Developers of electrical and electronic devices, in the process of creating them, proceed from the fact that the future device will operate under conditions of a stable supply voltage. This is necessary so that the electrical circuit of the electronic device, firstly, provides stable output parameters in accordance with its intended purpose, and secondly, the stability of the supply voltage protects the device from surges that are fraught with too high current consumption and burnout of the electrical elements of the device. To solve the problem of ensuring the constant supply voltage, some version of a voltage stabilizer is used. Based on the nature of the current consumed by the device, alternating and direct voltage stabilizers are distinguished.
AC voltage stabilizers
AC voltage stabilizers are used if voltage deviations in the electrical network from the nominal value exceed 10%. This standard was chosen based on the fact that AC consumers with such deviations retain their functionality throughout their entire service life. In modern electronic technology, as a rule, to solve the problem of a stable power supply, a switching power supply is used, in which an alternating voltage stabilizer is not needed. But in refrigerators, microwave ovens, air conditioners, pumps, etc. external stabilization of the AC supply voltage is required. In such cases, one of three types of stabilizer is most often used: electromechanical, the main link of which is an adjustable autotransformer with a controlled electric drive, relay-transformer, based on a powerful transformer having several taps in the primary winding, and a switch made of electromagnetic relays, triacs, thyristors or powerful key transistors, as well as purely electronic ones. Ferroresonant stabilizers, widespread in the last century, are now practically not used due to the presence of numerous shortcomings.
To connect consumers to a 50 Hz AC network, a 220 V voltage stabilizer is used. The electrical circuit of a voltage stabilizer of this type is shown in the following figure.
Transformer A1 increases the voltage in the network to a level sufficient to stabilize the output voltage at low input voltage. The regulating element RE changes the output voltage. At the output, the control element UE measures the voltage value across the load and issues a control signal to adjust it, if necessary.
Electromechanical stabilizers
This stabilizer is based on the use of a household adjustable autotransformer or laboratory LATR. The use of an autotransformer provides higher efficiency of the installation. The autotransformer adjustment handle is removed, and instead of it, a small motor with a gearbox is installed coaxially on the body, providing a rotation force sufficient to turn the slider in the autotransformer. The necessary and sufficient rotation speed is about 1 revolution in 10 - 20 seconds. These requirements are met by the RD-09 type engine, which was previously used in recorders. The engine is controlled by an electronic circuit. When the mains voltage changes within +- 10 volts, a command is issued to the motor, which turns the slider until the output voltage reaches 220 V.
Examples of electromechanical stabilizer circuits are given below: 
Electrical circuit of a voltage stabilizer using logic chips and relay control of an electric drive
Electromechanical stabilizer based on an operational amplifier.
The advantage of such stabilizers is their ease of implementation and high accuracy of output voltage stabilization. The disadvantages include low reliability due to the presence of mechanical moving elements, relatively low permissible load power (within 250 ... 500 W), and the low prevalence of autotransformers and the necessary electric motors in our time.
