Frequency electronic converters for electric pumps of water supply systems. Frequency converter for borehole pump Frequency converter for single-phase pump

Pumps are needed to adjust the power of the engines. As a result, the pressure in the system is maintained at the proper level. High-quality converters can save a large number of electricity. And this should be taken into account. In this case, pumps can be used in a variety of ways. The most common are systems for supplying water to the house. Converters are also needed for circulation pumps. Additionally, they can be installed in fountains and aquariums.

Features of converters

The hallmark of all pump converters is their simplicity. At the same time, they do not require any maintenance and work completely automatically. Additionally, it is possible to control them through a personal computer. You can also set individual schedules for the device. At the same time, the coefficient useful action they are about 90%. You should also know that pumps with converters do not need expansion tank. Thus, the pressure is always maintained at an optimal level.

What are the characteristics of the converters?

Input voltage and power are considered important characteristics of converters. Additionally, the manufacturer always indicates the type of control. To date, there are scalar and vector regulation of the device. The rated current parameter depends on the power of the model. You can also highlight the output frequency. It is usually specified in the range from 0.1 to 600 Hz. The overload capacity is calculated as a percentage. The degree of protection of the converter housing is indicated by a special marking. Working temperature device manufacturer is also required to indicate. Among other things, it is necessary to highlight the parameter of acceleration time, as well as braking.

Reviews of converters "Danfoss 2800"

The Danfoss frequency converter is quite easy to maintain as well as operate. In this case, dense installation of equipment is allowed. This is largely due to a reliable cooling system. To control the level of pressure in the device, special sensors are provided. Separately, it is worth mentioning the high-quality PID controller. The input is 220 V, and the power is 0.2 kW.

The output frequency ranges from 0.1 to 600 Hz. The frequency converter is controlled by a vector method. The full acceleration time takes an average of 30 seconds. Degree of protection of the body - class "IP20". The dimensions of this unit are as follows: height - 174 mm, width - 73 mm, and depth - 135 mm. The Danfoss 2800 frequency converter costs about 11 thousand rubles.

Model INVT GD10: specifications and reviews

Many customers appreciate these pump frequency converters for their large number of digital inputs. Among other things, the presence of a relay output should be highlighted. This converter can be used at temperatures from -10 to +50 degrees. The manufacturer provides a built-in PID controller.

Also, many positively appreciated the multifunctional keyboard. With its help, you can quickly access absolutely all parameters. Input voltage this device The rated power of the motor is 0.2 kW, and the frequency ranges from 0 to 400 Hz. The rated current parameter is 1.6 A. The degree of protection of the housing is IP20 class. The overload capacity of this converter is 150%. This model will cost the buyer 12 thousand rubles.

Converter "Vesper E3-8100"

The frequency converter "Vesper E3-8100" is able to boast of its modest size. Among other things, it has special communication adapters that are designed for the network. It should also be noted convenient optional remote control. It is equipped with modern software. Printed circuit boards protection devices are lacquered.

Dense installation of devices by the manufacturer is allowed. The type of control in this converter is vector. The rated power of the device is 0.75 kW, and the output voltage is 22 V. The output frequency of the device fluctuates around 200 Hz. The total acceleration time is 30 seconds and the deceleration time is 50 seconds. The degree of protection of the case is set to the class "IP20". The unit can be operated at temperatures from -10 to +50 degrees. The frequency converter "Vesper E3-8100" costs 13 thousand rubles.

INVT GD15 Converter Parameters

Voltage regulation in this converter occurs in automatic mode. There are five digital inputs in total. The PID controller is built-in type. The manufacturer also provides support for all standard programs. The keyboard is multifunctional and provides quick access to the system. Separately, it is worth mentioning the EMC filter, which is built into the case. The single-phase converter control is of scalar type.

The input voltage of the device ranges from 205 to 235 V, and the motor power is 0.4 kW. The output frequency is at around 300 Hz. In turn, the rated current indicator is 2.5 A. Within 10 seconds. the overload capacity of the converter is 180%. This model has the following dimensions: height - 140 mm, width - 80 mm, and depth - 134 mm. This device will cost the buyer 14 thousand rubles.

