Frequency converters for deep pumps. Frequency converters and problems of starting down pumps. What is the converter

In the article tell about how to organize automatic water supply Using the frequency converter. Consider the choice of the converter, compiling the automation system, additional features on control, management and protection of the pump asynchronous motor.

To achieve effective water supply and at the same time to ensure maximum protection of the pump engine only with the use of specialized converter techniques, made on the basis of an autonomous voltage inverter. This solution allows you to organize automation of uninterrupted water supply, used both for your own needs and industrial needs.

In independence, for what purpose a pump is used (borehole, rolling, self-priming, etc.), almost all the engines used in them can be divided into two types - single-phase and three-phase asynchronous engines. It is depending on the driving engine used in the pump, a selection of a requireful converter is selected.

What is the converter

This is an electric unit that converts the network electricity in accordance with the incoming task and an adjustable voltage output to the engine ranging from 0 to 220 V or from 0 to 380 V with a frequency of 0 to 120 or more Hz. Inside the converter is:

Unmanaged or semi-controlled Larionov Bridge, providing rectification of the network voltage, built on a semiconductor base from diodes or thyristors.
Condenser link smoothing the resulting voltage.
The key to reset the voltage recoulared during braking.
Autonomous voltage inverter based on IGBT keys, providing an alternating voltage of a given value and frequency.
Microprocessor control system responsible for performing all operations in the engine and engine protection.

The typical structure of the three-phase frequency converter made on the basis of the autonomous voltage inverter

Criteria for selecting the converter

The first thing to be taken into account is the compliance with the type of power supply network (220 V or 380 V). The second is the compliance of the power of the engine power converter, while it is desirable to have a small margin at rated power at the acquired converter (on average by 20-50%), which will ensure that it is necessary to ensure that it is necessary to turn off the system, as well as in various emergency situations.

For convenience, the converter must have a control screen. Most modern converters already in the basic configuration have built-in discrete and analog signal processing blocks, which will further build a small automation system on its database if they are not - you need to order them.

One of possible options Constructive execution of terminals used to connect discrete and analog signals to the converter

The main thing is that it should provide a pump is maintaining a given pressure value in a system of permanently changing flow rate of the water. At the same time, a slight decrease in the speed of rotation of the pumping part of the pump, made by the converter, since the pump operates with the "fan" type of load, leads to a more significant reduction in the necessary rotating electromagnetic moment and as a result - decrease in electricity costs.

Additional oven for the organization of automatic water supply

Analog pressure sensor.
Buttons start-stop system.
Water temperature sensor (for depth pumps).
Input high-speed fuses.
Output contactor.
Input and output choke (at low power can not be installed).

The "Start" and "Stop" buttons are connected to the discrete inputs of the converter and during the adjustment process, the necessary properties are purchased. Analog pressure sensor is connected to the corresponding analog input on the converter panel and is parameterized to specify the speed of rotation of the pump engine.

How the automation works

After pressing the "Start" button, the converter automatically turns on the output contactor and in accordance with the testimony of the pressure sensor starts the pump motor. After that, smoothly brings its speed to the necessary pressure to maintain a given pressure.

In the case of detecting an emergency converter or when you press the "Stop" button, the converter with the intensity required depending on the situation reduces the engine speed to a minimum and turns off the contactor.

The water temperature sensor for borehole pumps is necessary for indirect control of the pump temperature, since the use of the converter reduces the water flow rate and, as a result, worsens the cooling. This control can be neglected if the water temperature is guaranteed not to rise above 15-16 degrees Celsius.

If there is an embedded temperature sensor in the engine, it is worth connecting it to the corresponding input on the converter, it guarantees 100% engine protection from overheating during operation.

What you need to know when assembling the scheme and adjust the converter

It is necessary to carefully read the instructions for the pump and the converter. When setting up the system to the converter, you will need to record information at the rated engine speed, its power, rated current, voltage and frequency of the supply network, optimal overclocking time and braking, allowable engine overload when started and during operation.

You will need to set the functions of analog and discrete inputs and output to control the contactor. After that, choose the law of management, in this system - U / F or vector control. After that, it will be necessary to enable automatic paramitrication, during which the converter itself determines the resistance of the engine windings, calculates all the parameters for creating its mathematical model.

