Energy efficient high voltage motor. Improving the energy efficiency of asynchronous motors. Siemens energy-saving motors are available in CEMEP efficiency classes "EFF1" and "EFF2"

Energy efficiency is understood as the rational use of energy resources, with the help of which a reduction in energy consumption is achieved at the same level of load power.

On fig. 1a, b are examples of irrational and rational use of energy. The powers Рн of receivers 1 and 2 are the same, while the losses ΔР1 allocated in receiver 1 significantly exceed the losses ΔР2 allocated in receiver 2. As a result, the power consumption ΔРp1 by receiver 1 is greater than the power ΔРp2 consumed by receiver 2. Thus, receiver 2 is energy efficient compared to receiver 1.

Rice. 1a. Irrational use of energy

Receiver 2

Rice. 1b. Rational use of energy

In the modern world, energy efficiency issues are given Special attention. This is partly explained by the fact that the solution of this problem can lead to the achievement of the main goals of international energy policy:

improving energy security;
reduction of harmful environmental impact due to the use of energy resources;
increasing the competitiveness of the industry as a whole.

Recently, a number of energy efficiency initiatives and measures have been taken at the regional, national and international levels.

Energy Strategy of Russia

Russia has developed an Energy Strategy, which implies the deployment of an energy efficiency program as part of a comprehensive energy saving policy. This program is aimed at creating the basic conditions for the accelerated technological renewal of the energy industry, the development of modern processing industries and transport capacities, as well as the development of new, promising markets.

November 23, 2009 President Russian Federation YES. Medvedev signed Federal Law No. 261-FZ “On Energy Saving and Increasing Energy Efficiency and on Amendments to Certain Legislative Acts of the Russian Federation”. This law forms a fundamentally new attitude to the process of energy saving. It clearly outlines the powers and requirements in this area for all levels of government, and also lays the foundation for achieving a real result. The law introduces an obligation to account for energy resources for all enterprises. Organizations whose total annual expenditure on energy consumption exceeds 10 million rubles are proposed to be required to undergo energy audits by December 31, 2012 and then at least once every 5 years, based on the results of which an energy passport of the enterprise is drawn up, fixing progress on the energy efficiency scale.

With the adoption of the law ‘On Energy Efficiency’, one of the key articles of the document was the amendments to the Tax Code (Article 67 part 1), which exempt from income tax enterprises using facilities with the highest energy efficiency class. The Government of the Russian Federation is ready to provide subsidies and reduce the tax burden to those enterprises that are ready to raise their equipment to the level of energy-saving technology.

Energy efficiency of electric motors

According to RAO "UES of Russia" for 2006, about 46% of the electricity generated in Russia is consumed by industrial enterprises (Fig. 1), half of this energy is converted into mechanical energy by means of electric motors.

Rice. 2. Structure of electricity consumption in Russia

In the process of converting energy, some of it is lost as heat. The value of the lost energy is determined by the energy performance of the engine. The use of energy-efficient electric motors can significantly reduce energy consumption and reduce the amount of carbon dioxide in the environment.

Main indicator energy efficiency electric motor, is its coefficient useful action(hereinafter referred to as efficiency):

η=P2/P1=1 – ΔP/P1,

where P2 is the useful power on the motor shaft, P1 is the active power consumed by the motor from the network, ΔP is the total losses occurring in the motor.

Obviously, the higher the efficiency (and, accordingly, the lower the losses), the less energy the electric motor consumes from the network to create the same power P2. As a demonstration of energy savings when using energy efficient motors, let's compare the amount of power consumed on the example of ABB electric motors of the conventional (M2AA) and energy efficient (M3AA) series (Fig. 3).

1. M2AA series(energy efficiency class IE1): power Р2=55 kW, speed n=3000 rpm, η=92.4%, cosφ=0.91

Р1=Р2/η=55/0.924=59.5 kW.

Total losses:

ΔP=Р1–Р2=59.5-55=4.5 kW.

Q=4.5 24 365=39420 kW.

C=2 39420=78840 rub.

