Why do you need UPS. Uninterruptible power supplies: an attempt to develop a comprehensive testing methodology How to use an uninterruptible power supply

As civilization develops, it begins to consume more and more energy, in particular, electrical energy - machine tools, factories, electric pumps, street lights, lamps in apartments ... The advent of radio, televisions, telephones, computers gave mankind the opportunity to speed up the exchange of information, however, tied it to sources of electricity, since now, in many cases, the loss of electricity is tantamount to the loss of a channel for delivering information flow. This situation is most critical for a number of the most modern industries, in particular, where computer networks are the main production tool.

It has long been calculated that after a couple of months of work, the cost of information stored on a computer exceeds the cost of the PC itself. For a long time, information has become a kind of commodity - it is created, evaluated, sold, bought, accumulated, transformed ... and sometimes lost for a variety of reasons. Of course, up to half of the problems associated with the loss of information arise due to software or hardware failures in computers. In all other cases, as a rule, problems are associated with poor-quality power supply to the computer.

Ensuring high-quality power supply to PC components is the key to the stable operation of any computer system. The fate of whole months of work sometimes depends on the shape and quality characteristics of the mains supply, on the successful choice of power components. Based on these considerations, the following research methodology was developed, which is intended to become the basis for testing the qualitative characteristics of uninterruptible power supplies in the future.

1. GOST provisions
2. UPS classification (description, diagram)
   • Offline
   • Line Interactive
   • Online
   • Main types by capacity
3. Physics
   • a. Types of power, calculation formulas:
     • Instant
     • Active
     • Reactive
     • Complete
4. Testing:
   • Purpose of testing
   • General plan
   • Options to check
5. Equipment used in testing
6. Bibliography

Everything related to electrical networks in Russia is regulated by the provisions of GOST 13109-97 (adopted by the Interstate Council for Standardization, Metrology and Certification to replace GOST 13109-87). The standards of this document fully comply with the international standards IEC 861, IEC 1000-3-2, IEC 1000-3-3, IEC 1000-4-1 and IEC 1000-2-1, IEC 1000-2-2 publications in terms of electromagnetic compatibility levels in power supply systems and methods for measuring electromagnetic interference.

The standard indicators for power grids in Russia, established by GOST, are the following characteristics:

• supply voltage — 220 V±10%
• frequency — 50±1 Hz
• voltage waveform distortion factor - less than 8% for a long time and 12% for a short time

specified in the document and typical problems power supply. Most often we have to deal with the following of them:

• Complete loss of voltage in the network (no voltage in the network for more than 40 seconds due to disturbances in the power supply lines)
• Sagging (short-term decrease in voltage in the network to a value of less than 80% of nominal value for more than 1 period (1/50 of a second) are the result of turning on powerful loads, externally manifested as flickering of lighting lamps) and surges (short-term increases in mains voltage by more than 110% of the nominal value for more than 1 period (1/50 of a second) ; appear when a large load is turned off, externally appear as flickering of lighting lamps) voltages of different duration (typical for large cities)
• High-frequency noise - radio frequency interference of electromagnetic or other origin, the result of the operation of powerful high-frequency devices, communication devices
• Frequency deviation out of range
• High-voltage surges - short-term voltage pulses up to 6000V and up to 10 ms duration; appear during thunderstorms, as a result of static electricity, due to the sparking of switches, have no external manifestations
• Frequency run-out - a change in frequency by 3 or more Hz from the nominal (50 Hz), appear during unstable operation of the power source, may not appear outwardly.