Reviews about the model INVT GD20

These frequency converters for pumps are in great demand and have good system protection. Analog inputs and outputs are provided by the manufacturer. Also of note is the built-in C485 port with support for many standard programs. The braking module is built-in type. The EMC filter is available in class C2. The converter protection system copes quite well with different kind interference.

If necessary, the remote control in the device can be easily disconnected. The dimensions of the converter are quite compact and at the same time its weight is only 1.5 kg. The rated power of the unit is at the level of 0.7 kW, and the frequency fluctuates around 200 Hz. The rated current parameter is 4.2 A. The device can be used at temperatures from -10 to +40 degrees. Separately, it is worth mentioning the good overload capacity. The control type, in turn, is of the scalar type. This frequency converter costs (market price) about 12 thousand rubles.

Opinion of buyers about the device "Hyundai 700E"

This Hyundai frequency converter differs from other devices by its high-quality PID controller. In this case, the braking module is installed built-in type. The control panel is quite convenient and is equipped with a potentiometer to control the speed. This model is suitable not only for pumps, but also for fans. Among other things, it is often installed on various conveyors. The EMC filter is of built-in type.

The drives for this model are suitable from different manufacturers, and this is very convenient. The device is installed quite simply and is comfortable to use. For commissioning, you can use "Flashdrop". The type of control in this model is classified as scalar. The input voltage of the device ranges from 200 to 240 V. At the same time, the operating power single phase motor is 0.37 kW. We should also mention the wide range of output frequencies. The rated current parameter is at the level of 2.4 A, and the overload capacity is 150%. The degree of protection in the converter is set to class "IP20". The height of this unit is 202 mm, width - 75 mm, and depth - 142 mm, with a mass of 1.1 kg. The Hyundai 700E frequency converter costs 12 thousand rubles in a specialized store.

Characteristics of the converter "Schnider AT12"

Connecting the frequency converter "Schnyder AT12" to the circulation pumps is quite simple. This model differs from other devices in compactness and high performance. Among other things, the versatility of the device should be noted. Manufacturers have paid much attention to the security system.

The overload capacity parameter remains 150%. The motor is single-phase, with a power of 0.18 kW. In this case, the rated current parameter is 1.4 A. The total acceleration time is 20 seconds, and the deceleration time is 55 seconds. The output frequency indicator is on average at around 250 Hz. At the same time, it can rise to a maximum of 400 Hz. In turn, the input voltage of the converter is 220 V. This model costs 14 thousand rubles in the store.

Model "Lovara H3"

Frequency converters for Lovar N3 pumps have acceptable characteristics, but have one drawback. It is associated with the formation of condensate. This largely depends on unprotected contacts. The possibility of synchronous operation in this model is provided. It should also be noted the versatility of the device. Starting and stopping the engine can be done remotely. Current signals are received from 4 to 20 mA.

Temperature environment should be between 5 and 40 degrees. Depending on the pressure in the system, the engine speed is controlled automatically. The input voltage indicator is at the level of 400 V. The rated power of a three-phase motor is 3 kW. This model will cost the buyer 15 thousand rubles.

Converter FC-051

The frequency converter FC-051 is actively used for pumps and ventilation systems. This model is distinguished by a high-quality control unit. It should be noted and a good interface of the device. You can connect this converter to a personal computer. The blocking of the mechanical seal occurs automatically.

If necessary, the remote control can be easily detached. At the same time, the device can be launched from any distance remotely. At elevated pressure, the protective system immediately activates and blocks the engine. It also protects the system from various power surges. This model has an LED display. At the same time, only the most necessary indicators are available on the control panel. The noise level of the electric motor is within the normal range. This was largely achieved due to a high-quality variator that produces a stable frequency at 8 kHz.