2. M3AA series(energy efficiency class IE2): power P2=55 kW, speed n=3000 rpm, η=93.9%, cosφ=0.88

Active power consumed from the network:

Р1=Р2/η=55/0.939=58.6 kW.

Total losses:

ΔP=Р1–Р2=58.6-55=3.6 kW.

If we assume that this engine operates 24 hours a day, 365 days a year, the amount of energy lost and released as heat

Q=3.6 24 365=31536 kW.

With an average cost of electricity of 2 rubles. per kWh the amount of electricity lost for 1 year in monetary terms

C=2 31536=63072 rub.

Thus, in the case of replacing a conventional electric motor (class IE1) with an energy efficient one (class IE2), the energy savings are 7884 kW per year per motor. When using 10 such electric motors, the savings will be 78,840 kW per year or 157,680 rubles per year in monetary terms. Thus, the efficient use of electricity allows the company to reduce the cost of its products, thereby increasing its competitiveness.

The cost difference of electric motors with energy efficiency classes IE1 and IE2, amounting to 15621 rubles, pays off in approximately 1 year.

Rice. 3. Comparison of conventional electric motor with energy efficient

It should be noted that as energy efficiency increases, so does the service life of the motor. This is explained as follows. The source of engine heating is the losses generated in it. Losses in electrical machines (EM) are subdivided into the main ones, due to the electromagnetic and mechanical processes occurring in the EM, and additional, due to various secondary phenomena. The main losses are divided into the following classes:

1. mechanical losses (includes ventilation losses, bearing losses, brush friction losses on the commutator or slip rings);
2. magnetic losses (hysteresis losses and eddy currents);
3. electrical losses (losses in the windings during the flow of current).

According to the empirical law, the service life of insulation is halved with an increase in temperature by 100C. Thus, the service life of an energy-efficient motor is somewhat longer, since the losses and consequently the heating of the energy-efficient motor is less.

Ways to improve the energy efficiency of the engine:

1. The use of electrical steels with improved magnetic properties and reduced magnetic losses;
2. The use of additional technological operations (for example, annealing to restore the magnetic properties of steels, which, as a rule, deteriorate after machining);
3. Use of insulation with increased thermal conductivity and electrical strength;
4. Improvement of aerodynamic properties to reduce ventilation losses;
5. Using high quality bearings (NSK, SKF);
6. Increasing the accuracy of processing and manufacturing of engine components and parts;
7. Using the motor together with the frequency converter.

Another important parameter characterizing the energy efficiency of an electric motor is the load factor cosφ. The load factor determines the share of active power in the total power supplied to the motor from the network.

where S is the total power.

In this case, only active power is converted into useful power on the shaft, reactive power is needed only to create an electromagnetic field. Reactive power enters the motor and returns back to the grid at twice the grid frequency 2f, thus creating additional losses in the supply lines. Thus, a system consisting of motors with high efficiency values but low cosφ values cannot be considered energy efficient.

Barriers to the implementation of energy efficient electric drive systems

Despite the high effectiveness of energy efficient solutions, today there are a number of obstacles to the distribution of energy-efficient electric drive systems:

1. Replacing only one or two electric motors in the whole enterprise is not an essential measure;
2. Low level of consumer awareness in the field of energy efficiency classes of motors, their differences and existing standards;
3. Separate financing in many enterprises: the owner of the budget for the purchase of electric motors is often not the person who deals with issues of reducing the cost of production or incurs annual expenses for Maintenance;
4. Acquisition of electric motors as part of complex equipment, whose manufacturers often install low-quality electric motors in order to reduce the cost of production;
5. Within the same company, the cost of acquiring equipment and the cost of energy consumption over the service life are often paid under different items;
6. Many plants have stocks of electric motors, usually of the same type and same efficiency class.

An important aspect in matters related to energy efficiency of electrical machines, is to popularize the decision to purchase equipment based on an assessment of the total operating costs over the service life.

New international standards governing the energy efficiency of electric motors.

