Centrifugal submersible pump: water equipment. Well pumps

Autonomous water supply  - This is the dream of almost every resident of our country. This is due to the quality of water in the central system, which is getting worse and worse every year.

And the first question that needs to be solved when arranging a water well is the choice of a pump. After all, it is he who will be needed to transport water from the soil to consumers.

The main purpose of these power units is to supply water from the well to the pipeline network.

Their choice will largely determine the organization of the entire water supply system. Depending on this, there is a certain separation of pumps according to several criteria.

Installation location:

• deep. As the name implies, they plunge directly into the column of a water well and from there deliver water;
• superficial. They can be installed both in close proximity to a water source, and in a specially organized place - a pump chamber;

Operating principle:

• centrifugal. It consists of several rotating diffusers that create pressure in the pipe;
• vortex. Pumping occurs by rotation of the impeller;
• screw. This is a rotary type pump in which the required pressure is generated by the driven screws;
• vibrating. In his device there is a plastic diaphragm, the movement of which pushes a certain amount of liquid to the surface.

Each of these types of pumping equipment has a number of advantages and distinctive features. In order to understand the specifics of their application, you should consider the principle of operation of all the above units.

Submersible

This type of pumping equipment is part of a common water supply system. It is installed directly in the well and is constantly in the water.

To connect it, it is necessary to conduct an electric cable in a waterproof sheath.

There are several ways to activate submersible pumps:

• manual. A control unit with a button or switch is installed on the surface, which includes a mechanism;
• automatic start from capacity filling sensors (float in the storage tank), or when pressure drops in the accumulator. This is the most applicable way, since it fully automates the operation of the entire system.

When choosing a submersible pump, you should be very careful about its characteristics. They should be fully suited to the well parameters and device control method.

The most important of them are:

• performance. It shows the volume of water that the device can pump for a certain time - m³ / hour;
• pressure value - characterizes the ability of the pump to raise the water table by a certain number of meters. In this case, not only the depth of the well, but also the horizontal sections of the water supply should be taken into account. Their calculation does in the ratio 1:10. Those. if the well is 20 m deep and the horizontal part of the pipeline is 15 m, then the minimum pressure should be at least 20 + 15/10 \u003d 21.5 m;
• composition of water. It is necessary to take into account the composition of the water in the well. There is a special borehole pump for dirty water, which can, without prejudice to its condition, carry out filtering and pumping liquids. But there are also models for which the presence of small particles is fatal - there is a rapid wear of the mechanism.

Modern designations of these parameters on the pumps are as follows - 30/28. Those. the pump model is capable of pumping 30 m³ / h with a current head of water of 28 m. This is called the operating point of the equipment.

Now, knowing the technical characteristics of the choice, it is worth starting the analysis of the pumps according to the principle of operation.

Centrifugal

The principle of operation of a centrifugal or self-priming pump is based on the creation of a turbulent water flow by rotating one or more diffusers.

  Photo: centrifugal borehole pump

Due to the fact that the planes of the diffusers are turned in the opposite direction from the rotation of the rotor, there is an intensive absorption of fluid into the receiving pipe.

Principle of operation:

• when the blades rotate, excess pressure forms, as a result of which the water begins to move;
• after a certain amount of it has passed up the pipeline, the next batch of water enters the pump casing due to the same pressure;
• then the cycle repeats.

This type of equipment is one of the most popular when organizing simple water supply systems. Centrifugal borehole pumps belong to an affordable price category, easy to install and connect.

However, the outfit with this they have disadvantages:

• low mechanical strength of the diffuser. If there are pollutants in the water (sand, garbage, etc.), the diffuser can quickly fail. Therefore, it is recommended that you first equip the well with a bottom filter;
• before the first start-up, water should already be in the pump cavity. Otherwise, liquid will not flow to the surface.

Whirlwind

The device of vortex pump models includes several components.

  Photo: vortex pump

For its normal operation requires a constant flow of air from the outside. When the impeller rotates, a mixture of air masses and the working fluid located in the unit body is created.