Relay transformer stabilizers
The relay-transformer stabilizer is more popular due to the simplicity of the design, the use of common elements and the possibility of obtaining significant output power (up to several kilowatts), significantly exceeding the power of the power transformer used. The choice of its power is influenced by the minimum voltage in a particular AC network. If, for example, it is not less than 180 V, then the transformer will be required to provide a voltage boost of 40 V, which is 5.5 times less than the rated voltage in the network. The output power of the stabilizer will be the same number of times greater than the power of the power transformer (if you do not take into account the efficiency of the transformer and the maximum permissible current through the switching elements). The number of voltage change steps is usually set within 3...6 steps, which in most cases ensures acceptable accuracy of output voltage stabilization. When calculating the number of turns of windings in a transformer for each stage, the voltage in the network is taken to be equal to the operating level of the switching element. As a rule, electromagnetic relays are used as switching elements - the circuit turns out to be quite elementary and does not cause difficulties when repeated. The disadvantage of such a stabilizer is the formation of an arc at the relay contacts during the switching process, which destroys the relay contacts. In more complex versions of the circuits, the relay is switched at the moments when the voltage half-wave passes through the zero value, which prevents the occurrence of a spark, albeit provided that high-speed relays are used or switching occurs at the decline of the previous half-wave. The use of thyristors, triacs or other non-contact elements as switching elements increases the reliability of the circuit sharply, but becomes more complicated due to the need to provide galvanic isolation between the control electrode circuits and the control module. For this purpose, optocoupler elements or isolating pulse transformers are used. Below is a schematic diagram of a relay transformer stabilizer:
Scheme of a digital relay-transformer stabilizer based on electromagnetic relays
Electronic stabilizers
Electronic stabilizers, as a rule, have low power (up to 100 W) and high stability of the output voltage, necessary for the operation of many electronic devices. They are usually built in the form of a simplified low-frequency amplifier, which has a fairly large margin for changing the level of supply voltage and power. A sinusoidal signal with a frequency of 50 Hz from an auxiliary generator is supplied to its input from the electronic voltage regulator. You can use the step-down winding of a power transformer. The amplifier output is connected to a step-up transformer up to 220 V. The circuit has inertial negative feedback on the output voltage value, which guarantees the stability of the output voltage with an undistorted shape. To achieve power levels of several hundred watts, other methods are used. Typically, a powerful DC-AC converter is used based on the use of a new type of semiconductor - the so-called IGBT transistor.
These switching elements in switching mode can pass a current of several hundred amperes at a maximum permissible voltage of more than 1000 V. To control such transistors, special types of microcontrollers with vector control are used. Pulses with a variable width are applied to the gate of a transistor with a frequency of several kilohertz, which changes according to a program entered into the microcontroller. At the output, such a converter is loaded onto the corresponding transformer. The current in the transformer circuit varies according to a sinusoid. At the same time, the voltage retains the shape of the original rectangular pulses with different widths. This circuit is used in powerful guaranteed power supplies used for uninterrupted operation of computers. The electrical circuit of a voltage stabilizer of this type is very complex and practically inaccessible for independent reproduction.
Simplified electronic voltage stabilizers
Such devices are used when the voltage of the household network (especially in rural areas) is often reduced, almost never providing the nominal 220 V.
In such a situation, the refrigerator works intermittently and is at risk of failure, the lighting turns out to be dim, and the water in the electric kettle cannot boil for a long time. The power of an old, Soviet-era voltage stabilizer designed to power a TV is, as a rule, insufficient for all other household electrical consumers, and the voltage in the network often drops below the level acceptable for such a stabilizer.
There is a simple method for increasing the voltage in the network by using a transformer with a power significantly lower than the power of the applied load. The primary winding of the transformer is connected directly to the network, and the load is connected in series to the secondary (step-down) winding of the transformer. With correct phasing, the voltage at the load will be equal to the sum of the voltage taken from the transformer and the mains voltage.
The electrical circuit of a voltage stabilizer operating on this simple principle is shown in the figure below. When the transistor VT2 (field effect) located in the diagonal of the diode bridge VD2 is closed, winding I (which is the primary) of transformer T1 is not connected to the network. The voltage at the switched-on load is almost equal to the mains voltage minus a small voltage at winding II (secondary) of transformer T1. When the field-effect transistor opens, the primary winding of the transformer will be short-circuited, and the sum of the mains voltage and the secondary winding voltage will be applied to the load.
Electronic voltage stabilizer circuit
The voltage from the load, through transformer T2 and diode bridge VD1, is supplied to transistor VT1. The adjuster of the trimming potentiometer R1 must be set to a position that ensures the opening of the transistor VT1 and the closing of VT2 when the load voltage exceeds the nominal (220 V). If the voltage is less than 220 volts, transistor VT1 will close and VT2 will open. The negative feedback obtained in this way keeps the voltage across the load approximately equal to the nominal value.
