Frequency drive for pump. Operating principle and installation rules for a frequency converter for a pump. What is needed for high-quality installation of the converter

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Frequency converter for pump 220V (for single-phase pumps) is an electronic device that controls the turning on and off of the electric pump, regulating its operation depending on the supply conditions existing at each specific period of time. This device is designed specifically for household systems, where water supply is required for a relatively short time and usually has a pronounced consumption schedule.
Functions:
. Protection against “dry running”, which occurs when there is insufficient water in the suction.
. Automatic restart after pump shutdown due to dry running.
. Digital pressure display on the device screen.
. LEDs and indications on the display indicate the operating modes of the device, as well as the occurrence of errors.
. Emergency shutdown and notification of system failures.
. Digital input device for float or connection to external device control.
. Electrical connectors for convenient cable connection.

The pump starts to operate at maximum speed, and then gradually adjusts to work depending on the pressure required in the system. Thus, the outlet pressure is constant, ensuring more comfortable consumption.
The pressure is adjusted according to the maximum time interval (this value is set using the “Cool mode” parameter from 5 to 30 minutes, in accordance with the type of pump) during which water will be supplied to the consumer. After the set period, if there is still a demand for water supply, the pump motor starts to run at maximum speed to avoid overheating caused by reduced ventilation.

When all sources of consumption are closed, turning off the pump and subsequent cooling of the engine allows the control time to be reset for the next pump cycle (from its start). This time is calculated depending on the pause time and the operating time (one minute of pump rest corresponds to one minute of regulation in the next cycle).

Application:
. Electronic devices flow and pressure control.
. Frequency converters (inverters) for constant pressure control.
. Dry running protection.

Specifications:
Mains power: monophase 230V ±10% - 50/60Hz.
Output voltage: monophase 230V~.
Maximum engine power: 750W - 1hp
Maximum current per line: 6A, 230W~.
Maximum permissible pressure: 800 kPa (8 bar).
Maximum temperature liquids: 30°C.
Pressure loss: 0.7 bar at 150 l/min.
Switching pressure adjustment range: 1.5÷5 bar.
Hydraulic connection: male/female thread 1".
Modulation range electrical voltage: 230÷170 V.
Protection class: IP65.

Building life support systems use many pumps. They perform a wide variety of functions. The most famous of them is the circulation pump for heating systems. Besides circulation pumps in systems for various purposes the following are used:

• pumping units to increase pressure, necessary to supply water to the building when there is insufficient pressure in the city water supply system;
• circulation pump for heating systems;
• pumps for DHW systems, providing supply hot water at any time at any tap;
• pumps for removal and drainage of waste and dirty water;
• pumps for fountains and aquariums;
• pumps for fire protection applications;
• pumps for cold water and cooling systems;
• pumping units using rainwater for toilets, washing machines, cleaning or watering;
• borehole pumps

Today the pump is the most common and is used almost everywhere. Open the faucet and water will flow out, pumped by the pump. Each car has several pumps for oil, fuel, water, and coolant. A cyclist will not hit the road without pumping up his tires. When making an electron tube, the air is pumped out of it. Pumps pump, deflate, pump out and pump air, water, oil, milk, gasoline and even cement. From a water supply to a rocket, from a fan to a nuclear power plant - this is the range of applications of pumps.

But the pump itself cannot work. To operate it, you need an electric motor and a pressure or vacuum control device for vacuum pumps. The most famous and common method of regulation in a pumping system is regulation by a damper when the engine is running at full speed, and the pressure in the system is controlled using shut-off valves(valves, valves, bends, ball valves, etc.). If we draw parallels with driving a car, then throttle control looks something like this: the driver, pressing the gas pedal all the way, regulates the speed of the car with the brake pedal.

