Wiring diagram for a three-phase heating element. Scheme of connecting the electric boiler to the mains. The operation of the heating element in temperature control circuits

(and how to decrypt it)

The optimal source of energy for heating the evaporation tank is the apartment electrical network, with a voltage of 220 V. You can simply use a household electric stove for this purpose. But, when heated on an electric stove, a lot of energy is spent on useless heating of the stove itself, and is also radiated to the external environment, from the heating element, without doing useful work. This wasted energy can reach decent values ​​- up to 30-50% of the total power spent on heating the cube. Therefore, the use of conventional electric stoves is irrational in terms of economy. After all, for every extra kilowatt of energy, you have to pay. It is most efficient to use embedded in the evaporator tank el. heating elements. With this design, all the energy is spent only on heating the cube + radiation from its walls to the outside. The walls of the cube, to reduce heat loss, must be insulated. After all, the cost of heat radiation from the walls of the cube itself can also be up to 20 percent or more of the total power expended, depending on its size. For use as heating elements embedded in a container, heating elements from household electric kettles, or others suitable in size, are quite suitable. The power of such heating elements is different. The most commonly used heating elements are those with a power of 1.0 kW and 1.25 kW knocked out on the body. But there are others.

Therefore, the power of the 1st heating element may not match the parameters for heating the cube and be more or less. In such cases, to obtain the required heating power, you can use several heating elements connected in series or in series-parallel. By switching various combinations of heating elements connection, a switch from a household electric. plates, you can get different power. For example, having eight embedded heating elements, 1.25 kW each, depending on the switching combination, you can get the following power.

1. 625 W
2. 933 W
3. 1.25 kW
4. 1.6 kW
5. 1.8 kW
6. 2.5 kW

This range is quite enough to adjust and maintain the desired temperature during distillation and rectification. But you can get other power by adding the number of switching modes and using various switching combinations.

Serial connection of 2 heating elements of 1.25 kW each and connecting them to a 220V network gives a total of 625 watts. Parallel connection, in total gives 2.5 kW.

We know the voltage acting in the network, it is 220V. Further, we also know the power of the heating element knocked out on its surface, let's say it is 1.25 kW, which means we need to find out the current flowing in this circuit. The current strength, knowing the voltage and power, we learn from the following formula.

Current = power divided by mains voltage.

It is written like this: I = P / U.

Where I is the current in amps.

P is the power in watts.

U is the voltage in volts.

When calculating, you need to convert the power indicated on the heater case in kW to watts.

1.25 kW = 1250W. We substitute the known values ​​​​into this formula and get the current strength.

R = U / I, where

R- resistance in ohms

U- voltage in volts

I- current strength in amperes

We substitute the known values ​​\u200b\u200binto the formula and find out the resistance of 1 heating element.

Rtot = R1 + R2 + R3, etc.

Thus, two heaters connected in series have a resistance of 77.45 ohms. Now it is easy to calculate the power released by these two heating elements.

P = U2 / R where,

P - power in watts

R is the total resistance of all last. conn. heating elements

P = 624.919 W, rounded up to 625 W.

Table 1.1 shows the values ​​​​for a series connection of heating elements.

Table 1.1

Table 1.2 shows the values ​​for parallel connection of heating elements.

Table 1.2

Another important plus, which gives the series connection of heating elements, is the current flowing through them, reduced by several times, and, accordingly, low heating of the heating element body, thereby preventing the mash from burning during distillation and does not introduce an unpleasant additional taste and smell to the final product. Also, the resource of the heating elements, with this inclusion, will be almost eternal.

The calculations are made for heating elements with a power of 1.25 kW. For heating elements of other power, the total power must be recalculated according to Ohm's law, using the above formulas.