To cool the entire converter, there is powerful fan. It is installed at the base of the frame and securely fastened. In this case, the device can be used for a long time and not overheat. Additionally, it should be noted that the tracking system constantly monitors the external pressure. On centrifugal pumps this model can be installed. The control sensor can withstand a maximum output signal of up to 20 mA. This frequency converter costs (market price) about 16 thousand rubles.

Any equipment required for effective work pump for water and not included in its standard package, is called additional. As a rule, the following components are included in the standard package of a pumping station: a submersible or surface pump, a pressure gauge, a stainless steel hose, a hydraulic accumulator, a water pressure switch. Additional equipment includes such auxiliary products as a frequency converter for well pump, voltage regulators, source uninterruptible power supply(UPS), its second name is a voltage converter, various sensors, blocks, control relays and much more. In our article, we will consider the purpose and features of using the main additional equipment for pumps.

For any pumping station, protection against dry operation is very important. This can happen in conditions of water shortage in the source. In case of complete emptying of the water intake, the unit will work “dry”. This will lead to overheating of the impeller (impeller) and other important elements of the working chamber. As a result of thermal deformation, the parts may jam, and the unit will fail. To prevent this from happening, you will need a block that protects the unit from dry running. Such blocks include various details:

electronic controllers;
float mechanism;
electromechanical regulator (relay).

Consider the features of the device and the use of some of them.

simple controller

The electronic relay has a flow sensor that allows you to determine the presence or absence of water flow in the pipes. If the regulator indicates the absence of water in the pipeline, the device turns off the pumping equipment. On sale there are many varieties of controllers that differ in functionality and appearance. The simplest of them are equipped with only a flow sensor. The most advanced models can combine the functions of limiting pressure control for turning the unit on and off, as well as protection against running dry.

For a standard pumping station with electromechanical pressure control, it is enough to buy a simple electronic controller. Such a block will protect the unit from dry running. It is installed on the supply pipeline.

If you are using a pumping station without a hydraulic accumulator, then you will also need a control unit that protects against dry running. This device will ensure that pumping equipment stops when water consumption points are closed. The flow sensor will also work in this case, because the water flow will stop with the stoppage of flow from the pipeline.

Controller with additional options

Such an advanced controller for the operation of pumping equipment can:

control pressure with a built-in pressure gauge;
the device may try to automatically restart the pump after a certain period of time;
set the lower pressure threshold for turning on the unit;
control the upper and lower pressure thresholds (these are universal blocks that combine a pressure regulator and a flow sensor).

It is important to know: in some modifications of the new controllers, the user can independently change the upper and lower pressure thresholds within the specified limits.

Electromechanical devices for protection against dry running

Electromechanical control devices are designated by the letters LP3. They also protect the unit from dry running. At their core, they are the same pressure switches. However, there are slight differences:

such a unit works only with a small pressure;
this device turns off the pump when the lower pressure limit is reached, and turns it on when the upper limit is reached, while conventional relays do the opposite;
the device is practically insensitive to power surges;
its reliability and durability are much higher;
the price of this unit is lower compared to the cost of a conventional relay;
in the event of a pump stop due to dry running protection, the control unit will not restart the pump, the user will have to do it manually.

float mechanism

This device consists of a float, inside of which there is a steel ball, and an electric cable. When water is drawn into the device, the float block pops up. At this time, the ball is in a position where it closes electrical circuit. This leads to the start and operation of pumping equipment. If the float block lowers due to a drop in water level, the ball changes its position and opens the circuit, which turns off the device.

Surge Protectors

Attention: when starting the pumping equipment, the already low voltage in the suburban network may drop to a minimum, which will lead to the failure of household electrical appliances. The thing is that under such conditions, the devices will operate at maximum power to compensate for the missing voltage.

In addition, a lack of voltage will negatively affect the engine of pumping equipment, as well as the ability of the unit to provide sufficient water pressure. To prevent this from happening, you need to purchase a voltage stabilizer for units that pump water.