Allows you to control pumps more rationally and efficiently frequency converters, with the help of which the engine is supplied required quantity energy to create and maintain the required level of pressure/vacuum in a system, for example in a pipeline. In this case, up to 50% savings in energy consumption are achieved, and if we take into account that during its service life the engine consumes electricity in an amount that far exceeds its cost, then this indicator turns out to be extremely relevant. For example, during a year of operation for 8 hours a day, an 11 kW engine will consume electricity in the amount of about 85 thousand rubles. Frequency converter with such operating parameters, it will pay off within a year, and in the future it will bring profit to the enterprise.

Let us consider the methods described above for regulating pressure in a pumping system in more detail.

The top picture shows typical diagram calculating the required pump power. The pump power for a specific system is always calculated based on the level of maximum consumption, that is, with a certain margin. The blue line shows the pump curve - the supply part of the water supply system, which reflects the dependence of the discharge pressure on the fluid flow rate (flow). The red line is the system curve - the consuming part of the water supply, which also displays the interdependence of fluid flow and pressure, but in a mirror image. The intersection of these curves is the optimum point, when the pump provides the required flow and the required pressure level.

But in fact, the system operates in this mode extremely rarely, only at times of peak consumption. The rest of the time, the design power of the pump turns out to be excessive, and then in systems without regulation or using a damper, the following happens: when the flow rate decreases, the pump creates overpressure, the creation of which requires additional energy. The figure below clearly shows this.

The use of frequency converters, by reducing engine speed and, as a consequence, the supplied power, allows you to change the “pump curve” by adapting it to the “system curve”

Benefits of operating a water supply system with a frequency converter
High efficiency 90%
Low energy costs,
constant pressure in the system,
no need for automation
no need for maintenance
no expansion tank needed
no need for maintenance
no taps, couplings and tees are needed for diagnostics and draining of the expansion tank and automation,
implementation into any system MODBAS, IZERNET, PROFIVAS, etc.
control of pressure, switching on, by timer, night-day modes from any panel, computer, data is always on the screen before your eyes.
Monitoring current, voltage, faults, breaks, short circuits of the pump motor.

Pump control for water supply systems

As you know, water consumption for household and household needs fluctuates greatly throughout the day, during weekends and holidays. Many people take a shower, do laundry, wash dishes at the same time certain hours days and hardly use water at other times, for example, at night. This creates conditions for the occurrence of problems such as poor water pressure in the morning and evening hours, significant daily fluctuations in pressure in the water supply system and, as a result, accelerated wear of pipes and shut-off valves.

Fortunately, today pressure stabilization is not so challenging task. Today, the issue of increasing the overall efficiency of water supply system management is more pressing, that is, achieving maximum results with minimal energy consumption and minor investment in equipment modernization. Usage frequency converters at pumping stations allows you to brilliantly cope with this task. Statistics show that a frequency converter can reduce energy consumption at pumping stations by 30 to 50%, and their payback period ranges from one to one and a half years.

The figure on the left shows how to start a pump motor using a contactor.

The figure on the right shows starting a pump with a frequency converter.

This saving is achieved due to the fact that frequency converter capable of changing the speed of the electric motor smoothly over a wide range. In fact, this means that the pump motor will always consume exactly as much energy as necessary to maintain stable pressure, regardless of the current consumption of the water supply system at that particular moment. Smooth start, stop and change in engine speed also allows you to avoid hydraulic shocks in pipelines, reducing water losses and increasing the life of trouble-free operation of the pump, pipeline, shut-off and control valves and measuring instruments.

The video shows the principle of operation of a frequency converter in a pumping station

Selecting a frequency converter for pumps

Control Systems company offers frequency converters for solving a wide variety of pump control problems:

• control of single low-power pumps,
• cascade control of a group of pumps with replacement,

We work with many manufacturers of frequency converters KEB, OMRON, DELTA, VESPER, OPTIMELECTRO and will help you choose the frequency converter that suits your needs. single phase motor as well as for three-phase.

Most common industrial models of frequency converters can be used to control pumps, but for this they need to be programmed in a special way.

Frequency converters for pumps are adapted devices and show best results when working with pumping equipment. Frequency converters for pumps are more economical and functional in their field.

