Increasing requirements for the quality of electricity at the present time is a completely natural process. The requirements of the mentioned standards are due to two components. The first is the desire of consumers to protect themselves as much as possible from the consequences of emergency situations in the power system. The second component is related to the operating conditions of the load. This should include the requirements for stable and continuous operation of intelligent and power electrical equipment, reducing losses in the supply network, and so on. One of the effective options for technical solutions to the problem of power quality is sources uninterruptible power supply(UPS, English UPS).

The main task of the UPS is to provide the consumer with electricity at the moment the quality parameters go beyond the regulated norms (drawdown, voltage increase, significant shape distortion ...). By performing this task, the UPS can:

• disconnect from the power supply and transfer power to the load using its own source;
• supply the load with the corrected mains voltage.

In more expensive UPSs, a function to improve the quality of the consumed electricity can be implemented (power factor corrector integrated).

Types of "uninterruptibles"

There are three basic types of UPS.

1. Redundant UPS(standby, offline, back-ups). The simplest and cheapest technical solution(for example, the popular APC Back-UPS CS 500). In case of a significant overvoltage or undervoltage, the UPS is disconnected from the 220V network and switches to battery mode. Main elements of offline UPS: accumulators (battery), Charger, inverter, step-up transformer, control system, filter (Fig. 1).
   
   
   a)
   
   
   b)
   Rice. 1 Normal operation (a) and battery operation (b) The advantage of an offline UPS is low cost and high efficiency when operating from the mains. Disadvantages: a high level of output voltage distortion (high harmonics, ≈30% in the case of a square wave), the inability to adjust the input voltage parameters. The characteristics of the output voltage will be discussed in more detail below.).
2. Interactive UPS(English line - interactive). It is an intermediate type between a cheap and simple offline UPS and an expensive multifunctional online UPS (for example, ippon back office 600). Unlike an offline UPS, the interactive source has an autotransformer that allows you to maintain the output voltage level within 220V (+ -10%) during drawdowns / rises mains voltage(Fig. 2). As a rule, the number of voltage levels of an autotransformer ranges from two to three.
   
   
   (a)
   
   
   (b)
   
   
   (in)
   
   
   (G)
   Rice. 2 Operation of the interactive UPS at normal mains voltage (a), during mains voltage sag (b), at increased mains voltage (c), in case of mains voltage failure or significant increase (d) The output voltage is adjusted by switching to the corresponding tap of the transformer winding. In the event of a deep drawdown or a significant increase or complete disappearance of the mains voltage, this UPS class functions similarly to the offline class: it disconnects from the network and generates output voltage using battery power. Regarding the shape of the output signal, it can be both sinus and rectangular (or trapezoidal).
   Advantages of line-interactive compared to standby UPS: faster switchover time to offline work from batteries, stabilization of the voltage level at the output. Disadvantages: lower efficiency when operating from the network, more high price(compared to offline type), poor surge filtering (surge).
3. double conversion UPS(English double-conversion UPS, online). The most functional and expensive type of UPS. The bespereboynik is always included in a network. The input sine current is passed through the rectifier, filtered, then inverted back to AC. In the link direct current a separate DC/DC converter can be installed. Since the inverter is always in operation, the delay to switch to battery mode is practically zero. Stabilization of the output voltage during drawdowns or dips in the mains voltage is better, in contrast to the stabilization of the line - interactive UPS. The efficiency can be in the range of 85%÷95%. The output voltage is often sinusoidal (harmonic distortion<5%).
   
