Comparison UPS

— 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.

— 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.<...br>
— 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.

— Standard (Tower). UPS designed for floor mounting or placement on any suitable horizontal surface. This “installation” is extremely simple, and it is suitable even for the most powerful and heaviest devices, and therefore most modern uninterruptible power supplies (of all categories) are made in the usual Tower form factor. They are supposed to be placed vertically.

— Rack. Models for installation in telecommunication racks. Most of these uninterruptible power supplies belong to the professional equipment segment, designed to power servers and other similar electronics (which are also often mounted in a similar way). The most common standard of racks is 19", however there are other options, so it would not hurt to check the compatibility of the UPS with a specific rack separately. We also note that models of this type are often equipped with legs that allow you to place the device on the floor “sideways” or in a vertical position. Display (if available) in such models may have a rotating design for ease of reading parameters in both positions.

— Wall-mounted. Uninterruptible power supplies, primarily designed for wall mounting. Wall hanging may be the best option in tight spaces. However, such an installation is not the only option - many devices can optionally be installed on the floor. Also note that wall-mounted UPSs are often used for heating boile...rs. The main disadvantage of this form factor is the need to drill into the walls to install an uninterruptible power supply.

- Flat. UPS, structurally assembled in a low, flat housing. As a rule, this form factor allows for several options for installing equipment: the uninterruptible power supply can be installed horizontally or vertically. However, it is the horizontal method of installing the UPS that predominates. In fact, everything depends on the location of the uninterruptible power supply and its dimensions - it would not hurt to clarify this point separately.

— Extension cord. Uninterruptible power supplies that resemble an extension cord in appearance. Structurally, such UPSs consist of a set of sockets in one housing, with the sockets located on the top platform of the uninterruptible power supply. Often, the housing of such UPSs is provided with holes or fasteners for wall mounting.

The time required to transfer the load from mains power to battery power. In standby and interactive UPSs (see Type), a short-term power failure occurs at this moment — accordingly, the shorter the time to switch to the battery, the more uniform the power supply is provided by the source during a power failure. Ideally, the switching time for the traditional 50 Hz AC frequency should be less than 5 ms (a quarter of one cycle of the sine wave). With inverter UPSs, the transfer time is, by definition, zero.

The input voltage for which the UPS is designed. This parameter practically also determines the type of network — different voltages correspond to a different number of phases:

— 1 phase (230 V). Connection to ordinary household networks of the 230 V standard. It is these networks that are used by most devices powered by uninterruptible power supplies: computers, video and audio equipment, gas boilers, air conditioners, medical equipment, etc. Therefore, the vast majority of modern UPSs are designed specifically for 230 V. At the same time, relatively low-power models can work directly from the outlet, but for devices with a high maximum output power — from 3.5 kVA — a special connection format (directly to the shield) may be required.

— 3 phases (400 V). Connection to three-phase networks of 400 V format. Such networks are used to power powerful industrial equipment, as well as to supply energy from substations to entire segments of the power grid (for example, the entire building). Accordingly, in the case of a UPS, it makes sense to use such an input voltage only in the most powerful models designed for a significant load — for example, an entire data centre, or an industrial workshop with high requirements for process continuity. The effective output power of such “uninterruptible power supplies” is from 4 kW, and the output voltage (see below) can be either single- or three-phase....

— 1 phase (230 V) / 3 phases (400 V). Uninterruptible devices that allow connection to any of the types of networks described above. Most of these devices are, in fact, models for three phases, supplemented by the ability to work also from 230 V. Note that for operation from a single-phase network, such models usually need to be connected directly to the shield, and the output power with such a connection may be lower the claimed maximum (this point needs to be specified separately).

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.

The maximum current drawn by the UPS. In fact, the current reaches its maximum value only when the UPS is operating from the mains with maximum load power and a completely discharged battery. However, when calculating the load on the power grid, this parameter should be taken into account.

Bypass(by-pass) means such a mode of operation of the UPS, in which power is supplied to the load directly from an external source — the mains, diesel generator, etc. — practically without processing in the UPS itself. This mode can be activated either automatically or manually.

— The automatic bypass is a kind of safety measure. It turns on when the UPS in normal mode cannot supply power to the load — for example, when the UPS is overloaded due to a sharp increase in the power consumption of the load.

— Manual bypass allows you to enable this mode at the request of the user, regardless of the operating parameters. This may be necessary, for example, to hot-swap a battery (see below for details) or to start equipment that has a starting capacity greater than that of the UPS. Technically, it can also play the role of a security measure, but automatic systems are more reliable in this sense.

Some UPSs provide both options for enabling the bypass.

The voltage supplied by the uninterruptible power supply to the main power outlets.

— 1 phase (230 V). The operating voltage used in most types of equipment powered by a UPS: computers, servers, medical equipment, household air conditioners and refrigerators, gas boilers, etc. Accordingly, the vast majority of modern “uninterruptible power supplies” output exactly 230 V.

— 3 phases (400 V). The voltage used for powerful industrial units, as well as for powering numerous consumers — for example, for an entire data centre. Accordingly, such an output voltage is typical mainly for the most powerful UPSs; such devices also require a three-phase power supply at the input.

— DC (constant voltage). DC voltage is used to power a variety of low-voltage electronics. It is typical mainly for redundant mini-UPS.

The maximum output power supplied by the UPS, in other words, the highest apparent load power allowed for this model.

This indicator is measured in volt-amperes (the general meaning of this unit is the same as that of the watt, and different names are used to separate different types of power). The total power consumption of the load, implied in this case, is the sum of two powers — active and reactive. Active power is actually effective power (it is indicated in watts in the characteristics of electrical appliances). Reactive power is the power wasted by coils and capacitors in AC devices; with numerous coils and/or capacitors, this power can be a fairly significant part of the total energy consumption. Note that for simple tasks, you can use data on effective power (it is often given for UPS — see below); but for accurate electrical calculations it is worth using the full one.

The simplest selection rule for this indicator is: the maximum output power of the UPS in volt-amperes should be at least 1.7 times higher than the total load power in watts. There are also more detailed calculation formulas that take into account the characteristics of different types of load; they can be found in special sources. As for specific values, the most modest modern UPSs give out 700 – 1000 VA, or even less — this is enough to power a PC of average performance; and in the most "heavyweight" models, th...is figure can be 8 – 10 kVA and higher.