The rectified voltage from the VD1 bridge is also used to power the VT1 collector circuit (through the DA1 integrated stabilizer circuit). Chain C5R6 dampens unwanted drain-source voltage surges on transistor VT2. Capacitor C1 reduces interference entering the network during operation of the stabilizer. The values of resistors R3 and R5 are selected to obtain the best and most stable voltage stabilization. Switch SA1 provides switching on and off of the stabilizer and load. Closing switch SA2 turns off the automatic system that stabilizes the voltage at the load. In this case, it turns out to be the maximum possible at the current network voltage.
After connecting the assembled stabilizer to the network, trimming resistor R1 sets the load voltage to 220 V. It should be taken into account that the stabilizer described above cannot eliminate changes in the mains voltage that exceed 220 V, or that are below the minimum used in calculating the transformer windings.
Note: In some modes of operation of the stabilizer, the power dissipated by transistor VT2 turns out to be very significant. It is this, and not the power of the transformer, that can limit the permissible load power. Therefore, care should be taken to ensure good heat dissipation from this transistor.
A stabilizer installed in a damp room must be placed in a grounded metal case.
See also diagrams.
The stabilizer is a network autotransformer, the winding taps of which switch automatically depending on the voltage in the electrical network.
The stabilizer allows you to maintain the output voltage at 220V when the input voltage changes from 180 to 270 V. Stabilization accuracy is 10V.
The circuit diagram can be divided into low current circuit (or control circuit) and high current circuit (or autotransformer circuit).
The control circuit is shown in Figure 1. The role of the voltage meter is assigned to a polycomparator microcircuit with a linear voltage indication - A1 (LM3914).
The mains voltage is supplied to the primary winding of the low-power transformer T1. This transformer has two secondary windings, 12V each, with one common terminal (or one 24V winding with a center tap).
The diode rectifier VD1 is used to obtain the supply voltage. The voltage from capacitor C1 is supplied to the power circuit of microcircuit A1 and the LEDs of optocouplers H1.1-H9.1. And also, it serves to obtain exemplary stable voltages of the minimum and maximum scale marks. To obtain them, a parametric stabilizer is used on the US and P1. The limiting measurement values are set by trimming resistors R2 and R3 (resistor R2 is the upper value, resistor RZ is the lower value).
The measured voltage is taken from another secondary winding of transformer T1. It is rectified by diode VD2 and supplied to resistor R5. It is by the level of direct voltage on resistor R5 that the degree of deviation of the mains voltage from the nominal value is assessed. During the setup process, resistor R5 is preliminarily set to the middle position, and resistor RЗ to the bottom according to the circuit.
Then, an increased voltage (about 270V) is supplied to the primary winding T1 from an autotransformer of the LATR type, and resistor R2 sets the scale of the microcircuit to the value at which the LED connected to pin 11 lights up (temporarily, instead of optocoupler LEDs, you can connect ordinary LEDs). Then the input alternating voltage is reduced to 190V and resistor RЗ is used to set the scale to the value when the LED connected to pin 18 A1 is lit.
If the above settings cannot be made, you need to adjust R5 a little and repeat them again. Thus, through successive approximations, a result is achieved when a change in the input voltage by 10V corresponds to switching the outputs of microcircuit A1.
There are nine threshold values in total - 270V, 260V, 250V, 240V, 230V, 220V, 210V, 200V, 190V.