All necessary settings in modern digital converters can be made using a control panel with a liquid crystal indicator. A number of converter models are supplied with special softwareBy installing which on a personal computer, you can contact the control system via USB or COM.

Control panel converter

It is important to connect all the components of the automation systems and the engine correctly. Most converters have a built-in 24 V power supply, which can be used when drafting a circuit and creating an indication of the system using discrete outputs and LED lamps.

Pluses of using the System Converter - Pump Engine

When properly configured the converter, it controls the pressure in the water supply system and protects it from exceeding the specified pressure.

The converter itself includes the pump engine and rotates it at the speed in which the required pressure is maintained in accordance with the water consumption, usually this speed is lower than the nominal value, thereby achieving electricity savings. The engine acceleration passes for the time specified when setting the time (by the so-called ramp), this option allows not only to reduce the starting current in the system and, as a result, the engine overload, but also minimize the load on the mechanical part, so that the pump is extended and overrun Electricity.

Only with the help of the converter can effectively use the pumps with a three-phase asynchronous motor when powered from household power supply network 220 V.

The built-in protection converter is constantly monitored by the motor consumed by the motor, its rotation speed, temperature, which allows you to protect against short circuit, breaking the supply phase, jamming of the mechanical part, overload and overheating.

Frequency converter for borehole pump

This converter (inverter) is designed for frequency control of the rotor speed of the electric motor, and, consequently, the impeller of the well pump.

For this, the three-phase inverter is inverter (voltage 380 A, frequency 50 Hz) or single-phase (voltage 220V, frequency 50Hz) Current is converted into three-phase or single-phase current, but with a changing frequency and amplitude. Advantages of application frequency converter for a downhole pump:

1. Smooth inclusion of the electric motor, and therefore the entire pump. His working wheel Smoothly, gradually will dial working turns. Therefore, starting currents are dramatically reduced (for powerful, more than 10 kW of electric motors, starting currents can be 5-6 times higher than the nominal!), Mechanical load on the pump, eliminating the possibility of hydroudar. Thus, the pump resource is saved, and it can serve as a longer period. Do not forget about the well, for which the hydrowood is also not good.
2. If a borehole pump directly supplies water, bypassing membrane hydroaccumulator (for example, when watering) and at the same time waterscence less pump performance, then the frequency converter, having reduced the rotational speed of the impeller, will result in compliance with the power of the pump with the required water treatment. A decrease in power, this reduction of electricity consumption.

But along with advantages, the frequency converter has its drawbacks:

1. The length of the cable between the converter and the engine should not exceed 50 m. The cable's own capacity (which increases the length of the peak voltage on the terminals of the electric motor and the breakdown between its windings is possible.
2. The high cost of the transducer is ≈ 7-13 thousand rubles (for low power electric motors).

Currently, among well-known trademarks, the well pumps with a frequency converter produces Grundfos company (Denmark) - the SQE series, made of of stainless steel, Productivity 3.5 - 7 m 3 / h and pressure 68 - 107 meters. In addition to smooth start and power control The converters in these pumps perform the following protective functions:

- from the work "dry" (the working part of the pump is outside the water);

- from voltage jumps;

- OT of different kind overload.

Pumps grundfos series SQE is reliable, durable and economical. The only drawback is their high cost. For example. The estimated cost of the pump Sq 2-85 (3,5 m 3 performance, pressure of 109 m, the capacity of 1.15 kW) is 32 thousand rubles. And exactly the same (according to technical specifications) model with a frequency converter - SQE 2-85 is already 69 thousand rubles. That is, more than 2 times more expensive!

However, many companies produce frequency converters of different power to work with well pumps - Italtecnika Sirio (Italy), Hyundai (South Korea), Toshiba (Japan), Siemens (Germany), LLC "factory pumping equipment"(Russia), etc. So you can independently secure a smooth engine launch for the same Grundfos SQ 2-85. And it will cost cheaper. In the selection of the inverter, in principle, there is nothing complicated. The main criteria are the power of the pump engine, the necessary input and output voltages (for example, input - single-phase, 200-230 V, output - three-phase, 200-230 V).