After the resulting mixture enters the working chamber, its separation occurs, as a result of which the air exits through the supply pipe, and the working fluid begins to circulate in the chamber.

This creates an artificial vacuum, which initiates the absorption of water from the well.

This type of pump is characterized by low efficiency and can be used for shallow wells.

Screw

The main working part of this device is a screw pair consisting of a stator and a rotor.

  Photo: screw borehole pump

The stator has a direct shape and is connected directly to the electric motor. The junction is securely isolated. By means of the transmission pair, the rotational movements are transmitted to the stator, which in its shape is close to the screw.

A distinctive feature of this equipment is a fairly large self-priming rate - up to 10 m.

But at the same time, their use is limited by the depth of immersion - up to 15 m. This is a very reliable mechanism that can ensure the transfer of a large volume of water.

Vibrating

This type of pump refers to inertial action equipment.

  Photo: vibration pump

The principle of its operation is based on fluid oscillations due to changes in the geometry of the working chamber of the device. This is due to the movement of the piston rod, which, when exposed to alternating current, begins to move.

In this case, a hydraulic shock is created in the chamber, as a result of which water begins to move in the pump tank.

When the pump is connected to the mains, the armature attracts a magnet located on the rod. Since the voltage in the network has a sinusoidal shape, then every half a period the magnetization reversal of the poles occurs, as a result of which the piston returns to its original position due to the shock absorber.

The advantages of this type of pumping equipment include:

• reliability. This is due to the simple design of the pump;
• low requirements for water purity.

  Disadvantages:

• relatively low immersion depth - up to 5 m;
• during operation, vibrations are created that can damage the loose walls of the well.

In addition to all the above-described household devices, there are specialized ones. For example, sucker rod pumps, which are designed to pump oil from wells.

Important! They work very efficiently, but their operation requires special ground equipment. Therefore, boom models are not yet used in private water supply.

Surface

If the well depth does not exceed 8 meters, then the use of a surface pump is possible.

  Photo: surface borehole pump

It is installed either in the immediate vicinity of the well, or at a small distance from it. When choosing it, you must pay attention to the characteristics and high-quality check valve.

This part of the unit is responsible for the functioning of the entire system. Often, it is because of it that a quick failure of the equipment occurs.

Since the installation is not designed for direct contact with water, its housing must be protected from atmospheric precipitation.

To a greater degree, surface aggregates are used to create additional pressure in water pipes passing along the surface. This can reduce the load of the downhole pump installed in the well.

Principle of operation

All deep pumps  for wells necessary to supply drinking water through a pipeline to the consumer.

They are installed directly in the well and the following conditions are necessary to ensure their operation:

• power supply. For this, the power cable in a special sealed enclosure is connected to the device body;
• if the pump needs a constant flow of air, then from its body to the surface of the idea a flexible air hose.

The principle of operation of each model was considered above. But the main indicator for everyone is compliance with technical parameters - performance and pressure.

Mounting

The installation procedure of the pump in the well is crucial for its further operation.

For bulk mounting, you should determine the following parameters:

• the dimensions of the equipment should be smaller than the size of the well;
• power parameters must comply with operating conditions;
• the presence of a power connection.

In addition, stabilization equipment that protects the pump device from voltage surges, grounding and a flexible pipe with shutoff valves will be required.

Important! Before installation, it is necessary to dismantle the well head and carefully insulate the junction of the pump cable with the main power line.

Then a loop is put on the ear of the pump, which must be passed through the carabiner of the head. In the lowering process you need to follow. So that the electric cable and cable do not get tangled and are constantly at a certain distance from each other.

As soon as the equipment reaches the desired depth, the loop on the carabiner of the head is tightened and further strengthened. Then there is a connection to the main water system and the installation of shutoff valves.

Video: Installation

Repairs

Failure of the pump is often associated with non-compliance with operating conditions. Therefore, before installing the equipment, you must carefully read the instructions for use.