The schematic diagram of the autotransformer is shown in Figure 2. It is based on a converted LATR type transformer. The transformer body is disassembled and the slide contact, which is used to switch taps, is removed. Then, based on the results of preliminary measurements of voltages from the taps, conclusions are drawn (from 180 to 260V in steps of 10V), which are subsequently switched using triac switches VS1-VS9, controlled by the control system via optocouplers H1-H9. The optocouplers are connected in such a way that when the reading of microcircuit A1 decreases by one division (by 10V), it switches to the increasing (by the next 10V) tap of the autotransformer. And vice versa - an increase in the readings of microcircuit A1 leads to a switch to the step-down tap of the autotransformer. By selecting the resistance of resistor R4 (Fig. 1), the current through the LEDs of the optocouplers is set, at which the triac switches switch reliably. The circuit on transistors VT1 and VT2 (Fig. 1) serves to delay the switching on of the autotransformer load for the time required to complete the transient processes in the circuit after switching on. This circuit delays connecting the optocoupler LEDs to power.
Instead of the LM3914 microcircuit, you cannot use similar LM3915 or LM3916 microcircuits, due to the fact that they operate according to a logarithmic law, but here you need a linear one, like the LM3914. Transformer T1 is a small-sized Chinese transformer of the TLG type, for a primary voltage of 220V and two secondary voltages of 12V (12-0-12V) and a current of 300mA. You can use another similar transformer.
Transformer T2 can be made from LATR, as described above, or you can wind it yourself.
Ferroresonance stabilizer, take a transformer whose primary winding can withstand several times the input without any negative consequences. Connect a paper capacitor in series, the capacitance of which is selected experimentally so that the resonant frequency of the circuit formed by this capacitor and the primary winding is equal to the frequency of the supply network. The capacitor must also withstand a voltage several times higher than the input voltage. This is due to the fact that during resonance it increases significantly. Calculate the secondary winding in such a way that precisely at this increased voltage on the primary, the voltage on the secondary is equal to the required one. Use such a stabilizer only in AC networks and only if the frequency is stable. Together with a generator equipped with an internal combustion engine, such a stabilizer will work very poorly.
To make a parametric constant voltage stabilizer, take a stabilizing element - a gas or semiconductor zener diode. Turn on the latter in reverse polarity, since in direct polarity it opens like a regular diode. Connect a resistor in series, the resistance of which is calculated using the formula: R=(Uin-Ust)/(Ist+In), where UIn is the input voltage, Ust is the stabilization voltage, I is the stabilization current, which can be taken close to the load current, In - load current.
Take a zener diode designed for a maximum current of no less than the sum of Ist and In. Calculate the resistor power using the formula: P=(Uin-Ust)(Ist+In).
Before calculations, convert all units to the SI system, and the results will be obtained in the same way. Remove the output voltage from the zener diode.
To make a compensation DC voltage regulator, take a 7805, 7806, 7809, 7812 or 7815 chip, depending on what output voltage you need (5, 6, 9, 12 or 15 V, respectively). Install it on a large heat sink. Take two oxide capacitors with a capacity of 1000 μF, designed for a voltage of 25 V. Connect the negative terminals of both capacitors to the second terminal of the microcircuit, the positive terminal of the first capacitor to its terminal 1, the positive terminal of the second to its terminal 3. In parallel, turn on each of the oxide capacitors on ceramic any container. Take a source of unstable voltage that is approximately four volts higher than the required stable voltage. Connect it “plus” to pin 1 of the microcircuit, “minus” to pin 2. Remove the positive pole of the stable voltage from pin 3, and the negative pole from pin 2. The maximum output current for microcircuits 7805 and 7806 is 3 A, for the rest - 1.5 A. For microcircuits with the letters M and, especially, L in the middle of the designation, it is much less.
The ideal option for the operation of electrical networks is to change the values of current and voltage both in the direction of decreasing and increasing by no more than 10% of the nominal 220 V. But since in reality surges are characterized by large changes, electrical appliances directly connected to the network are in danger of losing their design capabilities and even failure.
Using special equipment will help you avoid trouble. But since it has a very high price, many people prefer to assemble a voltage stabilizer made by themselves. How justified is such a step and what will be required to implement it?
