Uninterruptible power supplies for computer composition. Uninterruptible power supplies without secrets

A power source is a special device that provides power to various energy consumers. Power sources are divided into primary and secondary.

The first group includes converters. Their main purpose is to convert any kind of energy into electrical energy. That is, the primary power source is a generator of electrical energy.

Primary power sources include chemical current sources (galvanic cells, fuel cells, batteries, redox cells) and others (photoelectric converters, electromechanical current sources, thermoelectric converters, MHD generators, radioisotope energy sources).

Secondary sources convert electrical energy. They allow you to get power for various devices with the required parameters. This group includes transformers and autotransformers, voltage stabilizers, current stabilizers, pulse converters, vibration converters, inverters, umformers.

Selecting a power supply (PSU)

When choosing or developing a PSU, one should take into account the operating conditions, the nature of the load, safety requirements, etc. The parameters must correspond to the requirements of the powered device. It is desirable to have a protection device, small weight and dimensions.

The power supply is a piece of electronic equipment, therefore, if any of its parameters are out of tolerance, it may lead to unstable operation or failure of the entire device.

Main types of secondary power supplies

Network power supplies are part of any electronic device. They are divided into the following types:
- transformerless;
- linear;
- impulse.

Transformerless

These devices are very simple, cheap, and do not require any configuration. The power supply circuit consists of only a few elements: an input circuit, a rectifier and a parametric stabilizer. The devices are rated for currents up to hundreds of mA. They are light in weight and small in size. The consumer is powered from the network through a quenching capacitor or resistor and is constantly under mains voltage. Therefore, when working, care should be taken: do not touch uninsulated elements.

Linear

They began to be used in radio-electronic engineering at the beginning of the 20th century. By now, they are outdated and are used mainly in cheap designs due to their inherent disadvantages: heavy weight and dimensions, low efficiency. The advantages of linear power supplies are simplicity and high reliability, low level noise and radiation.

The principle of operation of the power supply is extremely simple. The input voltage is supplied to the transformer, reduced to the required value, rectified, smoothed by a capacitor and fed to the input of the stabilizer, which consists of a transistor and a control circuit. "Excess" voltage is compensated by the regulating transistor. Therefore, it releases significant power in the form of heat. It is advisable to use a linear power supply at consumption currents up to 1A.

Switching PSUs

A special place is occupied by switching power supplies with a transformerless input and a high-frequency converter designed to operate at frequencies of 20-400 kHz. The efficiency of these devices reaches 90% or more. But so far they have not found wide application due to the high cost, complexity of the device, low reliability, and a high level of interference.

Features of DC power supplies

These devices are designed to produce a stable constant voltage or current. Accordingly, they have stabilization modes for both current and voltage. That is, with a maximum change in current, the voltage practically does not change, and similarly, with significant voltage fluctuations, the current remains constant.

There is a current cut-off mode. In this mode, voltage is removed from the powered device if the current exceeds the set value.
A modern power supply has several regulated outputs and additional outputs for fixed voltages (3.3V, 5V, 12V ...).

The PSU operation is controlled by a built-in microcontroller. Operating modes and individual parameters are recorded in memory cells.
The power of the power supply depends on the purpose of the device and the tasks to be solved. Manufacturers produce devices of low (up to 100 W), medium (up to 300 W) and high (over 300 W) power.

What is the difference between uninterruptible and backup power supplies

The backup power source is connected to the equipment only when the mains voltage fails. The connection can be made automatically or manually.

Uninterruptible power supplies (UPS) are used in equipment that does not have a mains power supply. They are connected permanently and provide the load with a stable power supply. The UPS is both the primary and backup power source. When the mains voltage fails, it automatically switches to backup power.

The uninterruptible power supply includes a mains power supply, a backup power source (battery), a charger, and a switching circuit.

The main types of UPS, application features

Periodic sudden power outages have become a common occurrence in our lives. Unfortunately, such power surges significantly shorten the life of household appliances and lead to the loss of electronic data.

Uninterruptible power supplies help to avoid unpleasant consequences. The modern market represents a wide range of these devices. The principle of operation is very simple: the device is plugged into the mains, and household appliances are connected to it. If the network is functioning normally, the uninterruptible power supply only accumulates energy. In the event of a power outage, the UPS will turn on.