All these factors can lead to the failure of fairly "thin" electronics, and, as is often the case, to data loss. However, people have long learned to defend themselves: filters mains voltage, “quenching” surges, diesel generators that provide power to systems in the event of a power outage on a “global scale”, and finally, uninterruptible power supplies are the main tool for protecting personal PCs, servers, PBXs, etc. Just about last category devices and will be discussed.
UPS classification

UPSs can be “separated” according to various criteria, in particular, by power (or scope) and by type of operation (architecture / device). Both of these methods are closely related to each other. By power, UPSs are divided into

1. Uninterruptible power supplies low power(with total power 300, 450, 700, 1000, 1500 VA, up to 3000 VA - including on-line)
2. Small and medium power(with total power 3–5 kVA)
3. Medium power(with total power 5-10 kVA)
4. big power(with total power 10-1000 kVA)

Based on the principle of operation of the devices, two types of classification of uninterruptible power supplies are currently used in the literature. According to the first type, UPSs are divided into two categories: online and off-line, which in turn are divided into reserve and line-interactive.

According to the second type, UPSs are divided into three categories: reserve (off-line or standby), line-interactive (line-interactive) and Double Conversion UPS (on-line).

We will use the second type of classification.

Let's start with the difference between UPS types. Backup Type Sources made according to the scheme with a switching device, which in normal operation provides connection of the load directly to the external supply network, and in emergency - transfers it to battery power. The advantage of this type of UPS can be considered its simplicity, the disadvantage is the non-zero switching time to battery power (about 4 ms).

Line Interactive UPS made according to the circuit with a switching device, supplemented by an input voltage stabilizer based on an autotransformer with switched windings. The main advantage of such devices is the protection of the load from overvoltage or undervoltage without going into emergency mode. The disadvantage of such devices is also a non-zero (about 4 ms) switching time to batteries.

double conversion UPS voltage differs in that in it the alternating voltage supplied to the input is first converted by the rectifier to direct, and then - using the inverter - again to alternating. Accumulator battery is permanently connected to the rectifier output and the inverter input and feeds it in emergency mode. Thus, a sufficiently high stability of the output voltage is achieved, regardless of fluctuations in the input voltage. In addition, interference and disturbances, which abound in the supply network, are effectively suppressed.

In practice, UPSs of this class behave like a linear load when connected to the AC mains. The advantage of this design can be considered a zero switching time to battery power, a minus is a decrease in efficiency due to losses during a double voltage conversion.

In all reference books on electrical engineering, four types of power are distinguished: instant, active, reactive and complete. Instant Power is calculated as the product of the instantaneous voltage value and the instantaneous current value for an arbitrarily chosen point in time, that is

Since in a circuit with resistance r u=ir, then

The period-averaged power P of the circuit under consideration is equal to the constant component of the instantaneous power

The average AC power over a period is called active . The unit of active power, the volt-ampere, is called the watt (W).

Accordingly, the resistance r is called active. Since U=Ir, then

Reactive power - a value that characterizes the loads created in electrical devices by fluctuations in the energy of the electromagnetic field. For a sinusoidal current, it is equal to the product of the effective current and voltage and the sine of the phase angle between them.

Full power - total power consumed by the load (both active and reactive components are taken into account). Calculated as the product of the RMS values ​​of the input current and voltage. The unit of measure is VA (volt-ampere). For a sinusoidal current is

Almost every electrical appliance has a label indicating either the total power of the device or the active power.
Testing

The main purpose of testing- to demonstrate the behavior of the tested UPS in real conditions, to give an idea of ​​additional characteristics that are not reflected in the general documentation for the devices, in practice to determine the influence of various factors on the operation of the UPS and, possibly, to help determine the choice of one or another uninterruptible power supply.

Despite the fact that there are currently a great many recommendations for choosing a UPS, during testing we expect, firstly, to consider a number of additional parameters that you should be interested in before purchasing equipment, and secondly, if necessary, adjust the set of selected methods and parameters testing and develop a basis for future analysis of the entire power path of systems.