Design and principle of operation of the stabilizer
Device design
If you decide to assemble the device yourself, you will have to look inside the body of the industrial model. It consists of several main parts:
- Transformer;
- Capacitors;
- Resistors;
- Cables for connecting elements and connecting devices.
The operating principle of the simplest stabilizer is based on the operation of a rheostat. It increases or decreases resistance depending on the current. More modern models have a wide range of functions and are able to fully protect household appliances from power surges in the network.
Types of devices and their features
Types and their applications
The classification of equipment depends on the methods used to regulate the current. Since this quantity represents the directional movement of particles, it can be influenced in one of the following ways:
- Mechanical;
- Impulse.
The first is based on Ohm's law. Devices whose operation is based on it are called linear. They include two elbows that are connected using a rheostat. The voltage applied to one element passes through the rheostat and thus appears on the other, from which it is supplied to consumers.
Devices of this type allow you to very simply set the output current parameters and can be upgraded with additional components. But it is impossible to use such stabilizers in networks where the difference between the input and output current is large, since they will not be able to protect household appliances from short circuits under heavy loads.
Let's watch the video, the operating principle of the pulse device:
Pulse models operate on the principle of amplitude modulation of current. The stabilizer circuit uses a switch that breaks it at certain intervals. This approach allows current to be evenly accumulated in the capacitor, and after it is fully charged, further to devices.
Unlike linear stabilizers, pulse ones do not have the ability to set a specific value. There are step-up and step-down models on sale - this is an ideal choice for the home.
Voltage stabilizers are also divided into:
- Single-phase;
- Three-phase.
But since most household appliances operate from a single-phase network, in residential premises they usually use equipment belonging to the first type.
Let's start assembling: components, tools
Since a triac device is considered the most effective, in our article we will look at how to independently assemble just such a model. It should be immediately noted that this DIY voltage stabilizer will equalize the current provided that the input voltage is in the range from 130 to 270V.
The permissible power of devices connected to such equipment cannot exceed 6 kW. In this case, the load will be switched in 10 milliseconds.
As for components, to assemble such a stabilizer you will need the following elements:
- Power unit;
- Rectifier for measuring voltage amplitude;
- Comparator;
- Controller;
- Amplifiers;
- LEDs;
- Load turn-on delay unit;
- Autotransformer;
- Optocoupler switches;
- Switch-fuse.
The tools I will need are a soldering iron and tweezers.
Manufacturing stages
To assemble a 220V voltage stabilizer for your home with your own hands, you first need to prepare a printed circuit board measuring 115x90 mm. It is made of foil fiberglass. The layout of the parts can be printed on a laser printer and transferred to the board using an iron.
Let's watch the video, a homemade simple device:
electrical circuit diagram
- magnetic core with a cross-sectional area of 1.87 cm²;
- three PEV-2 cables.
The first wire is used to create one winding, and its diameter is 0.064 mm. The number of turns should be 8669.
The two remaining wires will be needed to make other windings. They differ from the first one in diameter being 0.185 mm. The number of turns for these windings will be 522.
If you want to simplify your task, you can use two ready-made TPK-2-2 12V transformers. They are connected in series.
In the case of making these parts yourself, after one of them is ready, they move on to creating the second. It will require a toroidal magnetic circuit. For the winding, choose the same PEV-2 as in the first case, only the number of turns will be 455.
Also in the second transformer you will have to make 7 taps. Moreover, for the first three, a wire with a diameter of 3 mm is used, and for the rest, buses with a cross-section of 18 mm² are used. This will help prevent the transformer from heating up during operation.
connection of two transformers
It is better to purchase all other components for a device you create yourself in a store. Once everything you need has been purchased, you can begin assembly. It is best to start by installing a microcircuit that acts as a controller on a heat sink, which is made of aluminum platinum with an area of more than 15 cm². Triacs are also mounted on it. Moreover, the heat sink on which they are supposed to be installed must have a cooling surface.