To choose the right stabilizer, you need to consider the following nuances:

You need to know the magnitude of the starting currents. It can be obtained from the manufacturer or calculated by the formula. To begin with, we determine the operating current by dividing the motor power by the voltage (220 V) and multiplying by a power factor equal to 0.6-0.8. After that, we multiply the learned number by 4 and get the desired value.
The voltage stabilizer must have a power that allows you to connect to it not only pumping equipment.
Choose a stabilizer whose model is adapted to work with units that are equipped with an electric motor. For these needs, relay-type stabilizers, which have an increased stabilization speed, are the best suited.
For three-phase pumps, three-phase stabilizers with increased power are suitable.
As a rule, the stabilizer for the pump must be selected with a threefold excess of power.
The lower the input voltage, the more power you need to give to the stabilizer.
During operation, it is better to load the device by 80%, and not by 100%. This will increase the service life of the device.

Varieties of stabilizing devices:

thyristor;
relay;
electromechanical.

The choice of one or another type of stabilizer depends on the voltage level in the network, the distance at which the object is installed from transformer substation, voltage jump on this line. If there are no sharp jumps and high voltage indicators, you can choose an electromechanical device that has a smooth adjustment. For lines with network jumps, relay or thyristor models are suitable.

Frequency converter for pump

Various devices are used to control pumping equipment:

An alarm relay is required to shut down a running pump due to changes in operating mode.
In order to switch circuits in the required sequence, an intermediate relay is needed.
As we wrote above, a voltage relay is needed to protect against power surges.
To count the time to perform a certain operation, you need a timer.
To control the pressure in the pipeline and control automatic circuits, an electrocontact pressure gauge is useful.
To measure the temperature of bearings and seals, you need a thermal relay.
Level sensors give a signal to start or stop the unit due to a change in pressure or liquid level.
The vacuum relay maintains a given level of vacuum in the device chamber or in the inlet pipeline.
A jet relay is used to control the movement of fluid in pipes.

Important: The frequency converter is especially important in multi-pump systems.

Benefits of using a frequency converter to control a pump:

Soft start of the engine is carried out. This helps to reduce the impact of mechanical loads on pumping equipment. In addition, the reduction of starting currents reduces the risk of water hammer. The absence of water hammer favorably affects the durability and integrity of the entire hydraulic structure.
Thanks to this, the resource of the pumping unit is spent more economically. This will extend the life of the equipment.
The use of a frequency converter contributes to energy savings.

The disadvantages of a frequency converter for controlling pumping equipment include the following:

The high price of the device. Not even for buying on pumps high power the cost of such a converter will be rather big.
The pump control converter can only be used if the cable length is max. 50 m.

Uninterruptible power supplies

To ensure constant power supply of pumping equipment, special uninterruptible power supplies (UPS) are used, its second name is a voltage converter. The principle of operation of this device is based on the fact that in the presence of current in the mains, it charges special batteries. In the event of a power outage, the unit consumes electricity from the batteries. In doing so, it transforms D.C.(12V), giving out variable (220V).

In other words, if some additional devices are needed to control the pump, then the converter ensures its uninterrupted operation in the event of a power outage. This device is connected to rechargeable batteries and connects to the electrical network.

A frequency sinusoid in uninterruptible power supplies for pumping equipment is necessary, because without it the units will make a lot of noise and overheat. As a result, a thin winding can simply burn out. Typically, the UPS power is 1000-2000W. This power will be enough not only to ensure the operation of pumping equipment, but also to maintain the efficiency of heating boilers, TV and lighting throughout the house.

In our article, we examined the most necessary additional equipment that is needed to facilitate pump control, increase its efficiency, and protect against failure in case of changing operating conditions.

