Application of uninterruptible power supplies. Let's find out what can be made from an old uninterruptible power supply from a computer. An uninterruptible power supply is needed for it

After about three to six months of operation, the cost of the data stored on a new work computer begins to exceed the cost of the computer itself. In the case of a network server, this situation can arise within 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. If there is a power failure, one incorrect data writing session can destroy the entire file system.

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

In Russia, data from studies conducted in the USA by Bell Labs and IBM have become known. According to Bell Labs and IBM (USA), every Personal Computer exposed to 120 power emergencies per month.

Why should you use a UPS?

To answer this question, here's what you need to think about:

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 your critical equipment protected?
4. If you have virtualized your servers, have you considered the impact 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 three main functions:

1. Prevents damage caused by power surges and surges. Many UPS models continuously generate the correct output voltage waveform.
2. Prevents data loss and damage. Without a UPS, data stored on storage devices subjected to an improper shutdown may be damaged or even lost completely. 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 sufficient time to start in the event of a power loss.

9 power problems and how a UPS can help you deal with them

Eaton UPS solutions address all nine major power problems. They are designed to meet the requirements of power protection, distribution and management for offices, local networks, data centers, and for telecommunications equipment, medical and industrial markets.

For small office and home (SOHO) applications, Eaton offers budget solutions, such as Ellipse and Eaton 5110 for regular desktop systems. To protect critical systems such as network servers and high-power 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

Source: EATON CORPORATION. UPS Handbook

Typical power supply problems

Complete loss of mains voltage(no voltage in the network for more than 40 seconds due to disruptions in the power supply lines)

Subsidence(short-term decrease in network voltage to a value less than 80% of the nominal value for a time of more than 1 period (1/50 second) is a consequence of switching on powerful loads, externally manifests itself as flickering of lighting lamps) and surges (short-term increases in voltage in the network by more than 110% of the nominal value for a time of more than 1 period (1/50 of a second); appear when a large load is turned off, externally manifesting itself as flickering of lighting lamps) of different voltages 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 beyond acceptable limits

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

Frequency overrun a change in frequency of 3 or more Hz from the nominal (50 Hz), appears when the power source is unstable, but may not be externally visible.

All these factors can lead to failure of fairly “thin” electronics and, as often happens, to loss of data. However, people have long learned to protect themselves: line voltage filters that “dampen” surges, diesel generators that supply electricity to systems in the event of a power outage on a “global scale”, and finally, sources uninterruptible power supply the main tool for protecting personal PCs, servers, mini-PBXs, etc.

Types of power failures

ANNOUNCEMENTS

Uninterruptible power supply, UPS, UPS- as soon as they call this simple device capable of providing uninterrupted energy supply at sites of special importance. Such facilities primarily include nuclear energy enterprises, oil production and oil refining complexes and social infrastructure facilities.

Equally important is uninterrupted power supply and at home: effective operation of local computer networks and personal computers directly depend on electricity. In the event of power outages or a complete shutdown, it will allow the computer to work for a few more tens of minutes, which is enough to save the necessary data and safely shut down the computer.

It is clear that UPS prices for one computer and UPS prices for large production will differ 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 It is customary to divide it into several types. If we use power as the determining factor UPS, then among them there are devices of high, medium and low power. This or that 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 defining types UPS, it is generally accepted to consider the operating principle of uninterruptible power supply systems themselves. In this regard, the following categories are distinguished: UPS as online (on-line), offline (off-line) and linear-interactive (line-interactive).

Offline uninterruptable power source During normal operation, it provides connection to the main power supply. In emergency mode, the power is switched to backup sources, in this case to batteries. Main advantage UPS The offline type remains its ease of execution and unpretentiousness in operation.

Line Interactive UPS In addition to the switching device, they include an incoming voltage stabilizer. That is uninterruptable power source this type not only provides autonomous power supply devices during a power outage, but also protects against low or high voltage without a general switch to emergency mode.

Online uninterruptable power source built on the principle of double voltage conversion. The AC voltage received at the input is transformed into DC using a rectifier, and then becomes AC again using an inverter. All this helps to establish a stable level of output voltage, and also dampens interference from the main supply network.