The optimal source of energy for heating the evaporation tank is the apartment electrical network, with a voltage of 220 V. You can simply use a household electric stove for this purpose. But, when heated on an electric stove, a lot of energy is spent on useless heating of the stove itself, and is also radiated to the external environment, from the heating element, without doing useful work. This wasted energy can reach decent values ​​- up to 30-50% of the total power spent on heating the cube. Therefore, the use of conventional electric stoves is irrational in terms of economy. After all, for every extra kilowatt of energy, you have to pay. It is most efficient to use embedded in the evaporator tank el. heating elements. With this design, all the energy is spent only on heating the cube + radiation from its walls to the outside. The walls of the cube, to reduce heat loss, must be insulated. After all, the cost of heat radiation from the walls of the cube itself can also be up to 20 percent or more of the total power expended, depending on its size. For use as heating elements embedded in a container, heating elements from household electric kettles, or others suitable in size, are quite suitable. The power of such heating elements is different. The most commonly used heating elements are those with a power of 1.0 kW and 1.25 kW knocked out on the body. But there are others.

Therefore, the power of the 1st heating element may not match the parameters for heating the cube and be more or less. In such cases, to obtain the required heating power, you can use several heating elements connected in series or in series-parallel. By switching various combinations of heating elements connection, a switch from a household electric. plates, you can get different power. For example, having eight embedded heating elements, 1.25 kW each, depending on the switching combination, you can get the following power.

1. 625 W
2. 933 W
3. 1.25 kW
4. 1.6 kW
5. 1.8 kW
6. 2.5 kW

This range is quite enough to adjust and maintain the desired temperature during distillation and rectification. But you can get other power by adding the number of switching modes and using various switching combinations.

Serial connection of 2 heating elements of 1.25 kW each and connecting them to a 220V network gives a total of 625 watts. Parallel connection, in total gives 2.5 kW.

We know the voltage acting in the network, it is 220V. Further, we also know the power of the heating element knocked out on its surface, let's say it is 1.25 kW, which means we need to find out the current flowing in this circuit. The current strength, knowing the voltage and power, we learn from the following formula.

Current = power divided by mains voltage.

It is written like this: I=P/U.

Where I- current strength in amperes.

P- power in watts.

U- voltage in volts.

When calculating, you need to convert the power indicated on the heater case in kW to watts.

1.25 kW = 1250W. We substitute the known values ​​​​into this formula and get the current strength.

I = 1250W / 220 = 5.681 A

R=U/I where

R- resistance in ohms

U- voltage in volts

I- current in amperes

We substitute the known values ​​\u200b\u200binto the formula and find out the resistance of 1 heating element.

R \u003d 220 / 5.681 \u003d 38.725 ohms.

Rtotal = R1+ R2 + R3 etc.

Thus, two heaters connected in series have a resistance equal to 77,45 Ohm. Now it is easy to calculate the power released by these two heating elements.

P \u003d U 2 / R where,

P- power in watts

U 2- voltage squared, in volts

R- the total resistance of all last. conn. heating elements

P = 624.919 W, rounded up to the value 625 W.

Table 1.1 shows the values ​​​​for a series connection of heating elements.

Table 1.1

Table 1.2 shows the values ​​for parallel connection of heating elements.

Table 1.2

Another important plus, which gives the series connection of heating elements, is the current flowing through them, reduced by several times, and, accordingly, low heating of the heating element body, thereby preventing the mash from burning during distillation and does not introduce an unpleasant additional taste and smell to the final product. Also, the resource of the heating elements, with this inclusion, will be almost eternal.

Customs Union. Declaration of Conformity № ТС RU Д-RU.АВ98.В.00706
Valid from December 30, 2014 to 25.12.2019
Manufactured according to TU 3443-009-49110786-2002.
Complies with the requirements of technical regulations
Customs Union TR CU 004/2011

TEN connection diagrams (single-phase network)

Tubular electric heaters (TENY) as well as other consumers of electricity are connected to both single-phase and three-phase networks.

When connecting to a single-phase network (1 "phase" and "zero") more than one heating element, parallel, serial or combined connection schemes are used.