UPS are of the following types:

Redundant UPS. Suitable for office equipment, computers, home use. Efficiency is about 99%. This is a good uninterruptible power supply. The price is quite affordable. Unfortunately, such uninterruptible power supplies work not only when there is a power outage, but also when its parameters change, so the wear of the battery increases. In this case, you can suggest using an additional external power supply.

Line-interactive UPS. They only work in the event of a complete power outage. They can be used for office equipment, heating boilers, computer technology.

Double conversion UPS. This is the most expensive uninterruptible power supply. Its price exceeds 50 thousand rubles, but it's worth it. Double conversion UPSs bring the mains readings to perfection. Failover time is less than 1 ms. They are used to power medical equipment, servers, highly sensitive equipment.

Replacing UPS Batteries

Batteries - current power sources - are the weakest element of the UPS. 90% of UPS failures are due to battery failure. As a rule, sealed lead-acid batteries are installed in the UPS. The electrolyte is a gel-like mass based on sulfuric acid. This is one of the cheapest types of batteries. At the same time, they are quite efficient (low internal resistance, low self-discharge).

Lead batteries do not allow heavy discharge. In this case, they quickly lose capacity. Their service life does not exceed 5 years. High temperatures and frequent discharges significantly shorten battery life.
UPS Battery Selection Criteria:
. The battery must have the required voltage and dimensions.
. It is advisable to install batteries from well-known manufacturers.
. UPSs are suitable only for batteries specifically designed for them or batteries of certain brands.

An uninterruptible power supply (UPS) is an automatic device, the main function of which is to power the load using the energy of batteries in the event of a mains voltage failure or its parameters (voltage, frequency) exceeding acceptable limits. In addition, depending on the construction scheme, the UPS adjusts the power supply parameters.

There are three UPS construction schemes:

2. Backup UPS (off-line)

The principle of operation of a backup uninterruptible power supply is to supply the load with mains voltage, if any, and quickly switch to a backup power supply circuit (battery and inverter) when it fails or its parameters (voltage and frequency) go beyond the permissible limits. The battery is automatically recharged when the UPS is operating from the mains.

Distinctive feature such a scheme is the presence of an automatic load power switch (mains / battery).

The redundant UPS is used to power personal computers or workstations of local area networks. Almost all low-cost low-power UPSs offered on the domestic market are built according to a redundant scheme.

Advantages:

• compactness
• economy
• Ease
• relative cheapness

3. Interactive UPS (line-interactive)

The principle of operation of an interactive uninterruptible power supply is completely identical to the backup one, with the exception of stepwise stabilization of the output voltage by switching the autotransformer windings.

Interactive UPS is used to power personal computers, workstations and file servers of local area networks, office and other equipment critical to power failures.

Advantages:

• compactness
• economy
• step output voltage stabilization

sinusoidal output voltage

4. Online UPS (on-line)

The principle of operation of the online uninterruptible power supply is based on double voltage conversion: the input voltage is transformed into DC using a rectifier, and then back to AC using a reverse converter (inverter).

On-line UPS is used to power file servers and workstations of local area networks, as well as any other equipment that places high demands on the quality of mains power supply.

It is believed that the online scheme is the most advanced solution to date, allowing you to completely protect the load from all existing power failures.
Advantages:

• complete filtering of mains voltage from interference and surges, interference generated by the load is not passed back to the network
• supply of the load with a "clean" sinusoidal voltage, stable in magnitude and shape, both when operating from the mains, and when operating from batteries
• switching to batteries is instantaneous, with no transients

Compared to other types of UPS, online sources have a number of significant advantages, the main of which is the absence of a time interval between the loss of external power and the start of battery power supply. When characterizing this type of UPS, the expression "Switching Time 0" or "Zero Switching Time" is very often used, which in reality is not entirely correct, but fully describes the essence of this advantage.

Another advantage of a double conversion UPS is the ability to adjust not only the voltage, but also the frequency at the output of the source. In fact, online uninterruptible power supplies are the best voltage stabilizers. The output voltage of this type of UPS is always in the form of a pure sine wave.

