Backup power supply for computer. All about UPS for computers

An uninterruptible power supply (UPS) is automatic device, the main function of which is to power the connected load using the energy of the batteries when the mains voltage fails or its parameters (voltage, frequency) go beyond acceptable limits. In addition, some UPSs can adjust the power supply parameters when operating from the electrical network, i.e. perform the functions of a filter and stabilizer.

This article illustrates UPS selection using products from APC (American Power Conversion), a company founded in 1981 by three electrical engineers who graduated from the Massachusetts Institute of Technology (MIT).
The company's first UPS was released in 1984, and since 2007, APC is a division of Schneider Electric Corporation and is currently the market leader in uninterruptible power systems and the winner of numerous awards.

At the beginning of 2010, APC released an updated model of the RS series - Back-UPS RS 550 () This device has a new interesting function energy saving. It is implemented in the form of “dependent” UPS output sockets, which are de-energized if you turn off the computer connected to the “main” sockets of the device.
In this way, you can save energy by automatically turning off equipment such as hubs, modems, routers and other peripherals that are usually unnecessary when the computer is not working. Another important innovation that makes using UPS more convenient is the presence of a liquid crystal display that displays detailed information about the status of the UPS and the power grid.

For reference: B Russian Federation The standard for household power supply is as follows: effective voltage- 220 V ± 10%, frequency 50 Hz ± 1%, non-sinusoidal coefficient - long-term up to 8%, short-term up to 12%. Thus, the voltage in the network should change its value along a sinusoid with a period of 1/49 - 1/51 sec, be in the range of 196 V - 242 V and differ in shape from an ideal sinusoid by no more than 8%.

Power of sources uninterruptible power supply is indicated in volt-amperes (VA), and the power in the more usual watts (W) can be found by multiplying the power in volt-amperes by a factor of 0.6. For example, a UPS with a power rating of 700VA will protect equipment with a maximum consumption of 420 W with uninterruptible power.

You can calculate the power of the connected load by summing the power of all consumers connected to the UPS, for personal computers this power is always less than the rated power of their power supplies (usually one and a half to two times) and depends on the features of a particular configuration; it can be approximately calculated, for example, using.
Example: system unit a computer with a 350W power supply consumes 250W + 45W monitor = 295W, dividing this figure by 0.6, we get 491VA, i.e. For this configuration, the minimum suitable UPS power is 500VA.

Estimated time UPS operation at a given load level, the easiest way to find out is by looking at the documentation provided by the manufacturer. This article further provides links to runtime charts for all APC UPS families mentioned. Usually for maximum load time battery life measured in several minutes, which is usually enough to save user data and correctly turn off the equipment.

Remember also that the dependence of battery life on the power of the connected load has a non-linear form due to a drop in the efficiency of the converter when the load decreases relative to the rated load, for example, for the BackES series UPS this dependence has the form shown in the graph on the left. Understanding this fact will save you from buying too powerful UPS in order to ensure long work connected equipment - such an undertaking is unlikely to end successfully, since when operating from batteries at a power several times less than the rated power for the UPS, their resource will be predominantly consumed by the inverter, and not by the load.

Another factor that reduces the battery life of a UPS is a decrease in battery capacity. The capacity of rechargeable batteries decreases during their service life; this must be remembered if the batteries in a given UPS are used for a significant part of their life. life cycle(usually it ranges from two to four years).

The UPS is designed for uninterrupted supply electric shock computer and other devices connected to it in case of problems with the main power supply. The device is necessary for safe storage and completion of work, correct shutdown computer when there is a sudden loss of power. In this review we will talk about the best uninterruptible power supplies and how to choose the right UPS.

How to choose an uninterruptible power supply?

When choosing UPS, you should consider equipment features, which is planned to be attached to it and nature of problems in the electrical network.

If the problems are not related to undervoltage or overvoltage, but different types of protection are required network equipment(modem, router, access point) or a low-power PC with peripherals will be enough the simplest backup UPS(otherwise Standby or off-line). At the same time, its rated power must exceed the sum of the power consumption of the connected equipment. To avoid mistakes in conversion, it is better to take 1 VA equal to 1.4 W.

