Relay block with frequency converter. Frequency converter for 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, their efficiency is 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. The operating temperature of the device is also indicated by the manufacturer without fail. 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 reliable system cooling. 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. Full time acceleration 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. This single-phase control converter is of the 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 used 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 mounted in 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.

Drives for this model are suitable from different manufacturers and it's 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. In this case, the operating power of a 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. Rated power three-phase motor equals 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. Connect this converter to personal computer can. 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 high blood pressure works instantly protective system and block 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.

There is a powerful fan to cool the entire inverter. 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 the 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.

The basic element that ensures the functionality of the pump is the electric motor. Previously, the adjustment of the workflow occurred due to automation, now this task is solved by a frequency converter for pumps.

Functional purpose of the frequency converter in the design of the pump

The inverter (frequency converter) regulates the operation of the pump much better than the relay. It works at the same time as a stabilizer, automation and workflow regulator. Thanks to him, it provides high efficiency device:

• The level of electricity supply, if necessary, and the engine speed are reduced, which helps to protect the pump from premature wear.
• The formation of excess pressure in the pipes is prevented.
• The problem with power surges is solved, which also definitely increases the life of the pump.

Mostly already in the process of assembling the pumping station is implanted. To the number similar devices you need to include models of the very famous Grundfos pump.

Visually, it is a box equipped with electronics (several boards, a sensor that takes measurements, and an inverter that equalizes the voltage level) and a small-sized screen.

More expensive samples are equipped with microprocessors. Batteries, additional equalizers and so on can be built in.

The converters used can be of single-phase or three-phase type.

According to the principle of operation, the frequency converter is quite simple. Wave electric current applied to the device boards. Inverters and stabilizers located there ensure its alignment. At the same time, the sensor reads pressure data and other relevant information.

All information is redirected to the automation unit. Next, the frequency converter evaluates them, determining the power level that must be applied, and, in accordance with this, supplying the amount of electricity necessary to continue working.

As a result, the frequency converter can adjust the smooth start of motors, the water pressure level and stop operation in a critical situation. The list of all the "duties" assigned to the chastotnik is constantly expanding due to the improvements made by the developers.

The process of controlling the actions of the converter is carried out just by pressing the desired button, focusing on the data displayed on the screen. More expensive devices able to recognize more commands. The highest quality models are designed for several dozen operating modes with a change in speed and program.

The cost of installation and purchase of the converter is fully compensated within one year of operation.

List of positive functions of the frequency converter:

• The ability to equalize the input voltage.
• Ensuring pump power control.
• Creation of conditions allowing to save the electric power.
• Increase the duration of operation of pumping equipment.
• Providing the ability to work without a hydraulic accumulator.
• Stabilization of intrasystem pressure.
• Reducing the noise level of the pump.

He also works as a substitute for automation.

Negative points:

• The high cost of the device.
• Configuration and connection is usually only available to specialists.

The frequency converter works in the design of the pump as follows: with a significant drop in the pressure level in the hydraulic tank (determined using a relay), the frequency converter receives the appropriate signal and gives the command to start the electric motor. At the same time, everything is carried out “without sudden movements”, the power increases gradually, providing insurance against hydraulic overload. Currently, converter models provide regulation of acceleration time from 5 to 30 seconds.

During acceleration, the converter constantly receives information about the pressure level in the pipeline. Once this level is reached desired value, acceleration stops, the engine continues to operate at the reached frequency.

How to choose and install equipment?

The standard equipment of the pumping station consists of:

• Submersible or surface pump;
• pressure gauge;
• Hose equipped with stainless steel coating;
• Hydraulic accumulator;
• Water pressure switch.

To additional equipment include:

• Uninterruptible power supplies;
• Sensor;
• blocks;
• Control relays etc.

If the design of existing pumping equipment is not equipped with a frequency converter, then it can be implemented self-installation. Usually, in the documentation attached to the pump model, there are instructions regarding which converter a pump of this type can interact with.

In the absence of such information, it is necessary, based on significant parameters, to select the converter yourself:

1. Power level.

It is necessary to match the power of the electric drive and the converter.

1. Input voltage value.

An indication of the current at which the converter operates. Here it is necessary to take into account what potential fluctuations in the network can be (a low voltage level provokes a stop, a high voltage level causes a breakdown).

1. Pump motor category.

Single phase, two phase or three phase.

1. Limits of frequency control range.

For a well pump, 200 - 600 Hz is required (depending on what the primary power of the pump is), for a circular pump - 200 - 350 Hz.

1. Matching the number of control inputs/outputs to operational needs.

The more of them, the more options for managing the workflow.

1. Choice suitable way management.

In the case of a borehole pump, it is remote-type control, which allows control directly from home, and the circulation pump works perfectly with a remote control.