If assembling a 220V triac voltage stabilizer with your own hands seems complicated to you, then you can opt for a simpler linear model. It will have similar properties.
The effectiveness of a handmade product
What pushes a person to make this or that device? Most often - its high cost. And in this sense, a voltage stabilizer assembled with your own hands is, of course, superior to a factory model.
The advantages of homemade devices include the possibility of self-repair. The person who assembled the stabilizer understood both its operating principle and structure and therefore will be able to eliminate the malfunction without outside help.
In addition, all the parts for such a device were previously purchased in the store, so if they fail, you can always find a similar one.
If we compare the reliability of a stabilizer assembled with our own hands and manufactured at an enterprise, then the advantage is on the side of factory models. At home, it is almost impossible to develop a model with high performance, since there is no special measuring equipment.
Conclusion
There are different types of voltage stabilizers, and some of them are quite possible to make with your own hands. But to do this, you will have to understand the nuances of the operation of the equipment, purchase the necessary components and carry out their proper installation. If you are not confident in your abilities, then the best option is to purchase a factory-made device. Such a stabilizer costs more, but the quality is significantly superior to models assembled independently.
The reason for publishing the article about was the comment of one of our respected radio amateurs in a note about powerful voltage stabilizers that provide load currents of up to 3 amperes.
Here we will consider exactly network voltage stabilizers for household use, i.e. which provide at the output a consumer voltage of 220 volts that is standard for many countries (although this is not always the case - AndReas note). So, when there is a deviation of the mains voltage at the input of such a stabilizer, they are designed to bring it to a nominal 220 volts at the output. Thus, stable and uninterrupted power supply to household appliances or office equipment is ensured, which helps to significantly extend the life of household appliances.
I will not load you, dear radio amateurs, with theoretical material, since everything is already clear here. There are a lot of circuits of various network voltage stabilizers. Most of them also already contain filters against RF interference and other bells and whistles. But companies, when purchasing a ready-made network voltage stabilizer from them, always try to “pile up” a “left-handed”, already unnecessary product, for example, surge protectors. And the price of these devices sometimes reaches the point of absurdity.
First, a small remark. If you came to this page just to find a suitable stabilizer for yourself, you can search, for example,. Some models are quite worthy of attention.
Since the commentary was about network voltage stabilizers brand Defender, then I will dwell on them in a little more detail. If you study the range of stabilizers they offer, then the description of almost every device says the same purpose, namely: designed to protect the power supply of household audio and video equipment, computers, peripherals and other electronic equipment from prolonged increases or decreases in network voltage, pulsed interference, as well as for protection against high voltage.
Personally, for a computer and other low-power digital electronics, instead of any network stabilizers, I use an uninterruptible power supply (or an inverter or converter - as you like). This is an extremely useful device in all respects. It also saves from voltage deviation (by the way, some modern models of such inverters already have stabilizers built in), and from its complete drop to zero, and also protects from interference.
And network voltage stabilizers are not necessarily necessary, but are recommended for devices with electric motors and low-frequency transformers. But these same devices really need them outside the city, in the country, i.e. where the voltage on the power line allocated to you is much less than even 180 volts.