   
   Rice. 3 Functional diagram of one of the online UPS options. 3 shows a block diagram of the online UPS option. The mains voltage is rectified here by a semi-controlled rectifier. The impulse voltage is filtered and then inverted. In online UPS circuits, there may be one or more so-called bypasses (bypass switches). The function of such a switch is similar to the function of a relay: switching the load for battery power or direct from the network.
   Based on the online structure, not only low-power single-phase, but also industrial three-phase UPSs are created. The continuity of the power supply of large file servers, medical equipment, telecommunications is carried out exclusively on the basis of the online structure of the UPS.
4. Special types of UPS. Other specific UPS types are also used. For example, a ferroresonant uninterruptible power supply. In this UPS, a special transformer accumulates a charge of energy, which should be enough for the time of switching the power supply from the network to the batteries. Also, some UPSs use the mechanical energy of a super flywheel as a power source.

The main characteristics of the UPS.

1. Power. Power units: volt-ampere (VA), watt (W), volt-ampere reactive (VAr). Recall that there is total S, active P and reactive Q power. The equation relating powers
   S2=P2+Q2
   Active power(W) is spent on useful work, reactive (VAr) - does not perform useful work. Accordingly, apparent power, by definition, is the maximum power that a source must have to provide the load with the necessary energy. The ratio of active power to full power shows the quality of electricity use and is called the power factor (English Power Factor, PF):
   (incandescent lamps, heaters) has PF=1, full power equals active power. PC, microwave ovens, air conditioners have calculation example.
   Calculate an uninterruptible power supply for a computer (two PCs + two monitors). The power of a PC is easy to estimate, knowing how much power the power supply is designed for. Let the PC have 450 W power supplies (active power). With an unknown PF for a PC with a power supply without PFC (English Power Factor Corrector, power factor corrector), PF can be taken equal to 0.65. Similarly, we take the PF of the monitor equal to 0.65. The active power of the monitor is 50 watts. As a result, the total active power of the consumer (two jobs)
   R=450+50+450+50=1000 W
   Gross power (from formula 2):
   S= P/PF=1000/0.65=1538 (VA).
   If a power factor corrector (PF=1) is installed in the power supply units (PSU) of the PC and the monitor, then the total power S is equal to the active power.
   S=P=1000 (VA)
   For a load in the form of a PC, you can calculate the UPS without power reserve, based on the following facts:

• Computer power supplies have overload protection. In other words, the PC will not be able to consume more power than the declared power of the PSU.
• The power of the power supply is the maximum power. In fact, in idle mode (immediately after startup), PCs consume about 50% of their power.

Result.
So, the required minimum parameters of the UPS:

• for PCs with power supplies without PFC - 1 kW / 1540 VA.
• for PCs with power supplies with PFC - 1kW / 1kVA.

For the first option, an apc Smart-UPS C 2000VA uninterruptible power supply (linear-interactive UPS 2kVA / 1.3 kW) is suitable. For the second - UPS Ippon Smart Winner 1500 (1.35 kW) or Eaton 5SC 1500 VA (1.05 kW).
When calculating, it is important to take into account the short-term increase in power for loads such as electric motors. At the moments of starting, the current Istart is five, seven times higher than the rated In:
Istart=(5÷7)*In

Application features.

Uninterruptible power supplies for a heating boiler, as well as uninterruptible power supplies for gas boilers, have a feature associated with the operating modes of the neutral conductor. Often, boiler automation requires the connection of a neutral network. The fact is that the burner flame control circuit is connected to ground and in a four-wire 220V network, the neutral conductor and the boiler ground are ultimately closed through the physical ground. However, when the neutral is broken or when the consumer zero is mechanically disconnected from the zero of the power supply network (autonomous offline operation of the UPS), the flame control circuit is broken. The following solutions are available to resolve this issue:

conclusions

The starting point for choosing an uninterruptible power supply is to determine the nature of the load (UPS for a computer, for heating boilers ...). For responsible consumers and devices containing AC motors, expensive and functional online UPSs should be chosen. For PCs and office equipment, cheaper line-interactive or back IPBs are suitable. The next choice is to calculate the power and battery life of the UPS. It should also be possible to use a "through" zero. When forming the final solution, one should take into account the popularity of brands in the market: the leader APC owns about 50% of all sales, followed by Ippon, Eaton Powerware, Powercom with a significant margin.