Along with the advantages of online UPS, there are also some disadvantages, which include high cost (two or three times more expensive than line-interactive UPS), low efficiency (85% - 94%), increased heat dissipation and high level noise.

Despite some shortcomings, it is online UPSs that provide the highest level of protection for the power supply of a critical load. Therefore, to ensure uninterrupted power supply to such important and expensive devices as file servers, industrial equipment, telecommunication systems, etc., only online uninterruptible power supplies are used.

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Uninterruptible power supplies - a device that saved many household appliances from breakdown, computer files from death (when they did not have time to "preserve"), and owners from piquant situations (from changing diapers and cooking soup by touch to showering in the dark) during periods of sudden blackout .

And if you can survive temporary discomfort, then a burned-out refrigerator, for example, is painful to survive from the financial side.

An uninterruptible power supply, or, is designed to ensure that in the event of a power supply problem, the equipment does not immediately turn off. Bespereboynik, as it is popularly called, is effective in such cases:

• de-energized network;
• power surges, frequency or high frequency noise.

If the lights went out in the house, then such a device will allow you to finish important things without destroying your plans.

The device consists of several complex elements. These are not just batteries in the circuit, namely:

• lead-acid with a constant voltage of 24/36 volts;
• the UPS circuit for the computer allows you to convert direct current from the network into alternating current;
• microdevice - controls the battery charge not by 100% in order to extend the life of the uninterruptible power supply;
• system for charging such a unit, we have already learned);
• some models are equipped with voltage and frequency stabilizers.

Therefore, when choosing a UPS for a computer or a separate electrical appliance, pay attention to whether a stabilizer is included in the assembly.

This will affect the cost, but will prevent larger spending. For example, power surges can disable household appliances without a chance of repair. And then not only the last unsaved documents will die on the PC, but, possibly, the entire library of files accumulated over the years.

Purpose and principle of operation

The principle of operation is elementary simple: voltage passes through the uninterruptible power supply, thanks to a special device, the batteries are charged to the maximum that is available after being limited by the device itself.

When any problems are observed in the network, the source equalizes the voltage flow due to the built-in stabilizers, increasing or decreasing it. Also, in the absence of voltage in the circuit, the device instantly turns on and replaces the direct power source. For the user, this gap is not noticeable.

Various models are also provided for selection: from small and low-power units to machines that can provide energy for all electrical appliances during an emergency.

Before, you need to study the features different types of this equipment and make a correct calculation of its estimated power.

Such a unit will protect any electrical equipment from power surges in the network. You can read about tips on choosing a stabilizer for a refrigerator.

Common UPS Applications:

• boilers for heating residential premises;
• household appliances, television and audio systems;
• computer systems, as well as communications and communications;
• industrial-type equipment, bank electronic-digital devices and systems;
• other.

How to choose an uninterruptible power supply for a computer?

There are some parameters that must be considered when choosing an uninterruptible power supply. Otherwise, the device will either work incorrectly or completely break down.

So, let's define the main points that you need to know for right choice UPS for computer:

In conclusion, it is worth saying that the UPS is a necessary electrical appliance that will find its application with every computer.

Also, its availability is guaranteed not only by a diverse range of models, but also by a fairly low cost on a grand scale for any master's wallet.

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 effective options technical solutions to the problem of power quality - uninterruptible power supplies (UPS, eng. 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. The main elements of an offline UPS: batteries (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 the offline UPS, the interactive source has an autotransformer that allows you to maintain the output voltage level within 220V (+ -10%) during mains voltage drops / increases (Fig. 2). As a rule, the number of voltage levels of an autotransformer ranges from two to three.
   
   
   (A)
   
   
   (b)
   
   
   (V)
   
   
   (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. With a deep drawdown or a significant increase, or complete disappearance of the mains voltage, this class of UPS functions similarly to the offline class: it disconnects from the network and generates an output voltage using battery power. Regarding the shape of the output signal, it can be both sinus and rectangular (or trapezoidal).
   The advantages of line-interactive in comparison with a standby UPS: less time for switching to battery backup, stabilization of the output voltage level. Disadvantages: lower efficiency in mains operation, higher 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. A separate DC/DC converter can be installed in the DC link. 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.