The general plan for testing is as follows:

• Specifying a device class
• Indication of the characteristics declared by the manufacturer
• Description of the scope of delivery (presence of manual, additional cords, software)
• Short description appearance UPS (functions placed on the control panel and the list of connectors)
• Type of batteries (indicating the capacity of the batteries, serviced / maintenance-free, name, possibly interchangeability, the ability to connect additional battery packs)
• "Energy" component of tests

During testing, it is planned to check the following parameters:

• The input voltage range at which the UPS operates on mains without switching to batteries. Larger input voltage range reduces the number of UPS transfers to battery and extends battery life
• Switchover time to battery power. The shorter the transfer time, the lower the risk of failure of the load (device connected via the UPS). The duration and nature of the switching process largely determine the possibility of the normal continuation of the operation of the equipment. For a computer load, the allowable power interruption time is 20-40 ms.
• Switch to battery waveform
• Switchover time from battery to external power
• Oscillogram of switching from battery to external power
• Offline time. This parameter is determined solely by the capacity of the batteries installed in the UPS, which in turn increases with the maximum output power of the UPS. To provide autonomous power supply for two modern SOHO computers of a typical configuration for 15-20 minutes, the maximum output power The UPS should be around 600-700 VA.
• Output voltage settings for battery operation
• The shape of the pulse at the beginning of the discharge of the battery
• Pulse shape at the end of battery discharge
• UPS output voltage range when input voltage changes. The narrower this range, the less the effect of input voltage changes on the supplied load.
• Output voltage stabilization
• Output voltage filtering (if any)
• UPS Behavior in Output Overload
• UPS Behavior During Load Loss
• UPS efficiency calculation. Defined as the ratio of the output power of the device to the power consumption from the power supply
• Nonlinear distortion coefficient, which characterizes the degree of difference between the voltage or current waveform from a sinusoidal
  • 0% - sinusoid
  • 3% - distortion is not noticeable to the eye
  • 5% - distortion visible to the eye
  • up to 21% - trapezoidal or stepped waveform
  • 43% - the signal is rectangular

When testing, we will not use real workstations and servers, but equivalent loads that have a stable consumption pattern and a power utilization factor close to 1. The following set is currently considered as the main equipment that will be used during testing:

1. GOST 721-77 Power supply systems, networks, sources, converters and receivers of electrical energy. Rated voltages over 1000 V
2. GOST 19431-84 Energy and electrification. Terms and Definitions
3. GOST 21128-83 Power supply systems, networks, sources, converters and receivers of electrical energy. Rated voltages up to 1000 V
4. GOST 30372-95 Compatibility technical means electromagnetic. Terms and Definitions
5. Theoretical Electrical Engineering, ed. 9th, corrected, M.-L., Energia publishing house, 1965
6. Company promotional materials
7. Internet resource

Uninterruptible power supply, UPS, UPS- as soon as this simple device is not called, capable of providing uninterrupted energy supply at sites of particular importance. Such facilities, first of all, include nuclear power plants, oil producing, oil refining complexes and social infrastructure facilities.

Equally important is uninterrupted power supply and at home: effective work local computer networks and personal computers are directly dependent on electricity. In the event of power outages or when it is completely turned off, it will allow the computer to work for several more tens of minutes, which is enough to save the necessary data and safe shutdown computer.

It is clear that UPS prices for one computer and UPS prices for large production will be different from each other. Therefore, choosing UPS/UPS, you need to know about certain types of such devices.

Classification and types of UPS

Based on various parameters, UPS usually divided into several types. If power is used as the determining factor UPS, then among them devices of high, medium and low power stand out. One or another power class is used for various purposes, and it is clear that using a power of several hundred watts will not be entirely appropriate for a single computer at home.

Another classifying parameter that defines types UPS, it is considered to be the principle of operation of the uninterruptible power supply systems themselves. For this reason, the categories UPS as online (on-line), offline (off-line) and linear-interactive (line-interactive).

Offline uninterruptible power system during normal operation provides connection to the main supply network. In emergency mode, power is switched to backup sources, in this case, batteries. Main advantage UPS offline type remains its simplicity of execution and unpretentiousness in work.

Line Interactive UPS in addition to the switching device, they incorporate an input voltage stabilizer. That is uninterruptible power system of this type not only provides autonomous power supply devices during a power outage, but also protects against undervoltage or overvoltage without a general switch to emergency mode.