Device models and analogues

The table below shows brief overview several models optimized for pump control. Detailed information on models can be obtained on the card of the corresponding frequency converter.

Model	Power range	Entrance	Exit	Protection level	Ambient temperature	Notes, features
PD20	0.75…18.5 kW	3F 380V	Output frequency 0…50/60 Hz	IP65	-10…+40°С	Full-featured, high-protection inverters, motor-mountable, specialized for multi-pump applications
	0.37…2.2 kW	1F 220V	Output frequency 0…50/60 Hz	IP65	-10…+40°С	Full-featured inverters with a high level of protection, can be mounted on a motor, specialized for single small pumps
	15…315 kW	3F 380V	Output frequency 0…400 Hz	IP20	-10…+40°С	Scalar control, multi-function outputs and inputs, full range of pump functions
	0.75…400 kW	3F 230V 3F 460V	PID	IP20	-10…+50°С	Specialized models
	0.75…220 kW	3F 230V 3F 460V	PID	IP20	-10…+40°С	Specialized models available
	0.4…4 kW	1F 220V 3F 380V	Output frequency 0…600 Hz	IP20	-10…+50°С	For pumps and fans

Applications for frequency converters for pumps

Pump drives are optimized for the following applications:

• Ventilation and air conditioning systems (compressors, etc.)
• Housing and communal services, water supply and sewerage systems, heating (hot/cold water pumps, boiler room equipment, sewerage)
• Energy (equipment of thermal power plants, combined heat and power plants, boiler units)
• Technological lines in the processing industry (sand, slurry pumps)
• Other pumping units (pumping stations for water supply networks or power distribution points)
• Submersible, borehole pumps

Despite the above applications, such devices are also suitable for general industrial use.

Purpose of frequency converters for pumps

• Optimized control in pumping systems to maintain certain parameters at a given level (pressure, temperature, level, flow, water consumption)
• Group pump control
• Saving water and electricity at enterprises, resource conservation at pumping stations
• Protection of pipelines from water hammer, increasing the service life of fittings
• Complete protection of electric motors in pumping installations
• Automation of pumping stations

Advantages

Frequency converters for pumps have the following advantages:

• Typically have more high level protection
• Thanks to their specialization, they implement the most efficient control in pumping systems
• In most cases, they are multifunctional devices capable of fully automating a pumping station

Flaws

The shortcomings of devices are influenced by the control principles used in them. Depending on whether it is a scalar or vector converter, it has certain disadvantages. (links to pages)

Operating principle of frequency converters for pumps

The frequency converter for pumps converts the input power voltage into the output voltage that is optimal for the selected operating mode of the pump. In this case, a control loop is formed in the system with feedback on the selected parameter (for example, water pressure in the water supply system). The pressure sensor transmits information to the electronic unit of the inverter, and the converter, in turn, changes the output (frequency, voltage) in one direction or another to maintain constant water pressure in the pipeline.

Examples are presented in the figures:

Pumping station for two pumps
(automatic pressure maintenance, starting an additional pump from the network)

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

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

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

Let's look at the features of the device and the use of some of them.

Simple controller

The electronic relay has a flow sensor, which allows you to determine the presence or absence of water flow in the pipes. If the regulator indicates that there is no water in the pipeline, the device turns off the pumping equipment. There are many types of controllers on sale, differing in functionality and appearance. The simplest of them are equipped only with a flow sensor. The most advanced models can combine the functions of limit pressure control to turn the unit on and off, as well as protection against dry operation.

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

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

Controller with additional options

Such an improved controller for pumping equipment can:

• control the pressure using the built-in pressure gauge;
• the device may attempt to automatically restart the pump after a certain period of time;
• set the lower pressure threshold to turn on the unit;
• control the upper and lower pressure thresholds (these are universal units that combine a pressure regulator and a flow sensor).

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

Electromechanical devices for protection against dry operation

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

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

Float mechanism

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

Voltage stabilizers

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

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

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

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

Types of stabilizing devices:

• thyristor;
• relay;
• electromechanical.