1. Parallel connection of heating element

When connected in parallel, the following basic laws apply:

• The voltage on each heating element is constant and equal to the voltage in the network;
• If one of the heating elements fails, the rest continue to work;
• The total assembly power is the sum of the capacities of all heating elements installed in parallel;
• If heating elements of different power are installed in parallel, then the total power is calculated according to the formula: P total \u003d U 2 / R total, where P total is the total power, U is the voltage, R total is the total resistance of the assembly. The total assembly resistance Rtot is calculated by the formula: 1/Rtot =1/R 1 +1/R 2 +1/R 3 .

2. Serial connection of heating element

When connected in series, the following basic laws apply:

• The total assembly resistance is the sum of the resistances of all heating elements installed in series;
• If heating elements of the same resistance are installed in series, then the voltage on each heating element is equal to the total network voltage divided by the number of heating elements in the assembly. In other words: U total \u003d U 1 + U 2 + U 3.
• The total power of the heating element assembly is calculated according to the formula Ptotal =Utotal 2 /Rtotal, where Ptotal is the total power, Utotal is the total network voltage, Rtotal is the total resistance of the heating element assembly. The total assembly resistance R total is calculated by the formula: R total =R 1 +R 2 +R 3 .
• If one heating element fails, the common circuit breaks and the rest of the heating elements also stop working.

3. Combined heating element connection

With a combined connection of a heating element, the circuit should be divided into several sections (A and B), for which the laws of either parallel (A) or series (B) connections will apply, respectively.

The voltage value on all diagrams is indicated when connected to the network - 220V.

TEN connection diagrams (three-phase network)

Tubular electric heaters (TENY) as well as other consumers of electricity are connected to both single-phase and three-phase networks. When connecting to a three-phase network (3 "phases" and "zero"), two main connection schemes are used ("star" and "triangle"). In order to evenly distribute the load over the phases, the number of connected heating elements should be selected as a multiple of 3.

1. Connection of heating elements - "star"

The main laws that apply when connecting heating elements with a "star":

• Between any "phase" and "zero" is always 220V!
• In each branch of the "star" you can connect several heating elements connected to each other in series or in parallel (see connection diagrams in a single-phase network).
• The power of each branch of the "star" should be the same.

2. Connection of heating elements - "triangle"

The main laws that apply when connecting heating elements with a "triangle":

• Between any two "phases" is always 380V!
• In each branch of the "triangle" you can connect several heating elements connected to each other in series or in parallel (see connection diagrams in a single-phase network).
• The power of each branch of the "triangle" should be the same.
• The total power of the connection is the sum of the powers of the three branches.

The voltage value on all diagrams is indicated when connected to a three-phase network - 380V.

Therefore, for such a "gluttonous" consumer of electricity as an electric boiler, a lot depends on the stable operation of which in winter, it is important to make the correct wiring, choose reliable protective automation and connect correctly.

To better understand the principle of connecting the boiler, you need to know what it usually consists of and how it works. We will talk about the most common, heating elements boilers, the heart of which are Tubular Electric Heaters (TEH).

The electric current passing through the heater heats it up, this process is controlled by an electronic unit that monitors important indicators of the boiler using various sensors. Also, the electric boiler may include a circulation pump, control panel, etc.

Depending on the power consumption, electric boilers designed for a supply voltage of 220 V - single-phase or 380 V - three-phase are usually used in everyday life.

The difference between them is simple, 220V boilers are rarely more powerful than 8 kW, most often in heating systems devices of no more than 2-5 kW are used, this is due to restrictions on the allocated power in single-phase supply lines of houses.

Respectively 380V electric boilers are more powerful and can effectively heat large houses.
Connection diagrams, cable selection rules and protective automation for 220V and 380V boilers are different, so we will consider them separately, starting with single-phase ones.

Scheme of connecting the electric boiler to the mains 220 V (single-phase)

As you can see, the 220 V boiler supply line is protected by a differential circuit breaker, which combines the functions of a circuit breaker (AB) and. Also, without fail, grounding is connected to the device case.

Heating elements or heating elements (if there are several) in such a boiler are designed for a voltage of 220V, respectively, a phase is connected to one of the ends of the tubular electric heater, and zero to the other.