As civilization develops, it begins to consume more and more energy, in particular, electrical machines, 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

GOST provisions

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 less than 8% for a long time and 12% for a short time

The document also discusses typical power supply problems. 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 (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 the flickering of lighting lamps) and surges (short-term voltage increases in the network by more than 110% of the nominal for more than 1 period (1/50 of a second); appear when a large load is turned off, outwardly manifest 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 high-power 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 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, "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 the main tool for protecting personal PCs, servers, PBX and others. Just the last category of devices 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 are 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 entering the input is first converted by the rectifier to direct, and then using the inverter back to alternating. The storage battery is permanently connected to the rectifier output and 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 reduction in efficiency due to losses during double voltage conversion.

Physics

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

Usually, it is active power that is understood as the power consumption of the device.

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. Unit of measurement 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 demonstrate the behavior of the UPS under test in real conditions, give an idea of ​​additional characteristics that are not reflected in the general documentation for the devices, determine in practice the influence of various factors on the operation of the UPS, and possibly help determine the choice of one or another uninterruptible power supply.

Despite the fact that there are currently a lot of 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)
• Brief description of the appearance of the 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 of the UPS should be about 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 invisible to the eye
  • 5% distortion visible to the eye
  • up to 21% trapezoidal or stepped waveform
  • 43% the signal is rectangular

Equipment

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:

Bibliography

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 Electromagnetic compatibility of technical means. Terms and Definitions
5. Theoretical Electrical Engineering, ed. 9th, corrected, M.-L., Energia publishing house, 1965
6. Company promotional materials
7. Internet resource

Requirements for the quality of electricity are legally prescribed by state standards and rather stringent standards. Power supply organizations make a lot of efforts to comply with them, but they are not always implemented.

In our apartments, and in production, periodically arise:

complete blackouts for an indefinite period;

aperiodic short-term (10÷100 ms) high-voltage (up to 6 kV) voltage pulses;

surges and voltage drops with different duration;

overlays of high-frequency noise;

frequency drifts.

All these problems adversely affect the operation of household and office consumers of electricity. Particularly affected by the quality of the power supply are microprocessor and computer devices, which not only fail, but can completely lose their performance.

Purpose and types of uninterruptible power supplies

To reduce the risks of power supply failures, backup devices are used, which are commonly called uninterruptible power supplies (UPS) or UPS (derived from the abbreviation of the English phrase "Uninterruptible Power Supply").

They are manufactured with different designs to meet the specific needs of the consumer. For example, powerful UPS with helium batteries are able to support the power supply of an entire cottage for several hours.

Their batteries are charged from a power line, wind turbine, or other energy carriers through an inverter rectifier. They also feed the electrical consumers of the cottage.

When the external source is turned off, the batteries are discharged to the load connected to their network. The larger the capacity of the battery and the lower the current of their discharge, the longer they work.

Medium power uninterruptible power supplies can back up indoor climate control systems and similar equipment.

At the same time, the simplest UPS models are only able to complete the computer emergency shutdown program. At the same time, the duration of the entire process of their work will not exceed 9÷15 minutes.

Computer uninterruptible power supplies are:

built into the body of the device;

external.

The first designs are common in laptops, netbooks, tablets and similar mobile devices powered by a built-in battery, which is equipped with a power and load switching circuit.

laptop battery with built-in controller is an uninterruptible power supply. Its circuit automatically protects operating equipment from power failures.

External structures of the UPS, designed for the normal completion of desktop computer programs, are made in a separate unit.

They are connected via a power adapter to an electrical outlet. Only those devices that are responsible for the operation of programs are powered from them:

system unit with a connected keyboard;

monitor that displays ongoing processes.

Other peripheral devices: scanners, printers, loudspeakers and other equipment from UPS are not powered. Otherwise, when programs crash, they will take on some of the energy stored in the batteries.