In 2007, 2008 IEC has introduced two new standards concerning energy efficiency of electric motors: the IEC/EN 60034-2-1 standard establishes new rules for determining efficiency, the IEC 60034-30 standard establishes new energy efficiency classes for electric motors.

The IEC 60034-30 standard establishes three energy efficiency classes for three-phase asynchronous squirrel-cage motors (Fig. 4).

Rice. 4. Energy efficiency classes according to the new IEC 60034-30 standard

Currently, the designation of energy efficiency classes can often be seen in the form of the following combinations: EFF3, EFF2, EFF1. However, the class separation boundaries (Figure 5) are set by the old IEC 60034-2 standard, which has been replaced by the new IEC 60034-30 (Figure 4).

Rice. 5. Energy efficiency classes according to the old standard IEC 60034-2.

Article taken from szemo.ru

In energy-saving engines, due to the increase in the mass of active materials (iron and copper), the nominal values of efficiency and cosj are increased. Energy-saving motors are used, for example, in the USA, and give effect at a constant load. The feasibility of using energy-saving motors should be assessed taking into account additional costs, since a small (up to 5%) increase in nominal efficiency and cosj is achieved by increasing the mass of iron by 30-35%, copper by 20-25%, aluminum by 10-15%, t .e. increase in the cost of the engine by 30-40%.

Approximate dependences of efficiency (h) and cos j on the rated power for conventional and energy-saving engines manufactured by Gould (USA) are shown in the figure.

An increase in the efficiency of energy-saving electric motors is achieved by the following design changes:

· the cores, assembled from individual plates of electrical steel with low losses, are elongated. Such cores reduce the magnetic induction, i.e. steel losses.

· losses in copper are reduced due to the maximum use of grooves and the use of conductors of increased cross-section in the stator and rotor.

Additional losses are minimized by careful selection of the number and geometry of teeth and slots.

· less heat is generated during operation, which allows to reduce the power and size of the cooling fan, which leads to a decrease in fan losses and, therefore, a decrease in overall power loss.

Electric motors with increased efficiency reduce energy costs by reducing losses in the electric motor.

Tests carried out on three "energy saving" motors showed that at full load the resulting savings were: 3.3% for a 3 kW motor, 6% for a 7.5 kW motor and 4.5% for a 22 kW motor.

Savings at full load are approximately 0.45kW, which is at an energy cost of $0.06/kW. h is $0.027/h. This is equivalent to 6% of the operating costs of an electric motor.

The list price for a conventional 7.5kW motor is $171, while the high efficiency motor is $296 ($125 surcharge). The above table shows that the marginal cost payback period for a high efficiency motor is approximately 5,000 hours, which is equivalent to 6.8 months of motor operation at rated load. At lower loads, the payback period will be somewhat longer.

The efficiency of using energy-saving motors will be the higher, the greater the load of the motor and the closer its mode of operation to a constant load.

The use and replacement of engines with energy-saving ones should be assessed taking into account all additional costs and their service life.

UDC 621.313.333:658.562

ENERGY EFFICIENT ASYNCHRONOUS MOTORS FOR A REGULATED ELECTRIC DRIVE

O.O. Muravleva

Tomsk Polytechnic University E-mail: [email protected]

The possibility of creating energy efficient induction motors without changing the cross-section for adjustable electric drives, which allows for real energy savings. The ways of ensuring energy saving through the use of high-power asynchronous motors in pumping units in the sphere of housing and communal services are shown. The economic calculations carried out and the analysis of the results show the economic efficiency of using increased power engines, despite the increase in the cost of the engine itself.

Introduction

In accordance with the "Energy Strategy for the period up to 2020", the highest priority of the state energy policy is to increase the energy efficiency of industry. The efficiency of the Russian economy is significantly reduced due to its high energy intensity. According to this indicator, Russia is 2.6 times ahead of the United States, 3.9 times ahead of Western Europe, and 4.5 times ahead of Japan. Only partly, these differences can be justified by the harsh climatic conditions of Russia and the vastness of its territory. One of the main ways to prevent an energy crisis in our country is to pursue a policy that provides for the large-scale introduction of energy and resource-saving technologies at enterprises. Energy saving has become a priority area of technical policy in all developed countries of the world.