The main causes of malfunctions are:

• device operation without water. For most submersible pumps, water must be present during the first start-up and further operation. If this is not, then there is a high probability of engine overheating;
• if a voltage regulator is not installed, then, in the event of differences in the network, the electric motor may also be damaged;
• some models are very demanding on the composition of water. In particular, this applies to centrifugal, where the entire volume of liquid passes through the impeller. If there are small particles of dirt in it, moving parts can be damaged, and in the worst case, the engine rotor will jam and overheat.

If any of the above causes a breakdown, it is necessary to get the pump out of the well, disconnect it from the mains and the pipeline.

If you have experience conducting restoration work, you can try to repair it yourself. But it is best to contact a specialized repair company.

Often, cuffs and oil seals are needed to replace the compartments. It is recommended that they be replaced at least 2 times a year.

Video: pump stuck in the well, what needs to be done

How to choose

The right choice of one or another model is fundamental when arranging autonomous water supply.

In order for it to be optimally close to the existing system parameters, it is necessary to find out the following parameters:

• well parameters - depth and dimensions;
• debit. This indicator indicates the maximum amount of water that can be obtained from the well in a certain time. This is necessary to select the optimal power of the pumping equipment;
• pump parameters - power and height of the water column. Power is needed to calculate the amount of water supplied to the system based on 1 person. On average - 200 l / day.

And only after that you can start choosing a specific model.

Centrifugal submersible pumps are the most common type of equipment for pumping water, used both in the home and for production needs. Surface pumps can reach a maximum of 8–9 meters.
  For its rise from deeper water intakes, models are used that can work in the water column. Next, we will tell you: what is the principle of operation of a submersible centrifugal pump, how this equipment is classified and completed. To understand this issue will help and video in this article.

All about centrifugal pumps

A distinctive feature is the following principle: the fluid in the housing moves under the influence of the force arising from the movement of the impeller. In this case, the camera in which it is located has a constant volume.
So:

• Only the group of vane pumps, which belongs to the class of dynamic ones, works this way. In turn, blade units are divided into: axial and centrifugal. For example, the principle of operation of volumetric pumps is completely different.
    The difference between these groups of equipment is that in volumetric pumps, fluid is absorbed and then expelled from the chamber by reducing its volume.

Centrifugal pumps have their own classification, and we will give it in the form of a table:

	What is the difference between centrifugal pumps?
1.	Horizontal or vertical execution of the housing and, accordingly, the placement of a shaft in it. Centrifugal can have one and the other embodiment.
2.	The number of impellers or steps. Single wheel pumps vary in shaft location. It can be hidden in the case, or act as a console beyond its contours. These units are called console.
4.	One-way or two-way water supply to the working chamber.
5.	According to pressure characteristics, they are divided into 3 types: low, medium and high pressure.
6.	Liquid is drained from the working chamber in two ways: turbine and spiral.
7.	It features centrifugal pumps and a housing connector: transverse and longitudinal.
8.	According to the speed of the impeller, the pumps are divided into three groups: normal, low-speed and high-speed.
9.	The method of connecting the engine to the housing also plays a role. There are drive models equipped with a pulley or gearbox, but there are options, and most of them are where the engine is connected using a coupling.
10.	By the type of pumped liquid, all pumps are distinguished, and not just centrifugal ones. These are pumps for clean water, for fecal sewage, for drainage, for aggressive or viscous liquids.

• If we talk about dynamic pumps, as such, they include a large group of pumping equipment. These include surface and submersible centrifugal pumps; screw pumps; vortex; disk electromagnetic. As you can see, the list is not small.
• The leading position in it is occupied by centrifugal submersible pumps: the principle of operation of this equipment allows you to pump significant volumes of water, lift it from great depths, and deliver it over long distances. They are ideally suited for installation in deep wells and wells, just in each case, you need to choose the right pump power.

The difference in technical specifications can be huge. There are small models weighing 5-7 kg, and there are units above human growth.
  Take, for example, submersible centrifugal pump  ESP. This is a powerful unit, with a feed up to 2000m - it is used for installation in oil wells.
  For the extraction of water from deep, mainly used are pumps of the ECV type. The price of any pump unit depends not only on its power, but also on the completeness.

