Uninterruptible power supply unit faults and repairs. Do-it-yourself uninterruptible power supply circuit. Working uninterruptible power supply
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Sources have long taken the place of a necessary component in modern computer systems and sets of other devices used both in enterprises and at home. Many consumers are familiar with the operating features and types of UPS. For them, a common one for a computer or, for example, specialized uninterruptible power supplies for boilers are not something new and unfamiliar. Especially on the territory of our country, where power grids, to say the least, are not characterized by the stability of the indicators given to end consumers. And the supply of electricity, it’s no secret to anyone, can be unexpectedly stopped, albeit for a short time, but at any moment.
Such a useful and necessary UPS
Before moving on to considering the possibilities of repairing a UPS with your own hands, which is what will be discussed below, we should once again note the importance of these devices. Uninterruptible power supplies are a kind of barrier between devices that consume electricity and the troubles that instability of the electrical power supplied to the equipment can bring. Developers are constantly improving their products and making them more versatile.
Thus, the UPS device allows you to organize, in most cases, fairly reliable protection not only for valuable user information in the case of a PC in the event of an unexpected shutdown of the lights, but also for the hardware components of other devices that are sensitive to voltage surges or its disappearance. But even a device designed to protect other devices from damage can sometimes fail itself. Let's look at the main components that make up an uninterruptible power supply, as well as relatively easy-to-fix UPS faults.
UPS device
At their core, sources are quite complex electronic devices consisting of many components. If you look at the diagram of a UPS, almost any one, you will find that the device consists of the following components:
- converters;
- switches;
- electrical energy storage devices (in most cases, a battery).
Why do breakdowns occur?
It is known that the more complex a system is, the greater the likelihood that it will fail due to the failure of one or more individual components. In general, the complexity of a UPS device is due to a fairly wide list of functions that the device must perform. This includes not only the ability to supply energy to electrical devices at the moment of voltage loss in the network, but also stabilizing and protective functions. There are devices that have even broader requirements. For example, uninterruptible power supplies for boilers must, in addition to the above, have the correct sine wave at their output. This complexity of the system makes it possible for some malfunctions to occur, although this does not happen often. What to do in this case? How to repair a UPS yourself?
Precautionary measures
Before proceeding with manipulations with the device, it should be borne in mind that the UPS is a complex electronic device and precautions must be taken when carrying out repair work. All operations with an uninterruptible power supply can be carried out only after making sure that the device is de-energized. No tips and secrets of UPS repair heard from friends or found on the Internet will save you from electric shock in case of rash actions and careless handling of live components!
Where to begin?
Of course, a UPS, like any other electronic device, requires the implementation of some basic rules during its operation. Very often, the cause of a malfunction that seems to the user is incorrectly connected wires, weakening or oxidation over time of their connection terminals, etc. Before thinking about carrying out serious repairs to the device, you must carefully inspect the connection of the wires, check their functionality, the absence of fractures and breaks in the cables, supplying the UPS, finally make sure that there is power in the outlet.
Performance Support
In most cases, the device in question serves its owner for many years and without any problems. At the same time, to achieve this state of affairs, regular maintenance of the UPS is required, which consists of replacing the battery (approximately every two years) and general monitoring of the health of electronic components. If in order to control the properties of capacitors, resistors and other electronic elements you need quite deep knowledge in electronics and circuit design or a trip to a service center, then almost anyone can replace a UPS battery that has failed or lost its properties over time. Almost every device owner has to carry out such UPS repairs with his own hands at least once during the life cycle of the uninterruptible power supply.
Fuse
If the uninterruptible power supply does not turn on after a voltage drop or as a result of a short circuit in the supply network, it is likely that even disassembling it will not be necessary to restore the device’s functionality. The first thing you need to do when repairing a UPS yourself is to check the integrity of the fuse and replace it if necessary. Since this component fails quite often, UPS manufacturers design their devices in such a way that the user can carry out the procedure independently. Spare fuses themselves are often included in the delivery package of the uninterruptible power supply. If they are not there, a protective element similar to the one removed from the device can be purchased at any store that sells radio components. To replace the fuse, you need to find a special tray containing it on the case and remove/unscrew - depending on the design - the contents. After replacement, install the tray in its place. The procedure is described in more detail in the instructions for the UPS, but in general, any home handyman can figure it out without it.
Battery Replacement
To replace the battery you will need very little time and the only tool is a Phillips screwdriver. Initially, you need to unscrew several screws that fasten the parts of the case and are located at the bottom of the UPS, in special holes. This will allow you to remove the top cover and access the battery. In most cases, the battery is not secured in any special way inside the case and can be removed quite easily. You just need to disconnect the two wires that are connected to the battery using terminals. After removing the energy storage source from the UPS case, you need to determine its marking and purchase a similar battery from a specialized store. The UPS is assembled in the reverse order:
- Battery installation.