Uninterruptible power supply systems are currently becoming very popular. It doesn’t matter where a modern person lives - in a city apartment, in a country house, various household appliances, digital computer equipment, and life support systems have become firmly established in his life.

Purpose and categories of UPS

The requirements for the quality of power supply for all these devices are increasing. Power quality of external electrical networks does not always satisfy the population. Sharp voltage drops occur, both in the direction of decreasing and increasing its value. This has a very adverse effect on the operation of household equipment, and sometimes leads to its failure. Protect yourself from such troubles helps to install uninterruptible power supplies, from which devices that are most sensitive to such sudden changes are powered.

Depending on the circuit solutions that determine the main characteristics of uninterruptible power supplies, they can be divided into several categories. Each of them ensures uninterrupted operation of a certain group of consumers.

Backup UPS

They can only protect simple home appliances and desktop computers.

If the mains voltage is normal, consumers are connected directly to it. When the voltage in the network fluctuates, the equipment switches to power from the battery, which is an integral part of the UPS. Noise and high-frequency impulses are partially suppressed, the voltage is maintained at a given level, and recharging is performed battery. Stabilization of the mains voltage supplying equipment connected to its output is not carried out for uninterruptible power supplies of this category.

The need to switch to battery operation in each uninterruptible power supply model is determined differently. The limits of operation from the network are determined by the developer of this model. They are installed based on the conditions of normal functioning of the consumer equipment.

Battery operation will continue until the voltage in the network returns to normal. After that, there is a switch to reverse side. The source battery must provide at least a five-minute reserve when operating from it. This is enough to save data on the computer and trouble-free shutdown of the consumer equipment.

The disadvantages of uninterruptible power supplies in this category include the following:

1. Lack of mains voltage stabilizer.
2. Long switching time (~20 ms).
3. Step form of output voltage.
4. Presence of high frequency interference.

Switching to autonomous power mode occurs at any slight deviation of the mains voltage parameters from the norm. This leads to rapid battery wear.

Linear interactive sources

Models in this category are equipped with network voltage stabilizers, which are made according to an autotransformer circuit. Switching of its windings, depending on the value of the input mains voltage, occurs stepwise according to the commands of the microprocessor built into the UPS circuit. Thus, it is possible to maintain a voltage at the output of the unit close to normal (220−230) V. Additionally, the circuit has a filter that protects the consumer from network interference.

Connecting the battery and disconnecting from the network occurs when the voltage parameters at the input of the unit go beyond the stabilization thresholds. The number of autotransformer terminals is not enough to maintain the rated voltage at the output. There are also tolerances on the shape of the input signal. For large distortions, a transition to battery mode power supply of consumer equipment.

The process of switching to battery power is fairly smooth for most consumers and takes no more than 4 ms.

Thus, Comparing sources of this category with backup UPSs, you can notice their advantages:

1. Mains voltage stabilization has a stepwise nature.
2. The output voltage shape is close to a sinusoid.
3. Network interference filtering.
4. Saving battery life due to fewer starts.

Ferroresonant power supplies

At their core, they are linear active sources. A ferroresonant transformer serves as a mains voltage stabilizer. It can store magnetic field energy, which maintains voltage in secondary winding transformer at switching moments. The transition process lasts no more than (8−16) ms. This is acceptable for most consumers. The voltage form at its output is sinusoidal, protected from network interference. The source performs its functions based on commands from its own network analysis and control unit.

Linear uninterruptible devices

Double conversion UPSs fall into this category. They include an AC-to-DC converter (rectifier) ​​and a DC-to-AC converter (inverter). The output voltage of the inverter is used to power the equipment connected as a load. The rectifier voltage is used to recharge the internal battery. It is included in the rectifier circuit and is constantly in active mode, which depends on the quality of the input AC voltage.