Design and completeness of centrifugal pumps

As we have already said that the main part of a centrifugal pump that provides the movement of water in the working chamber is that it is mounted on a shaft and moves freely. The wheel consists of a pair of disks located at a short distance from each other.
Connect their smoothly curved blades that rotate in the opposite direction:

• The inner space of the wheel, limited by the planes of the disks, and intersected by the blades, forms channels that are filled with water when the pump is turned on. In most models, the impellers are enclosed in a chamber.
    But there are options for pumps with an open impeller - they can pump water with a certain content of suspended particles. It is such a modification that you can see in the photo below.

• In the process of the mechanism, under the action of a certain force, the liquid is ejected from the impeller. Thus, a vacuum is created inside its channels, and pressure rises at the periphery.
  In order for the water pressure to be stable, the flow of fluid to the wheel, as well as the outlet from it, must be continuous.
• For water drainage, inside the case there is a spiral chamber expanding towards the exit. At its end there is a diffuser with a pressure pipe connecting during installation with the pipeline.

But in order to make this connection and start the pump in operation, it must be equipped with a certain set of devices and connecting fittings.

• First of all, it is a non-return valve with a filter screen. The valve holds water in the working chamber, filled before starting the engine, and the grid does not allow large suspensions in the mass of water to enter the pump housing. The same valve is placed on the pressure pipe - it prevents the outflow of fluid back to the unit.
• In addition, control valves are installed on the pressure pipe and on the suction part. A safety valve is installed behind the valve located on the pipeline. Its task is to protect the feed pipe from water hammer.

• In the upper segment of the housing, a valve must be installed to remove air when filling the pump. A gulf device is also included. In addition, the pump is equipped with two devices: a pressure gauge for measuring pressure, and a vacuum gauge necessary to determine the rarefaction index on the suction pipe.
• If a centrifugal pump is included pumping station, then it can be additionally equipped with a start-up protection device, and devices for regulating the process of equipment operation in automatic mode.

Such a kit is always accompanied by the manufacturer's instructions and an installation diagram, with which you can prepare the pump for operation and connect it to the pressure pipe with your own hands.

The operation of centrifugal pumps used for wells proceeds according to this scheme: the rotation of the wheel contributes to the generation of kinetic energy that enters the blades.

Centrifugal force moves the fluid located in the area of \u200b\u200bthe wheel into the body of the device, and new water flows instead of it under a certain pressure.

The continuous rotation of the wheel also facilitates the passage of fluid, which is pressed against the wall before being pushed into the hole. The pressure in the pump becomes lower at the inlet, and vice versa on the wheel, it comes to high values. The advantage of this type of equipment is continuous fluid supply.

Types of Submersible Pumps

Pumps submersible type be divided into many classes. Pumps are classified according to their use, features and main characteristics. The most popular with self-priming and normally suction pumps. Such an apparatus may contain many stages or be single-stage. Due to its properties, self-priming units are able to function in water with a high gas content.

The most popular varieties of pumps are:

• horizontal single-stage pumps in the form of a console. Used to work with various liquids, which are similar in chemical composition to water;
• horizontal pumps with many stages contribute to the creation of high heads in the presence of a small fluid supply;
• sand. This is a kind of "suction pump", necessary for working with industrial wastewater;
• fecal pumps are necessary in order to pump liquids with a huge number of polluting particles.

Submersible pumps are also divided into:

• semi-submersible
• submersible.

The first group of equipment is characterized by comfort in maintenance and ease of operation, however, for their installation it is necessary to be extremely careful and always comply with the requirements. Otherwise, the equipment will not guarantee correct operation. Semi-submersible type pumps are advisable to be mounted on level wells.

Submersible pumps are another matter. This type of equipment is ready for installation on absolutely any surface, and there will be no difficulties with installation. Even a layman can correctly install such a device. The only drawback of this pump is the sensitivity of the apparatus to the presence of large particles in water.

Centrifugal Pump Repair

Modern pumps used for work in the wells are high-quality equipment that is designed for continuous and fairly high loads. However, it also happens that the device suddenly ceases to function, thereby violating the entire scheme of water supply to the house. Often it is not known which element allowed the device to be turned off. In this regard, the question arises: where should I start the diagnosis?