- Connecting wires, observing polarity.
- Installation and connection of parts of the device body.
Complex repair
If the above tips have been followed, that is, the UPS is connected correctly, the fuse in the device is intact and the battery is working, but the uninterruptible power supply still does not work properly, probably the most correct solution would be to contact a service center to repair the device. The fact is that the UPS circuit is quite complex for the average user; diagnosing and replacing, if necessary, individual electronic components without special tools and the skills of a craftsman at home is often simply not feasible. Thus, trying to repair a non-working device without certain knowledge and skills, as well as without the availability of appropriate equipment, a home repairman can only aggravate the situation.
In general, if you decide to repair a faulty UPS yourself, you must first weigh your strengths and capabilities. The average user is most often required to carry out simple manipulations, which would be more correctly classified as servicing the device rather than repairing it. It is better to entrust the elimination of complex breakdowns to professionals.
All electronic equipment requires power supply, and most often we use an industrial current network of 220V, 50 Hz.
But sometimes “force majeure” situations may arise when the electricity is suddenly “cut out”. If a sudden power outage is not very scary for household equipment, then for, for example, computers it can lead to irreversible consequences: uninstalled programs, loss of information, and so on.
If in large cities the power supply is more or less stable, but in rural areas this is a fairly common occurrence...
To avoid annoying misunderstandings associated with a sudden power outage, many manufacturers recommend using uninterruptible power supplies(or whatever they are simply called UPS). They are, of course, produced by industry, but such a source can be collected on one's own.
In addition to providing protection in the event of a power outage, uninterruptable power source may also be useful in “field” conditions when the need arises get 220 volts from a 12 volt battery.
We have already reviewed a similar scheme on our website, which allows us to get 220 Volts from 12, here she is, here is another diagram taken from the magazine Radio Amateur, No. 2, 1999.
Homemade uninterruptible power supply circuit
Uninterruptable power source provides:
In direct mode, conversion of DC voltage 12 V to AC voltage 220 V/50 Hz with a maximum current consumption of no more than 6 A. Output power - up to 220 W (1 A):
Reverse mode (battery charging mode). At the same time, the charge current is up to 6 A; .
Quick switching from forward to reverse mode.
The UPS diagram is shown in the figure. A clock generator is made on elements VT3, VT4, R3...R6, C5, C6, generating pulses with a frequency of about 50 Hz. He, in turn, controls the operation of transistors VT1, VT6, the collector circuits of which include windings IIa, IIb of transformer T1. Diodes VD2, VD3 are protection elements for transistors VT1, VT6 in forward mode and rectifiers in reverse mode. Elements C1, C2, L1 form a network filter, VD1, SZ, C4 - a clock generator filter. Let's look at how the circuit works in both modes.
Direct mode (=12 V / -220 V). A voltage of +12 V is alternately applied to windings IIa or IIb, and transformer T1 converts it to a voltage of 220 V/50 Hz. This voltage is present at the XS1 socket, and all kinds of consumers are connected to it (incandescent lamps, TV, etc.)
The indicator of normal operation is the lighting of LEDs VD4, VD5. The load current can reach 1 A (220 W).
Reverse mode (-220 V / = 12 V). To work in reverse mode, you need to connect the power supply to connector XP1 and apply -220 V to it. After this, toggle switch SB1 is switched. In this case, the mains voltage enters the primary winding of transformer T1, and the clock generator is turned off. Thanks to this, two 10V alternating voltages are obtained on the secondary windings of T1, which are rectified by diodes VD2, VD3. An indicator of normal operation in reverse mode is the lighting of the VD5 LED. Boiling in the GB1 battery jars indicates the charging process.
Details and design, T1 is any transformer that provides two voltages of 10V at a current of up to 10 A. It is best to use cores of the ShL and PL types, which are easier to disassemble. Coil L1 is made on a K28x16x9 M2000NM ferrite ring and contains two windings of 10 turns of wire with a diameter of 0.5...0.71 mm.
Transistors VT1, VT6 and diodes VD2, VD3 are attached through mica spacers, lubricated with heat-conducting paste, onto one common radiator with an area of at least 200 cm2.