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

Functional Purpose Frequency Converter in Pump Design

The inverter (frequency converter) provides the regulation of the pump operation much better than the relay. It works at the same time as a stabilizer, automation and workflow control. Thanks to him is provided high efficiency Device:

The level of electricity supply is reduced, if necessary, and frequency of rotation of the engine, which helps to protect the pump from premature wear.
Education is prevented in overpressure pipes.
The problem with the voltage jumps is solved, which also definitely increases the service life of the pump.

Mostly during the assembly process of the pumping station is implanted. The models of the very famous pump of Grundfos should be attributed to the number of similar devices.

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

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

The converters used may be single-phase or three-phase type.

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

All information is redirected to the automation unit. Further, the frequency converter is evaluated by determining the power level to be submitted, and, accordingly, submitting the amount of electricity required to continue operation.

As a result, the frequency converter can adjust the smoothness of the launch of the electric motors, the water pressure level and the work stop in the critical situation. The list of all assigned duties is constantly expanding in view of the improvements produced by developers.

The process of controlling the actions of the converter is carried out by only by pressing the desired buttons to the data on the data displayed on the screen. More expensive devices are able to recognize more teams. The most high-quality models are designed for several dozen operating modes with a change in speed and program.

The cost of installing and buying the converter is fully compensated for one year of operation.

List of positive frequency converter functions:

The ability to level the input voltage.
Ensuring the power adjustment of the pump.
Creating conditions that save electricity.
Increase the duration of operation of pumping equipment.
Providing work opportunities without a hydroaccumulator.
Stabilization of intrasystem pressure.
Reducing the noise effect of the pump.

He also works as a deputy automation.

Negative moments:

High cost of instrument.
Configuration and connection is usually available only to specialists.

The frequency converter works in the pump design as follows: with a significant drop in the pressure level in the hydraulic panel (determined by the relay), the frequency of the corresponding signal receives the corresponding signal and gives the command to start the electric motor. In this case, everything is carried out "without sharp movements", the capacity is growing gradually, providing insurance against hydraulic overload. Currently, the converter models provide the regulation of overclocking time from 5 to 30 seconds.

While overclocking the converter is increasingly obtaining information about what the pressure level in the pipeline is carried out. As soon as this level reaches the desired value, overclocking stops, the engine operation continues on the frequency achieved.

How to choose and install equipment?

Standard complete set of pumping station consists of:

Submersible or surface pump;
Pressure gauge;
A hose equipped with a stainless coating;
Hydroaccumulator;
Water pressure relay.

TO additional equipment Believe:

Uninterruptible power sources;
Sensor;
Blocks;
Managers relay etc.

If the design of the already existing pumping equipment is not equipped with a frequency converter, then it can be done independent installation. Usually, in the documentation pump attached to the model, there are indications as to which the transducer can interact the pump of this type.

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

Power level.

Matching is required between the power of the electric drive and the converter.

The input voltage value.

Specifying at what strength the current converter works. Here it is necessary to consider what can be potential fluctuations on the network (low voltage level provokes a stop, high - breakdown).

Pump engine category.

Single phase, two-phase or three-phase.

The boundaries of the frequency control range.

The well pump requires 200 - 600 Hz (depending on what the primary power of the pump), for the circular pump - 200 - 350 Hz.

Compliance of the number of inputs / outputs of operational needs.

What they are more, the greater the possibilities of managing the workflow.

Choice suitable way Control.

In the case of a well pump - remote control control, allowing control directly from the house, and the circulation pump works well with the remote control.

Determine the reliability of the purchased devices needs to be indirectly by the duration of the warranty period. Accordingly, than it is more, the better quality.

Where to install a transducer for the pump?

Frequency converters having a hydraulic connection are installed directly on the pressure line. Without such an connection, only the water pressure sensor connected to the IF is attached to the highway.

Convert is located as close as possible to the pump, but only inside the heated room. The overall diagram of the power connection is simple and does not cause difficulties.

Models of transducers for pump

Grundfos Cue.

Transducers manufactured by the company located in Denmark and the producing pumps. As a result, these frequencies are designed to maximize the design of the pump models from Grundfos. The device is responsible for the thin regulation of the entire mechanism, the execution of protected and control functions. CUE system converters are distinguished by a variety of high-quality models (more than 15 types in assortment), but their value is appropriate. In addition, the price directly depends on whether the frequency converter is required for the mechanism. Among the spectrum of models, you can find converters and for a single-phase pump (), and for three-phase (Micro Drive FC101).