You can normalize the “floating” value of the mains voltage Automatically adjustable (AVR) models. They are already of the interactive type (Smart UPS), and since stabilization there is carried out in stages, you should start from the sensitivity of your equipment to a drop in supply voltage. The simplest uninterruptible power supply systems have one boost stage, more advanced models have two or three. In other words, the latter perform normalization more accurately.

U gaming computers middle and high power its own characteristics. Almost without exception, all of them are equipped with power supplies with active power factor correction (APFC). Without going into details, we note that such power supplies are not “friendly” with backup and inexpensive interactive UPS (whose output signal has a step approximation). Alternatively, you should focus on uninterruptible power supplies with double power reserve. Or to uninterruptible power supplies with a “pure” sine wave, including the online type.

Briefly about the latter. Double conversion UPS provide better protection against all types of power supply problems than others, and in some cases there is simply no alternative. You have to pay for everything. Both literally and figuratively. The cost of online models is high, but they have the lowest efficiency.

Uninterruptible power supplies in our rating are grouped by type, and in each category they are arranged in order of increasing power.

Uninterruptible power supply, UPS or uninterruptible power supply - equipment that allows you to protect home appliances: LCD panel, LCD TV, washing machine, refrigerator and even a gas boiler from power surges, as well as save your work on the computer, and, therefore, save time and nerves. But it is not enough just to buy a protective device; you need to select a model that will correspond to the technological operating conditions. In this article we will tell readers how to choose a UPS for their home based on power, operating time and other parameters.

Type of execution

It is necessary to determine what electrical problems most often occur. If these are frequent outages, then it is enough to select and install a backup UPS. It is quite enough for saving documents, playing games, working with programs and shutting down the computer correctly.

The disadvantage of this variety is the lack of a stabilizing device. As a result, when switching to backup power, there is a short power interruption. Therefore, it is important to choose high-quality models, since they are equipped with capacitors of sufficient capacity, and the harm from a short-term power outage is minimized. At the same time, the average price of a backup uninterruptible power supply in 2017 is about 4,500 rubles.

If, in addition to power outages, frequent ones are noticed, it is better to choose a linear-interactive uninterruptible power supply. The reason is that backup models are unstable to voltage surges, which is why the storage device suffers and will have to be changed frequently. This is due to additional financial costs.

The disadvantage of a line-interactive UPS is the creation of network interference that starts in electrical network general use. Also, the disadvantage of this variety is high level noise during operation. This is approximately 40–50 dB, so if you want to choose an uninterruptible power supply for household appliances in the bedroom, avoid this option.

There is another type of uninterruptible power supply - on-line. The devices are powered directly from the charger or battery. This 100% guarantees the absence of unexpected power surges and network interference. The choice of such an uninterruptible power supply is associated with significant financial costs. At the same time, the consumer receives the following disadvantages:

1. Low level of efficiency due to the double voltage conversion system. Simply put, this type is inferior to the other two in terms of power.
2. Rapid wear of storage devices and batteries.

It's obvious that optimal choice– a line-interactive UPS, since no one is immune from sudden power surges. They can lead to the complete loss of sensitive household appliances, electrical appliances and home computer. It is recommended to choose a linear-interactive version both for the office and for home use. This optimal cost in 2017, which varies from 3300 to 1500 rubles, as well as a set of functionality.

Separately, we can distinguish a type of uninterruptible power supply that is installed on a gas boiler. This is necessary to ensure the operation of the circulation pumps. Without them, water circulation in the system, and therefore the operation of the boiler, is impossible.

To do it correctly, you need to familiarize yourself with its technical characteristics, in particular, the starting currents and pump power. The power of the uninterruptible power supply should be 2.5 times higher than the above indicators. To ensure long-term operation of a gas boiler, it is necessary to buy models that allow you to connect additional batteries. It is best to choose an on-line uninterruptible power supply for such purposes.

Power

An important selection criterion is the power of the UPS. It is measured in volt-amperes, designated VA. To convert them to the more familiar watt indicator, you need to multiply volt-amperes by 0.6. The result obtained is the maximum total power of the equipment that the uninterruptible power supply can withstand, because through it the voltage is supplied to the devices and equipment. For example, for a PC you need to choose an uninterruptible power supply with at least 500 VA.

