How to choose a voltage regulator

Voltage stabilizer - a device absolutely necessary in every home. It is also needed at the production site, but here we will focus on household stabilizers designed to protect household appliances and equipment from power surges and currents. Typically, the voltage in the trunk is 220 or 380 V at a frequency of 50 Hz. But due to various factors - connecting consumers of high power, peak loads in the evening or morning hours, accidents on power lines, the current can deviate from the set parameters by percent voltage by 25 - 40 in both directions.

Too low, as well as too high mains voltage is equally dangerous and undesirable for household appliances. Sudden jumps are doubly dangerous. Refrigerators, televisions, household pumps and boilers, computers can simply stop working. Input circuits, complicated electronics of settings blocks may burn out, other damages may occur, which are quite expensive to repair.

How the voltage regulator works

To determine which voltage stabilizer for the home is better to choose, you need to know the basic principles of their operation, what are the stabilizers and what are the important parameters, and what you can not pay attention to.

At its core, the stabilizer is an adjustable feedback transformer. Alternating current from the line enters the primary winding and excites approximately the same current in the secondary winding, to which consumers are connected. If the number of turns on the primary coil is changed, then the current in the secondary, in which the number of working turns remains the same, will change accordingly. On the change in the ratio of the number of turns and built the work of adjustable transformers.

Inductive coupling is very reliable and does not provide for direct contact of the windings - only through a metal core. Such transformers allow you to almost instantly change the parameters of the output current, you only need to configure the control of the current collector depending on the voltage in the supply network, so that when the current drops in the mains in the secondary winding, it increases, and when the voltage is exceeded, it decreases.

A controlled transformer is the basis of all household stabilizers. Differences in them concern only control schemes.

Types of voltage stabilizers

The market is dominated by two types of stabilizers - electromechanical and electronic.

Electromechanical voltage stabilizers

In electromechanical stabilizers, the current in the coil is regulated by a contact slider, which moves along the surface, changing the number of working turns. Anyone who remembers a school physics course can imagine a rheostat from experiments in the classroom. The electromechanical voltage regulator works in approximately the same way, only the slider is moved not by hand, but by means of an electric motor.

Electromechanical stabilizers are very reliable and allow you to smoothly change the voltage in the secondary coil. But with their simplicity, they also have a number of disadvantages:

• like most mechanical devices have tangible inertia - the delay in operation is noticeable to the naked eye;
• carbon contacts wear out over time and require replacement;
• the noise at work is barely audible, but still there.

Before choosing a voltage regulator of electromechanical type, it is necessary to compare the response speed indicated in the product passport in units of V / s. The better this indicator, the better the stabilizer for sensitive instruments.

Electronic voltage regulators

Electronic stabilizers work somewhat differently. Feedback and switching using thyristor, seven-phase or relay circuitsthat change the number of windings connected to the network. Such stabilizers work absolutely silently, do not heat up and are characterized by a very high response speed. But here, there were some drawbacks - electronic stabilizers regulate the output voltage stepwise. Although the differences are not too large, they can add dissonance to the operation of electronics or engines.

Ferromagnetic Voltage Regulators

Ferromagnetic stabilizers are devices that are practically not manufactured for domestic purposes, although you can still find early models that were very popular decades ago. Their work is based on changing the position of the ferromagnetic core relative to the coils. The system is very reliable, but bulky and noisy. The main disadvantages are operation only under load and possible distortion of sinusoidal characteristics. For modern electronics and household appliances, they are unsuitable, but for powerful electric motors, hand tools and welding machines, their use is quite acceptable.

How to choose a voltage regulator by parameters

There are only a few really important parameters that characterize the performance of the stabilizer and the convenience of its use. It:

• number of phases;
• power;
• range of adjustments;
• response speed;
• availability of overload protection;
• connection method.

What voltage stabilizer to choose for a private house can be solved only by correctly outlining the range of tasks that it will perform, having considered the main characteristics in the complex.

Network or trunk stabilizer

By the method of connection, stabilizers are divided into trunk and network. The first ones are installed at the entrance of the power supply network to the house and regulate the voltage supplied to all consumers without exception - lighting, heating, alarm, household appliances. As a rule, a modern house is an energy-saturated system with a high level of current consumption. Therefore, the power of the main stabilizers starts from 3 kW.

