “softly” shut down work in case of power problems. When the voltage level is normal, the UPS supplies power to the load from the mains, and when the voltage drops or fails, it switches to its own battery. The resource of this battery is usually small — on the order of several minutes, which is usually enough only to save data. Also, such UPSs can smooth out short-term power surges, however, if such surges occur constantly, this wears out the battery and adversely affects the source itself. Redundant UPSs are widely used in home and office environments, they are usually of low power.
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Smart. A kind of development of the idea of backup UPS; such sources not only provide power in case of a decrease or loss of voltage in the network — they also play the role of voltage stabilizers. The design of such UPSs includes a special regulator (usually in the form of a transformer) that compensates for changes in input voltage and supplies a stable voltage to the output. This allows you to supply constant voltage to the load without the use of batteries, making such blocks well suited for operation in networks with unstable voltage — they not only protect the load, but also do not wear out themselves. Interactive UPSs also mostly have low power and battery capacity and are used to protect individual devices.<
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— Inverter (online). Another name is "double conversion". The most advanced type of UPS providing the highest degree of protection. The name comes from the inverter — an output voltage generator that directly supplies power to the load. The inverter itself simultaneously receives power from two sources — from the network and from a charged battery. In the event of a critical decrease or loss of voltage in the network, the inverter continues to supply energy, only from the battery. Such a scheme avoids voltage surges when switching from the mains to the battery (which is a serious drawback of the two types of UPS described above and can even damage the especially sensitive electronics connected to them). Inverter UPSs have the highest power (up to the ability to power an entire building) and can be designed for a three-phase connection (see "Input voltage"), and some models allow you to select batteries of different capacities, depending on specific needs. On the other hand, inverter UPSs are not very efficient, noisy and expensive, so they are mainly used when high power or advanced protection is critical.
— Low voltage. Miniature UPS for low-voltage electronics backup. Mini devices provide a low voltage DC output (typically 9V, 12V, 15V, or 18V). Traditional sockets are not provided for in their design, and you can usually connect one consumer to them. For example, when there is a power outage from a backup mini-UPS, a short-term autonomous power supply is established for the router (for up to one hour), security systems.Full load operating time
UPS continuous operation time from a fully charged battery when connected to a load with a power equal to the UPS output power (maximum or effective, depending on the type of load, see the relevant paragraphs for details). For a UPS designed to work with a home or office PC, a time of about 10-15 minutes is considered sufficient, this is enough to save data and complete work. To power servers, it is worth using devices with an operating time
of 20 minutes or more.
Half load operating time
UPS continuous operation time from a fully charged battery when connected to a load with a power equal to half the output power of the UPS (maximum or effective, depending on the type of load, see below for details). The operating time with such a load is much longer than for a full load, and even in the simplest models it can reach 20-30 minutes.
Input voltage range
In this case, the input voltage range is implied, in which the UPS is able to supply a stable voltage to the load only due to its own regulators, without switching to the battery. For redundant UPSs (see "Type") this range is quite small, approximately 190 to 260 V; for interactive and especially inverter ones, it is much wider. Some UPS models allow you to manually set the input voltage range.
Output voltage accuracy
This parameter characterizes the degree of difference between the AC voltage at the output of the UPS and the perfect voltage, the graph of which has the shape of a regular sinusoid. The perfect voltage is so named because it is the most uniform and creates the least unnecessary load on the connected devices. Thus, the distortion of the output voltage is one of the most important parameters that determine the quality of the power received by the load. A distortion level of 0% means that the UPS produces a perfect sine wave, up to 5% — slight sine wave distortion, up to 18% — strong distortion, from 18% to 40% — a trapezoidal signal, more than 40% — a square wave.
Total battery capacity
The capacity of the battery installed in the UPS. For models with multiple batteries, this is both the total working capacity and the capacity of each individual battery: the batteries in such devices are usually connected in series, so that their total capacity corresponds to the capacity of each individual cell.
Theoretically, a higher battery capacity means the ability to power loads of a given capacity for longer. However, in fact, this parameter is more of a reference than practically significant. The fact is that the actual amount of energy stored by the battery depends not only on the capacity in amp-hours, but also on the voltage in volts; this voltage is often not specified in the characteristics, despite the fact that for accurate calculations it must be known. So when choosing, you should focus on more "close to life" characteristics — first of all, on the directly claimed operating time in different modes (see above).
Full charge time
The time it takes to fully charge the UPS battery. Note that in this case, this time is calculated according to special rules: not from 0 to 100% of the charge, but from a state in which it is impossible to maintain half the load, up to 90% of the charge. Of course, a full charge will take a little longer. However, this data is closer to practice than the “from 0 to 100%” calculation: the inability to work at half load makes the UPS practically useless, and this condition can be taken as zero, and 90% of the battery is already able to provide a good guarantee in case of a power failure.
Cold start
The ability to turn on the uninterruptible power supply in the "cold start" mode.
A
cold start is a turn-on mode in which there is no external power, and the load connected to the UPS is powered immediately from the uninterruptible battery (which, of course, must be charged). This mode is especially useful in emergency cases — for example, if you urgently need to print a document, but there is no light.
Battery hot swap
The ability to replace the battery directly during the operation of the UPS, without disconnecting it from the network and the load. To do this, the device is switched to bypass mode (see "Bypass (direct connection)") or, if there are more than one battery, it switches to another battery. The
hot-swappable battery is useful, for example, in the event of a battery failure, or to replace dead batteries with fresh ones if there is no time to charge.