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

Frequency converter for pump

Various devices are used to control pumping equipment:

1. An alarm relay is required to switch off a running pump due to changes in operating mode.
2. In order to switch circuits in the required sequence, an intermediate relay is needed.
3. As we already wrote above, to protect against power surges you will need a voltage relay.
4. To count the time for performing a certain operation, a timer is needed.
5. To monitor pressure in the pipeline and control automatic circuits, an electric contact pressure gauge is useful.
6. To measure the temperature of bearings and seals, you need a thermostat.
7. Level sensors provide a signal to start or stop the unit due to changes in pressure or liquid level.
8. The vacuum relay maintains a given level of vacuum in the device chamber or in the inlet pipeline.
9. A jet relay is used to control the movement of liquid in pipes.

Important: The frequency converter is especially important in systems with multiple pumps.

Advantages of using a frequency converter to control a pump:

• The engine starts smoothly. This helps reduce the impact of mechanical loads on pumping equipment. In addition, reducing starting currents reduces the risk of water hammer. The absence of water hammer has a beneficial effect on the durability and integrity of the entire hydraulic structure.
• Thanks to this resource pumping unit is spent more economically. This will extend the service life of the equipment.
• Using a frequency converter helps save energy.

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

• High price of the device. Even for the purchase of low-power pumps, the cost of such a converter will be quite high.
• The pump control converter can only be used if the cable length is no more than 50 m.

Uninterruptible power supplies

To ensure constant power supply to pumping equipment, special uninterruptible power supplies (UPS), also known as voltage converters, are used. The operating principle of this device is based on the fact that when there is current in the electrical network, it charges special batteries. When there is a power outage, the unit consumes electricity from the batteries. At the same time, it transforms D.C.(12 V), producing alternating (220 V).

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

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

In our article we looked at the essentials additional equipment, which is necessary to facilitate pump control, increase its efficiency, and protect against failure in the event of changes in operating conditions.

ANS with frequency converter

In the “Pumps” section we will consider automatic pumping stations with frequency converter. These stations are intended for supply in systems autonomous water supply clean water, which does not contain chemically aggressive substances, mechanical and long-fiber inclusions with a constant specified pressure. The frequency converter (inverter), smoothly changing the engine speed, ensures constant pressure in the water supply system regardless of water consumption, thereby saving energy, increasing efficiency and implementing basic protective functions(full engine protection, pump protection from running in “dry running” mode), increasing the service life of the automatic pumping station. Automaticpumping station with frequency converter consists of centrifugal pump, driven by an asynchronous motor, frequency converter and . The operation of the frequency converter is controlled by a pressure sensor with an analog output, 4-20 mA, which is mounted on the pressure pipe of the pump.

Main characteristics and design

Main characteristics of pumping stations with frequency converters:

• Temperature environment: from +1ºС to +40ºС;
• Maximum relative humidity: 50% at +40ºС (without condensation)
• Protection class: IP-54
• Temperature of the pumped liquid: from +1ºС to +40ºС;
• Type of pumped liquid: water that does not contain chemically aggressive substances and solid suspensions;
• Rated motor power: up to 2.2 kW (3 HP);
• Frequency converter input voltage:

Inverter IMTP 2.2kW x 1~(100-244)V / for pump 3~(100-244)V (50-60 Hz);

Inverter ITTP 2.2kW x 3~(200-440)V/ for pump 3~(200-440)V/ (50-60 Hz);

• Frequency converter output voltage: depending on input voltage and motor characteristics;
• Frequency at the output of the frequency converter: 0-55 Hz;
• Nominal electric current at the converter input: 11 A for (IMTP), 6.5 A for (ITTP);
• Rated electric current at the converter output: 10 A for (IMTP), 6.0 A for (ITTP);

The design of a pumping station with an inverter is shown in (Fig. 1). It consists of a centrifugal pump driven by an asynchronous motor, a frequency converter, an analogue pressure sensor, a hydraulic accumulator (with a capacity of 19, 20 or 24 liters as standard), a pressure gauge, connecting fittings and electrical connections.