Network regulators are designed to protect one, less often two devices of the same type. They are connected to a conventional outlet and are an intermediate link between the trunk and the consumer. The power of network stabilizers is relatively small, but there can be several in the house.

These are relatively inexpensive devices that protect complex and expensive equipment if there is no main stabilizer, or the load on it is very large. Network stabilizers are installed both in residential buildings and in offices, hospitals, contact points, where a lot of high-precision electronic equipment that is sensitive to voltage surges works.

Number of Stabilizer Phases

One of the main determining parameters when deciding which voltage regulator is best to choose for a home. A single-phase network requires a stabilizer with a recommended connection of 220 V. There are three ways to solve the problem of stabilizing a three-phase current: buy three single-phase stabilizers, to adjust each phase, install the stabilizer only on one phase, to which the most sensitive consumers are connected, and install a powerful three-phase device controlling tension throughout the house.

You should know that most household stabilizers of small and medium power are three synchronized single-phase in a common housing. For high power, usually three transformers are used, assembled on one core. They are more reliable and easier to adjust.

Power

To understand how to choose a voltage stabilizer for a private house, you need to know exactly how much electricity is consumed in the house theoretically and practically. The first digit is determined very simply - the capacities of all consumers, from the light bulb to the borehole pump and the welding machine in the garage, are added up arithmetically. This figure shows how much power is needed with all the devices turned on at the same time.

But this indicator is not the upper limit - many tools and devices of household appliances are equipped with electric motors that consume much more current when starting up than when working even at maximum load. This so-called reactive power leads to the fact that the total consumption significantly increases.

The next step is to multiply the power of each device with an electric motor, taken in kVA (indicated in the passport) by 2 and add to the existing figure. Then increase the result by another 25%, in case of unforeseen circumstances. After such difficult calculations at first glance, you will get the real power of the stabilizer, which must be installed in the house.

Power consumption (Wt.) Of popular industrial and construction equipment:

Power consumption (W) of household electrical appliances:

The average power of a three-phase stabilizer of a one-story house with a garage and a full range of household appliances barely exceeds 10 kW. It is not so much and not too expensive. For a two-three-room apartment, 5 kW is enough, and for a two-story mansion, a stabilizer of 15 - 25 kW is needed.

But when choosing a stabilizer in terms of power, it is also necessary to pay attention to the range of current voltage adjustments. It should be in the range of 150 - 250 V. Only in this part of the line of possible deviations does the power of the stabilizer correspond to the maximum stated in the passport. If the manufacturer has indicated a wider range, for example 140 - 280 V - even better, your house will be protected more reliably. But at the same time, the cost of the device increases slightly.

But the price is not the main factor. Buying a stabilizer with a minimum adjustment range, for example 280 - 240 V, is not recommended, except as a network, if the house has a common trunk. Such devices are not too expensive, but they can only equalize voltage within narrow limits.

For special cases, when the deviations in the supply network can be more than 120 V (down), complex and expensive stabilizers are used that can operate in this range. Usually they are combined installations with electromechanical and electronic regulation, working in parallel. But such a technique is rarely required, so the average buyer is practically not interested in it.

By power in the lineup of each manufacturer there are single-phase stabilizers up to 10 kVA and three-phase 5 - 30 kVA. Anyone, not necessarily a professional electrician, can choose them, focusing on the above calculation methodology. It is not worth buying stabilizers with a power of 35 - 100 kVA for a house or a summer residence. They are designed for installation in office and shopping centers, workshops and other facilities with high current consumption.In addition, they are massive and expensive, and paying for excess power that will never be used is not practical.

Output accuracy

No stabilizer gives exactly 220 V. There is always a variation in performance. State standards allow deviations of up to 10% in both directions. As a rule, even very sensitive equipment, including inverters, computers, and communication devices, with such distortion of parameters, work quite reliably. Domestic consumers were initially designed for such deviations and in operation also did not create problems.

According to the accuracy of the output voltage, the electromechanical stabilizers really give out 220 ± 3% V, and electronic ones - 220 ± 1% V, but then their reaction time is an order of magnitude, or even two, lower. If the electronic regulator is able to change the output voltage for hundredths of a second, then the electromechanical will spend on it from 0.5 to 1-2 seconds.