Online uninterruptible power system built on the principle of double voltage conversion. The alternating voltage supplied at the input is transformed into a constant voltage with the help of a rectifier, and then again becomes alternating with the help of an inverter. All this contributes to the establishment of a stable level of output voltage, and also dampens the interference of the main power supply.

After about three to six months of operation, the cost of data stored on a new working computer begins to exceed the cost of the computer itself. In the case of a network server, this situation can occur as early as a few weeks after its installation.

In 50 - 70% of cases, the cause of failures in the operation of electronic devices is poor-quality power supply. In the event of a power failure, one incorrect data write session can destroy the entire file system.

Even if failures do not lead to catastrophic consequences immediately, after a while the sensitive electronic filling of your PC may simply “revolt” due to constant on / off cycles.

In Russia, the data of studies conducted in the United States by Bell Labs and IBM have become known. According to Bell Labs and IBM (USA), each Personal Computer exposed to 120 power outages per month.

Why use a UPS for you

To answer this question, you should think about the following:

1. What happens if your facility loses power right now?
2. Have you thought about the harm caused by data corruption or loss?
3. If you have a universal voice and data network, is all critical equipment protected?
4. If you have virtualized your servers, have you considered the impact of this on your UPSs?
5. How much power do your UPS modules consume? What is their efficiency?
6. How often do you update and maintain your IT equipment (including servers)? What about your UPS?

UPSs are mainly used to protect IT equipment and other loads from problems that reduce power quality. The UPS performs the following main three functions:

1. Prevents harm caused by power surges and surges. Many UPS models continuously generate the correct output voltage waveform.
2. Prevents data loss and corruption. Without a UPS, data stored on storage devices that have been improperly shut down can be corrupted or even completely lost. In combination with the appropriate software, the UPS can perform a graceful shutdown of the system.
3. Ensures the availability of networks and other applications, preventing downtime. UPSs can also be combined with generators to give the generators enough time to start up in the event of a power failure.

9 power problems and how a UPS can solve them

Eaton UPSs are designed to solve all nine major power problems. They are designed to meet the requirements of power protection, distribution and management for offices, LANs, data centers, as well as telecommunications equipment, medical and industrial markets.

For small office and home (SOHO) applications, Eaton offers budget solutions, such as Ellipse and Eaton 5110 for general desktop systems. To protect critical systems such as network servers and powerful blade servers, Eaton offers line-interactive and online UPSs such as the Eaton 5125, 9130, Evolution, EX, MX, MX Frame, 9155, 9355, 9390, 9395 and Blade UPS

A source: EATON CORPORATION. UPS Handbook

Typical Power Supply Problems

Complete power failure(no voltage in the network for more than 40 seconds due to disturbances in the power supply lines)

subsidence(a short-term decrease in the voltage in the network to a value of less than 80% of the nominal value for more than 1 period (1/50 second) is the result of turning on powerful loads, externally manifests itself as flickering of lighting lamps) and bursts (short-term voltage increases in the network by more than 110 % of the nominal for more than 1 period (1/50 second); appear when a large load is turned off, outwardly appear as flickering of lighting lamps) voltages of different duration (typical for large cities)

High frequency noise- radio frequency interference of electromagnetic or other origin, the result of the operation of powerful high-frequency devices, communication devices

Frequency deviation out of limits

High voltage surges- short-term voltage pulses up to 6000V and duration up to 10 ms; appear during thunderstorms, as a result of static electricity, due to the sparking of switches, have no external manifestations

Frequency overrun- a change in frequency by 3 or more Hz from the nominal (50 Hz), appear during unstable operation of the power source, may not appear outwardly.

All these factors can lead to the failure of fairly "thin" electronics, and, as is often the case, to data loss. However, people have long learned to defend themselves: mains voltage filters that “quench” surges, diesel generators that provide power to systems in the event of a power outage on a “global scale”, and finally, uninterruptible power supplies are the main tool for protecting personal PCs, servers, PBXs and etc.