Based on power, UPSs are divided into three classes:

• compact – up to 1000VA;
• medium – 1000–5000VA;
• large – more than 5000VA.

Accordingly, for a country house and apartment it is better to choose the first two types; the latter is more suitable for enterprises where it is necessary to ensure stable electrical power large number technology.

Attention! Before making the final choice, you need to calculate the total load power of household appliances and equipment that you plan to connect to the UPS, add 20–40% to it and multiply by 0.6. The resulting figure will be the optimal indicator of the power of the uninterruptible power supply, which will be expressed in VA. We talked about this in a separate article.

Battery life

It is necessary to pay attention to the battery life indicator. The optimal time here is 5–7 minutes. It is assumed that this time is enough for the PC to shut down correctly. For the rest of the equipment, simply protecting against power surges is enough.

There are models that can provide power household appliances within 20 minutes, but such a resource will cost more than standard modifications. The right solution is to choose a UPS that provides the ability to connect additional batteries. This will significantly increase the battery life, but this option will also require additional costs, but not so impressive.

Attention! The battery life indicators are on the packaging, the UPS box, or should be in the “Characteristics” section of the online store.

Number of sockets

UPS are supplied different amounts sockets from 1 to 8. The best option for home – 4–6 sockets. It is important to take into account another factor - the technical orientation of the connectors. They are:

1. Euro - intended for .
2. Computer.

Some sockets may be designed to protect against network interference and not have a connection to the battery. This must also be taken into account when choosing an uninterruptible power supply.

The best manufacturers and models

It is equally important to choose the right UPS company so as not to become a victim of a low-quality counterfeit. Today the most the best manufacturers Uninterruptible power supplies are the following 3 brands:

1. Ippon
2. Powercom

If you buy a model from one of these companies, then a quality guarantee will be provided. In addition, we provide to your attention a rating of the best UPS in terms of price and quality that can be purchased for home use.

Among the interactive models we can recommend:

• APC by Schneider Electric Smart-UPS 750VA/500W USB & Serial 230V
• Ippon Back Basic 650 Schuko
• APC by Schneider Electric Smart-UPS 1500VA LCD 230V
• Powercom RAPTOR RPT-2000AP
• CyberPower UT1500EI

The following backup uninterruptible power supplies received good customer reviews:

• Ippon Back Basic 650 IEC 5.0
• Powercom SPIDER SPD-1000N
• APC by Schneider Electric Back-UPS CS 350 USB/Serial

Well, with a double converter we can recommend 1 of the 5 UPS provided:

• P-Com Pro 3S
• Ippon Innova RT 1000
• Powercom VANGUARD VGS-2000XL
• EATON 9130 1000 BA
• APC by Schneider Electric Smart-UPS RT 10000VA 230V

Other Features

For home use, you can choose a device that has additional functionality:

• Network status is displayed using LED indicators or LCD screens. The second option is more informative, since it displays the network voltage and charge level. Here the choice is determined solely by the preference of the buyer.
• USB connector. Its presence allows you to connect a laptop or computer to the UPS and install special software that will automatically shut down the PC.
• Availability of additional ports: RJ-11, RJ-45. They allow you to protect against network interference: modem, router, network card. This useful feature for home.
• Function cold start. Allows the use of household appliances and other electrical equipment without mains voltage. For example, boot your computer to send important message or heat water, make tea, coffee or other hot drinks. This is a useful feature for homes and organizations.
• Design. Here the choice is limited to to a greater extent color, as almost all uninterruptible power supplies rectangular shape, similar to cinder block or brick.

Important! It is advisable to choose a model that allows you to change the batteries yourself. This will save time and money at service centers.

Well and one more useful advice– a homemade analogue of a UPS can be a combination surge protector and stabilizer. This will protect household appliances from breakdowns as a result of voltage surges if there is no money to purchase an uninterruptible power supply. Finally, we recommend watching this useful video

Which UPS to choose? We raised this topic in the previous article and looked at the types of uninterruptible power supplies that manufacturers offer. Today we’ll talk about how to choose an uninterruptible power supply depending on your tasks and the type of your equipment, and we’ll also calculate required power UPS.