1. Pump - This is the main element of an automatic pumping station.
2. Hydraulic accumulator used for correct operation of the pressure sensor and increasing the reserve volume drinking water, regulating the number of pump starts and stops, and also serves as a base for mounting the pump.
3. Frequency converter (inverter) serves for smooth start and stop asynchronous motor, controls the pump drive according to a given operating algorithm, and also provides complete engine protection. The speed of the electric motor is adjusted by changing the frequency AC and the magnitude of the voltage supplied to the engine. The inverter is attached directly to the place of the standard terminal box of the pump motor. The inverter is cooled by air supplied by the motor fan.
4. Pyaternik used for convenient and quick installation pressure sensor, pressure gauge and flexible hose.
5. Flexible hose with an angle used to connect pumping equipment to a hydraulic accumulator
6. Pressure gauge used for visual monitoring of pressure on and off of an automatic pumping station.
7. Connection cables are used to connect the frequency converter to the mains power supply and connect the pressure sensor to the inverter.

Installation, electrical connection and adjustment

Before installing the station, you must select the correct installation location. It is recommended to mount the station with the inverter in a pit, ground floor or basement on a horizontal, level surface, in a dry, ventilated and weather-protected place. The station can be connected directly to water supply network or draw water from a container. It is necessary to make sure that the total pressure in the water supply network and the maximum pressure created by the pump does not exceed the maximum operating pressure (nominal pressure) of the pump itself and the accumulator. On the suction and pressure pipes immediately before automatic station It is necessary to install shut-off valves and detachable connections for ease of dismantling and repair.

Suction pipe:

1. must have the same nominal bore as the suction pipe of the pump, or, if possible, one size larger.
2. should be as short as possible, without truncation of diameter and sharp turns. The longer the suction line, the more resistance it creates, and the less depth the pump can lift water to the surface.
3. must be positioned so that it always slopes upward towards the pump. Avoid education air jams in the suction pipe.
4. must be sealed and prevent liquid leaks or air leaks. All connections must be carefully checked for leaks.
5. must always be installed with a mesh to prevent air from entering the pump and pipeline after the pump is stopped. Check valve with mesh also protects the pump and downstream equipment from large particles such as leaves, branches and insects.

Pressure pipe:

The diameter of the pressure pipeline is calculated based on the number of water points and the maximum possible water consumption.

Electrical connection:

These automatic pumping stations with a frequency converter are manufactured and configured, as a rule, according to individual order and for specific tasks. Full assembly installation and configuration of the station takes place in service center. From the electrical connections, the consumer only has to plug the plug into a grounded socket if the frequency converter is monophase IMTP, or supply 380 V power with a four-wire cable if the frequency converter is three-phase ITTP. Electrical connections The ITTP frequency converter is shown in (Fig. 2) power section.

The frequency converter has an input filter, thanks to which possible interference in the power supply network is eliminated. In addition, the inverter is equipped with a built-in overcurrent fuse, guaranteeing absolute protection for the motor, which has a rated power not exceeding the rated power of the frequency converter.

The IMTP monophase frequency converter is installed on asynchronous three-phase motors with a voltage of ~220 V, 50/60 Hz. The windings of such a motor must be connected in a delta circuit if the motor is designed for a voltage of 230V in delta / 400V in star.

The ITTP three-phase frequency converter is installed on an asynchronous three-phase motor with a voltage of ~200-440 V, 50/60 Hz. The windings of such a motor must be connected in a star if the motor is designed for a voltage of 230V in delta / 400V in star.

(Fig. 3) shows the motor connection diagrams using the “delta” and “star” circuits.

The inverter can operate pumps with a power of up to 2.2 kW (3HP) and a frequency of 50 to 60 Hz. The frequency converter is equipped with output current protection; There is no need to install additional protection devices between the inverter and the pump in order to protect the motor in case of an emergency.