Types of power failures

ANNOUNCEMENTS

All types of uninterruptible power supplies are designed to perform a set of the following basic functions

• Protection against small and short interruptions in the main power supply network.
• Filtration of emerging impulse disturbances and noise reduction.
• Backup power supply to the load during the set period of automation.
• Short circuit and overload protection.

More complex models have a set additional features:

• Automatic deactivation of protected equipment during longer critical power outages, as well as restart when the required parameters are restored.
• Monitoring of the main parameters of the functioning of the source, tracking the level of its performance.
• Displaying basic information about the operating UPS, as well as the parameters of the input voltage of the mains supply.
• Automatic signaling in case of abnormal calls.
• The presence of an installed timer for customizable shutdown or inclusion of the consumer at a set time.

Scope of application depending on the type of UPS

Backup uninterruptible power supply- the most common in this market segment. It is widely used in combination with home or office computers or low power LAN workstations. It is also effective in terms of protection. household appliances, which does not require a special quality of power supply, allows a power outage for a certain time and the occurrence of deviations from the input voltage parameters on average + -5%.

Interactive UPS can also act as a backup. However, its main tasks are broader: in addition, it performs stepped voltage stabilization, which allows it to be used in combination with electrical devices with increased inrush currents. This is any appliance or other equipment that uses an electric motor, the start of which for a short time requires increased power. In particular, the operation of the refrigerator in conditions of deviation from the norm of voltage parameters can lead to its overload and failure. However, the efficiency of these protective devices is somewhat lower than the same parameter for the backup ones.

Online or double conversion uninterruptible power supply provides the most effective protection for file servers and more complex workstations. It is used in combination with the equipment of financial institutions, medical clinics and research centers. That is, almost everywhere where you need absolutely high-quality power supply with the absence of even short-term voltage dips. But in everyday life similar devices firstly, ineffective high price at low loads), and also they are characterized by increased noise and impressive heat dissipation.

Application by type of current

Online or double conversion uninterruptible power supply

Such uninterruptible power supplies are necessary to ensure the protection of electrical devices that are connected to a 24 V, 48 V and 60 V network.

AC UPS

Uninterruptible power supplies of this type are used in combination with the most important consumers that require a voltage of 220 or 380V.

Power Application

UPSs are divided into three power groups:

• - low power;
• - devices of medium power;
• - modular systems high power.

Low-power UPSs are widely used for domestic purposes, as well as to protect against possible critical situations of individual consumers in offices or small industries.

Medium power devices are responsible for high-quality and uninterrupted power supply to local networks, data centers and various telecommunications equipment, as well as means of remote communication.

A high power uninterruptible power supply has several advantages in use at once. It is able to provide protection for both a separate residential cottage and a large production process. In addition, such a UPS is a kind of modular system, which allows you to synchronize several sources into one rack 19"" to obtain higher power values ​​when solving specific technological problems.

The main purpose of an uninterruptible power supply (UPS) is to temporarily provide power to equipment during power outages. Connecting computers via UPS is accepted everywhere. True, for many users this is a kind of “rule of good manners”, and the practical meaning of this ritual eludes them. “Well, a UPS protects your computer from power surges….” Let's try to figure out: what, from what and how does an uninterruptible power supply protect?

By internal device and logic of operation, all UPSs are divided into three classes: passive, line-interactive and double conversion UPS. Accordingly, they cope with accidents in the power grid to a different extent and belong to different price categories.

Passive(stand-by, VFD, back-UPS, redundant) sources are the simplest and cheapest. In them, the battery power circuit is usually turned off, and starts only when the mains voltage fails. The switchover time from mains operation to battery operation is tenths of a second, and the output signal when running on battery is noticeably different from the "correct" sine wave. As a rule, a simple noise filter and a fast-acting fuse are installed at the input of such UPSs. The first partly smooths out impulse noise, and the second should work with a significant increase in voltage in the mains. Passive UPSs are designed to power home and office PCs. A small "dip" in the output voltage at the time of switching to the battery computer blocks nutrition is not terrible.

