Connecting electricity to the house is a primary task when electrifying a section of SNT or located in a particular area.

, as a rule, is necessary when using electrical equipment that requires a three-phase connection, which includes electric boilers, water heaters, as well as various types of installations with an electric drive, the power supply of which requires a three-phase connection.

Three-phase electricity input 15 kW into the house is carried out similarly to a single-phase electricity connection to the house, with the exception of technical feasibility. That is, if you need connect 380 volt 3 phase to the garden plot , then the electrical network laid across the territory of a garden partnership or other type of cooperative must meet the technical requirements, or, more simply, street power lines must be three-phase.

Input of 380 Volts into the house Technically, it is not much different from a single-phase input, with the exception of the electrical equipment used installed in the input distribution device installed on a pipe stand or in the distribution board in the house, as well as the cable entry from the pole to the pipe stand.

allows you to distribute the load on the electrical network in a balanced manner, in contrast to single-phase input, and also allows you to connect modern heating equipment that requires a three-phase power supply network.

It is also worth noting that many people believe that a three-phase network will allow them to consume more power, that is, turn on more devices. This is not entirely true. The maximum permitted power is indicated in the technical specifications for the connection. As a rule, for a three-phase network this is per household, and for a single-phase network - 10 or the same 15 kW. Obviously, the power gain is small, or may be non-existent.

However, we should not forget that with the same power for a three-phase network, you can use an input cable of a significantly smaller cross-section. The reason is literally on the surface: the power, and therefore the current, is distributed across three phases, loading the individual phase wire to a lesser extent. The rating of the input circuit breaker in a three-phase network, accordingly, will also be lower.

Ours is ready to carry out three-phase type, as well as install an input distribution device and

Nowadays, we cannot do without a high-quality and well-thought-out power supply system. If, when purchasing an apartment, this problem is solved not by the owner of the property, but by a construction company, then there is a choice for supplying electricity to a private home. The apartment has already been supplied with single-phase power, and this voltage is quite sufficient there. However, in the private sector, a three-phase network may be quite relevant. In this article we will tell you which electrical network is better: three-phase or single-phase, as well as how to supply 380 Volts to a private house according to the law and what documents are needed for this.

Advantages and disadvantages of a three-phase power supply system

It is no secret that three-phase power supply to a private home is becoming more and more relevant, and this is connected not only with the voltage level. Let's look at all the advantages of 380 Volts and here is a list of them:

1. Connecting the most common ones in everyday life and in production with a squirrel-cage rotor. When connected to a single-phase circuit, their power, torque, and efficiency are lost. After all, they were originally designed for three phases. The use of such electric machines in a private home may be necessary when installing a grinding, drilling or woodworking machine and other types of equipment. An owner who has the skills to operate such equipment will always find a use for it. A powerful pump is always useful at the dacha, so running 380 Volts won’t hurt here either.
2. By connecting three phases, the owner of a private house receives, by and large, three independent single-phase networks at once, which he can dispose of at his own discretion. To do this, in order to obtain a single-phase voltage of 220 Volts, you need to connect one wire to the phase and the other to zero. It will be called phase. The voltage between two phases is 380 Volts and is called linear. You can read more about phase and line voltage in the article:.
3. In the event of a breakdown or emergency at a distribution substation, one or even two phases may burn out. At the same time, the owner of a private house with three phases will at least have lighting and a refrigerator working. It must be remembered that for three-phase motors, operation on two phases will entail its inevitable failure.

Keep in mind that there are pitfalls here too. A three-phase network is needed if the power of a single-phase network is not enough. And even if single-phase is not enough, there is no need to rush to connect three phases, it is better to clarify the possibility of a single-phase network - this procedure is much simpler than matching and connecting three phases.

Three phases must be connected if it is necessary to power three-phase ones that cannot operate in single-phase mode, or if a large number of electrical appliances and equipment are used simultaneously, for example, if the house has a large household or some small-scale production has been established.