It is necessary to determine the reliability of the purchased devices indirectly by the duration of the warranty period. Accordingly, the larger it is, the better the quality.

Where to install the pump converter?

Frequency converters with hydraulic connection are installed directly on the pressure line. Without such a connection, only a water pressure sensor connected to the inverter is attached to the line.

Convert is located as close as possible to the pump, but only inside the heated room. General scheme connecting to the power supply is simple and hassle-free.

Pump transducer models

• Grundfos Cue

Converters manufactured by a company based in Denmark that manufactures pumps. As a result, these frequency converters are designed in maximum accordance with the design of Grundfos pump models. The device is responsible for the fine regulation of the operation of the entire mechanism, the performance of protective and control functions. The transducers of the Cue system are distinguished by a variety of high-quality models (more than 15 types in the range), but their cost is appropriate. In addition, the price directly depends on the frequency converter required for the mechanism of what power. Among the range of models, you can find converters for both a single-phase pump () and a three-phase one (Micro Drive FC101).

• Erman E-9

The converters of this company are budget-friendly. They are responsible for torque compensation, smooth start, pressure control and have various control modes for up to 24 numbers. Compliance with power is selected on an individual basis. There is a protective housing that protects against dust and dirt.

• Hyundai N 50

Single-phase frequency converter. Can be used in household appliances. The power level is 0.7-2.5 kW. Small-sized, which makes it convenient to install in any devices. Notable for providing fine tuning thanks to several setting modes and 16 discrete speeds. It costs about twice as much as the previous model.

• PowerFlex 40

Models of this brand are versatile and very popular. Them distinguishing feature— high-quality drive and vector control. The drive, among other things, dampens noise during engine operation, automatically picks up the speed electric motor, protects the entire mechanism from overload and overheating, ensures a smooth start. Cost comparable to Grundfos Cue.

Using the pump in autonomous water supply and heating systems

Pump models in this category are considered very productive, but they are characterized by an excessively high level of energy consumption, which, of course, makes operation difficult. Of course, frequency converters can reduce the amount of energy consumption, the level of pressure and extend the service life.

Most modern pumps are designed according to the throttling principle. The electric motors of these mechanisms are in operation at the upper power limit, that is, literally for wear. Often, due to the lack of smoothness when turned on, powerful hydraulic shocks are observed that spoil the design of the pump. To fine-tune such a mechanism, you also need to try hard.

The calculation of data for pumping equipment is always based on the power limit, although the mechanism experiences the maximum load only occasionally at peak water consumption, which happens infrequently. The rest of the time, the implementation of work at the limit of possibilities is completely unjustified. Just at such moments, the frequency converter for the circulation and borehole pumps reduces energy consumption by 30 - 40%.

Among other things, the use of a frequency converter in the pump station that provides water delivery helps to prevent the problem of "dry running". It is relevant in cases where there is no water inside the system, and the engine is running further. Due to the “dry run”, the engine may overheat and the mechanism as a whole may break. This once again proves the need to use a converter.

Single-phase frequency converter for a pump within a domestic water supply system

Ergonomics of devices is a very significant indicator in the framework of consumer services. Improving this parameter for a water supply system using a low-power single-phase pump model is difficult, since this requires a converter with an input / output voltage level of 1x220V, and it is not easy to find one.

Usually household pumps have no complaints about energy consumption, but this does not compensate for the cost of the purchase, due to its rare use.

However, the installation of the converter does not lose its relevance, since it helps to maintain a constant network pressure. In other words, a request for comfortable operation is made here.

This option is especially important when using hot water. That is, the use of a chastotnik eliminates temperature fluctuations and changes in pressure force.

Single-phase converters are suitable for both submersible and surface pumps.

Single-phase frequency converter for home use

Converters standard type usually not equipped with a hydraulic connection. An attempt to independently upgrade the device for such needs may be useless, even if a specialist takes up the matter.

Recognizing this problem, frequency converter manufacturers have created a special single-phase frequency converter for a pump that supplies domestic water systems.

One of these converters is equipped with a hydraulic connection and capable of performing all standard chastotnik tasks.

The frequency converter for the pump (inverter) performs frequency regulation of pumps, stabilizes, automates and regulates their operation. They provide the ability to change the voltage frequency to increase the efficiency and economy of pumping equipment for water supply systems, as well as increase its wear resistance.

It has been established that an electric water pump with a frequency converter can save up to 50% of electricity, and its operation is much more convenient to control.

1 What are frequency converters?

Often, manufacturers of water pumps, even at the stage of assembling their designs, include frequency converters in them. For example, as in Grundfos pumps, which are in high demand. In more expensive models, microprocessors are used as converters, however, not all electric water pump equipment provides for frequency converters and their separate purchase and installation may be required.