ERMAN E-9

Converters of this company are characterized by budgetary. They are responsible for compensation for the torque, the smoothness of the launch, pressure control and possess different control modes of the number up to 24. Power matching is individually selected. There is a protective housing that protects against dust and dirt exposure.

Hyundai N 50.

Single-phase type frequency converter. Can be used in household appliances. The power level is 0.7-2.5 kW. Small-sized, making it easy to install in any devices. Notable in that it provides a fine setting due to several setup modes and 16 discrete speeds. It is about twice as much more than the previous model.

PowerFlex 40.

Models of this brand are distinguished by universality and are very popular. Them distinctive feature - Quality drive and vector control. The drive besides otherwise, shifts during the engine operation, automatically picks up the speed of rotation electric engine, protects the entire mechanism from overload and overheating, provides a smooth start. According to the cost comparable to Grundfos Cue..

Using the pump in autonomous water supply and heating systems

The models of the pump of this category are considered very productive, but differ in an overly high level of energy consumption, which, of course, makes it difficult. Reduce the volume of energy consumption, the pressure level and extend the service life allow you to explain the same frequency converters.

Most of the modern pumps are designed in accordance with the principle of throttling. Electrical motors of these mechanisms are in operation on the upper power limit, that is, literally on wear. Often due to the lack of smoothness, when turned on, powerful hydraulic blows are observed, spoiling the pump design. To accurately configure such a mechanism, it is also pretty to try.

The calculation of data for pumping equipment is always based on the maximum power level, although the maximum load does the mechanism experience only episodically during the peak water consumption, which happens infrequently. The rest of the time to work at the limit of possibilities is completely unjustified. Just at such moments, the frequency converter for a circulating and downhole pump reduces energy consumption by 30 - 40%.

Among other things, the use of a frequency converter in the pump station providing water delivery allows you to prevent the problem of "dry stroke". It is relevant in cases where there is no water inside the system, and the engine is running on. Due to the "dry stroke", an engine overheating and the breakdown of the mechanism as a whole can occur. This once again proves the need to use the converter.

Single-phase frequency converter for the pump within the water supply system

Ergonomics of instruments is a very significant indicator within the framework of domestic services. Improving this parameter for the water supply system using a low-power single-phase pump model is difficult, since this requires a transducer with an input / output voltage level of 1x220V, and find such difficult.

Typically, household pumps do not have complaints of energy consumption, but this does not compensate for the purchase costs, due to its rare operation.

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

This option is especially important when using hot water. That is, the use of the frequency eliminates the temperature surges and changes in the pressure of the pressure.

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

Single-phase frequency converter for home use

Standard type converters are usually not equipped with hydraulic connections. An attempt to independently modernizing the device under such needs can be useless, even if a specialist will take out for the case.

Realizing this problem, manufacturers engaged in the release of frequency converters created a special single-phase frequency converter for a pump providing household systems water supply.

One of the similar converters is equipped with a hydraulic connection and capable of performing all standard Tasks PLATES.

Pumps used in systems autonomous water supply and heating are productive, but at the same time the equipment is quite costly in operational terms due to high level power consumption. Reduce costs and significantly extend the service life of the pump can be complied with its frequency converter, which we will talk about in this article.

You will learn why you need and what functions the frequency converter performs. The principle of operation of such a device, their types, specifications, and recommendations for the choice of converters for boreholes will be given circulating pumps.

1 Why do you need a frequency converter?

Almost everyone modern pumpsimplemented in the budgetary and medium price categories are designed according to the principle of throttling. The electromotor of such aggregates always operates at maximum power, and changing the flow / pressure of the fluid feed is carried out by adjusting the shut-off reinforcement, which changes the cross section of the bandwidth.

Such a 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 swing water along the pipes at maximum power. Also, the problem is high power consumption and rapid wear of the system components - both the pump and shut-off reinforcement with the pipeline. Yes, and about the accurate setting of such a water supply system of the house from the well of speech can not be.

The above disadvantages are incorporated by pumps equipped with a frequency converter. This element allows you to effectively control the pressure generated in the water supply pipe or heating, by changing the value of the electricity incoming on the motor.

As can be seen in the diagram, the pumping equipment is always calculated by the parameter of the limit power, but in the 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 shows, saves up to 30-40% of electricity during the operation of circulating and borehole pumps.