Operating modes of uninterruptible power supplies with double voltage conversion

On-Line UPS has two main operating modes:

A) Online mode(or Online mode).
The UPS operates in this mode when the mains input is within the allowable range (input range - see UPS technical data). In this mode, the load is powered according to the scheme "Input network -> Rectifier -> Inverter -> Load". At the same time, the Charger is working, the batteries (batteries) are being charged.

B) Battery (autonomous) mode(or Onbattery / Battery Mode).
The UPS goes offline if the input mains voltage is outside the allowed range (input range - see UPS technical data). The load is powered according to the "battery -> Inverter -> Load" scheme. The charger does not work, the batteries are exhausted.

The transitions between modes A) and B) are carried out without interruption of the output voltage (switching time is zero). There are no transitional processes.

Comment: in data sheets, the input range is usually referred to as "UPS input range without battery transfer" or "acceptable input voltage range (without battery transfer)".

It is recommended to initially turn on the UPS when the mains is normal, i.e. The UPS starts to work in the network mode. It is also allowed to start without a network (“cold” start or start from batteries), but at the same time you need to be sure that the battery is normal. It is recommended not to overload the UPS as most loads are unstable. The recommended maximum UPS load is 75%. It is also necessary to ensure that the starting load currents (if any) do not exceed the rated output power of the UPS.

Attention! Operation of the UPS without a battery is prohibited, except when the battery pack is being replaced.

In addition to the two main operating modes, the UPS has two service modes bypass (bypass):

They may also be referred to as emergency mode or maintenance mode.

May also be called "sleep" or "standby" mode.

The UPS enters this mode if the input mains voltage is lost and the UPS has worked for the set time in battery mode, the batteries have discharged to the set minimum threshold (battery power is exhausted) and the load has been de-energized. Now the device is operating in the network standby mode - all power units in it are turned off, only the control board, the central processing unit (CPU), the screen are working, the CPU is waiting for the input voltage to appear.

There are two options:

• If mains appears within a few hours (or several days depending on battery type) while the UPS is in mains standby mode, the UPS will fully start up and enter normal mains operating mode (A).
• If the mains does not appear for a long time (the time threshold depends on the type of battery), then the UPS will turn off completely.

Attention: also see Appendix 1 to this article “Discharge logic, auto-shutdown after discharge, switching on when the input network is restored”.

Comment: some UPSs with the “full autostart” function activated do not have a standby (input) network, that is, after the input network fails and the battery runs out of time, the UPS is completely turned off.

On-Line UPS have emergency mode:

G) Emergency operation.
The UPS goes into it when any internal sensor sends an alarm to the CPU, such as over temperature, or high inverter output voltage. In this case, the corresponding power emergency unit is turned off, sound and / or light alarm is given. If necessary, the load is switched to the bypass supply.

Also, the emergency mode or alarm may be activated briefly during the start / self-test process, this is normal.

Attention: in many UPS models, the emergency sound and light signaling is given as follows: the red LED (Fault) is on, a constant sound signal is emitted.

Attention: if the fault event is not significant, such as a slight overload (or overtemperature), then when the source of the problem is eliminated, such as a decrease in load (or room temperature), the UPS will automatically return to operating mode. But, in case of a serious accident (for example, there was a large overload, while the UPS itself was not damaged), the unit may block and to return it to operating mode, it is necessary to perform a complete restart of the device with its shutdown.

On-Line UPS have the following start modes:

H) Start mode
This is a transient (momentary) mode that the UPS or UPS is in during the transition from off to fully on.

Possible start options:

1. "Cold" start. The UPS is off. There is no input network. Manually start the inverter. The UPS enters normal battery mode.
2. Network start. The UPS is off. The UPS input is energized (mains OK). The UPS enters battery charging mode with the inverter disabled (Mode E).
3. Inverter start. The UPS is in battery charge mode with inverter off (mode E). The network is normal. Manually start the inverter. The UPS enters normal Online mode (A).
4. Autostart on network recovery. The UPS is in standby mode for the input mains (F). The network has arrived. The UPS enters normal Online mode (A).
5. Full auto start from the network. The UPS is off. The UPS input is energized (mains OK). The UPS goes into normal Online mode (A) if the full autostart function is available.
6. Program start.
7. And others

Attention! In start mode, when mains is present, most UPSs will temporarily activate the bypass (the load is powered through the electronic bypass). This is the default behavior of most UPS models. However, if the electronic bypass blocking function is activated while the inverter is off (see below), even in the start mode, the bypass will not turn on!