Thus, you can choose both a pump with a frequency converter already included in the system with all options, or purchase them separately with the possibility of connecting additional features, depending on changing needs.

Pump inverters are a combination induction motor with a phase rotor, which operates in the generator-converter mode. It is controlled by a microprocessor equipped with great functionality, and the chastotnik itself, despite the rather complex structure, has a simple interface, thanks to which it can be easily controlled by a regular user.

The frequency controller for the water pump is installed on the electric motor, at the location of the standard terminal box or on the wall, in a special cabinet. The inverters themselves differ in power and weight and are characterized by the presence reliable protection from overload.

1.1 Why use chastotniki?

1. It protects the motor from current overloads and voltage surges.
2. It eliminates the occurrence of destructive water hammers, smoothing out the starting torques of the engines.
3. It protects the pump from idling.
4. It increases the efficiency of the pump by 30-50%, and also reduces the number of breakdowns.

All frequency converters are equipped with a special pressure sensor that automatically turns the pump on or off, while controlling that the user-set pressure in the system remains unchanged.

This makes it possible to pump freely, regardless of its temperature, and even pump aggressive liquids.

1.2 Complete sets of frequency converters

There are many types of pumps on the market with frequency regulation for any choice with different functionality. Among the pumps with a frequency converter, there are equipment equipped immediately with everything necessary to ensure the safe and economical operation of your pump, as well as those that need additional equipment.

In the first case, you will get a more expensive, versatile and robust design, and in the second - the frequency converter itself will be inexpensive, for which each option purchased will cost a little more, and its connection and configuration will have to be done by hand.

2 How to choose a converter?

What you should pay attention to when selecting frequency converters for your pump:

1. Equipment power - this determines the speed of the pump, controlled by the converter.
2. Input voltage range - the voltage level in the network at which the frequency converter retains its functionality. In this case, it is worth calculating what voltage can occur in the network. This indicator will allow the converter to "survive" the voltage fluctuations in the network, fully maintaining its performance.
3. Frequency Range - Make sure the equipment you select is producing the exact frequency that the pump mechanism and motor can support.
4. Number of control inputs - to enter various commands that may be required when controlling the pump (start, reverse, stop, emergency stop and etc.). The inputs are set by the user. If you are looking to build complex system, in this case, the more inputs, the better, for domestic use, a frequency converter with a small number of inputs is suitable.
5. Number of output signals - will be required for analog control of the converter.
6. Management method - how it is carried out operational management converter (via control inputs from a stand-alone or local console, from a PC or controller, switchable or combined control).

Given the characteristics presented, you will be able to choose the equipment that is right for your pump and for your needs.

2.1 SIRIO ENTRY 230 frequency converter for pumps (video)

3 What is needed for a quality installation of the converter?

Chastotniki are installed in a special pump control cabinet (shun) with a frequency converter or in any other place where the basic requirements for their normal functioning are met.

To be produced correct installation frequency converter, it is necessary to take into account the following nuances:

• Good ventilation must be ensured at the location of the chastotnik.
• The ambient temperature must not be lower than 10˚C or higher than 45˚C.
• The relative humidity must be less than 90%, and the installed equipment must not be exposed to water.
• There must be no flammable and flammable materials and liquids in the immediate vicinity of the frequency converter.
• The device must not be exposed to direct sunlight.
• Do not allow oil, dust or steel chips to be present nearby.
• It must be placed in a place with completely absent vibrations.
• Installation must be carried out on a stable surface without slopes.
• Do not install the equipment in an area of ​​electromagnetic interference.

Also note that the higher the inverter is installed above sea level, the higher its power rating will be.

Using the recommendations presented, you can choose a frequency converter for pumps that is perfect for organizing the operation of your water pumping equipment. Various models are perfect for downhole equipment, as well as for fountain and other compressors that are used in residential and private homes.

Frequency converters for deep pumps are used in artesian water supply systems as an alternative to a water tower. Artesian pumping stations, which use frequency converters, are much cheaper than a water tower, they exclude water hammer in the water supply system, increase the life of deep pumps, improve the performance of the water supply system and save 25-40% of electricity.

Despite all their advantages, frequency converters sometimes lead to annoying disappointment due to problems that arise when starting a deep pump. It would seem that everything was done correctly, the frequency converters were selected not according to the pump power, but according to its rated current, all parameters were set, and at start-up the pump accelerates to 20 - 25 Hz and the frequency converter turns off due to overcurrent. You would not wish such a situation to anyone, they bought frequency converters, but there was no result.

Let's look at the main reasons why we “sin” on frequency converters and the main practical techniques that sometimes help to “persuade” frequency converters and, under adverse circumstances, they will still ensure the normal functioning of an artesian pumping station.