Pressure stabilization. The PV installation maintains pressure in the right level(value set by the user) regardless of the time of day, the number of open valves and the configuration of the line. This and a number of pluses: with hot water with the help of a flow, the temperature of the liquid is unchanged; household appliances connected to the water supply work optimally.
Protecting the pump from overheating. The frequency converter includes a flow switch. Therefore, the pumping device is protected from "dry running".
Smooth start. It eliminates overload when voltage is applied to the electric / motor.
Energy consumption optimization. Since the pump is constantly switched from one mode to another, en / consumption becomes more economical. If the pumping device is of high capacity, the reduction reaches 50%. According to some estimates, only on this frequency converter pays off in about 1.5 years.
Reducing the risk of leaks (breaks in the line). The explanation is simple - the pressure is maintained within the normal range, and therefore emergencies due to its jumps are excluded. It turns out that the frequency converter indirectly saves on materials and time required to troubleshoot the system. Consequently, and the associated overspending of water (penetration into the ground, spreading over the floor ground floor) will not be.
Increasing the life of the pump. The frequency converter regulates the strength of current and voltage (0 - 230 V), and the absence of their sharp jumps prolongs the operating life of the pumping device.
Remote control. Some models of the inverter have a USB (COM) port, and you can change the settings from a PC; additional convenience for the user.
Emergency shutdown of the pump. Therefore, one of the functions of the frequency converter is protective.
There is no need to include a hydraulic accumulator in the circuit. When the pump and the emergency work together, it is simply not needed.

Automation of the operation of pumping equipment can be considered the most important aspect in the field of technical development of water supply and sanitation systems. This is important not only for stations that provide water to settlements.

A smart well pump will also make operation comfortable autonomous water supply. To do this, it is very important to correctly calculate the borehole pump, and, accordingly, to select a frequency converter for it.

The video in this article will help you do it yourself.

Advantages of automatic water supply

In order to achieve the most gentle operation of the equipment, everything is automated at pumping stations - from starting and stopping the units, and ending with the control of water flow. Devices that help to exercise total control over the system transmit signals to the scoreboard in the control room.

Approximately the same, only on a smaller scale, occurs in the case of automation. home pump. Let's look at the advantages that automation gives to the system.

So:

The most important thing is that the smooth start and stop of the pump motor reduces the likelihood of water hammer to zero, and the careful operation mode helps to extend the life of any equipment. This reduces the costs associated with the operation of the water intake.
First of all, it is the consumption of electricity. Its price is steadily growing, and everyone feels it: both individuals and enterprises. Frequency regulation of the operation of pump motors makes it possible to reduce the volume of storage tanks, and even completely abandon them.

In such cases, they use a device called: "inverter control unit for a borehole pump" - it is what you see in the photo above. The inverter combines various combinations of control devices that the pump itself is not equipped with, and, among other things, has a built-in frequency converter.

Functionality and selection of the frequency converter

It is clear that the maximum consumption of water occurs only at certain moments, and most time, the pump power is excessive. The frequency converter allows you to configure the system so that during the "rush hour" the pump gives out full power, and at other times it reduces speed.

From the number of rotations in a certain period of time of the pump wheel, the pressure developed by it depends, and, accordingly, the performance. The essence of using a frequency converter is to make the motor shaft rotate at a given pace. At the same time, the frequency alternating current received from the mains, changes its value.
Modern converters have the widest range, and are able to convert voltage both above and below the characteristics of the mains supply. The circuit of this device is divided into two parts: a power one, consisting of a group of transistors or thyristors, and a control one, which, in fact, is an electronic key.
The control part consists of digital microprocessors, and performs all control and protective functions. Since the structure of the power section has characteristic differences, frequency converters are divided into two groups. One of them includes devices with an intermediate DC link.

The second group does not have this link, and is called "frequency converters with direct connection". Devices without an intermediate link have a higher efficiency, and are able to "curb" the most powerful high-voltage motor. Despite the fact that the price this option higher, the system in which it is implemented is an order of magnitude more economical in terms of costs.
What is the cost savings? The fact is that such converters have a small frequency range, and it cannot be equal to or exceed the characteristics of the supply network. The standard frequency of the current in the network is 50 Hz, and the device converts it to 30 Hz and below, down to zero. Consequently, the consumption of electricity is reduced - here's the savings for you!