Quite a long time ago they took the place of a necessary component in modern computer systems and sets of other devices used both in enterprises and at home. Many consumers are familiar with the operating features and types of UPS. For them, a regular uninterruptible power supply for a computer or, for example, specialized uninterruptible power supplies for boilers are not something new and unfamiliar. Especially on the territory of our country, where power grids, to say the least, are not characterized by the stability of the indicators given to end consumers. And the supply of electricity, it’s no secret to anyone, can be unexpectedly stopped, albeit for a short time, but at any moment.
Such a useful and necessary UPS
Before moving on to considering the possibilities of repairing a UPS with your own hands, which is what will be discussed below, we should once again note the importance of these devices. Uninterruptible power supplies are a kind of barrier between devices that consume electricity and the troubles that instability of the electrical power supplied to the equipment can bring. Developers are constantly improving their products and making them more versatile.
Thus, the UPS device allows you to organize, in most cases, fairly reliable protection not only for valuable user information in the case of a PC in the event of an unexpected shutdown of the lights, but also for the hardware components of other devices that are sensitive to voltage surges or its disappearance. But even a device designed to protect other devices from damage can sometimes fail itself. Let's look at the main components that make up an uninterruptible power supply, as well as relatively easy-to-fix UPS faults.
UPS device
At their core, uninterruptible power supplies are quite complex electronic devices consisting of many components. If you look at the diagram of a UPS, almost any one, you will find that the device consists of the following components:
- converters;
- switches;
- electrical energy storage devices (in most cases, a battery).
Why do breakdowns occur?
It is known that the more complex a system is, the greater the likelihood that it will fail due to the failure of one or more individual components. In general, the complexity of a UPS device is due to a fairly wide list of functions that the device must perform. This includes not only the ability to supply energy to electrical devices at the moment of voltage loss in the network, but also stabilizing and protective functions. There are devices that have even broader requirements. For example, uninterruptible power supplies for boilers must, in addition to the above, have the correct sine wave at their output. This complexity of the system makes it possible for some malfunctions to occur, although this does not happen often. What to do in this case? How to repair a UPS yourself?
Precautionary measures
Before proceeding with manipulations with the device, it should be borne in mind that the UPS is a complex electronic device and precautions must be taken when carrying out repair work. All operations with an uninterruptible power supply can be carried out only after making sure that the device is de-energized. No tips and secrets of UPS repair heard from friends or found on the Internet will save you from electric shock in case of rash actions and careless handling of live components!
Where to begin?
Of course, a UPS, like any other electronic device, requires the implementation of some basic rules during its operation. Very often, the cause of a malfunction that seems to the user is incorrectly connected wires, weakening or oxidation over time of their connection terminals, etc. Before thinking about carrying out serious repairs to the device, you must carefully inspect the connection of the wires, check their functionality, the absence of fractures and breaks in the cables, supplying the UPS, finally make sure that there is power in the outlet.
Performance Support
In most cases, the device in question serves its owner for many years and without any problems. At the same time, to achieve this state of affairs, regular maintenance of the UPS is required, which consists of replacing the battery (approximately every two years) and general monitoring of the health of electronic components. If in order to control the properties of capacitors, resistors and other electronic elements you need quite deep knowledge in electronics and circuit design or a trip to a service center, then almost anyone can replace a UPS battery that has failed or lost its properties over time. Almost every device owner has to carry out such UPS repairs with his own hands at least once during the life cycle of the uninterruptible power supply.
Fuse
If the uninterruptible power supply does not turn on after a voltage drop or as a result of a short circuit in the supply network, it is likely that even disassembling it will not be necessary to restore the device’s functionality. The first thing you need to do when repairing a UPS yourself is to check the integrity of the fuse and replace it if necessary. Since this component fails quite often, UPS manufacturers design their devices in such a way that the user can carry out the procedure independently. Spare fuses themselves are often included in the delivery package of the uninterruptible power supply. If they are not there, a protective element similar to the one removed from the device can be purchased at any store that sells radio components. To replace the fuse, you need to find a special tray containing it on the case and remove/unscrew - depending on the design - the contents. After replacement, install the tray in its place. The procedure is described in more detail in the instructions for the UPS, but in general, any home handyman can figure it out without it.
Battery Replacement
To replace the battery you will need very little time and the only tool is a Phillips screwdriver. Initially, you need to unscrew several screws that fasten the parts of the case and are located at the bottom of the UPS, in special holes. This will allow you to remove the top cover and access the battery. In most cases, the battery is not secured in any special way inside the case and can be removed quite easily. You just need to disconnect the two wires that are connected to the battery using terminals. After removing the energy storage source from the UPS case, you need to determine its marking and purchase a similar battery from a specialized store. The UPS is assembled in the reverse order:
- Battery installation.
- Connecting wires, observing polarity.
- Installation and connection of parts of the device body.