Several other disadvantages of the three-phase power supply system should also be noted. One of the disadvantages is the need for each of the phases. The second drawback is the great difficulty in connecting, purchasing another shield, protective devices, etc. The third drawback is a great danger from the point of view of electric shock, since the house will have not only a single-phase voltage of 220 V, but also a linear voltage of 380 V

As you can see, the advantages of powering the consumer from a 380 Volt network are not always obvious. Now it’s worth figuring out what documents are needed to connect a three-phase network. This is what we will talk about now.

How to connect three phases

Of course, before moving on to the technical side of the issue and directly to the connection, you need to contact the company that is the electricity supplier in this particular region. To do this, the customer must clearly understand and agree on the following points:

• Network power.
• Meter type and tariff. This can be a multi-tariff meter or a single-tariff one.
• Number of phases (in this case 3).
• Connection diagram.
• An organization that is extremely necessary to protect people from electric current in the event of breakdown or deterioration of insulation resistance.

Important! Self-connection to power grids is prohibited by law! The procedure for connecting and organizing power supply must be performed by highly qualified personnel. In order to connect a private house to a three-phase network, it must be completely de-energized, and doing this without an energy service is also prohibited.

Suppliers adhere to clear requirements and rules. Therefore, if the distance from a private house to 380 Volt networks, most often passing through poles, is more than 300 meters within the city (500 outside the city), then in order to install electricity you will have to pay also.

It is also important to note that it is often necessary to provide information about the condition of the home's electrical wiring before connection. If the house has old electrical wiring, then there is a high probability that representatives of the electrical networks will not only not give permission to connect three phases, but will also reduce the limit on a single-phase network to the minimum for safety reasons, since the wiring cannot withstand a heavy load.

The next key issue in connecting a home to a 380 Volt network will be the power that the consumer will take from the network.

There are three degrees:

• first - no more than 16 kW;
• the second - from 16 to 50 kW.
• the third - from 50 to 160 kW.

Of course, it is better to organize power supply with a power reserve, especially since the increase in the number of devices that operate on this type of energy is still obvious. However, the cost of this system will be higher.

It is also important to note about the power limit - most often up to 15 kW is allocated for the average consumer. And in this case, everything depends on the state of the electrical networks, the power of the transformer in the transformer substation or transformer substation. If the power is small, then the supplying organization distributes approximately the power to houses and above this power it is impossible to connect, especially three phases. In this case, to connect three phases of the required power limit, a separate transformer is needed - this is a more complicated procedure, since you need to purchase a package transformer substation and connect it to a high-voltage network of 6 (10) kV. Therefore, the average consumer has to be content with a certain power limit of a single-phase network.

The list of documents required to connect 380 Volts (in addition to the application itself) includes:

1. Identification.
2. Law-abiding taxpayer identification number.
3. Title documentation for residential or non-residential premises (in case of connecting a garage).
4. Approved complete residential plan (if available).

A copy is made of these documents and submitted to the company's electricity supplier. However, verification with the originals is also required.

Some suppliers may also request additional documents, just in case, you should also take them with you:

• Information about power and a list of all available electrical equipment in a private home, garage or country house. Depending on where three-phase electricity needs to be routed. If the connection is made to an area that does not have electrical equipment, then you will have to indicate its estimated types and power.
• Information about their maximum power.
• Approximate time of commissioning of housing, if it is not yet a residential property.

Installing multi-tariff meters is very profitable, since if you do not use powerful devices during peak hours, you can save significantly. For example, at night the cost of electricity is several times cheaper than during the day.

Procedure for registering a multi-tariff meter:

1. Preparation of an application requesting the installation of an electric meter.
2. Obtaining technical specifications for this meter, which must be purchased if the electricity supply company does not have this equipment. Often they themselves provide services not only for connection, but also for the sale of metering devices.
3. Acquisition, as well.
4. Calling a representative of the energy supply company to check that the meter is connected correctly, as well as its sealing.
5. Making changes to the agreement or drawing up a new one, when organizing a new connection of three phases.
6. Obtaining permission to connect 380 Volts.

By the way, there is also such an option as converting single-phase voltage to three-phase. You can find out more by following the link.