First of all, you should check whether the shaft of the electric motor with the impeller rotates freely. This element seizes up when foreign objects hit it. If these objects are not detected on time, the stator winding of the electric induction motor will surely burn.

If everything is in order with the shaft, we assemble the lower part of the engine, but disassemble its upper part by placing the pump vertically. This situation will save you from oil leakage. Remove the cover by unscrewing the bolts. A starting capacitor, as well as a bundle of wires, come across my eyes. We give the scheme to help.

We pick up a multimeter and use it to measure resistance on the windings of an electric motor. The starting winding should have a resistance of 35-40 Ohms, and the working one - 10-15 Ohms. With a resistance of equal infinity, a breakdown such as a winding break can be diagnosed. Too little resistance indicates that an interturn internal circuit has occurred in the windings.

If you cannot figure out how to repair submersible pumpBetter seek professional help.

Most of our fellow citizens who own a suburban area have to solve many problems. One of these is the organization of a centralized water supply system. This element is fundamental to creating a comfortable environment. The fact is that without it it is impossible not only to live comfortably away from civilization, but also to provide watering of plants.

Most often solve a similar problem by using a pump. However, in order to choose the most suitable model, it is necessary to take into account the source of water. If water will be supplied from deep sources, such as wells, wells, the submersible pump would be the best choice. Although there are various models in the category of similar devices, still the best opt for centrifugal plantsthat provide the most efficient water supply from the wells.

Submersible centrifugal pump: principle of operation

The design of the centrifugal pump provides for special wheels having a predetermined rotation speed. It is they that make it possible to create centrifugal forces that ensure the circulation of water.

If we talk in more detail about the design of centrifugal pumping units, then it includes following items. Surely it presents steps, the amount of which directly affects the height of the water rise. Most often, single-stage models are offered on the market. However, their effectiveness is low, due to their inability to provide the necessary pressure force.

To serve deep water sources, it is best to choose multi-stage pumps. In them, each step takes part in creating pressure, and together they ensure the efficiency of the entire apparatus.

The impellers used in such pumps may vary in diameter. Actual depends on him installation performance. In other words, this affects how much water the selected device can deliver for a certain period of time.

Among the advantages possessed by such devices, it is worth highlighting high reliability and performance. Most often, they are made using special materials with high quality and wear resistance. Particular attention is paid to areas where maximum friction is created. They are coated with a special coating or they place graphite inserts there.

For submersible centrifugal pumps there are many advantageswhich make them the preferred option:

• high level of performance and reliability;
• high durability;
• high rate of efficiency;
• the ability to provide optimal pressure;
• water flow is continuous;
• it is possible to ensure the transportation of water to a considerable height;
• lack of difficulties in operation and maintenance;
• affordable price.

At the same time, such installations have one serious drawback: they are designed to transport exclusively pure water. If these pumps are used to pump dirty liquid, this ends with their breakdownas for submersible centrifugal pumps of any type. The fact is that the ingress of impurities and foreign substances into the hydraulic system leads to its clogging, due to which the impeller can no longer work in normal mode.

All submersible type centrifugal pumps on the market can be presented in the following groups:

Based on the number of steps used, they distinguish: single-stage and multi-stage.

Depending on the degree of pressure, the pumps are divided into models with low, medium and high pressure.

Depending on the type of water supply to the impeller, models are distinguished single and double feed.

Based on the location of the shaft, these pumps can be classified into models with horizontal and vertical position.

Based on the housing connector, the pumps can be classified into horizontal and vertical.

Depending on the method of removing water from the impeller into a special channel, these units are spiral and turbines.

Based on the speed of operation, the pumps can be divided into slow, normal and fast.

On the basis of such a feature as a method of connecting an electric motor, drive and clutch models.

Residential centrifugal pump models designed for domestic use are more compact and have lower power. Their capabilities do not allow them to be used to carry out large volumes of work, they are most effective for providing water supply to small objects.