In the near future, the problem of energy saving will increase its rating with the accelerated development of the economy, when there is a shortage of electric energy and it can be compensated in two ways - by introducing new energy generating systems and energy saving. The first way is more expensive and time-consuming, and the second one is much faster and more cost-effective because 1 kW of power with energy saving costs 4...5 times less than in the first case. Large costs of electrical energy per unit of the gross national product create a huge potential for energy saving in the national economy. Basically, the high energy intensity of the economy is caused by the use of energy-wasting technologies and equipment, large losses of energy resources (during their extraction, processing, transformation, transport and consumption), and the irrational structure of the economy (a high share of energy-intensive industrial production). As a result, a vast energy saving potential has been accumulated, estimated at 360.430 Mtce. tons, or 38.46% of modern energy consumption. The realization of this potential can allow, with the growth of the economy by 2.3 ... 3.3 times over 20 years, to limit the growth of energy consumption by only 1.25.

ny goods and services in the domestic and foreign markets. Thus, energy conservation is an important factor in economic growth and improving the efficiency of the national economy.

The purpose of this work is to consider the possibilities of creating energy-efficient asynchronous motors (AM) for controlled electric drives to ensure real energy saving.

Possibilities for creating energy efficient

induction motors

In this work, on the basis of a systematic approach, effective ways to ensure real energy savings are determined. A systematic approach to energy saving combines two areas - the improvement of converters and asynchronous motors. Taking into account the possibilities of modern computer technology, improvement of optimization methods, we come to the need to create a software-computer complex for designing energy-efficient induction motors operating in controlled electric drives. Taking into account the great potential for energy saving in housing and communal services (housing and communal services), we will consider the possibility of using an adjustable electric drive based on asynchronous motors in this area.

The solution to the problem of energy saving is possible with the improvement of an adjustable electric drive based on asynchronous motors, which must be designed and manufactured specifically for energy-saving technologies. Currently, the energy saving potential for the most popular electric drives - pumping units is more than 30% of the power consumption. Based on monitoring in the Altai Territory, the following indicators can be obtained using a controlled electric drive based on asynchronous motors: energy savings - 20.60%; saving water - up to 20%; exclusion of hydraulic shocks in the system; reduction of starting currents of motors; minimization of maintenance costs; reducing the likelihood of occurrence emergencies. This requires the improvement of all parts of the electric drive, and, above all, the main element that performs electromechanical energy conversion - an asynchronous motor.

Now, in most cases, in a controlled electric drive, serial general-purpose asynchronous motors are used. The level of consumption of active materials per unit of IM power has practically stabilized. According to some estimates, the use of serial IM in controlled electric drives leads to a decrease in their efficiency and an increase in installed power by 15.20%. Among Russian and foreign experts, there is an opinion that special engines are needed for such systems. A new approach to design is currently required due to the energy crisis. The mass of blood pressure has ceased to be a determining factor. An increase in energy performance comes to the fore, including by increasing their cost and the consumption of active materials.

One of the promising ways to improve the electric drive is the design and manufacture of induction motors specifically for specific operating conditions, which is favorable for energy saving. At the same time, the problem of adapting the AM to a specific electric drive is solved, which gives the greatest economic effect under operating conditions.

It should be noted that the production of IM specifically for a controlled electric drive is produced by Simens (Germany), Atlans-Ge Motors (USA), Lenze Bachofen (Germany), Leroy Somer (France), Maiden (Japan). There is a steady trend in the world of electrical engineering to expand the production of such motors. In Ukraine, a software package for designing IM modifications for a controlled electric drive has been developed. In our country, GOST R 51677-2000 has been approved for IM with high energy performance, and their release will probably be organized in the near future. The use of AM modifications specially designed to provide effective energy saving is a promising direction for improving asynchronous motors.