1.1 Device and work algorithm

The frequency converter for water pumps is an electrical device that converts a constant voltage of the power supply into a variable on a predetermined amplitude and frequency. Almost all modern converters are made according to the double current change diagram. This design consists of a 3rd of the main parts:

unmanaged rectifier;
pulse inverter;
control system.

The key element of the design is the pulse inverter, which in turn consists of 5-8 key-transistors. Each of the keys is connected to the corresponding element of the winding of the electromotor stator. In foreign converters, IGBT transistors are used in Russian - their domestic counterparts.

The control system is represented by a microprocessor, which in parallel performs the protection functions (turns off the pump at strong current fluctuations in the power supply) and control. In the well-type water pumps, the control element of the converter connects to the pressure relay, which allows the pumping station to function in fully automatic mode.

The algorithm for the operation of the frequency converter is quite simple. When the pressure relay determines that the pressure level in the hydraulic panel fell below the allowable minimum, the signal is transmitted to the converter and it starts the pump electric motor. The engine accelerates smoothly, which reduces hydraulic loads affecting the system. Modern converters allow the user to independently set the time of overclocking the motor in the range of 5-30 seconds.

In the process of acceleration, the signal sensor continuously transmits data on the pressure level in the pipeline to the converter. After it reaches the required value, the control unit stops overclocking and supports the specified motor turn frequency. If the water consumption point connected to the pump station will begin to spend more water, the converter will increase the feed pressure by increasing the pump performance, and vice versa.

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

If the pump you use does not have a built-in frequency converter, then you can purchase and install such a power regulator yourself. Usually manufacturers of pumps in technical passport Indicate which specifically the converter will suit this model of equipment.

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 current at which the converter remains operational. It is necessary to choose with a loaf of oscillations that can be in your power grid (reduced voltage leads to a stop of the device, with an increased it may simply fail). Also consider the engine type of pump - three, two or single-phase.
The adjustment frequency range - for borehole pumps is optimal to be the range of 200-600 Hz (depends on the initial power of the pump), for circulating 200-350 Hz.
The number of moves and outputs of the control - than them are more, the more commands and, as a result, the modes of operation of the converter in will be able to configure. The automation allows you to set the speed of revolutions when starting, several modes of maximum revolutions, acceleration pace, etc.
The control method - for a well pumping station it will be the most convenient to be remote control, which can be placed inside the house, while the converter with a remote control is perfect for circulation pumps.

If you have left all the instruments on the market and faced the fact that there is simply no suitable for the characteristics of the equipment, it is necessary to narrow the selection criteria to a key factor - the current consumed by the engine, which is selected rated power converter.

Also choosing a frequency control unit, especially from domestic or Chinese manufacturers, consider the warranty service life. By its duration, it is possible to indirectly judge the reliability of the technique.

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

Rockwell Automation (Germany) is more affordable in the price plan. Company We offer a line of PowerFlex 4 and 40 converters for low-power circulation pumps and a PowerFlex 400 series for borehole pumping stations (from one converter 3 parallel to the connected pump can be opened.

Consider that the price of a good converter sometimes may come up to the cost of the pump, so the connection and configuration of such an instrument must be performed exclusively by specialists.

Automation of pumping equipment, can be considered the most an important aspect in the field of technical development of water supply and drainage systems. This is important not only for stations providing water settlements.

The smart pump for the well will make the same comfortable operation of the autonomous water supply. To do this, it is very important to correctly make the calculation of the downhole pump, and according to the calculated calculations, pick up the frequency converter for it.

The video in this article will help you do it with your own hands.

Advantages of automatic water supply

To achieve the most gentle mode of operation of the equipment, on pumping stations, everything is automated - ranging from starting and stopping the units, and ending with water flow control. Devices that help carry out total control over the system transmit signals to the scoreboard in the control room.

Approximately, only on a smaller scale, occurs and in the case of automation of the home pump. Let's consider what advantages gives the system automation.

So:

Most importantly, this is: a smooth start and stop of the pump engine, reduces the likelihood of the occurrence of hydrowards to zero, and the careful mode of operation contributes to the extension of the service life of any equipment. At the same time, the costs associated with the operation of water intake are reduced.
First of all, this is the consumption of electricity. Its price is growing steadily, and all this is felt: both individuals and enterprises. Frequency regulation The operations of the pump engines makes it possible to reduce the volumes of cumulative tanks, and even completely refuse them.