Complex repair
If the above tips have been followed, that is, the UPS is connected correctly, the fuse in the device is intact and the battery is working, but the uninterruptible power supply still does not work properly, probably the most correct solution would be to contact a service center to repair the device. The fact is that the UPS circuit is quite complex for the average user; diagnosing and replacing, if necessary, individual electronic components without special tools and the skills of a craftsman at home is often simply not feasible. Thus, trying to repair a non-working device without certain knowledge and skills, as well as without the availability of appropriate equipment, a home repairman can only aggravate the situation.
In general, if you decide to repair a faulty UPS yourself, you must first weigh your strengths and capabilities. The average user is most often required to carry out simple manipulations, which would be more correctly classified as servicing the device rather than repairing it. It is better to entrust the elimination of complex breakdowns to professionals.
UPSs are used to protect various types of electrical equipment, primarily computer equipment, from power surges, and can also support their operation for several minutes, hours or even days during a complete power outage
An uninterruptible power supply can cope with the following electrical problems: complete shutdown of the power supply network, high-voltage impulse noise, long-term and short-term voltage surges; high-frequency noise or interference occurring in the electrical network, frequency deviation of more than 3 Hz.
Important parameters of the UPS are the time it takes to switch the load to power from the batteries and the battery life.
Uninterruptible power supply is the basis of the construction circuit |
Backup UPS design in operating mode, the load is powered from the electrical network, which the uninterruptible power supply filters for high-voltage pulses and electromagnetic interference with passive filters.
If the mains voltage deviates beyond the normalized values, the load is automatically connected to battery power using an inverter circuit, which is included in each UPS. As soon as the network voltage returns to normal, the uninterruptible power supply will switch the load to power supply from the network.
Interactive UPS diagram similar to the backup circuit, but additionally a step voltage stabilizer based on an autotransformer is installed at the input, which allows you to regulate the output voltage. During normal operation, UPSs operating according to an interactive circuit do not regulate the frequency, but in the absence of voltage, it begins to be powered by an inverter with a battery. The advantage of this scheme is a shorter switching time. In addition, the inverter is synchronized with the input voltage.
Double conversion UPS circuit works as follows: The input AC voltage is converted to DC, then back to AC using an inverter. In the absence of input voltage, switching the load to battery power occurs instantly, since the batteries are constantly connected to the circuit.
Main blocks and components that may be included in the UPS:
Switching device
Network filter
Charger
Accumulator battery
Inverter: AC-DC Converter, DC Voltage Stabilizer, DC-AC Converter
Bypass switching device
Current sensor
Source filter
temperature sensor
Interface
Display device
Input mains voltage 220V, 50Hz is supplied through a switching device and a surge filter to the charger. A surge protector is necessary to prevent interference from entering the mains supply; the charger charges the battery provided that mains voltage is available.
The inverter is included in any UPS. It is built on the basis of a semiconductor converter of direct voltage from the battery into alternating voltage supplied to the load. Often an inverter combines the functions of both the inverter itself and the charger. Depending on the type of UPS, the inverter produces voltage of different shapes
Bypass is a switching device. This device is used to directly connect the input and output of the UPS, eliminating the power redundancy circuit.
The bypass performs the following functions:
turning on or off the UPS
transferring the load from the inverter to bypass in case of overloads and short circuits at the output
transferring the load from the inverter to bypass in order to reduce electricity losses
The static bypass is assembled on the basis of a thyristor switch from back-to-back thyristors connected in parallel. The key is controlled by the UPS control system
The switching power supply was taken ready-made for 28 V, 50A, but you can assemble it yourself and there are a great many circuits. Two 12-volt car batteries connected in series are connected to the switching power supply. The inverter was also used ready-made, since the price of its components is almost twice as high as the finished device. This UPS is enough for almost a day of energy consumption in a small private house. In case of a long outage, and in our Siberian expanses this often happens, I turn on the diesel generator for 6 hours.
UPS diagram |
Our UPS is designed for the following capabilities: direct conversion from direct 12 volt voltage to alternating voltage 220 V with a frequency of 50 Hz. The maximum power of this UPS circuit is 220 W. The reverse conversion is used to charge the battery. Charge current 6 A. The circuit provides fast switching from direct conversion to reverse mode.
A clock generator is made on the radio components VT3, VT4, R3...R6, C5, C6, generating pulses with a repetition frequency of 50 Hz. The generator sets the operating mode of bipolar transistors VT1, VT6. Windings IIa, IIb of the transformer are connected to their collector circuit. The network filter is assembled on passive components C1, C2, L1, and the clock generator filter is based on radio elements VD1, SZ, C4.