The rated characteristics of circuit breakers must fully correspond to the load connected to them. There is no indicated power on the machines; only the voltage and current for which it is designed are indicated on the case. We talked about this in a separate article.

As for the technical part, namely connecting three-phase voltage to a private house, it is better to entrust this matter to specialists, because In the absence of experience and skills, it will be almost impossible to carry out the three phases on your own.

Humanity makes full use of modern technical inventions that are fundamentally new. Life sometimes forces you to study sophisticated layouts and be amazed at the tricks of home-grown techies. And even if we're not fans, sometimes we just want to be in on things. In fact, to understand the issue, you just need to go from elementary to complex, from beginning to end. And it’s better to start by clarifying unclear things.

What is a three-phase network?

Phase means a change in direction between the magnitudes of the electrical network at the same point in time. In the case of 3 f. current, use three voltages oriented in 3 different directions. Thus, the network voltage is calculated by adding vector quantities, and is not equal to the algebraic sum of all voltages.

Let's look at the example of the same engine. When applying 380 V to the coil, different phase pairs are used in a specific sequence for each winding. That’s why they characterize the 380 circuit by adding (220 + 220 + 220 = 660)V. This explanation is very simplified and not entirely complete, but hopefully well presented. Yes, and it is written so that it is clear to us, electric “teapots”.

In technical terms, in a three-phase electrical network, circuits of conductors carry three variable values ​​of physical quantities that reach instantaneous peaks at different times. Taking one conductor as a reference, the other two flows are delayed in time by one third and two thirds of one current cycle. This delay between phases has the effect of transferring power during each cycle and also allows the production of a rotating magnetic field.

Winding connection methods

Engines in everyday life and in amateur practice drive a variety of mechanisms - a circular saw, an electric plane, a fan, a drilling machine, and pumping equipment. Without knowing how electric motors work, it is better not to get into the weeds with frequency drives. Engines are:

• permanent
• and alternating current (asynchronous and synchronous).

The mechanism includes a rotor and a stator. The principle of electromagnetic induction, studied in school, underlies the principle of their operation. Most of the electric motors produced are “asynchronous”. Where did this word come from? The rotation frequency of the moving part (rotor) always lags behind the rotation frequency of the magnetic field of the stationary part (stator). The output frequency scale varies - 1000, 1500, 3000... rpm. And all because the rotor is able to rotate on the shaft at different speeds inside the core.

Depending on the number of poles, the units are one-, two-, or three-pole. In the stator core of the latter there is a winding for each phase, the ends of which are brought out to the terminal box. How can you increase the speed of an asynchronous motor (IM) without losing power? By changing the number of pole pairs.

To move on to other methods, and there are two more of them, we cannot do without the symbols “star” and “triangle”. The three windings of the coil can be connected in two ways: at a point or in a circle, hence the names of the connections “star” and “triangle”.

What happens if a three-phase motor connected by a triangle is connected to a 380 V power supply? In this case, the starting current values ​​can increase seven times, which will lead to network overload. When dealing with engines, you need to be extremely careful. When buying a product, be sure to think about whether the nameplates show a triangle/star icon (and not vice versa star/triangle) at the same voltage of 220/380 V.

How to connect a three-phase motor to a 220 V network

The use of a three-pole AD in a single-phase electrical network is of interest to many owners of private houses. The units are increasingly in demand in households. They are quite simple in design and easy to use. However, in terms of connecting the motor to a single-phase network, not everything is so simple.

The pulsating field of a single-phase current is not capable of causing the rotor of an electric motor to rotate - such a current must be converted into multiphase and then only supplied to the unit.

You should not pay attention to rationalization proposals using LATRs and other home-made structures. We are not involved in the field of transcendental nanotechnology and science fiction; we cannot count on fees for the support of “Nobel laureates.” Today, there are two sensible ways to convert single-phase current into multiphase - this is connecting the unit through:

1. phase shifting capacitor;
2. a frequency converter.

Let's look at them one by one.