Attention! If the input network is normal, then after the UPS exits the start mode, two options are possible:

1. The UPS goes into battery charging mode with the inverter disabled (E), with most UPSs operating in electronic bypass mode (this is how most UPSs behave by default). But if the electronic bypass blocking function is activated when the inverter is off (see below), then the bypass will not turn on, the load is de-energized! In any case, now for a full start of the UPS, it is required to start the inverter with the buttons. This is how most UPSs behave by default.
2. If the UPS has full auto-start on mains function enabled (see below), after exiting the start mode, the UPS will automatically start the inverter and the UPS will automatically fully start and enter the mains operating mode (A).

Comment: usually in this mode, the UPS performs a self-test (see mode I).

Comment: some UPSs perform a battery test in this mode (see mode J).

On-Line UPS have a self-test mode:

I) Self-test mode.
In this mode, the CPU checks all the internal units of the UPS, when a fault is detected, the corresponding alarm is given. In most UPSs, the mode is activated during the UPS startup process. Often UPS and battery testing is combined.

On-Line UPS have battery test mode:

J Battery test mode.
In this mode, the rectifier is turned off, that is, the UPS is forcibly switched to battery mode, the load is powered by batteries, the CPU makes a conclusion about the health of the battery from the battery discharge curve, and if necessary, an alarm indication is given about faulty or replacement batteries.

Comment: in many UPSs, when the test is completed successfully, no messages are displayed, if the result is negative, appropriate signals are given, for example, an audible signal, an orange “weak battery” LED or a similar message on the screen, a crossed-out battery symbol lights up, etc.

Comment: the mode can be activated forcibly with the buttons manually, with the help of software, according to a special internal program of the CPU.

Comment: Some UPSs may include periodic battery testing.

Comment: in some UPSs, the test mode is activated during the start of the UPS or its inverter, and if the test fails, for example, the batteries are depleted or not connected, then the UPS will not start.

Addendum I

1. Logic of work

1.1 The logic of the discharge, auto-off after the discharge, switching on when the input network is restored

Network OK

• 1000 VA / 700 W UPS (with battery 9-12 Ah) is turned on manually.

• Load connected. The UPS is running at 50% load (350W) in online mode. The UPS has an estimated runtime of 30 minutes.
• Batteries are being charged. Float charge voltage for one 12V battery (float charge voltage) ~ 13.6 ... 13.8V (less often, for some models 13.8 ... 14.2 V).
• The network was lost, the UPS went into battery mode.
• The UPS normally powers the load in battery mode for 30 minutes.
• After 30 minutes, the UPS output turns off (batteries are discharged, the load is de-energized). This occurs when the voltage across each 12 volt battery reaches 10 volts. This is the end-of-discharge rating of most sealed lead-acid AGM batteries. But the UPS itself continues to work, the logic board, the CPU, the screen work. This mode can be called network standby mode (F).
• At the moment of load disconnection, the battery voltage increases to 11-12 V per battery, since the discharge power has sharply decreased from ~ 360 W to about 10 W (1-3 kVA UPS logic boards consume 5-15 W), so the UPS has the ability to continue for a long time work.
• In this standby mode (F), the UPS can be from several hours to several days, depending on the number and capacity of the battery.

• • If the input mains appears when the UPS is in mains standby mode, the UPS will automatically fully return to normal mains mode.

Comment: The UPS may not activate the inverter immediately, but after a while, when the batteries are sufficiently charged. This corresponds to the program embedded in the CPU - the UPS should not turn on completely until the battery is charged and until at least a minimum autonomy time is guaranteed. This algorithm protects the UPS from cases of short-term appearance and disappearance of mains voltage, etc.

• • If there is no input network, then the UPS will be in this standby mode (from several hours to several days, depending on the number and capacity of the battery) until the voltage on each 12-volt battery drops to 10 V (in some UPS up to 7-9V per battery). Upon reaching this threshold, the UPS will turn off completely.