Such a limited range does not allow the use of converters of this type on an industrial scale. But for household pumps this is just what you need.

Selection of a pump for a well

First of all, it must be borne in mind that the power characteristics of the pump must exceed the calculated consumption. That is, there should always be a reserve of power.

The calculation is based on the following data:

depth and
Casing pipe diameter
, and if it is simpler - the distance from the water mirror in the well to the surface of the earth with the pump running
Total daily water consumption for a family, keeping animals and watering (calculated based on existing standards)
Well distance from home
Height of water supply (taking into account the number of storeys of the building)
Pressure pipe diameter

The pump pressure for a well, from which water will be supplied directly to the house, is the sum of the length of vertical and horizontal distances, multiplied by the resistance of the pipeline - this coefficient is a constant value, and is equal to 1.15.

If there is a storage tank in the water supply system, then the pressure of the hydraulic tank is also added to the sum of the distances. Pressure is expressed in atmospheres, and each atmosphere is equal to 10 vertical meters.
Consider how the calculation will look like specific example. Let's say you have a well with a dynamic level of 35 m. It is located 20 m from two-story house 7 m high. At the same time, a hydraulic accumulator with a capacity of 60 liters and a pressure of 3 atm is installed in the house.

The calculation of the pressure will look like this: H \u003d (35 + 20 + 7 + (3 * 10)) * 1.15 \u003d 105 meters.

If we take into account a small margin, then you can buy a pump with a pressure characteristic of 110-115m. As you can see, this calculation is not particularly difficult. Now let's talk about the criteria for selecting a frequency converter, abbreviated as PE.

Transducer selection

As for the technical characteristics of the inverter, they must be related to the type and power of the electric motor to which it will be connected. Further, it is necessary to take into account the required control range, as well as the level of tuning accuracy and maintaining the torque on the motor shaft.

The design features of the inverter, that is, its dimensions, configuration, built-in or remote control, also matter. The vast majority are set asynchronous motors. To them, the frequency converter is selected according to power, and it is better if this characteristic of the converter is an order of magnitude higher than that of the pump.

There are converters with vector control that allow you to maintain the rotation speed under variable loads, as well as work without reducing the speed in the zero range. Such converters most accurately control the torque and shaft speed. This is especially important when there are two pumps in the network.
In general, frequency converters have their own classification. Like any other electrical equipment, they can be single-phase and three-phase. The version of the inverters can be household, for a 220V network. There are also industrial converters with power up to 500V, and high-voltage converters up to 6000V.
The degree of IP protection is also different. By type of control, PE are divided into vector and scalar. All leading manufacturers of pumping equipment offer consumers inverter units. Typically, manufacturers link converter models to specific pump modifications and give recommendations for their use.

The buyer does not even need to think much about the choice: the sales consultant will show you the converter model suitable for this pump and explain to you what the features of its use are.

Pumps used in systems autonomous water supply and heating, are productive, but at the same time quite costly equipment in terms of operation due to high level energy consumption. You can reduce costs and significantly extend the life of the pump by equipping it with a frequency converter, which we will discuss in this article.

You will find out why you need it and what functions the frequency converter performs. The principle of operation of such devices, their varieties, specifications and recommendations are given for the choice of converters for borehole and circulation pumps.

1 Why do you need a frequency converter?

Almost all modern pumps sold in the budget and middle price categories are designed according to the throttling principle. The electric motor of such units always operates at maximum power, and the change in the flow / pressure of the fluid supply is carried out by adjusting stop valves, which changes the cross section of the through hole.

This principle of operation has a number of significant drawbacks, it provokes the appearance of water hammer, since immediately after turning on the pump begins to pump water through the pipes at maximum power. Another problem is the high energy consumption and rapid wear of the system components - both the pump and the shut-off valves with the pipeline. Yes, and there can be no talk of fine-tuning such a water supply system at home from a well.

The above disadvantages are unusual for pumps equipped with a frequency converter. This element allows you to effectively control the pressure created in the water supply or heating pipeline by changing the amount of electricity supplied to the motor.