To connect the boiler, it is required to lay a three-core cable (Phase, Working zero, Protective zero - ground).

If you couldn’t find a suitable differential automatic switch off or it’s just too expensive in your chosen line of protective automation, you can always replace it with a bunch of Circuit Breaker (AB) + Residual Current Device (RCD), in which case the diagram for connecting a single-phase boiler to the mains looks like So:

Now it remains to choose the cable of the desired brand and section and the ratings of protective automation, for the correct electrical wiring to the electric boiler.

In choosing, it is necessary to build on the power of the future boiler, and it is best to calculate with a margin, because in the future, if you decide to change the boiler, you will no longer be able to choose an older model (more powerful), without a serious alteration of the wiring.

I will not load you with unnecessary formulas and calculations, but simply lay out a table for selecting a cable and protective automation, depending on the power of a single-phase electric boiler 220 V. In this case, the table will take into account both connection options: through a differential switch and through a bunch of Circuit breaker + RCD.

For laying, the characteristics of the copper cable of the VVGngLS brand, the minimum allowable PUE (electrical installation rules) for use in residential buildings, will be indicated, while the calculations are made for the route from the meter to the electric boiler 50 meters long, if you have this distance more, you may need to adjust the values.

Table for the selection of protective automation and cable cross-section according to the power of the electric boiler 220 V

The residual current device (ouzo) is always selected one step higher than the circuit breaker paired with it, but if you can’t find the RCD of the required rating, you can take the protection of the next step, the main thing is not to take it lower than it should be.
There are usually no particular difficulties and inconsistencies when connecting an electric boiler to 220V, we move on to the three-phase version.

The general electrical circuit for connecting a 380 V electric boiler is as follows:

As you can see, the line is protected by a three-phase differential current circuit breaker, and a ground is necessarily connected to the boiler body.

As usual, according to tradition, I lay out the connection diagram of a three-phase electric boiler with a bunch of circuit breaker (AB) plus a residual current device (RCD) in a circuit that is often cheaper and more affordable Diff. machine.

The choice of ratings of protective automation and cable cross-section for three-phase electric boilers of various capacities is conveniently done according to the following table:

In three-phase electric boilers, three heating elements are usually installed at once, sometimes more. At the same time, in almost all domestic boilers, each of the tubular electric heaters is designed for a voltage of 220 V and is connected as follows:

This so-called star connection, for this case, and the neutral conductor is supplied to the boiler.

The heating elements themselves are connected to the network as follows: a jumper is connected at one of the ends of each of the tubular electric heaters, the phases are connected in turn to the remaining three free ones: L1, L2 and L3.

If your boiler has heating elements designed for a voltage of 380 V, their connection scheme is completely different and it looks like this:

Such a connection of the heating element of an electric boiler is called a "triangle" and with the same voltage of 380 V, as in the previous Zvezda method, the boiler power increases significantly. In this case, a neutral conductor is not required, only phase wires are connected, while the electrical connection diagram accordingly looks like this:

Do not deviate from the wiring diagrams allowed for your electric boiler, if there are heating elements for 220V with a three-phase connection, do not redo the circuit to a "triangle". As you understand, theoretically they can be reconnected and get a voltage of 380 V on the heating element, respectively, and an increase in their power, but at the same time they will most likely simply burn out.

How to determine the correct connection scheme for a heating element with a star or a triangle and, accordingly, what voltage are they designed for?

If the instructions for connecting your electric boiler are lost or there is simply no way to refer to it, you can determine the correct connection scheme at home as follows:

1. First of all, inspect the terminals of the heater, most likely the manufacturer has already prepared the contacts for a certain scheme. So, for example, to connect with a "star" and heating elements for 220V, the three terminals will be connected by a jumper.

2. The very presence of a zero terminal - “N”, indicates that the heating element is 220 V and it is required to connect them according to the “Star” scheme. At the same time, its absence does not mean at all that the heating element is 380 V.