Self-installation of a submersible pump

It is advisable to entrust the execution of such work to qualified specialists. However, not all owners can afford their services. In this case, you can install the submersible pump yourself.

Materials

First you need to take care about the availability of the necessary elements:

If you need water for watering plants in the yard, you will have to prepare a hose;

Work technology

In technological terms installation procedure  Such equipment includes the following steps:

• We connect a pipe or hose to the pump.,
• Then you need to connect the cable;
• If you need to change the location of the water pump, this must be done carefully and never take up the cable and hose. Otherwise, you can inadvertently damage it, which in some cases can result in a complete failure of the device;
• The safest way to move the device is to use a safety cable for this purpose;
• After that, you can lower the pump, then you should check it and carry out a test run;
• It is necessary to allow the device to work for an hour, after which it is turned off, thereby giving it a break.

In the next three days, special attention should be paid to whether there are problems in the operation of the pumping unit. If the device copes with its task, then you can start using it in normal mode.

Repair of centrifugal submersible pumps

If you find certain malfunctions in the operation of the pumping equipment, the first thing you need to inspect the device. The fact is that individual malfunctions can be eliminated by the owner on his own, without resorting to the services of specialists.

Most often, the pump motor contains mineral oilwhose main task is to provide cooling of the winding and create additional insulation. In household models, it is represented by one phase and two windings, among which one is working, and the other is starting. A non-polar capacitor is connected to the latter. It has a capacitance equal to 10-40 uF. The design of the pump is used asynchronous electric motor  with one phase.

• If you find a malfunction in the pump, then first you need to find out if there are problems with the rotation of the motor shaft equipped with an impeller. There are frequent situations when foreign objects penetrate the cochlea, which cause jamming of the shaft. If you do not remove them in a timely manner, this can lead to combustion of the motor stator winding.
• Having not found any problems with the shaft, the rotation of which is free, it is necessary to assemble the lower part of the engine and disassemble the upper one. When doing this work, remember that the pump must remain upright at all times. Otherwise, oil will flow from its body.
• After the bolts holding the cover are unscrewed, it must be removed. Next, you get access to the wires and the start capacitor. To simplify the task of repairing a centrifugal submersible pump, it is desirable to have a diagram of this device. Then it will be easier for you to understand where and which components are located.
• Using a multimeter, it is necessary to determine the resistance of the motor windings. Regarding the working winding, the value of this parameter is usually 10-15 Ohms. For the launcher, it is 35-40 ohms. If during measurements it was found that the resistance indicator tends to infinity, then this is a hint that the winding is damaged. In some cases, the device may show an extremely low resistance value. Based on this, we can conclude that an internal inter-turn fault has occurred in the windings.
• If you were able to find out exactly what kind of malfunction occurred in the pump, you must try to fix it on your own. A failed part should be replaced with a new one, after which the pump can successfully fulfill the task assigned to it.

What determines the cost of the pump

The models of submersible-type centrifugal pumps that are offered today in online stores, as well as at points of sale for home goods and repair differ in prices. Moreover, the last parameter is determined by the technical capabilities of the device and the manufacturer. Sometimes consumers decide to purchase them directly from the manufacturer, immediately drawing up a service agreement with him.

The assortment of the domestic market of domestic water pumps is represented by models manufactured by Russian and foreign companies. If we talk about devices of domestic production, then in terms of performance they can compete on an equal footing with imported samples. At the same time, the price of these devices is often lower. For this reason, pumps, manufactured by Russian companies, and are in high demand among consumers. By purchasing such equipment, the owner gets the opportunity to save on their repair and maintenance. Also, he does not have problems with the acquisition of spare parts, which are available in a wide range in any specialized store.

Conclusion

Choosing a centrifugal pump to solve water supply problems, it will not hurt the owner to know about his device and the principle of operation. Quite often, many people have to independently service such installations, so knowledge of the design features of this device can be very useful for proper pump setup and repair in case of trouble. This primarily concerns Russian-made models, since they have a simple device, and spare parts for them are affordable for every domestic consumer.