This raises the question of a reasonable choice suitable engine from a diverse range of manufactured motors in terms of design, modifications, because the use of general industrial asynchronous motors for an electric drive with variable speed turns out to be non-optimal in terms of weight, size, cost and energy indicators. In this regard, the design of energy-efficient asynchronous motors is required.

An asynchronous motor is energy efficient, in which, using a systematic approach in design, manufacture and operation, efficiency, power factor and reliability are increased. Typical requirements for general industrial drives are the minimization of capital and operating costs,

including maintenance. In this regard, and also due to the reliability and simplicity of the mechanical part of the electric drive, the vast majority of general industrial electric drives are built on the basis of an asynchronous motor - the most economical engine, which is structurally simple, unpretentious and has a low cost. An analysis of the problems of controlled induction motors showed that their development should be carried out on the basis of a systematic approach, taking into account the peculiarities of work in controlled electric drives.

At present, in connection with the increased requirements for efficiency by solving issues of energy saving and improving the reliability of the operation of electrical systems, the tasks of modernizing asynchronous motors to improve their energy characteristics (efficiency and power factor), obtaining new consumer qualities (improving environmental protection) are becoming particularly relevant. , including sealing), ensuring reliability in the design, manufacture and operation of asynchronous motors. Therefore, when performing research and development in the field of modernization and optimization of asynchronous motors, it is necessary to create appropriate methods to determine their optimal parameters, from the condition of obtaining maximum energy characteristics, and calculation of dynamic characteristics (start-up time, winding heating, etc.). As a result of theoretical and experimental studies, it is important to determine the best absolute and specific energy characteristics of asynchronous motors, based on the requirements for an adjustable AC drive.

The cost of a converter is usually several times higher than the cost of an induction motor of the same power. Asynchronous motors are the main converters of electrical energy into mechanical energy, and to a large extent they determine the efficiency of energy saving.

There are three ways to ensure effective energy saving when using a controlled electric drive based on asynchronous motors:

Improving blood pressure without changing the cross section;

Improving IM with a change in the geometry of the stator and rotor;

Choice of IM of general industrial design

more power.

Each of these methods has its advantages, disadvantages and limitations in application, and the choice of one of them is possible only through an economic assessment of the relevant options.

Improvement and optimization of asynchronous motors with a change in the geometry of the stator and rotor will give a greater effect, the designed motor will have better energy and dynamic characteristics. However, at the same time, the financial costs for the modernization and re-equipment of production for its production will amount to significant amounts. Therefore, at the first stage, we will consider measures that do not require large financial costs, but at the same time allow for real energy saving.

Research results

Currently, IM for a controlled electric drive is practically not being developed. It is advisable to use special modifications of asynchronous motors, in which the stamps on the stator and rotor sheets and the main structural elements are preserved. This article discusses the possibility of creating energy-efficient IM by changing the length of the stator core (/), the number of turns in the phase of the stator winding (#) and the wire diameter using the factory cross-sectional geometry. At the initial stage, modernization of asynchronous motors with a squirrel-cage rotor was carried out by changing only the active length. As base engine an asynchronous motor AIR112M2 with a power of 7.5 kW was taken, manufactured by OAO Sibelektromotor (Tomsk). The values of the length of the stator core for calculations were taken in the range /=100.170%. The results of calculations in the form of dependences of the maximum (Psh) and nominal (tsn) efficiency on the length for the selected motor size are shown in fig. one.

Rice. 1. Dependences of the maximum and nominal efficiency for different lengths of the stator core

From fig. 1 shows how the efficiency value changes quantitatively with increasing length. The upgraded IM has a nominal efficiency higher than that of the base motor when the length of the stator core is changed up to 160%, while the highest values of the nominal efficiency are observed at 110.125%.