What kind of uninterruptible power supply you need depends on several main points:

1. What kind of network problems do you want to protect your equipment from?
2. Design features of the equipment you want to connect to the UPS.
3. Planned load power on the UPS.
4. Required battery life.

So, in this article we will look at choosing an uninterruptible power supply, taking into account the following questions:

• We calculate the battery capacity for a known battery life.
• We calculate the battery life, knowing the capacity of the UPS.

Why do you need a UPS?

The answer to the question: which uninterruptible power supply to choose depends primarily on why you need it.

Note that if you only need power stabilization and do not need to ensure autonomous operation of the equipment during a power outage, it is more advisable to buy a separate stabilizer.

Also, quite often they use a combination of a stabilizer + an inexpensive UPS (the uninterruptible power supply is connected to the network AFTER the stabilizer). Such a tandem not only allows you to regulate the voltage if this is not provided in the UPS, but also extends the life of the UPS batteries.

What equipment are you buying a UPS to protect?

Which UPS to choose also depends on the design features of the connected equipment.

The general rule is this: you can connect almost any equipment to a UPS with the correct sine wave at the output; you just need to correctly calculate the power. Not all equipment can be connected to other UPS, especially the offline type.

How to calculate the power of a UPS?

In order to choose the right uninterruptible power supply, you need to calculate the total power of the equipment that you are going to connect to it. Power values ​​can be clarified in the technical specifications (data sheet or instructions for the equipment).

Let's look at a hypothetical example.

We want to connect to the UPS:

• 250 W computer,
• 60 W LCD monitor,
• 2000 W air conditioner (cos φ = 0.8).

There is one point here: even if the power of all devices is expressed in one unit, in in this case in W, you need to calculate two powers: in volt-amperes and watts.

Power in volt-amperes and watts - what's the difference?

Power, which is expressed in volt-amperes (VA, VA) is called full power. It shows the actual load of the equipment, taking into account active and reactive ones.

Power, which is expressed in watts (W, W), is called active power.

These are two different quantities, and both need to be taken into account when choosing a UPS the power you need. This is especially important if you are going to connect a reactive load to the UPS, since in such equipment the apparent and active power can differ significantly.

Calculation of power in volt-amperes.

To convert active power (in watts) to full power in volt-amperes we use the formula:

Where:

• VA - apparent power,
• W - active power,
• P - equipment power factor.

If the equipment belongs to the active load, and this is almost all network, telecommunications equipment, lighting and heating devices, that is, equipment without inductance, without reactive power, as well as computer equipment With power supply units with power factor adjustment (APFC), the current factor can be taken equal to 1, or better with a small margin - 0.95.

If you are going to connect a UPS laser printer, air conditioning, fluorescent lamps - equipment that has electric motors and the like, everything where there is inductance and reactive power, as well as computers with power supplies without APFC, the current power factor must be looked at in the device passport or on the sticker on the back wall. For this technique it is most often indicated. The power factor is indicated as Power Factor(PF) or cos φ.

In the case where the manufacturer has not indicated the value of the power factor, but the load is clearly not fully active, you can take the most common value: 0.7.

Let's return to our example.

The power supply in the computer does not have power factor adjustment, so we take the P value equal to 0.7. It's the same on the monitor. In total we get the full power:

• for a computer with a monitor: (250+60)/0.7 =442 VA,
• for air conditioner: 2000/0.8 =2500 VA,
• Together: 2942 VA.

So, should we buy a 3000VA uninterruptible power supply? Take your time, it's not that simple.

Calculation of power in watts.

Most often the simplest case occurs - when the power is in watts, it is also called active power, is already indicated in the documentation for the equipment. If not, you can convert the power from volt-amps to watts using the same methodology as for total power.

Let's calculate the power of our equipment in watts:

• computer with monitor - 310 W,
• air conditioner - 2000 W,
• Together: 2310 W.

In our online store, among UPS for 3000VA, for example, there are:

How to calculate the required capacity of an uninterruptible power supply?

Usually, when choosing an uninterruptible power supply, we have some specific requirements for the time during which it will support the operation of the equipment connected to it in the event of a power outage. Many manufacturers indicate an approximate range, for example, they write that depending on the load, the battery life will be 4-20 minutes. Or they indicate that when working at maximum load this time will be 5 minutes.