Options for constructing UPS working diagrams

Computer and industrial UPSs are manufactured according to three main options:

redundant power supply;

interactive scheme;

double conversion of electricity.

With the first method back-up scheme, denoted by the English terms "Standby" or "Off-Line", the voltage is supplied from the network to the computer through the UPS, in which electromagnetic interference is eliminated by built-in filters. It is also installed here, the capacity of which is supported by the charge current regulated by the controller.

When the external power supply disappears or goes beyond the established standards, the controller directs the energy of the battery to the power supply of consumers. To convert direct current to alternating current, a simple inverter is connected.

Benefits of UPS Standby

Off-Line uninterruptible power supplies are highly efficient when energized, operate quietly, emit little heat, and are relatively cheap.

Flaws

UPS Standby stand out:

long transition to battery power 4÷13 ms;

distorted form of the output signal produced by the inverter in the form of a meander, and not a harmonic sinusoid;

lack of voltage and frequency adjustment.

Such devices are most common on personal computers.

UPS interactive circuit

They are designated by the English term "Line-Interactive". They are performed according to the previous, but more complicated scheme by including a voltage stabilizer using an autotransformer with step regulation.

This provides an adjustment of the output voltage, but they are not able to control the frequency of the signal.

Noise filtering in normal mode and switching to inverter power in case of accidents occurs according to the UPS Standby algorithms.

By adding a voltage stabilizer of various models with control methods, it made it possible to create inverters with a waveform not only of a meander, but also of a sinusoid. However, a small number of control stages based on relay switching does not allow full stabilization functions to be realized.

This is especially true for cheap models, which, when switching to battery power, not only overestimate the frequency above the nominal value, but also distort the shape of the sinusoid. Interference is introduced by a built-in transformer, in the core of which hysteresis processes occur.

In expensive models, inverters on semiconductor switches work. Line-Interactive UPSs are faster when switching to battery power than Off-Line UPSs. It is provided by the operation of synchronization algorithms between the incoming voltage and the output signals. But at the same time there is some underestimation of efficiency.

The Line-Interactive UPS cannot be used to power asynchronous motors that are massively installed on all household appliances, including heating systems. They are used to operate devices with, where the power is filtered and rectified at the same time: computers and consumer electronics.

double conversion UPS

This UPS circuit is named after the English phrase On-line "and works on equipment that requires high quality power. It produces a double conversion of electricity, when the sinusoidal harmonics of the alternating current are constantly converted by the rectifier into a constant value, which is passed through the inverter to create a repeated sinusoid at the output.

Here, the battery is constantly connected to the circuit, which eliminates the need for its switching. This method practically eliminates the period of preparation of the uninterruptible power supply for switching.

The operation of the UPS On-line according to the state of the battery can be divided into three stages:

charge stage;

waiting state;

discharge to the computer.

Charge period

The input and output circuits of the sine wave are interrupted by the UPS internal switch.

The battery connected to the rectifier receives charge energy until its capacity is restored to optimal values.

Ready period

After the end of the battery charge, the automation of the uninterruptible power supply closes the internal switch.

The battery maintains a buffer ready state.

Discharge period

The battery is automatically switched to power the computer station.

Double conversion uninterruptible power supplies have a lower efficiency in line mode than other models due to the energy consumption for generating heat and noise. But in complex structures, techniques are used to increase efficiency.

UPS On-line is capable of correcting not only the magnitude of the voltage, but also its frequency of oscillation. This distinguishes them from previous models and allows them to be used to power various complex devices with asynchronous motors. However, the cost of such devices is much higher than previous models.

UPS Composition

Depending on the type of operating circuit, the uninterruptible power supply kit includes:

accumulators for accumulation of the electric power;

Maintaining battery performance;

sine wave inverter,

process control scheme;

software.

For remote access to the device, a local network can be used, and the reliability of the circuit can be increased due to its redundancy.

Some uninterruptible power supplies use the "Bypass" mode, when the load is powered by a filtered mains voltage without the operation of the main circuit of the device.