Line Interactive(line-interactive, VI, Smart-UPS) UPSs are distinguished by the fact that they have a battery power circuit always on. When the voltage at the input of the “uninterruptible power supply” disappears, its output sockets almost instantly switch to the internal converter - this transition is almost imperceptible for powered devices. In addition, many line-interactive UPSs are capable of automatically maintaining an output voltage of 220 V. This is done in two ways.

While the mains voltage is in the range from 175 to 275 V, the AVR mechanism (Automatic Voltage Regulation, automatic voltage regulator) is activated. If the input voltage deviates by 10 to 25% below the nominal value, the UPS increases the output voltage by 15%. When the input voltage deviates by 10% to 25% above the nominal value, the UPS reduces the voltage by 15%. If the mains voltage is outside the limits, the line-interactive UPS switches to battery power. In this mode, it continues to work until either the mains voltage returns to normal or the battery is discharged. However, such UPSs should not be considered as voltage stabilizers. The mode of "stabilization" is forced and short-term!

V double conversion UPS(double conversion, VFI, Online-UPS) the output voltage is always supplied from the converter, the converter is constantly running from the battery, and the battery is continuously charged from the mains. In fact, the input and output of the UPS are galvanically isolated from each other, and a stabilized voltage is supplied to the output. This is the most reliable, but at the same time uneconomical scheme. The UPS itself turns out to be expensive, large and heavy, the converter gets very hot and requires fan cooling, and energy losses during the conversion amount to tens of percent.

Double conversion UPS is used only to power servers and computers in critical cases. Such models rarely go on sale - they are usually delivered to order. Most likely, to power work computers, you will purchase passive, maximum, line-interactive UPSs.

The power of uninterruptible power supplies is usually indicated in volt-amperes (VA, VA). To convert these values ​​into more familiar watts (W), you need to multiply the power in volt-amperes by a factor of 0.6. For example, a UPS with a power rating of 600 VA will provide power to appliances with a maximum consumption of 360 watts. If you give a large load, the current protection will work, and the “uninterruptible” will turn off. In practice, it is desirable to provide about 30% power margin. Thus, the most common 600 or 650 VA UPSs are suitable for powering a computer with a real consumption of 200-250 watts and a monitor that draws about 30-60 watts more.

If the arrangement of computers in the room allows, it is more profitable to use one powerful UPS instead of several small ones. For two office computers, you will need an uninterruptible power supply with a capacity of about 1000 VA. To power three computers standing side by side, one source with a capacity of about 1400 VA is enough.

So what does the UPS protect against?

The filters in the power supply of the computer and monitor also do a good job of limiting impulse noise from the network. However, two filters are better than one! Surge protection is also important. If, for example, the neutral wire in the shield burns out, a voltage of almost 380 V may appear in the outlet. In this case, varistors and fuses usually burn out in power supplies for computers and monitors. Repair cheap, but takes time. In theory, the UPS should respond to a power surge before the fuses in the equipment connected to it burn out.

However, data protection comes first. If the computer's power is turned off in an emergency, all unsaved information is lost. The UPS allows you to either save open documents and gracefully shut down, or put the computer into sleep mode. Manually saving documents is easiest. Switching to battery power, the UPS starts beeping loudly. Once you hear such a warning - check if everything is saved. Next, look at the situation: either just turn off the computer, or put it into sleep mode.

To enable automation, it is necessary to connect the control port (USB or RS-232, depending on the model) of the uninterruptible power supply to the computer with a signal cable and install the necessary software on the computer. Unfortunately, many users are not even aware of this possibility! The UPS is controlled by a built-in microcontroller. Its firmware (firmware) constantly monitors voltages and currents in external circuits, when turned on and periodically during operation, it performs electronics and battery testing. It also outputs to the control port information about the current mode of operation, the status of the UPS components. Through the cable, these data are sent to the computer, where they are processed by the monitoring program.

To work with the UPS, it is advisable to use the program offered by its manufacturer. For example, for APC (www.apc.com) this is the Power-Chute program, for Ippon (www.ippon.ru) - WinPower2009 and Ippon Monitor, etc. The program can be installed from the disk that comes with the kit, but it is better to download the most its latest version from the manufacturer's website.