3. The most reliable way to find out the heating element is to look at the marking indicated either on the flange to which the tubular electric heaters are fixed

Or on the heating element itself, its parameters are necessarily squeezed out:

If you can’t find out for sure the voltage for which your electric boiler and the connection diagram of its heating element are designed, but it’s “very necessary” to connect, I advise you to use the “Star” scheme. With this option, if the heaters are designed for 220 V, they will operate normally, and if they are 380 V, they will simply give out less power, but most importantly they will not burn out.

In general, there are different cases, and it is very difficult to cover all of them in the format of one article., that's why be sure to write your questions, additions, stories from personal experience and practice in the comments, it will be useful to many!

. Tubular electric heaters (heating element) are designed to convert electrical energy into heat. They are used as basics in heating devices (devices) for industrial and domestic purposes, heating various media by convection, heat conduction or radiation. Tubular heaters can be placed directly in the heated medium, so their scope is quite diverse: from irons and kettles to furnaces and reactors.

The heating element is an electric heating element made of a thin-walled metal tube (shell), the material for which is copper, brass, stainless and carbon steel. Inside the tube is a spiral of nichrome wire, which has a high electrical resistivity. The ends of the spiral are connected to metal leads, which connect the heater to the supply voltage.

The spiral is isolated from the tube walls by a compressed electrical insulating filler, which serves to remove thermal energy from the spiral and securely fixes it in the center of the tube along the entire length. Fused magnesium oxide, corundum or quartz sand is used as a filler. To protect the filler from the penetration of moisture from the environment, the ends of the heating element are sealed with a thermal and moisture-resistant varnish.

The heater leads are isolated from the tube walls and rigidly fixed by ceramic insulators. The supply wires are connected to the threaded ends of the terminals using nuts and washers.

The heating element works as follows: when an electric current passes through a spiral, it, heating up, heats the filler and the walls of the tube, through which heat is radiated into the environment.

When heating gaseous media, they are used to increase heat transfer from heating elements. ribbing made of material with good thermal conductivity. As a rule, a corrugated steel tape wound in a spiral onto the outer shell of the heating element is used for finning.

The use of such a constructive solution helps to reduce the overall dimensions and current load of the heater.

2. Schemes for the inclusion of heating elements in a single-phase network.

Tubular electric heaters are designed for a specific value power and voltage, therefore, to ensure the nominal mode of operation, they are connected to the supply network with the appropriate voltage. According to GOST 13268-88, heaters are manufactured for rated voltages: 12 , 24 , 36 , 42 , 48 , 60 , 127 , 220 , 380 V, however, heating elements designed for voltages of 127, 220 and 380 V have found the greatest use.

Consider possible options for including a heating element in a single-phase network.

2.1. Plugging in.

Heating elements with a power of no more than 1 kW (1000 W) can be safely plugged into an outlet through an ordinary plug, since the majority of electric kettles and boilers with which we heat water have such power.

Through a regular plug, you can turn on parallel two heating elements, but both heaters should have a power of no more than 1 kW (1000 W), since when connected in parallel, their total power increases to 2 kW (2000 W). Thus, several heaters can be turned on, but their total power should not exceed 2 kW, and a more powerful plug must be used to plug into the outlet.

There is a situation when there are several heaters lying around at home, designed for an operating voltage of 127 V, the hand does not rise to throw them away, and you cannot turn them on to the home network. In this case, the heaters turn on successively, which makes it possible to apply increased voltage to them. When two heaters with a voltage of 127 V are connected in series, their power remains the same, and the total resistance doubles. For example, when two heaters with a power of 500 W are turned on, their total power will be 1000 W.

However, this scheme has one drawback: if any of the heating elements fails, then both will not work, since the electrical circuit will break and the power supply will stop.

It must also be remembered that when two heaters with an operating voltage of 220 V are connected in series, their total power decreases twice, because due to the increase in total resistance, each heater will receive about 110 V instead of the prescribed 220 V.