In such cases, the device is used, which is called: "Inverter control unit for a well pump" - you can see it in the photo from above. The inverter combines various combinations control deviceswhich is not equipped with the pump itself, including, has a built-in frequency converter.

Functionality and selection of the frequency converter

It is clear that the maximum water consumption occurs only at certain points, and most of the time the pump power is excessive. The frequency converter allows you to customize the system so that the pump issued a pump in the "rush hour" full powerAnd the rest of the time has reduced the turns.

From the number of rotations at a certain time of the pump wheel time, the pressure developed by them, and, accordingly, performance. The essence of the use of the frequency converter is to force the motor shaft at a specified pace. In this frequency alternating currentobtained from the power grid changes its magnitude.
Modern converters have a wide range, and are able to convert the voltage both higher and below the characteristics of the power supply. The diagram of this device is divided into two parts: a power consisting of a group of transistors or thyristors, and control, in essence, which is an electronic key.
It consists of a control part of digital microprocessors, and performs all control and protective functions. Since the structure of the power part has characteristic differences, frequency converters are divided into two groups. One of them includes appliances with a DC intermediate link.

The second group of this link does not have, and is called "frequency converters with direct link." Devices without intermediate link have a higher efficiency, and are able to "curb" the most powerful high-voltage engine. Despite the fact that the price of this option is higher, the system in which it is embedded, on costs, it turns out an order more economical.
Due to what is the savings? The fact is that such converters have a small frequency range, and it cannot be equal, or exceed the characteristics of the supply network. The regulatory frequency of the current in the network is 50Hz, and the device converts it to 30 Hz and below, right up to zero. Therefore, the consumption of electricity is reduced - here you are saving!

Such a limited range does not allow the use of transducers of this type in industrial scale. But for household pumps This is exactly what is needed.

Slection of pump for well

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

Calculation is based on such data:

Depth I.
Diameter of casing
, and if it is simpler - the distance from the water mirror in the well, to the surface of the earth with the pump running
The total daily flow consumption for the family, the content of animals and watering (calculated on the basis of existing standards)
Well remote home
Water height (the flood of the building is taken into account)
Diameter of pressure pipeline

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

If there is a cumulative capacity in the water supply system, then the pressure of the hydraulic is added to the distance of the distances. Pressure is expressed in the atmospheres, and each atmosphere is equal to 10 vertical meters.
Consider how the calculation will look like specific example. Suppose you have a well with a dynamic level of 35 m. It is 20m from two-storey house 7 m high. In this case, a hydroaccumulator was installed in the house with a capacity of 60 liters and a pressure of 3 atm.

The pressure calculation will look like this: H \u003d (35 + 20 + 7 + (3 * 10)) * 1,15 \u003d 105 meters.

If you take into account a small margin, you can buy a pump with a pressure of 110-115m. As you can see, this calculation does not represent this calculation. Now let's talk about the criteria for selecting the frequency converter, abbreviated by PE.

Selection of the converter

Concerning technical characteristics PE, then they should relate to the type and power of the electric motor to which it will connect. Next, you need to take into account the necessary range of regulation, as well as the level of accuracy of setting up and maintain torque on the motor shaft.

Constructive features of the inverter, that is, its dimensions, configuration, built-in or remote control, are also important. Overwhelming majority are installed asynchronous motors. ChP is selected to them in power, and 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 speed of rotation with variable loads, as well as work without reducing revolutions in the zero range. Such converters most accurately monitor the torque and the frequency of rotation of the shaft. This is especially important when two pumps work on the network.
In general, frequency converters have their own classification. Like any other electrical equipment, they can be single-phase and three-phase. The embodiment of the inverters can be household, for the 220V network. There are also industrial converters, up to 500V, and high-voltage - up to 6000V.
The degree of IP protection is also different. According to the type of management, PE is divided into vector and scalar. All leading manufacturers of pumping equipment are offered to the consumer and inverter blocks. Typically, manufacturers link converter models to specific pump modifications, and provide recommendations for their use.

The buyer and think is not particularly necessary above the choice: the seller's consultant will indicate you a model of a converter suitable for this pump, and will explain to you that the features of its use are concluded.