In the application settings you need to set the parameters automatic shutdown. As a rule, there are two options to choose from: either turn off the computer through certain time after switching to backup power, or do it some time before the expected complete discharge of the batteries.

How long can a "bespereboynik" be able to work on battery power?

It depends on the battery capacity and power consumption. Most popular models have one battery with a voltage of 12 V and a capacity of 7 Ah. Theoretically, a UPS with such a battery has an energy reserve of about 80 watt-hours. Simply put, it should power a load with a power of 80 W for about 1 hour, 160 W for about half an hour, 300 W for about 15 minutes, etc. In reality, taking into account conversion losses, this time is about half that.

In sources with a power of more than 800 VA, two of the same batteries or one, but with a larger capacity, are usually installed. Tables or calculators for determining time battery life at different loads for different models are given on the websites of manufacturers. However, "offhand" it can be assumed that any model will be able to power the load of its rated power for about 5-15 minutes. If you need to provide long enough battery power to your computer, it is better to take a UPS high power with large batteries. It will work only at a third or a quarter of the rated power. But such a load, low for himself, he will be able to supply energy for half an hour or longer.

Uninterruptible power is also useful for network equipment (switches, routers, NAS). Otherwise, when the power is turned off, the network will immediately “fall”, and documents opened from network folders, cannot be saved. You can power the switch from the UPS of the workplace closest to it, although it is more correct to install a separate “uninterruptible power supply” of low power for this.

Battery life is limited. As it works, its capacity steadily decreases and after 3-5 years of operation it drops to almost zero. Even before the indicator on the UPS signals the need to replace the battery, it becomes noticeable that the battery is no longer “holding a charge”. Each time the battery life is reduced. In principle, a couple of minutes is enough to save documents and shut down the computer correctly. When the UPS starts to turn off even earlier, it is definitely time to change the battery.

Replacing the battery is easy. In popular APC brand UPSs and some others, the battery is located under a removable hatch or cover. To get to the battery in Ippon, SVEN and similar UPSs, you need to unscrew the four screws on the bottom and separate the case halves. In the instructions and on the official website, you are unlikely to find a description of self-disassembly and replacement: like printer manufacturers, UPS manufacturers receive a significant share of their income from the sale of "original" batteries with their installation in authorized service centers.

Nevertheless, almost all computer stores sell sealed lead-acid batteries in the most common sizes. The brand and manufacturer do not play a role: these are quite standard products. First, open your "uninterruptible" and find out which battery is installed in it. For most "office class" UPS (500-700 VA), batteries marked 12V 7Ah with dimensions of 151 × 94 × 65 mm are suitable. Installing new battery, try to tightly put the terminals on the contact petals of the battery. If the terminals are loose, they can be gently tightened with pliers.

After installing the battery, it is advisable to calibrate the UPS so that its firmware evaluates and remembers the parameters of the new battery. Fully charge the battery within a day. After that, remove the plug from the socket so that the UPS switches to autonomous power. Allow the battery to fully discharge until the uninterruptible switch turns itself off. It is better to use not a computer as a load (although in extreme cases this is permissible), but several light bulbs with a total power of about 300 watts. Then reconnect to the mains and turn on the UPS - let the battery charge and the device will continue to operate normally. In addition to calibrating the device as a whole, this procedure is also a “training” of the battery. After a full cycle of "discharge - charge" the battery begins to use its capacity to the maximum.

Why do many UPSs have telephone (RJ-11) and network (RJ-45) sockets?

No phone or the local network"bespereboynikam" are not needed by definition. It's just that as a "bonus" in the same case with the device, there are pass-through filters for impulse noise for the telephone line and the network. Connect one jack to a telephone jack on the wall, and plug the telephone into the other. If a high-voltage interference occurs on the telephone line, for example, during a thunderstorm, the filter will smooth out the voltage surge and protect the phone.