Let's start with the fact that a good half of the artesian deep-well pumps work with rewound electric motors, whose operating current is much higher than the nominal passport value for these pumps. So it turns out that we choose frequency converters according to the rated current of the pump, and the real current is much higher. In such situations, all our "gadgets", which we will consider below, may not help, therefore, when choosing frequency converters, do not be too lazy to measure the real current of the deep pump - after all, every electrician has a current clamp.

Now about the submersible wire, with the help of which the frequency converters are connected to the artesian submersible pumps. This wire is not cheap, and some people “save” on its cross section, choosing a smaller one to make it cheaper. Do not do this, you want the voltage drop over the entire length of the submersible wire to not exceed 2% of nominal value supply voltage. The calculation of the wire cross section is simple and can be carried out by anyone who has not forgotten Ohm's law. If you count not hunting, then you can use the table that is given in some passports for submersible pumps. For example: motor power 2.2 kW, current 6 A, with a wire length of 70 meters, its cross section must be at least 1.5 mm. square, and with a length of 200 meters - 4 mm. square.

With high mineralization of artesian water, especially in the presence of chalk, sometimes there is a "sticking" of bearings and impellers to the pump housing. In such cases, the frequency converters are unable to accelerate the pump and trip due to overcurrent. To exit this situation, it is necessary to turn on the pump in the opposite direction. In this mode, downhole pumps operate with less load, and frequency converters can accelerate the pump, after which it is necessary to restore the working direction of rotation. These manipulations can be carried out manually, or you can program the frequency converters so that they automatically do this themselves at each start.

If your real motor current does not exceed the rated current of the frequency converter, if the cross-section of the water-immersed wire is normal, if nothing “sticks” to you, and the frequency converters turn off when the pump is started due to overcurrent, then you can reduce the switching frequency, for example , up to 1 kHz. Oddly enough, but reducing the switching frequency sometimes helps to solve the problem of starting a deep pump. Why frequency converters in such cases “work” better, we will not consider in this article, but simply note for ourselves that this is due to wave processes flowing in a long line, which is a motor cable connecting frequency converters with deep-well pumps.

Further, frequency converters take into account the load torque characteristic of the drive mechanism and are optimized for the quadratic dependence of load torque on speed for operation with pumps. However, the dependence of the load moment of a deep pump on its speed is somewhat different from the quadratic dependence of the moment of cantilever and monoblock pumps, especially at low speeds, where deep pumps very often get stuck. To overcome this "inconsistency" it is necessary to abandon the optimized quadratic dependence and choose a constant load moment characteristic, as for screw and scroll compressors. At a constant torque, frequency converters accelerate the deep pump without problems, but their efficiency, in terms of energy savings, is somewhat worse. Therefore, the deep pump must be accelerated with a constant torque, and after acceleration, switch to a variable torque characteristic.

It is easy to see that the problems mentioned above arise when the frequency converters are selected head to head according to the rated current of the deep pump without any margin. Let's choose together with you a frequency converter for a deep pump, for example, ETsV 6-10-120, with a power of 5.5 kW with a rated current of 14 A. A specialized frequency converter VLT FC 202, with a power of 7.5 kW with a rated current of 16 A and with current overload of 110% for 60 seconds at first glance is quite suitable, but operating practice shows that with this choice you constantly have to deal with problems starting the pump. If you choose a frequency converter of the following standard size, with a power of 11 kW with a rated current of 24 A, then you will not even guess about the existing problems of starting deep pumps. The stock never hurts, frequency converters will work in light mode, which favorably affects their reliability and durability, in addition, spare parts are supplied for frequency converters with a power of 11 kW and above, and for 7.5 kW and below they are not supplied. As for the cost, 11 kW is 25% more expensive than 7.5 kW - the choice is yours.

And in conclusion, I would like to draw your attention to the fact that the service center not only talks about real problems and how to deal with them, but also sells frequency converters as an official distributor of Danfoss, and we will be grateful if you buy them from us. You also benefit from working with service center, because everyone can sell, but not everyone can make repairs or solve problems that arise in the process of work.

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 and what functions a 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 medium price category, are designed according to the principle of throttling. 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 hydraulic shocks, 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, pump equipment always calculated from the power limit parameter, however, in the mode maximum load the pump works 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

A frequency converter for water supply pumps is an electrical device that converts the direct voltage of the mains into an alternating voltage according to 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 design element 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 technical passport indicate which particular converter is suitable for this equipment model.

1. Power - the voltage converter is always selected based on the power of the electric drive to which it is connected.
2. 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.
3. 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.
4. The number of strokes and control outputs - the more of them, the more commands and, as a result, the operating modes of the converter, you can configure. Automation allows you to set the speed at start-up, several modes of maximum speed, acceleration rates, etc.
5. 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.