We have developed our own resource laid down in them by designers, you just need to follow the rules for their operation. Often, mean, dry phrases from the instructions remain incomprehensible to us, which means they don’t "come to mind", we simply ignore them. And in vain, for the price of this burnt downhole pump, the village left without water. Let's start with the design of the well pump.
Submersible water pump consists of a submersible water-filled electric motor and a centrifugal borehole pump, usually with several stages. The steps are mounted on the shaft of the pump 11 and with the help of ties 3 are attached to the base 16 of the pump. On the other hand, an electric motor is attached to the base.
   The stage of the centrifugal submersible pump consists of a cage 7, in which a ring 8 and a blade vane 6 (LO) are fixed, as well as an impeller 9 (PK), mounted on the shaft of the borehole pump using a key 12. The spacer bushings 10 are fixed to each other on the shaft of the RC .
The shaft bearings are the upper and lower rubber bearings. The upper bearing 4 is located in the housing 5, to which the head of the pump 1 with a check valve 2 is attached. The head has a tapered thread for connecting the pump to the lifting column.
   Bearings are lubricated by pumped water.
   The lower end of the ECV pump shaft and the rotor shank of the electric motor rotor are interconnected by means of a clutch 15 and keys 13 and 17.
   Adjusting washers 14 are installed between the shaft and the shank to set the necessary clearance between the RC and the LO.
   The borehole pump electric motor is a three-phase asynchronous with a squirrel-cage rotor and an insulated neutral wire. The windings of the phases are connected by a star.
   On the stator housing 20, upper 19 and lower 24 bearing shields are fixed, as well as a ring 25 for attaching the bottom 30 with thrust axial bearing elements to the stator housing. Each shield has two bearings 21. A package of plates of the magnetic circuit 22 is pressed inside the stator housing, forming grooves for laying the stator winding. The stator winding is made of a special winding wire type PVDP with polyethylene insulation, capable of ensuring the operation of the motor completely immersed in water. The ends of the windings are brought to the surface using an immersion cable 18 type runway.
   The rotor 23 has a conventional squirrel cage design with aluminum or copper conductors. A heel 26 is fixed at the lower end of the rotor using a key and a retaining ring. The heel and thrust bearing 27 together with the sphere 29 form a thrust bearing assembly for absorbing hydraulic axial forces, as well as the mass of the rotor of the electric motor and pump for wells.
   Before installing the submersible pump in the well, the electric motor is filled with water. Water is drained through a special plug 28 in the bottom. Water is used to lubricate bearings and cool the stator. The base is covered with a mesh to prevent large mechanical impurities from entering the well pump.

Having more or less clarified for ourselves how the submersible pump is designed for wells, we will understand more clearly the requirements that manufacturers impose on the operating conditions of the submersible well pump. Conventionally, they can be divided into installation and workers. The first covers the range of rules for preparing for installation and its implementation, the second - the range of rules that must be observed when operating an electric pump.

Before mounting the submersible pump into the well, the following work and checks must be done.

In some cases, during prolonged transportation or storage, the preservative compound hardens and washing twice is not enough. In such cases, it makes sense to leave the electric motor filled with water for a day. This must be done without fail if the pump shaft for the wells does not rotate.

To check rotation, a number of holes are provided on the coupling, where the lever is inserted. In some cases, rotation can be checked from the head of the submersible pump using an allen wrench (or a screwdriver in the case of four-inch pumps) worn on a mounting nut from the upper end of the pump shaft. In the event that for some reason the shaft does not rotate, or rotates with difficulty, jamming, its operation in the well will necessarily lead to failure. In the best case, the service life will simply be reduced. Suppose a preservative is not sufficiently washed, or polystyrene RK has injection flows. Both that, and another after some time of work of the submersible pump will be eliminated, however the increased moment of resistance, and, consequently, the increased load current until the moment of elimination will contribute to electrothermal aging of the insulation of the stator winding.