• The UPS is in the off state.

• Now, if the network appears, the UPS will turn on completely on its own (even with a heavily discharged / faulty / missing batteries) only if the autostart function is available (this is an option, see below). Most UPSs do not have this feature by default, in which case the UPS can only be fully started manually. In this case, most UPSs will start normally even with heavily discharged / faulty batteries. However, there are models of devices with a battery test at start, which will not start if the batteries are faulty / discharged below normal / absent. Usually the batteries can be severely discharged if the mains fails, the UPS runs out of autonomy, then shuts down and is left disconnected (no mains input!) for a few weeks/months.

Comment: the figures above are approximate //other values ​​are possible

1.2 Logic of work depending on the frequency of the input network. Input, output frequency

Similar to the acceptable input voltage range, the UPS also has an acceptable input frequency range:

• The UPS operates in Online mode (A) when the input mains frequency is within the allowable range (see UPS technical data).
• The UPS goes into battery mode (B) if the input mains is outside the allowed frequency range (see specifications UPS).

In battery mode, in the absence of the input network, the voltage frequency at the output of the UPS is highly stable (quartz stabilization) due to the lack of synchronization with the network. The typical frequency maintenance accuracy for different types of UPS is from 50 Hz +/-0.05% to 50 Hz +/-0.5%.

In mains mode (A), the UPS output voltage is synchronized with the input mains voltage, that is, if the input mains frequency is within the allowable range, then the output frequency is equal to the input frequency. Synchronization (equality of phases and frequencies) is necessary for a safe transition between inverter and bypass modes.

Example 1: Input frequency range for 2kVA: 50Hz ±4Hz. Input network frequency 52 Hz. The output of the UPS is 52 Hz. The UPS is in online mode (A).

Example 2: input frequency range for 2 kVA: 50 Hz ±4 Hz. Input network frequency 55 Hz. At the output of the UPS we have 50 ± 0.25 Hz. The UPS is in battery mode (B).

Comment: Sometimes frequency problems (when synchronizing the UPS with the mains) occur when the UPS is powered by various diesel generators. Make sure that the generator power is selected correctly and its frequency and voltage are normal. Contact the service center.

Note: In some UPSs, the acceptable input frequency range can be changed upon request.

2 Additional features

2.1 Function 1: blocking the electronic bypass when the inverter is off

Function 1: disable bypassline when UPS is started with input power

While the inverter is not running, the electronic bypass is disabled. The bypass is also turned off during start-up and testing.

Initially, the UPS is completely disabled. We connect the UPS to the network. The inverter is always off! The load continues to be de-energized until we start the inverter (or it starts automatically).

There is a dangerously high voltage of 247 volts in the input network, which is too high a value. If the bypass turns on when the UPS is turned on (in start mode, test mode, in battery charge mode with the inverter turned off), then this can damage the load, so a bypass lockout mode is needed to protect it.

Attention!

Attention! Even if this blocking function is enabled, the bypass will still turn on in case of overload, alarm, etc. If this is unacceptable, then the bypass line can be disconnected completely from the network, but the user must understand that he drastically reduces the safety of the system.

Comment: in some UPSs, this function can be activated independently (for example: Pro-Vision Black M) .

Comment: In some UPSs, this function can be activated upon request.

2.2 Function 2: full automatic power on (auto start) when mains is present

Function 2: complete autostart of UPS when mains is ok

Initially, the UPS is completely disabled. We connect the UPS to the network. The UPS starts up automatically by itself. There is no need to press any buttons to fully start the UPS.

Example when this function is needed:
The UPSs are located at remote GSM base stations, so it is not possible to turn on the UPS manually after they are completely turned off (after a long absence of the network), so an autostart is needed.

Attention! Most UPSs have this feature disabled by default.

Comment: in some UPSs the function can be activated upon request, for example in 1-3 kVA LT.

Comment: some UPSs have this feature enabled by default (Smart-Vision S, Older Power-Vision).

2.3 Electronic bypass range setting function

The electronic bypass line can only be activated (e.g. in the event of an overload) if the input mains voltage is within a certain range (see UPS specifications). For example: 220 V ±10%.