But this is approximate, and we need to be absolutely sure that the UPS we purchased will provide battery operation for a certain list of equipment. Or calculate how long our chosen UPS model will hold our load.

We calculate the battery capacity for a known battery life

For calculations we need:

• The total active power (in watts) of the equipment that we are going to connect to the UPS (W).
• Battery life (T).
• Rated battery voltage.

We use the formula:

Where:

• T - time of planned autonomous operation (h),
• P - power of connected equipment (W),
• KPD - efficiency of the uninterruptible power supply (you can take about 0.85).

And the formula for converting capacity in Wh to capacity in AH:

Let's say we need the computer and monitor from the example above to work for 2 hours after a power outage.

Capacity (Wh) = 2 * 310 / 0.85 = 730 Wh.

However, battery capacity is usually indicated in ampere-hours. To convert watt-hour capacity to ampere-hour capacity, you will need to specify the rated voltage of the batteries.

For 12V batteries:

Capacity (A*h) = 730/12 == 60.83 ≈ 61Ah.

For 24V batteries:

730/24 = 30.42 ≈ 30Ah.

Since most often a UPS uses 1-2 batteries, less often 4, with a capacity of 7-9AH, then select a UPS standard for such values ​​of total capacity it will be difficult for us. It is best to buy an uninterruptible power supply with the ability to connect external batteries and select the capacity according to your needs.

Catalog of UPS with the ability to connect external batteries.

UPS efficiency (approximately 0.85).

We use the formulas:

• V - rated battery voltage (V),
• AH - capacity of one battery (AH),
• N is the number of batteries.

• E- total capacity(Wh)
• KPD - efficiency of the uninterruptible power supply (by default you can take 0.85,
• P is the power consumption of the connected equipment.

Let's take the PowerCom BNT-800AP USB UPS as an example. The manufacturer claims a battery life of 5 minutes at maximum load. How long can our computer and monitor work with a power consumption of 310 W?

Total capacity (Wh) UPS = 12V * 7.2AH * 1 = 86.4 Wh.

Time = 86.4*0.85 / 310 = 0.237 hours ≈ 14 minutes.

Conclusion

Now let's briefly summarize.

In order to select a UPS, you must:

• Define, what type of UPS do you need.
• Calculate the required full and active power UPS, taking into account inrush currents and a small margin.
• If you need to maintain power for a certain time, calculate how much UPS capacity is needed for this. And depending on the calculated capacity, buy a regular uninterruptible power supply or a UPS and a set of additional batteries for it.

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Regular blackouts and power outages can lead to equipment simply burning out. It’s good if we are talking about some inexpensive device, but in the case of a refrigerator, computer, boiler, the loss will be significant. Such an unpleasant situation can be safely prevented by buying solar battery It’s not at all necessary, just choose the best uninterruptible power supply and stop worrying every time the light blinks.

The best uninterruptible power supplies - which company to buy

Quality devices are offered by American, Taiwanese, English and Russian brands. The top five manufacturing companies have remained virtually unchanged over the years:

1. APC– previously a leading independent American manufacturer, now part of Schneider Electric, producing products in the mid-price segment. The company was founded in 1982.
2. Powercom is the largest Taiwanese manufacturer, annually producing more than 250 thousand units of products.
3. Ippon is a trademark owned by the English company Nippon Klick Systems LLP, operating on Russian market since 2002.
4. P-Com is an international company operating on the Russian market, with a representative office in Moscow.
5. INELT is a Russian brand that appeared in 2002. It produces UPS for computers, refrigerators, and boilers.

Rating of the best uninterruptible power supplies

The selection of the best was carried out on the basis of various indicators reflecting the quality of the products. The key criteria for assessing the UPS when selecting leaders were:

• Reliability of operation;
• Duration of service life;
• Ease of use;
• Consumer reviews;
• Price/quality ratio;
• Brand;
• Silence;
• Power;
• Weight and dimensions;
• Brand.

It is these indicators that must be taken into account when choosing a UPS.

The best uninterruptible power supplies

Uninterruptible power supplies are necessary for the most expensive equipment - boilers, refrigerators, computers. They ensure autonomy during sudden failures of the central power supply, protecting it from damage caused by unstable voltage.