2.2. Switching on via circuit breaker.

It will be much more convenient if the heating elements are energized using an automatic switch. To do this, it is necessary to provide an automatic machine in the house shield, or install the automatic machine directly next to the heating device. Supply and disconnection of voltage will be carried out on/off automatic switch.

The next option for turning on the heaters is carried out by a two-pole switch, which is the most preferable, since in this case the phase and zero are broken simultaneously and the heating element is completely disconnected from the general circuit. Voltage is applied to the upper terminals of the switch, and the heater is connected to the lower terminals.

If an electric heater is used to heat water in the house, then to protect against electric shock in the event of a breakdown in the insulation of the heater, it makes sense or a difavtomat.

In this case ground conductor connected to the body of the heating element or connected to a special screw fixed on the tank body. A ground sign is depicted next to such a screw. Consider a circuit with a difavtomat:

Protection with a difavtomat works as follows: when the insulation of the heater breaks down, a phase appears on its body, which, using the least resistance, will “go” along the ground conductor RE and create leakage current. If this current exceeds the setting, then the difavtomat will work and turn off the voltage supply. If the circuit happens short circuit, then in this case the difavtomat will work and de-energize the heating element.

When using an RCD between it and the heater, it is necessary to install an additional single-pole circuit breaker, which, in the event of a short circuit, will turn off the voltage supply to the heater and protect the RCD from a short circuit current. In the event of an insulation breakdown, the RCD will turn off the voltage supply.

2.3. The operation of the heating element in temperature control circuits.

In automatic temperature control circuits, the supply voltage to electric heaters is supplied through the contacts of starters, contactors or thermal relays. Together, the link heater - thermostat" or " heater - thermal relay - contactor» is the simplest temperature controller that can be used to maintain the temperature in rooms or liquid media. The contactor is used in the circuit for multiplying contacts and for switching a powerful load, for which the thermal relay contacts are not designed.

The thermal relay can operate in the modes " Heat" or " Cooling”, which are selected by a switch located on the front side of the relay. The work of the heating element will be considered in the mode " Heat”, since this is the mode most often used.

Let's consider the scheme heater - thermostat».

A1 and A2 A2 and the left outlet of the heater.

A1 K1 K1 connected to the right output of the heater. The temperature sensor is connected to the terminals T1 and T2.

K1 is open and no voltage is supplied to the heating element. As soon as the temperature drops below the set value, a signal will come from the sensor and the relay will give a command to close the contact K1. At this moment, the phase through a closed contact K1 will go to the right output of the heater and the heater will begin to heat up. When the set temperature is reached, a signal will come from the sensor again and the relay will open the contact K1 and turn off the heater.

Let's consider the scheme heater - thermal relay - contactor».

The 220 V supply voltage is applied to the input terminals of the two-pole circuit breaker. From the output of the machine, the voltage is supplied to the power terminals of the thermal relay A1 and A2. Zero is connected to the thermal relay terminal A2, conclusion A2 contactor coils and the lower output of the heater.

Phase is connected to the thermal relay terminal A1 and jumper is transferred to the left output of the contact K1 and constantly present on it. Right contact pin K1 connected to output A1 coils of the contactor and the lower power contact of the contactor. The upper power output of the contactor is connected to the upper output of the heater. The temperature sensor is connected to the terminals T1 and T2.

In the initial state, when the ambient temperature is higher than the set value, the relay contact K1 is open and no voltage is supplied to the heating element. When the temperature drops below the set value, a signal comes from the sensor and the relay closes the contact K1. Phase through closed contact K1 goes to lower power contact output and output A1 contactor coils.

When a phase appears at the output A1 coil, the contactor is activated, its power contacts are closed and the phase falls on upper heater output and it starts to heat up. When the set temperature is reached, a signal will come from the sensor again, the relay will open the contact K1 and de-energizes the contactor, which in turn de-energizes the heater.

You can also watch a video about heaters, which explains and shows the operation of each circuit.

Let's finish this for now, and in the second part we will consider.
Good luck!