Changing only the length of the core and, as a result, reducing losses in steel, despite a slight increase in efficiency, is not the most effective way to improve an induction motor. It would be more rational to change the length and winding data of the motor (the number of turns of the winding and the cross section of the stator winding wire). When considering this option, the values of the length of the stator core for calculations were taken in the range /=100.130% . The range of changes in the turns of the stator winding was assumed to be N = 60.110%. The base engine has the value No = 108 turns and n = 0.875. On fig. 2 shows a graph of the change in the efficiency value when changing the winding data and the active length of the motor. When the number of turns of the stator winding changes in the direction of decrease, there is a sharp drop in the efficiency values to 0.805 and 0.819 for motors with a length of 100 and 105%, respectively.

Engines in the range of length variation /=110.130% have efficiency values higher than those of the base engine, for example, No=96 ^»=0.876.0.885 and No=84 with 1=125.130% have n»=0.879.0.885. It is advisable to consider motors with a length in the range of 110.130%, and with a decrease in the number of turns of the stator winding by 10%, which corresponds to N = 96 turns. The extremum of the function (Fig. 2), highlighted dark color, corresponds to the given values of length and turns. In this case, the efficiency value increases by 0.7-1.7% and is

We see the third way to ensure energy saving in the fact that it is possible to use an asynchronous motor of general industrial performance of higher power. The values of the length of the stator core for calculations were taken in the range /=100.170%. The analysis of the data obtained shows that for the investigated engine AIR112M2 with a power of 7.5 kW, with an increase in its length to 115%, the maximum efficiency value n,wx=0.885 corresponds to the power Р2wn=5.5 kW. This fact indicates that it is possible to use motors of the AIR112M2 series with an increased length with a power of 7.5 kW, instead of the basic 5.5 kW motor of the AIR90M2 series, in an adjustable electric drive. For a 5.5 kW engine,

The power consumption per year is 71,950 r. One of the reasons for this fact is the reduction in the share of electricity to cover losses in the IM due to the operation of the engine in the region of increased efficiency values.

An increase in engine power must be justified by both technical and economic necessity. In the study of high-power engines, a number of IMs of general industrial use of the AIR series were taken in the power range of 3.75 kW. As an example, let's consider IM with a rotation speed of 3000 rpm, which are most often used in pumping units of housing and communal services, which is associated with the specifics of the regulation of the pumping unit.

Rice. Fig. 3. Dependence of savings over the average service life on the useful power of the engine: the wavy line is built according to the results of the calculation, the solid line is approximated

To justify the economic benefits of using increased power engines, calculations were made and a comparison was made of engines with the power required for a given task and engines with a power one step higher. On fig. 3 shows graphs of savings for the average service life (E10) from the useful power on the motor shaft. Analysis of the obtained dependence shows

economic efficiency of using high power engines, despite the increase in the cost of the engine itself. Energy savings over the average service life for engines with a rotation speed of 3000 rpm is 33.235 thousand rubles.

Conclusion

The huge potential for energy saving in Russia is determined by the high costs of electrical energy in the national economy. A systematic approach to the development of asynchronous controlled electric drives and the organization of their mass production can provide effective energy saving, in particular, in housing and communal services. When solving the problem of energy saving, an asynchronous controlled electric drive should be used, which currently has no alternative.

1. The task of creating energy-efficient asynchronous motors that meet specific operating conditions and energy saving must be solved for a specific controlled electric drive using a systematic approach. A new approach to the design of asynchronous motors is currently being applied. The determining factor is the increase in energy performance.

2. The possibility of creating energy-efficient asynchronous motors without changing the cross-sectional geometry with an increase in the length of the stator core up to 130% and a decrease in the number of turns of the stator winding up to 90% for controlled electric drives is considered, which allows real energy saving.

3. Ways to ensure energy saving through the use of high-power asynchronous motors in pumping units in the housing and utilities sector are shown. For example, when replacing the AIR90M2 engine with a power of 5.5 kW with the AIR112M2 engine, the energy saving is up to 15%.

4. The conducted economic calculations and analysis of the results show the economic efficiency of using increased power engines, despite the increase in the cost of the engine itself. Energy savings over the average service life is expressed in tens and hundreds of thousands of rubles. depending on the engine power and is 33.325 thousand rubles. for asynchronous motors with a speed of 3000 rpm.