As you can see in the diagram, pumping equipment is always calculated according to the power limit parameter, however, in maximum load mode, the pump operates only during periods of peak water consumption, which is extremely rare. In all other cases, the increased power of the equipment is unnecessary. The frequency converter, as statistics show, allows you to save up to 30-40% of electricity during the operation of circulation and borehole pumps.

1.1 Device and operation algorithm

The frequency converter for water supply pumps is an electrical device that converts constant pressure mains into alternating at a predetermined amplitude and frequency. Almost all modern converters are made according to the double current change scheme. This design consists of 3 main parts:

uncontrolled rectifier;
pulse inverter;
control system.

The key element of the design is a pulse inverter, which in turn consists of 5-8 transistor keys. A corresponding element of the stator winding of the electric motor is connected to each of the keys. Foreign converters use IGBT class transistors, while Russian converters use their domestic counterparts.

The control system is represented by a microprocessor, which simultaneously performs the functions of protection (turns off the pump in case of strong current fluctuations in the mains) and control. In borehole water pumps, the control element of the converter is connected to a pressure switch, which allows the pumping station to operate in a fully automatic mode.

The operation algorithm of the frequency converter is quite simple. When the pressure switch determines that the pressure level in the hydraulic tank has fallen below the permissible minimum, a signal is transmitted to the converter and it starts the pump electric motor. The engine accelerates smoothly, which reduces the hydraulic loads affecting the system. Modern converters allow the user to independently set the acceleration time of the electric motor within 5-30 seconds.

During the run-up process, the signal transmitter continuously reports the pressure level in the pipeline to the transmitter. After it reaches the required value, the control unit stops acceleration and maintains the set engine speed. If the water point connected to the pumping station begins to consume more water, the converter will increase the supply pressure by increasing the pump capacity, and vice versa.

1.2 Operation of the pump in tandem with a frequency converter (video)

If the pump you are using does not have a built-in frequency converter, then you can purchase and install such a power controller yourself. As a rule, pump manufacturers in the technical data sheet indicate which particular converter is suitable for this equipment model.

Power - the voltage converter is always selected based on the power of the electric drive to which it is connected.
Input voltage - indicates the current strength at which the converter remains operational. Here it is necessary to choose with an eye to the fluctuations that may be in your power supply (low voltage leads to the device stopping, with increased voltage it can simply fail). Also consider the type of pump motor - three, two or single phase.
Adjustment frequency range - for borehole pumps, the optimal range will be 200-600 Hz (depending on the initial power of the pump), for circulation pumps 200-350 Hz.
The number of moves and control outputs - the more of them, the more commands and, as a result, the converter operating modes, you can configure. Automation allows you to set the speed at start-up, several modes of maximum speed, acceleration rates, etc.
Control method - for a borehole pumping station, it will be most convenient to use remote control, which can be located inside the house, while a converter with a remote control is perfect for circulation pumps.

If you have filtered out all the devices on the market and are faced with the fact that there is simply no equipment suitable for its characteristics, you need to narrow down the selection criteria to a key factor - the current consumed by the motor, according to which the rated power of the converter is selected.

Also, when choosing a frequency control unit, especially from domestic or Chinese manufacturers, consider the warranty period. By its duration, one can indirectly judge the reliability of the technique.

A few words about manufacturers. The leading company in this area is Grundfoss (Denmark), which supplies the market with over 15 different models of converters. So, for pumps with a three-phase electric motor, the Micro Drive FC101 model is suitable, for single-phase pumps (operating from a standard 220V mains) - FC51.

More affordable in terms of price is equipment from Rockwell Automation (Germany). The company offers a line of PowerFlex 4 and 40 converters for low-power circulation pumps and a PowerFlex 400 series for downhole pumping stations(3 pumps connected in parallel can operate from one converter at once.

Keep in mind that the price of a good converter can sometimes reach the cost of a pump, so the connection and configuration of such a device should be carried out exclusively by specialists.