The positive qualities of a UPS in this category include:

1. Output voltage stability.
2. Possibility of replacing the battery without shutting down the UPS.

The disadvantages include:

1. Low odds useful action(efficiency).
2. Battery life is reduced due to constant operation.

Devices in this category are used to operate the equipment of large organizations whose servers store important data. They must be saved in case of any changes in the network and any disruptions in its operation.

Main characteristics

When purchasing a UPS, you must carefully understand the requirements for it. It is necessary to choose the model that best satisfies the “price - quality” criterion.

When choosing an uninterruptible power supply, great attention should be paid to comparing the characteristics different models. These include the following:

• UPS power.
• time battery life.
• switching time to battery operation and back.
• range of input voltage changes.
• limits for changing the network voltage frequency.

Power is calculated from the total load of the source. Its value should be at least one and a half times greater than the power of consumers. The optimal power of a unit installed in an apartment is considered to be 1000 VA (1000 volt-amperes).

The switching time directly depends on the size of the load connected to the this moment to the source output. The more current it consumes, the shorter the battery operating time. The capacity of the installed battery also determines the operating time.

Any UPS model has visual signaling elements. These can be light bulbs of various colors, LED indicators that determine the state of the uninterruptible power supply at the current moment.

Constantly lit green indicators are a sign of normal operation of the unit. If the LED operates in pulse mode (its intermittent glow), then problems are possible or have already arisen. This is a warning signal that attracts attention.

A constant glow of the red indicator indicates an emergency situation. Its occurrence is accompanied by warnings sound signals in the form of intermittent beeps.

Operating rules

Correct operation of the equipment is the key to its long and reliable operation. The basic rules that must be followed when operating an uninterruptible power supply include:

• The need to constantly monitor the light indication and sound alarm of the unit.
• Connecting consumers that really require uninterruptible power.
• Grounding the UPS using a socket with three sockets for connecting the device plug.

If there is a power outage, you must turn off all equipment that is turned on at that moment. It is advisable to leave the UPS plugged in for possible battery recharging after the network fault is resolved. Operating the unit with a discharged battery leads to its rapid failure. The battery life is limited and is no more than 5 years.

Compliance with these simple but necessary rules will extend the life of all equipment that requires uninterrupted power supply, and most importantly, it will preserve important information on computer hard drives, which could be irretrievably lost in the event of sudden malfunctions in electrical networks.

UPS stands for "uninterruptible power supply". Abbreviation in English - UPS (Uninterruptible Power Supply) , therefore the names UPS, YUPS, and oopsnik are also common.

The main function of an uninterruptible power supply is to ensure the supply of electricity to the equipment connected to it during outages in the main network. But, depending on the type of equipment, the parameters of such autonomous power supply may be required to be radically different. Accordingly, the UPS market offers different types of devices, which differ in a lot of parameters:

• principle of operation: offline, linear-interactive, online;
• type of automatic voltage regulation;
• quality of filtering network interference;
• capacity (number of ampere-hours, or in other words - how long the battery life will last);
• time to switch to batteries during a power outage;
• possibility of connecting additional external batteries;
• various additional functions (filtering sockets, sockets for telephone and network cables, LCD display, synchronization with a PC), etc.

How to choose a UPS with such a variety of models ? How to understand how they differ? In this article we will look at the main types of uninterruptible power supplies, their differences, and what additional functions manufacturers equip UPS with. In the next one - how to choose a UPS depending on the features of your equipment, how to calculate its required power, etc.

Three main types of UPS

Off-line (Back-UPS, backup, Standby) uninterruptible power supply

Example of a backup UPS: model .

The operating principle of this type of uninterruptible power supply is very simple:

As long as there is electricity in the network within the set values, the UPS supplies the connected devices with voltage directly from the network, while simultaneously recharging the battery. The power passing through the UPS is not regulated; pulses and noise are filtered at the simplest level, using passive filters. The signal shape corresponds to the network signal, i.e., a sinusoid.

As soon as the mains power is lost, the UPS switches to battery power. Inverter converting D.C. from battery to alternating current at the output, this type of UPS has one of the simplest ones installed, so the waveform does not follow the correct sine wave. The maximum that manufacturers do is to bring it somewhat closer to a sinusoid, making it stepwise.