1. Phase shift using capacitors

In three-phase circuits, creating a rotating magnetic field is not a problem; during energy generation, an EMF is induced in the stator windings due to the rotation of the magnetized rotor. Some manage to resort to simple “tricks”. Various schemes are used, for the compilers of which the main question is to ensure the operation of electrical equipment without loss of power. For example, there is a method of shifting the phases in the windings relative to each other.

It is enough to connect a capacitor in parallel with one of the windings, first selecting the device rating in such a way as to ensure the necessary phase shift. This option is not bad if you follow the old rule: the fewer and simpler the parts, the more reliable the system as a whole. The capacitor, of course, is a relatively cheap thing, it can be installed in a minute, but it requires special skills. But the second method with a converter, although a little expensive, pays off in convenience. Agree, this is a very important factor.

1. Frequency generators operating from a single-phase network

The frequency in our network is constant and equal to 50 Hz. The frequency converter is used to convert single-phase alternating current of 50 Hz into three-phase, with a frequency from 1 to 800 Hz. The entire process technology comes down to controlling the rotation speed of an asynchronous electric motor. Connecting the inverter means choosing the correct cable cross-section, wire types, and additional equipment. Do not think that by opening the page in the instructions, the essence will immediately become clear to you. You may not even achieve the result by connecting the wires according to the diagram if you do not pay attention to some nuances. For what exactly?

Do-it-yourself converter from one to three phases.

Since the three-pole motor needs to be powered through a state of emergency from a single-phase network, two cables are needed: to the frequency switch a two-wire one (up to 50 m you can use only an unshielded cable, a shielded one - up to 15 m), from - only a three-wire one. One of the wires is grounding, the rest are phase. The cross section is selected according to the technical data sheet for the frequency generator. The required voltage in the wires is obtained from the current and resistance (according to the cross-section) of the cable using the familiar formula: U = R*I. Calculation data should be taken according to the PUE.

It is recommended to buy a frequency generator with a double margin, at least 2 kV. Its nominal value is designed only for the power of the machine, which means that at best it will turn off due to heat, at worst it will smoke. All of them are assembled according to the same circuit, using two thyristors controlled by a multivibrator. The scheme is simple. It is better to choose a simple and more powerful one. Buy where there is a choice and always with a guarantee.

Frequency converter 220-380, whose company is better?

Let's answer the question to the point. There are countless Asian manufacturers on the sales market of such equipment. Let's stop listing. The domestic emergency assembler is a kind of lottery (sometimes it depends on what day of the week the device is assembled).

Frequency drivers from Siemens usually fully meet the requirements. Products produced by ABB or Danfoss are quite easy to set up. It is better than others in terms of price and quality. Buy without hesitation. Judging by the reviews, they have a very decent device. Dynamic performance is enhanced by vector control, which also provides high torque at low frequencies during starting and running.

Universal compact CP models do an excellent job of converting network parameters; their obvious advantages are expressed in the following:

• the ability to generate “full” three-phase current;
• no loss in engine power;
• Suitable for any electric motor design;
• The constructivity is very simple.
• own energy consumption is minimal.

Where frequency converters are used single-phase input-output 1 ph. 220 V

Asynchronous motors (AM) are more often used in everyday life than in industry, in particular in the system of single-pole duct fans and water pumps. It is no secret that difficulties arise associated with adjusting the rotation speed of blood pressure. This is the task of single-pole input-output frequency converters 220-220.

Uneven torque may cause abnormal noise and vibration in the unit. To regulate the speed of three-phase electric motors, single-pole 220/380 V frequency changers (input/output) are used, sometimes with a special controller used to control the device.

These types of converters are intended for use in technological (pumps and fans, transport mechanisms, extruders, mixers, etc.) and energy-saving equipment (pump control stations, climate and air conditioning systems, etc.). Models are available with the possibility of mounting on a DIN rail. They have a wide outlet. The smart control panel provides a comfortable working environment.