Attention: do not confuse this range of the bypass line with the UPS input range without a battery transfer (see above).

Attention: the bypass input voltage range is usually small. This is due to the fact that during the bypass transition<->Inverter load must be reconnected from 220V voltage (inverter) to 220V bypass line ±10%.

If the bypass input voltage range were wider, the following problems could occur:

• Switching a load from a 220 V line to a 150 V line causes a dangerous surge of current.
• Supplying the load with a voltage of 140 V, for example, is impractical or even dangerous.

Attention: on some UPSs this range can be changed. However, it is better not to do this unless necessary! To avoid damage to the UPS.

On-Line UPS in line-interactive mode

Comment: By default, N-Power UPSs are produced in the Russian and European standard of phase voltage 220 V, 230 V (for three-phase models, respectively, line voltage 380 V, 400 V).

Attention! Do not change the output voltage settings unless absolutely necessary.

2.7 UPS rated/output frequency setting function

The frequency standards are the following values: 50 Hz, 60 Hz.

The ability to change the rated/output frequency is different for all UPSs. Please contact our service center for advice. In most cases, the change is only possible at the factory by prior order or at the N-Power service center.

Comment: N-Power UPSs are by default produced in the Russian and European voltage frequency standard of 50 Hz.

On-Line UPS in stabilizer / frequency converter mode

With the bypass (reserve) line or synchronization unit disabled, many UPSs can operate as converters (for example, 60 Hz -> 50 Hz) or frequency stabilizers. For all questions related to this mode, please contact the N-Power service center.

Appendix II

Customer question for 1000 LT:
It is clear that according to your requirements, the UPS cannot be operated without battery. But, I would like to understand whether the inverter will turn on in the absence of AB when connected to the network? The same case if the batteries fail, which will lead to the discharge of the battery below the permissible level. Whether a full start from the network without AB works or not, you will have to check it yourself.

Answer:

Yes, for all small UPSs, the factory (development engineers) prohibits long-term operation of the UPS without batteries, i.e. as a voltage stabilizer. It is allowed to operate the UPS without a battery for up to several hours while replacing the batteries. Therefore, if you try to operate the UPS for a long time without a battery, you will void the warranty. Turning on the inverter, including with bad / missing batteries, is described in this article above.

Cases of defective or heavily discharged (even missing) batteries may be similar / indistinguishable, so the answer to your question “Does full autostart work from the network with faulty / heavily discharged / missing batteries in the MEV1000LT”: I confirm that, YES (when ordering a UPS with the function full autostart). The exception is severe battery malfunctions, as a result of which the charger will not be able to start and enter the “float charge” mode, for example, a battery crack and electrolyte leakage, a short circuit to the case, in this case the UPS will go into emergency mode.

Comment: the function "full autostart when mains is present" is disabled in this UPS model in all current shipments. On request, UPSs are supplied with this feature enabled.

Double Conversion UPS Operating Mode List

OnLine UPS Modes:

• A - network mode (or Online mode)
• B - battery (autonomous) mode (or Onbattery mode)
• C - electronic bypass mode
• D - manual bypass mode
• E - battery charge mode with inverter off
• F - standby (input) network
• G - emergency mode
• H - start mode
• I - self-test mode
• J - battery test mode

Appendix I:

1 Operation logic

1.1 The logic of the discharge, auto-off after the discharge, switching on when the input network is restored

1.2 The logic of operation depending on the frequency of the input. networks. Input, output frequency.

2 Additional features:

2.1 Function 1: electronic bypass lockout when the inverter is off

2.2 Function 2: full auto-on (auto-start) when network is present

2.3 Electronic bypass range setting function

2.4 Possibility (function) of operation of On-Line UPS in line-interactive mode

2.5 Mode (function) GreenMode

2.6 UPS rated/output voltage setting function

2.7 UPS rated/output frequency setting function

2.8 Possibility (function) of On-Line UPS operation in stabilizer / frequency converter mode

in case of an accident, maintenance, and other necessary.
The transition to manual bypass is made acc. UPS instructions (usually, the inverter must be turned off first and the UPS is transferred to the electronic bypass) otherwise, you can. accident.