The UPS also switches to off-line autonomous power supply if the voltage level in the network falls below or rises above the threshold values, they can be different depending on the brand of uninterruptible power supply.

Switching time to batteries in various models is from 5 to 20 ms. This is relatively long, and for some equipment models such a long delay may adversely affect operation . The long-term operation of the relay is due to the fact that the device needs the phases of the mains and battery voltages to coincide when the autonomous power is turned on, and since they are not synchronized, this takes some time.

Scheme of operation of a backup uninterruptible power supply.

Pros of Standby UPS:

• inexpensive price,
• high efficiency,
• silent operation.

Flaws:

• long switchover to battery operation (from 5 to 20 ms);
• the output signal shape is not a sinusoid;
• filtering interference, noise and impulseson the line is quite rough;
• there is no voltage and frequency adjustment when operating from the network.

Line-interactive UPS

Example of a line-interactive UPS: model

Buyers choose this type of uninterruptible power supply most often, as it optimally combines functionality and price.

IN circuit diagram operation of line-interactive UPS includes AVR - module for automatic regulation of incoming network voltage. That is, unlike a backup UPS, it not only passes power through itself, but also stabilizes it, although not smoothly, but in steps.

When operating from the mains at normal voltage levels, the line-interactive uninterruptible power supply passes the incoming signal through passive interference and noise filters, while the battery is charged.

When the voltage in the network increases or decreases, the line-interactive UPS makes its stepwise adjustment. When the voltage reaches a certain threshold, the AVR lowers or lowers it by a fixed amount (or percentage). Several such threshold-steps can be specified in the AVR operating scheme; also, for working with a lower and higher level, a different number of adjustment steps can be assigned (for example, 2 for an increase, and 1 for a decrease).

If the mains voltage drops or rises to values ​​that lie outside the available input range of the uninterruptible power supply, the device switches to battery operation, just as in the case complete shutdown electricity. These minimums and maximums may vary depending on the load on the UPS. For example, if the UPS is 70% loaded and the voltmeter shows 160V in the network, the uninterruptible power supply switches to the batteries. And at 30% load and a voltage of 150V, it still makes adjustments using an AVR transformer.

Some linear-interactive models are no different in the shape of the output signal from backup-type uninterruptible power supplies: they have a stepped sine wave. Some manufacturers, especially with the growing demand for UPS for boilers, equip their uninterruptible power supply systems with inverters that produce the correct sine wave.

The switchover time to battery operation in a pure sine wave line-interactive UPS is faster than that of its standby counterparts. The reason is that in UPSs of this type, the voltage waveforms coincide (both from the network and from the battery, this is a sinusoid), which speeds up phase synchronization and, accordingly, the start of autonomous power supply.

Pros of line-interactive UPS:

• reasonable price,
• silent operation,
• automatic regulation of incoming voltage,
• in some models - pure sine wave at the output,
• switching time is less than in backup ones (on average 4-8 ms, in some models 2-4 ms).

Flaws:

• no frequency adjustment,
• insufficiently complete filtering of interference, noise and network impulses,
• voltage regulation is not smooth, but stepwise,
• The efficiency is lower than in an off-line uninterruptible power supply.

Double conversion UPS (on-line)

Double conversion UPS example: model .

This is the most expensive, but also the most best view UPS. It is optimally suited for expensive, capricious equipment, for which not only constant voltage is important, but also frequency, as well as effective noise filtering, a signal in the form of a pure sine wave, and the absence of delays when switching to battery operation.

In fact, such an uninterruptible power supply operates constantly, stabilizing, filtering the incoming signal, equalizing the frequency and shape of the output signal.

In mains mode, the incoming AC voltage is stabilized and converted to DC by the rectifier and distributed between the battery (for recharging if necessary) and the inverter. The inverter converts direct current into alternating current, producing an output signal in the form of a pure sine wave, the correct frequency, the correct voltage. Interference and noise are completely absent - they simply do not remain after double conversion.