Filling with water is carried out through a special hole in the upper bearing shield of the electric motor, which is closed by a mesh stopper-filter during operation. Some designs of electric motors have mesh plugs filters instead of drain plugs. In this case, the filling of the well pump engine occurs spontaneously in the well, when the pump is immersed in water. After immersion, before starting the well pump, wait at least 15 minutes to completely fill the engine with water. It is strictly forbidden to lower the submersible pump into the well without a drain plug. This is due to the fact that it increases the likelihood of sand and other mechanical impurities contained in the pumped water getting into the engine, which leads to abrasive wear of the heel and thrust bearing, subsidence of the motor shaft and the submersible pump and, as a result, mechanical damage to the RC and LO.
   The most important electrical parameter of an electric motor is the insulation resistance of the stator winding, which is measured after the motor is filled with water.

In the case when the drain hole is closed with a strainer plug, it is possible to measure the insulation resistance when a submersible pump is immersed in a tank such as a bathtub or barrel. It is important that the well pump motor is fully submerged. This is not entirely convenient. Long-term practice of incoming control of electric pumps coming from the factory has shown that if the resistance measured "dry" has a value of more than 500 MΩ, then, as a rule, in the filled state, the resistance value will be normal. This is due to the fact that if there are defects in the insulation, the humidity contained in the atmospheric air will noticeably reduce the value of the insulation resistance. You can use this circumstance and not fill the engine with water. However, if the resistance is below 500 MΩ, the measurement will have to be done in a state filled with water.
   After checking the insulation resistance of the electric motor, a current-supply cable is connected to its terminals.

The measurement is made by attaching the test lead to one end of the megohmmeter, and a metal vessel with water to the other end of the device. It is important to verify the integrity of the insulation of the winding and the lead-in cable with the connection point before lowering the pump into the well, since possible cable damage during installation will be reliably determined only in this case.

When installing a submersible water pump in a well, the following requirements must be observed:
   First of all, the current lead cable spoils during installation. Defects occur due to cable bending, mechanical damage to the riser pipes, cable damage to the casing when the submersible water pump is lowered into the well.

In other words, it is important to protect the cable from mechanical damage during installation work, since with normal insulation resistance of the engine and the joints, the unit will have to be dismantled if the total resistance of the cable-engine system is below 10 MΩ.
   After installation of the submersible pump and the head of the well, it is necessary to connect the wellhead equipment and casing with the grounding circuit of the pumping station in accordance with the EMP.

When installing a downhole pump in the filter zone, the cross section of the well at this location is significantly narrowed. In this case, the flow rate of pumped water in this section sharply increases, which leads to the removal of sand from the filter. As a result, the abrasive wear of the working parts of the pump for wells will lead to its failure.

The calculation of the electrothermal regime of a submersible water pump takes into account the cooling effect of the water flow around the stator. The speed of this flow for normal cooling should be at least 1 m / s. This condition is achieved by matching the diameters of the casing and the submersible pump. Suppose a 6 "pump is located in an 8" or 10 "column, and the cross section between the column wall and the stator surface will be larger and the flow rate will decrease, impairing cooling. This in turn will cause an increase in the stator temperature, and hence the windings, which is inevitable will lead to accelerated aging of the insulation and its deterioration.This circumstance dictates another requirement related to
operating conditions.

With a fully closed valve, the flow rate is zero, therefore, the flow rate of cooling water around the stator is also zero. Hence the increase in temperature of the winding and accelerated wear of the insulation. Any wear of the insulation leads to a breakdown on the housing and the failure of the submersible pump.
   For the same reason (accelerated wear of insulation), the frequency of turning on the well pump is limited.

Each inclusion of a pump for wells is accompanied by inrush currents that determine the occurrence of modes similar to emergency ones.

The switching frequency is determined by the action of automation, which turns on the pump for wells when the lower water level in the tower is reached and turns off the pump when the upper water level in the tower is reached. The difference in altitude is determined by the design of the level sensor, which is designed so that at the highest flows of the submersible pump, the maximum frequency will remain below the permissible level.
   Based on our long-term practice of servicing pumps for wells, we have given those moments of pre-installation preparation, installation and operation of submersible pumps, the neglect of which most often led to the failure of the water pump.

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