Well, okay, lyrics aside, let's continue on the merits. As I learned, Defender AVR network voltage stabilizers use an autotransformer circuit with digital control, while previously a circuit with analog control was used. Example of an analog control circuit:
Unfortunately, we could not find any more information about Defender household stabilizers. In general, such companies are reluctant to reveal, so to speak, trade secrets. Although, there would be something to hide if there are a lot of similar developments in the public domain (edit. AndReas). But we have prepared a few more network voltage converter circuits. I don’t think that all manufacturers of such devices can offer something radically new. All of their so-called developments are based on publicly available circuit solutions. Here is one of them:
The network voltage stabilizer, the diagram of which is presented just above, includes one, two or three additional transformer windings in series with the load when the network voltage deviates. If the mains voltage is lower than required, then the additional windings are switched on in phase with the mains, and the load voltage becomes higher than the mains voltage. If the mains voltage becomes higher than normal, the windings are switched on out of phase with the mains voltage, leading to a decrease in the voltage across the load. The transformer in the diagram is designated T1, and the additional windings are designated IV, V, VI by Roman numerals. Comparators DA3...DA8 are configured to operate depending on the mains voltage levels of 250 V, 240 V, 230 V, 210 V, 200 V and 190 volts, respectively. If the network voltage exceeds the specified levels, then at the outputs (pin 9) of those comparators for which the specified condition is met, a voltage of a high logical level (logical 1) is applied, amounting to about 12 V. Thus, the difference in the response levels of the comparators is 10 V, or approximately 5% of mains voltage. The response levels of comparators DA5 and DA6 differ by 20 volts. This corresponds to a regulation zone of 220 V ± 5%. It should be noted that state standards establish the permissible mains voltage from 187 V to 242 V. This stabilizer, as you can see, provides higher accuracy in maintaining the mains voltage. This can be reflected like this:
Instead of the comparators indicated in the diagram, you can use the K1401CA1 microcircuit. KR142EN8B was used as stabilizers. Diode bridges VD1 and VD2 can be replaced with KTs402...KTs405, KTs409, KTs410, KTs412. VD4…VD7 – any with an allowable reverse voltage of more than 15 V and a forward current of more than 100 mA. Oxide capacitors - K50-16, K50-29 or K50-35; the rest are KM-6, K10-17, K73-17. Relay K1 - K5 - foreign production Bestar BS-902CS. Relays of this type have a winding with a resistance of 150 Ohms, designed for an operating voltage of 12 V, and a switching type contact group, designed for switching a voltage of 240 V at a current of 15 A. Transformer T1 is made on a magnetic core ШЛ50х40. Winding I is wound with PEV-2 0.9 wire and contains 300 turns; winding II -21 turns of wire PEV-2 0.45; winding III - 14 turns of wire PEV-2 0.45; windings IV, V, VI each contain 14 turns of PBD 2.64 wire. It is convenient to use a standard transformer of the OSM1-0.63 type, in which all windings except the primary (it contains 300 turns) are removed, and the secondary windings are wound in accordance with the above data. When manufacturing a transformer, the same terminals of windings I, IV, V, VI should be marked (indicated by dots in the diagram). The rated power of such a transformer is 630 W. To this network voltage stabilizer You can connect a load of up to 3 kilowatts. If the accuracy of maintaining the output voltage is needed lower, then the number of secondary windings of transformer T2 can be reduced to two, and their voltage increased from 10 volts to 15 volts. In this case, the number of comparators will also decrease, and their response thresholds should be set according to the voltages of the secondary windings T2.
The configuration of this network stabilizer is as follows:
The simplest in terms of circuitry are electromechanical network voltage stabilizers. The main components of this type of device are an autotransformer and an electric motor, for example, RD-09 with a built-in gearbox that rotates the autotransformer engine.
Everything is very simple. The mains voltage is controlled by an electronic circuit, which, when it deviates, sends signals to the electric motor to rotate the rotor clockwise or counterclockwise. Rotating, the rotor moves the autotransformer engine, thereby ensuring a stable output voltage. Here are a few circuits of electromechanical network stabilizers:
Another type of network voltage stabilizers are relay ones. They provide higher output power up to several kilowatts. The load power can even exceed the power of the transformer itself. When choosing the transformer power, the minimum possible voltage in the electrical network is taken into account. If, for example, the minimum network voltage is at least 180 volts, then a voltage boost of 40 volts is required from the transformer, i.e. 5.5 times less than the mains voltage. The output power of the entire stabilizer will be the same number of times greater than the power of the power transformer. The number of voltage regulation stages usually does not exceed 3...6, which ensures sufficient accuracy in maintaining the output voltage. Here are some relay type stabilizer circuits.