This constant “inclusion” of the uninterruptible power supply into the network provides one of its significant advantages: Instant switching to battery operation. Actually, it’s hard to even call it “switching”, since power passes through the rectifier, battery (during charging) and inverter constantly. When the network voltage drops below threshold values ​​or there is a complete power outage, the inverter simply begins to take part of the energy from the battery, and not from the rectifier. It happens instantly.

Double conversion UPSs usually have another operating mode: bypass. This is a backup line that goes directly from the input to the output of the UPS, bypassing the rectifier, battery and inverter. It allows in critical moments for the UPS: overload (for example, with starting currents), failure of the inverter and others - to supply electricity directly to the connected devices, avoiding failure of the device elements.

Constant operation of the UPS has a certain disadvantage: increased heat generation, which requires efficient cooling. Therefore, UPS online are most often equipped with fans, which makes their operation in residential areas not as comfortable as other types of silent uninterruptible power supplies.

Pros of online UPS:

• constant voltage stabilization,
• constant frequency stabilization,
• pure sine wave at the output,
• effective filtering of noise, impulses and interference,
• Instant switching to batteries.

Flaws:

• high price,
• increased noise level,
• the lowest efficiency among all types of UPS.

When choosing an uninterruptible power supply, you need to take into account that there are exceptions. Some line-interactive UPSs may cost more than online models from another manufacturer, the switching time to battery operation in a backup UPS may be no more, or even less, than in some line-interactive UPS, etc. Therefore, In any case, you need to read the specifications specific model.

Additional UPS functionality

In addition to determining the type of uninterruptible power supply you need, when choosing a UPS you should also pay attention to what functionality is included in it. UPS can have various additional functions and design features:

Synchronization with PC. This feature is not present in the cheapest models, but it is very convenient. Using a special software The UPS transmits data in real mode to the computer about the state of the power line and battery charge level. In addition to the purely informational component, there are also features such as, for example, autonomous shutdown of the computer while saving data in all applications during a power outage.

Cold start. An uninterruptible power supply equipped with this function can be turned on when there is no power in the network. For example, the lights went out, you saved documents, turned off the computer and UPS, but after a while there was an urgent need to copy the document to a USB flash drive. A cold-start UPS can be turned on even if there is still no power in the network and get the job done.

Previously, connectors for connecting devices in a UPS looked basically like this:

This IEC 320 standard connector is ideal for connecting a variety of computer equipment. However, equipment with a regular power cord is the same WiFi router, you can’t connect it to it. For these purposes, you can use a surge protector with a similar connector, which is connected to the UPS, and then connect various equipment to it. But this is not always convenient.

Therefore, now many models have simply begun to be supplemented with Schuko-type sockets (in our country they are often called Euro sockets) so that the equipment can be turned on directly:

Sockets for filtering interference. A UPS may be equipped with an outlet or several for sensitive equipment that does not provide power support during a power outage but protects the connected equipment from utility power interference.

Sockets for telephone line, twisted pair. High-voltage pulses can be transmitted not only directly via an electric power cable, but also in the event of various accidents and breakdowns - both via a telephone cable and twisted pair cable. To protect telephone, network and computer equipment Some manufacturers provide special connectors (input/output) where you can connect a telephone or Internet line.

To be continued in the next article.

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

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

More complex models have a set additional functions:

• Automatic deactivation protected equipment during longer critical power outages, as well as restart when the required parameters are restored.
• Monitoring the main parameters of the source’s functioning, tracking its performance level.
• Displays basic information about the operating UPS, as well as the parameters of the input voltage of the supply network.
• Automatic alarm when abnormal calls occur.
• Availability of an installed timer for configurable shutdown or switching on of the consumer at a set time.

Scope of application depending on UPS type

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 local network 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 uninterruptible power supply 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 sophisticated 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, such devices are firstly ineffective (high cost at low loads), and they are also characterized by increased noise and impressive heat dissipation.

Application by current type

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.

Application by power

UPSs are divided into three groups based on power:

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

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 that allows you to synchronize several sources into one 19" rack to obtain higher power values ​​when solving specific technological problems.