Part of the UPS has a step voltage regulator "Booster", controlled by automation.

Depending on the need to perform complex technical solutions, uninterruptible power supplies can be equipped with additional special functions.

Greetings, my dear readers! In the current Russian realities, the owners of stationary computers are forced to solve the problems of uninterrupted power supply. This problem can be solved with the help of uninterruptible power supplies. Their diversity in the computer market allows you to choose a UPS for your specific needs. We will talk about what a UPS is and what uninterruptible power supplies are in this article.

A UPS, or uninterruptible power supply, is a device that acts as an energy "accumulator". In the event of a power outage, the UPS automatically switches the computer's power supply to power from the built-in batteries, which allows you to shut down correctly and save all the necessary documents.

Variety of uninterruptible power supplies

Uninterruptible is your guarantee of the safety of documents and computer components as a whole. After all, if the computer is turned off incorrectly, the hard drive, the motherboard, and the RAM can suffer.

We figured out what an uninterruptible power supply is. Let's move on to the next question.

What are UPS?

Uninterruptible power supplies are divided into three types:

1. Offline UPS;
2. Line-interactive UPS;
3. Online UPS (double conversion UPS).

Consider separately each of the types of uninterruptible devices. This information will help you choose a UPS for your needs.

Offline UPS

The principle of operation of this type of power supply is to automatically switch the computer or other connected device to power from the built-in batteries when disconnected from the external power supply.

Often a mechanical relay acts as a switch, and you may hear a clicking sound when the UPS switches from external power to batteries and vice versa.

This type has become widespread among ordinary users and in offices.

To pluses such UPSs can be attributed to simplicity, compactness and low cost. The main minus is the inability to stabilize the input voltage, and therefore your computer will not be protected from sudden voltage drops. Also, this type has increased wear of batteries.

Line Interactive UPS

This type of uninterruptible power supply is in most cases used to protect network and other telecommunications equipment, as well as groups of computers.

The main feature of these sources is the ability to adjust the output voltage without connecting to batteries, regardless of what voltage (high or low) at the input.

Pluses This type of UPS are small size, low cost, automatic voltage regulation, cost-effective.

But he also has minuses- this is a relatively long switching to batteries, the impossibility of adjusting the shape of the output voltage when working from an external power supply, the change in the output voltage occurs in steps.

double conversion UPS

This type of UPS performs voltage conversion twice: the input AC voltage is converted to DC, and then the DC is converted to the reference AC voltage and supplied to the devices.

This type is used where a reference voltage is required, and the powered devices are demanding on the quality of the power supply. Connected devices can be very different: ordinary workstations, file servers, network devices and other power-hungry equipment.

pros online UPS has essential: full control of input and output voltage, zero waiting time for switching to batteries, connected equipment does not affect the external power grid in any way.

Minuses are also available: high cost, complex design, power consumption "on oneself" in the double conversion mode.

For home and office, the first type of UPS is enough. But if there is a financial opportunity, then I would recommend you the last look. This is the most reliable type of protection for your computer equipment from low-quality voltage.

Main characteristics of the UPS

The UPS has several main characteristics that you should pay attention to when buying. Let's consider them below.

1. Power. This characteristic directly determines what equipment can be connected to this UPS. Always choose a source with a power reserve. This will avoid possible problems with lack of power.

Usually this characteristic is indicated by the value VA or W. If the value is indicated in VA (VA), then multiply it by 0.6 to get a value in Watts that is more understandable to us.

1. UPS type. I talked about the types of uninterruptible devices above. We came to the conclusion that a double conversion UPS would be the most optimal, but for home needs, an offline or line-interactive source would be sufficient.
2. Battery life. This value is very important, since it determines how long the computer will work without external power. Typically, the battery life is set in the range of 5-30 minutes. Please note that at maximum load on the UPS, the time without electricity is significantly reduced.