Best Double Conversion UPS

APC by Smart-UPS RT 10000VA 230V – manufactured by Schneider Electric, has a power level of 10,000 W. When fully loaded, it can operate for about 4 minutes. At 50% load, the model runs for more than 13 minutes. Allows you to connect 8 simultaneously various types technology. For convenience, there is an audible alarm. The device weighs 111 kg.

Advantages:

• High power;
• Possibility of changing the battery;
• Many input connectors;
• Works reliably;
• Protects against power surges and failures;
• Doesn't heat up.

Flaws:

• Noisy;
• Does not function for long at maximum load;
• Short lifespan battery;
• Expensive;
• Big.

Smart Power Pro 1000 – device medium power(600 W) from Ippon, intended for power supply of personal computers. Duration of operation at maximum load is about 5 minutes. In the event of a power outage, the device switches to battery operation in 3 milliseconds. It is equipped with two alarms, light and sound, informing the user about the charge status. Works with noise level< 40 дБ и весит 9.6 кг.

Advantages:

• High reliability – protects the PC from voltage failures;
• Optimal price/quality ratio;
• Fast battery charging (up to 4 hours);
• There is an LED indication.

Flaws:

• Noisy;
• Available in only one color (white);
• LCD display missing;
• The fuse is getting hot.

P-Com Pro 3H – operates at a power of 800 W. At a load of 50% it operates for 40 minutes. In mode full load operates for five minutes. The model is equipped with an informative LCD display, which contains all the necessary data about the state of charge of the battery and how much longer it can keep the boiler operating. The housing has a tower-type shape and operates at temperatures not exceeding 40°C, while producing a noise of 45 dB.

Advantages:

• Powerful;
• Works for a long time on battery power;
• Instantly switches between mains and battery;
• Weighs little;
• Warns when the battery is completely discharged;
• Microprocessor control.

Flaws:

• Expensive;
• Short battery life;
• High battery cost.

P-Com Pro 3H is also suitable for peripheral equipment, workstations, cash registers.

Inelt Monolith K 3000 ULT is a device with a power of 3000 W and a liquid crystal display, two output jacks for simultaneous connection of several devices. Made in China. Input voltage type – single-phase. Protects electrical appliances from power surges at room temperatures of 0–40°C. Can be located at altitudes up to 3000 m above sea level.

Advantages:

• Instant selection of operating modes;
• Availability of an informative display;
• Long operating time without connecting to the network (about 5 minutes at full load);
• Charges quickly.

Flaws:

• The model is considered noisy;
• Batteries need to be purchased separately;
• The cost is above average for the class;
• A small number of output connectors;
• External batteries.

EATON Ellipse ECO EL650 – model high power(1650 W) is intended for backup power supply in emergency situations. If necessary, it automatically turns off everything peripherals, saving energy for the main equipment. The number of connectors for devices is from 4 to 8, depending on the specific design. The operating time at half the maximum load is 11 minutes. On full charge the battery requires 4 hours.

Advantages:

• Reliability, protects the PC from voltage failures;
• Long battery life;
• Sufficient number of input connectors;
• Charges quickly.

Flaws:

• The device is loud;
• Expensive;
• Lack of LCD display;
• The socket is not suitable for all devices.

Which uninterruptible power supply to choose

If uninterrupted power supply is needed to solve a problem with unstable voltage, attention should be paid to double conversion or line-interactive UPS models. At frequent shutdown light, you will need more powerful backup devices. Here's what it's suitable for:

• For use as backup power Eaton's Ellipse ECO EL650, P-Com's Pro 3H, and Inelt's Monolith K 3000 ULT will be useful. These models operate for a long time on battery power.
• For use with constant power surges UPS are better suited « APC by Schneider Electric-UPS RT 10000VA 230V" and "Power Pro 1000" from the Smart brand. These models have increased reliability indicators and are able to withstand any voltage surges.

Before you do right choice, it’s worth finding out why UPSs are needed in general, what they are and when which models are used. The answers to all these questions are in this video:

You need to choose the best uninterruptible power supply based on the purpose of its purchase, but, definitely, the power should be at its best.