(Fig. 4) shows connectors for connecting control signals: , or , as well as a connector for connecting frequency converters to a cascade.

The station with a frequency converter must be connected to the electrical supply network in accordance with current safety standards and regulations. The equipment connection point must be equipped with the following components:

• Equipment protection device (RCD) with a rated leakage current of 30 mA
• Automatic switch with a minimum gap between contacts of 3 mm.
• Grounding

Setting up the frequency converter:

After assembling an automatic pumping station with a frequency converter in a service center, it is installed on a stand for hydraulic testing and adjustments. It is necessary to fill the suction pipe and the pump itself with liquid and remove all air. To automatically adjust the frequency converter to the pump parameters, it is necessary to disconnect the hydraulic accumulator and install a shut-off valve at the outlet pipe behind the pressure sensor. To enter the “ENGINE PARAMETERS” settings, you must first enter the PASSWORD. Then you need to set the rated current of the motor, which is indicated on the nameplate. When starting for the first time, you need to check the correct direction of rotation of the engine by observing the rotation of the fan. The direction of rotation can be changed by changing the value of the parameter: "MOTOR PARAMETERS", rotation from 0 to 1. At the first start, the frequency converter determines the maximum operating characteristics of the pump. After testing, you must “SAVE DATA”. To save the data obtained during testing, you need to select YES and confirm by pressing Enter. Then the desired one is set working pressure“SET PRESSURE” using the (+) and (-) buttons.

• Checking that the engine stops when the feed is closed: After the received data has been saved during the first start, it is necessary to open the shut-off valve on the supply, press the Start button and wait a while for the pressure to stabilize, and then slowly close the shut-off valve and make sure that the engine has stopped (after about 5 - 10 seconds ). The message “MINIMUM FLOW” will appear on the display. This value must be precisely adjusted to reliably stop the engine. The absolute value of engine stopping power is shown on the display.
• Checking the functioning of the pump when running dry: To check that the pump stops in the “dry running” mode, it is necessary to close the valve on the supply pipeline so that the pump runs in the “dry running” mode. After approximately one minute ( factory setting delay time) the pump must stop, indicating “DRY RUN” on the display. If after this time the pump does not stop, you need to set a higher value for the COS FI parameter (default value 0.55).

On the front panel of the frequency converter there are LEDs, a display and control buttons; the purpose and description of the LEDs, display indications and control buttons is shown in (Fig. 5).

The frequency converter comes with instructions for using the inverter. This manual describes in great detail the installation and connection of the inverter, commissioning, settings and emergency conditions.

Before putting an automatic pumping station with a frequency converter into operation, it is necessary to check the pressure in the air chamber of the hydraulic accumulator, which should be approximately 0.2-0.3 bar (atm.) lower than the pump start pressure. You can control the pressure level in the hydraulic accumulator using a conventional automobile pressure gauge . If the pressure is insufficient, it must be raised to the required level using a pump or compressor. If the air pressure is higher than necessary, bleed off excess air to normal.

Operation, maintenance and repair

At correct installation and compliance with operating conditions automatic pumping stations with frequency converter practically do not require maintenance and repair. For correct operation of the pressure sensor, approximately once every six months it is necessary to service the accumulator and check the air pressure in it. You can see how to properly check the pressure and set up the hydraulic accumulator . If the station will not be used for a long time (for example, in winter), it is recommended to disconnect it from the water supply system and rinse it clean water, then drain the water completely and install in a dry, heated room. Before starting to operate the station, it is necessary to fill the suction pipeline and the pump itself with water. Before starting an automatic pumping station with a frequency converter into operation after a long period of inactivity, you must make sure that the motor shaft rotates freely (not jammed) by turning it by the blower impeller.

And in conclusion, the following can be noted: the initial costs of purchasing a pumping station with a frequency converter are significant, but they more than pay off during operation, due to saving electrical energy.

Thank you for your attention.