Stabilizer protection systems

Like transformers, protection systems on all types of stabilizers are required. Their schematic diagram and tasks are approximately the same, they are triggered when the supply current exceeds the permissible loads and disconnect the consumer from the network. When the supply current returns to normal, the flow is restored automatically.

The stabilizer also has its own effective protection system - it is a rather complex device with a mass of electronics that is sensitive to voltage and current overloads. With a short circuit in the network, a sharp surge in current can occur, which can literally burn circuits.

The auto-protection system will disconnect the primary winding and the adjustment system from the supply current until its normal parameters are restored. The inclusion of the stabilizer in the work is also usually done in automatic mode, but there are models with manual inclusion after an emergency stop.

Additional functions and options

Considering the issue of choosing a voltage stabilizer for an apartment or a house, one should not lose sight of a number of additional functions that simplify operation, make it safer and expand the functionality of the installation. Often, from two stabilizers of the same phase, power and adjustment range, it is worth choosing one that has more functions, even if it costs a little more.

Voltmeter and ammeter

Household stabilizers are equipped with measuring devices - voltmeters required, ammeters - as an option. The devices show the output voltage after stabilization and the current strength in each phase. If you need to find out the voltage in the supply network, then some stabilizers provide such an opportunity - just press a special button and the voltmeter switches to measure the input network parameters. Most household stabilizers are equipped with analog (pointer) voltmeters and ammeters of sufficiently high accuracy.

But recently, many stabilizer manufacturers have switched to digital devices - this significantly improves the design and, of course, allows you to increase the cost of installation. Although it doesn’t have a big influence on the measurement accuracy, when controlling the operation of a household stabilizer, tenths and hundredths of units of measurement do not play a special role.

Many stabilizers are equipped with an LED alarm, which can inform about the normal operation of the device, exit from the mode, critical overloads and other conditions of both the network and the device itself. Each of the manufacturers uses the number of LEDs and their color, which seems to him the most convenient. Before starting the operation of the stabilizer, it is necessary to familiarize yourself with the value of each bulb and the mode of its operation - glow, blinking, and frequency of flashes.

The stabilizers work in automatic mode and the possibility of manual adjustment is not provided. But control devices perform a rather important function - you can always determine the range of voltage and current deviations for each phase and turn off the consumer, which cannot work in these conditions.You can also visually control the total current power in the home network, using the data of control devices and the formula P =UI.

The ability to switch the delay of the appearance of voltage at the output

Another convenient option is the output voltage delay button. This is necessary so that after stabilizing all the stabilizer circuits start operating mode and supply the current with the required characteristics to the network. Usually for this, the stabilizer household level takes 5 - 7 seconds. But with a high level of power consumption in the home network, this time may not be enough, the button allows you to extend it to several minutes and eliminate possible false starts.

Bypass Mode

It is very convenient if the bypass function is provided in it, that is, conditions for the direct passage of current, bypassing all adjustment circuits and transformer equipment. This is very convenient when the supply voltage is much lower than the allowable range of operation or you need to connect a device that exceeds the critical level of the stabilizer in power. In this case, the switch allows the electric current to go directly to the consumer, and the stabilizer is in standby mode.

Forced cooling fan

Up to approximately 10 kVA, stabilizers are cooled by convection flows circulating freely through the ventilation openings of the housing. Higher power plants are equipped with forced fans.

Features of installation and connection

As a rule, connecting stabilizers is not difficult, especially network and single-phase mains. Network controllers plug into a regular home power outlet. The same sockets (one, two or more, depending on power) are displayed on their case, to which any device of a household level can be connected.

Trunk stabilizers are connected using a terminal block with 5 pins. Two - for the wires of the mains, two - to enter the home network and one for grounding (required). When installing the stabilizer near the entry point of the cable line into the house, you can connect it yourself. But you should turn off the main circuit breaker (switch). Under voltage, it is extremely dangerous and unacceptable to connect according to all safety regulations.

Put a stabilizer of any power after the meter. The three-phase stabilizer is equipped with a nine-terminal block. It must be connected by a professional electrician, using special tools. Installed stabilizers on the wall or on the floor, depending on the power and version.

As a rule, their operation is permitted only at positive temperatures and normal humidity. At T ≥ +40 ⁰C thermal protection of the device may work, therefore, the stabilizer should be installed away from heating appliances in places that are closed from direct sunlight.