BIBLIOGRAPHY

1. Energy strategy of Russia for the period up to 2020 // TEK.

2003. - No. 2. - S. 5-37.

2. Andronov A.L. Energy saving in water supply systems by means of frequency regulation of the electric drive // Electricity and the future of civilization: Mater. scientific-technical conf. - Tomsk, 2004. - S. 251-253.

3. Sidelnikov B.V. Prospects for the development and application of non-contact adjustable electric motors // Energy saving. - 2005. - No. 2. - S. 14-20.

4. Petrushin V.S. System approach in designing adjustable asynchronous motors. conf. IEEE-2003. - Crimea, Alushta, 2003. - Part 1. -S. 357-360.

5. GOST R 51677-2000 Electric asynchronous machines with power from 1 to 400 kW inclusive. Engines. Performance indicators. - M.: Publishing house of standards, 2001. - 4 p.

6. Muraviev O.P., Muravieva O.O. Induction variable speed drive as the basis of efficient energy saving // The 8th Russian-Korean Intern. Symp. Science and Technology KORUS 2004. - Tomsk: TPU, 2004.

V. 1. - P. 264-267.

7. Muraviev O.P., Muravieva O.O., Vekhter E.V. Energetic Parameters of Induction Motors as the Basis of Energy Saving in a Variable Speed Drive // The 4th Intern. Workshop Compatibility in Power Electronics Cp 2005. - June 1-3, 2005, Gdynia, Poland, 2005. -P. 61-63.

8. Muravlev O.P., Muravleva O.O. Power Effective Induction Motors for Energy Saving // The 9th Russian-Korean Intern. Symp. Science and Technology KORUS 2005. - Novosibirsk: Novosibirsk State Technical University, 2005. - V. 2. - P. 56-60.

9. Vekhter E.V. The choice of high-power asynchronous motors to ensure energy saving of pumping units in housing and communal services // Modern equipment and technologies: Proceedings of the 11th Intern. scientific-practical conf. youth and students. -Tomsk: Publishing House of TPU, 2005. - T. 1. - S. 239-241.

UDC 621.313.333:536.24

SIMULATION OF THE OPERATION OF MULTIPHALE ASYNCHRONOUS MOTORS IN EMERGENCY OPERATION MODES

D.M. Glukhov, O.O. Muravleva

Tomsk Polytechnic University E-mail: [email protected]

A mathematical model of thermal processes in a multiphase asynchronous motor is proposed, which makes it possible to calculate the temperature rise of the winding at emergency modes. The adequacy of the model was verified experimentally.

Introduction

The intensive development of electronics and microprocessor technology leads to the creation of high-quality adjustable AC electric drives to replace electric drives direct current and an unregulated AC drive due to the greater reliability of AC motors compared to DC machines.

Regulated electric drives are gaining the field of application of unregulated ones both to ensure technological characteristics and to save energy. Moreover, preference is given to alternating current machines, asynchronous (IM) and synchronous (SD), since they have better weight and size indicators, more high reliability and service life, easier to maintain and repair compared to DC collector machines. Even in such a traditionally "collector" area as electric vehicles, DC machines are giving way to frequency-controlled AC motors. An increasing place in the production of electrical engineering plants is occupied by modifications and specialized designs of electric motors.

It is impossible to create a universal frequency-controlled motor suitable for all occasions. It can only be optimal for each specific combination of the law and control method, the frequency control range and the nature of the load. A multi-phase asynchronous motor (MAD) can be an alternative to three-phase machines when powered by a frequency converter.

The purpose of this work is to develop a mathematical model for studying the thermal fields of multiphase asynchronous motors both in steady state and in emergency operating modes, which are accompanied by a shutdown (break) of phases (or one phase) in order to show the possibility of operation asynchronous machines as part of an adjustable electric drive without the use of additional cooling means.

Thermal field modeling

Features of the operation of electrical machines in an adjustable electric drive, as well as high vibrations and noise, imposing certain requirements on the design, require other approaches in the design. At the same time, the features of polyphase motors make such machines suitable for use in controlled applications.