These three characteristics are the most important. In addition to them, the UPS has many more characteristics. For example, when choosing an uninterruptible power supply in a store, pay attention to what power connectors are installed in the source, whether there is a display and additional interfaces (RJ-11, USB), how many batteries are installed, and others.

Frequently occurring problems

1. The most common problem that occurs with the UPS most often is the failure of the battery. A dead battery can be identified by the fact that the uninterruptible power supply stops holding the load - when the electricity is turned off, the computer immediately turns off. Also, a damaged battery can manifest itself differently: the uninterruptible power supply does not turn on at all, or it turns on and beeps continuously. I wrote about how to change the battery in an uninterruptible power supply in. It says about a specific UPS, but the principle of replacement in all sources is practically the same.
2. The UPS may not turn on at all due to a blown fuse.
3. If the uninterruptible power supply starts normally, but the computer does not turn on, then check the wires, they may come out of the sockets.

I hope my article was useful for you and you learned something new for yourself. If you still have questions, you can ask them in the comments.

Everyone is probably familiar with the situation when, when changing equipment to a newer one, you don’t know what to do with the old one, which has already become obsolete, but so far quite good. If there is no need to use the old computer for its intended purpose, then you can come up with new purposes for its components. To do this, it will be useful to know what can be done from an uninterruptible power supply for a computer.

From the old uninterruptible power supply, you can get a lot of devices in haste. Among other things, among them are especially useful in everyday life:

• Charger;
• simple inverter;
• UPS for gas boiler;
• 12 volt source (for radio and other purposes).

Charger

To make a charger out of an old uninterruptible power supply, you need to proceed as follows:

1. firstly, the primary and secondary circuits of the transformer are determined;
2. 220 V is supplied to the primary by inserting into the voltage regulator circuit (a rheostat for a light bulb is suitable);
3. a bridge of about 40-50 amperes is connected to the secondary transformer winding;
4. connect the terminals and the corresponding poles of the battery.

Voltage calibration will be carried out by an impromptu regulator within 0-15 volts.

You will have to control the charge level according to the indicator or using a voltmeter.

Simple inverter

A transformer without a battery will make a working inverter for a car. The assembly process will proceed as follows:

1. disassembly of the uninterruptible power supply: removal of the battery, bite off the terminals, stripping the ends;
2. search for a connector for connecting to the network (if there is a connector, it should be removed, if not, the wires are bitten off the board, the ends are stripped);
3. the wires from the battery using a soldering iron must be connected to the wires from the connector located on the rear panel, the soldering points are not isolated;
4. the cigarette lighter socket is soldered to the device, observing the polarity and insulating the soldering points;
5. the internal speaker of the device is excluded (it is torn off with pliers or the board is removed);
6. assembling the case by adding standard sockets (for some UPSs, they are already included in the original design).

Read also: We will explain in detail how to connect an uninterruptible power supply to a computer

UPS for gas boiler

A computer UPS is also suitable for a gas boiler. Conversion process should be done like this:

1. removal of a faulty power supply;
2. creation of terminal clamps, taking into account the polarity (it is better to make clamps of different colors to indicate plus and minus) by making 2 holes, fixing the terminal clamps and soldering to them the wires previously suitable for the internal power supply from the computer;
3. to prevent premature failure of the device due to overheating, it will be necessary to install fans with or without a housing connected in series (to start them, it is recommended to use an LED by soldering its leads to the winding of a small relay, and you will need to solder a wire from the incoming “+” battery to one of the relay contacts battery, and to the second - a free red wire from the fan, another free black wire is soldered to the minus of the battery).

12 volt source

Failed uninterruptible power supply can be adapted to a 12 volt source. This is done very simply. First, you will need to connect an outlet to the uninterruptible power cord. To do this, one end is initially cut off from it. After performing this procedure with the help of an uninterruptible you can charge your phone. By further simple transformations described above, you can increase the power of a home-made device (see the part about the inverter).