In order to avoid complications that are often encountered during the operation of 3-pole electric motors in single-phase networks, you should adhere to the following rules:

1. the power of the engine used as a state of emergency is selected greater than the power of the electric drive connected to it;
2. in practice, 4 kW converters are capable of solving all existing economic problems in a private home. You can focus on a load of 2-3 kW, which is acceptable for the power grid;
3. the operating current of the converter in normal mode must be greater than its value indicated in the passport of this type of electric motor (otherwise the power supply will simply burn out);
4. is carried out in a strict sequence: the emergency starts first, then the 3-pole consumers. The equipment is turned off in the reverse order.

Conclusion

Today is not yesterday, but if it happens that you need to connect a three-pole 230 V motor, we think you can handle it. After all, in fact, everything should be clear. You will need a regular 1-pole frequency converter 220-380 V.

In a private house, apartment, country house, that is, in domestic conditions, the most common standard single-phase voltage is 220 Volts, which is obtained by connecting the consumer to one phase and a neutral conductor. This voltage is called phase voltage; its generator is mainly a 6 kV/380 V power transformer installed at the distribution substation that supplies the given consumer. Sometimes, especially in a private home, it becomes necessary to start and operate an asynchronous three-phase motor designed for 380 Volts. There are schemes that make it possible to connect this motor to a single-phase 220 V network, but in this case the power of the electrical asynchronous machine is greatly lost. Accordingly, the question arises of how to get 380 Volts from 220 at home, for efficient operation of the electric motor.

What is important to know

In a three-phase network, all three phases have a shift of 120 degrees. If it were necessary to convert three-phase 220 Volts to 380V, or single-phase 220V to the same, but with a voltage of 380V, then this can be done very simply using a conventional step-up transformer. In this problem, it is necessary not just to increase the voltage, but to obtain a full-fledged three-phase network from a single-phase one.

There are three main ways in which this manipulation can be done:

• using an electronic converter (inverter);
• by connecting two additional phases;
• due to the use of a three-phase transformer, but the power is still reduced.

Before converting the mains voltage, you need to consider whether it is possible to connect the motor to a standard single-phase network without loss of power. First you need to look at the plate on the engine itself, some of them are designed for both of these voltages, as shown in the first photo. You just need a capacitor for starting.

The second plate shows that the machine is designed exclusively for star connection of windings and a voltage of 380 Volts:

You can, of course, disassemble the engine and find the ends of the windings, but this is already problematic. Let us dwell in more detail on the creation of a high-quality three-phase network of 380 V from 220.

Methods for obtaining 380 V from 220

Voltage transformer

This device is more widely known as an inverter, and it consists of several blocks. To begin with, the device rectifies this single-phase voltage, and then inverts it into an alternating voltage of a given frequency. In this case, there can be any number of phases shifted by a certain degree, but optimally for the operation of generally accepted standard electrical equipment it is three and, accordingly, their shift is 120 degrees. Making such a complex device at home is very problematic, so it is recommended to simply buy it; besides, the market for this product is very developed.

Here is the schematic diagram of the inverter:

And this is what it looks like in the factory building:

Often, these devices not only convert single-phase to three-phase voltage, but also protect electric motors from overloads, short circuits and overheating.

Three phase method

This method must be agreed upon with Energonadzor or the electrical energy supply company, since this requires the connection of two additional phases from the panel, which are on each floor of apartment buildings.

Here the question is not how to convert single-phase voltage, but how to connect it, and for this you only need a three-phase extension cord, and if everything is done legally, then a meter.

Three-phase transformer

To turn 220 Volts into 380 Volts, you need a three-phase transformer of the required power for the voltage of one of the windings 220 V and the other 380 V. Most often, they already have windings connected in a star or triangle. After that, the voltage from the network is connected directly to two phases of the winding on the lower side, and to the third terminal through a capacitor. The capacitance of the capacitor is calculated from the ratio of 7 μF for every 100 W of power. The rated voltage of the capacitor must be at least 400 Volts. Such a device cannot be connected without a load. In this case, there will still be a decrease in both engine power and efficiency. If the converter is made using an electric motor rather than a transformer, then the output will have a three-phase voltage, but its value will be the same as in the network, namely 220 V.