In the recent past in different countries the world had its own energy efficiency standards. For example, in Europe they were guided by the SEMER standards, Russia was guided by GOST R 5167 2000, the USA - by the EPAct standard.

In order to harmonize the requirements for energy efficiency of electric motors, the International Energy Commission (IEC) and the International Organization for Standardization (ISO) adopted a single standard, IEC 60034-30. This standard classifies low-voltage asynchronous electric motors and unifies the requirements for their energy efficiency.

Energy efficiency classes

The IEC 60034-30 2008 standard defines three international energy efficiency classes:

• IE1– standard class (Standard Efficiency). Roughly equivalent to the European class EFF2.
• IE2 – high class(High Efficiency). Roughly equivalent to EFF1 class and US EPAct class at 60 Hz.
• IE3– premium. Identical to NEMA Premium at 60 Hz.

The standard applies to almost all industrial three-phase squirrel-cage asynchronous electric motors. The exceptions are engines:

• operating from a frequency converter;
• built into the design of equipment (for example, a pump unit or fan) where independent testing cannot be carried out.

Correlation of a single international standard with the norms of various countries of the world.

Capacity distribution according to different standards

The IEC 60034-30 standard covers electric motors with power from 0.75 to 375 kW with the number of pole pairs 2p = 2, 4, 6.

SEMER indicators were distributed according to efficiency for electric motors with power up to 90 kW and polarity 2p = 2.4.

Epact standards – power values ​​from 0.75 to 150 kW with a paired number of poles 2p = 2, 4, 6.

Features of standardization

Thanks to the uniform IEC standard, motor customers around the world can easily identify the equipment with the required parameters.

The IE energy efficiency classes described in IEC/EN 60034-30 are based on test results carried out in accordance with the international standard IEC/EN 60034-2-1-2007. This standard defines energy efficiency based on power loss and efficiency.

Note that Russian market Electric motors have their own characteristics. Domestic manufacturers can be roughly divided into two groups. One group indicates efficiency as the main indicator, the other does not indicate anything. This creates distrust in electrical equipment, which serves as a barrier to purchasing Russian products.

Methods for determining energy efficiency

There are two methods for determining efficiency: direct and indirect. The direct method is based on experimental power measurements and has some inaccuracy. New standard involves the use of an indirect method, which is based on the following parameters:

• initial temperature
• load losses, which are determined through measurements, evaluation and mathematical calculation

Efficiency indicators are comparable only with the same method for determining the values. The indirect method implies:

1. Measurement of power losses calculated from load tests.
2. Estimation of input power losses at rated load up to 1000 kW.
3. Mathematical calculation: an alternative indirect method is used to calculate P (power) losses. Determined by the following formula:

η = Р2/Р1=1-ΔР/Р1

where: P2 - useful power on the engine shaft; P1 – active power from the network; ΔР – total losses in electric motors.

A higher efficiency value reduces losses and power consumption of the electric motor and increases its energy efficiency.

A number of Russian standards, for example, GOST R 54413-2011, can be correlated with international standards.

The differences between Russian standards and international ones are:

• in some features of mathematical calculations to determine equipment parameters;
• in differences in units of measurement;
• in testing processes;
• in the parameters of the test equipment;
• under test conditions;
• in the features of operation.

In Russia, the same energy efficiency classes are adopted as in Europe. Information about classes is contained in passport data, technical documentation, markings and nameplates.

Other useful materials:

Energy efficiency refers to the rational use of energy resources, through which a reduction in energy consumption is achieved at the same level of load power.

In Fig. 1a, b show examples of irrational and rational use of energy. The powers Рн of receivers 1 and 2 are the same, while the losses ΔР1, released in receiver 1, significantly exceed the losses ΔР2, which are released in receiver 2. As a consequence, the power consumed ΔРп1 by receiver 1 is greater than the power ΔРп2 consumed by receiver 2. Thus, receiver 2 is energy efficient compared to receiver 1.

Rice. 1a. Waste of energy

Receiver 2

Rice. 1b. Rational use energy

IN modern world energy efficiency issues are paid special attention. This is partly explained by the fact that solving this problem can lead to the achievement of the main goals of international energy policy:

• improving energy security;
• reducing harmful environmental impacts due to the use of energy resources;
• increasing the competitiveness of industry as a whole.

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

Energy strategy of Russia

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

November 23, 2009 by President Russian Federation YES. Medvedev was signed Federal law No. 261-FZ “On energy saving and increasing energy efficiency and on introducing amendments to certain legislative acts of the Russian Federation.” This law creates 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 real results. The law introduces an obligation to account for energy resources for all enterprises. Organizations whose total annual costs for energy consumption exceed 10 million rubles are proposed to be required to undergo energy inspections until 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, recording progress on the energy efficiency scale.

With the adoption of the Law ‘On Energy Efficiency’, one of the key articles of the document were amendments to the Tax Code (Article 67 Part 1), which exempt from income tax enterprises using facilities with the highest energy efficiency class. The Russian government 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 equipment.

Energy efficiency of electric motors

According to RAO UES of Russia data 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 through electric motors.

Rice. 2. Structure of electricity consumption in Russia

During the process of energy conversion, part of it is lost in the form of heat. The amount of 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 carbon dioxide content in the environment.

The 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 electric motor shaft, P1 is the active power consumed by the electric motor from the network, ΔP is the total losses occurring in the electric 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. To demonstrate energy savings when using energy-efficient motors, let’s compare the amount of power consumed using 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, rotation speed n=3000 rpm, η=92.4%, cosφ=0.91

Р1=Р2/η=55/0.924=59.5 kW.

Total losses:

ΔP=P1–P2=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 Р2=55 kW, rotation 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=P1–P2=58.6-55=3.6 kW.

Assuming 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 kW/h the amount of lost electricity for 1 year in monetary terms

C=2·31536=63072 rub.

Thus, if a conventional electric motor (IE1 class) is replaced by an energy efficient one (IE2 class), the energy savings amount to 7884 kW per year per motor. When using 10 such electric motors, the savings will be 78,840 kW per year or in monetary terms 157,680 rubles/year. Thus, the efficient use of electricity allows the enterprise 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 15,621 rubles, pays off in approximately 1 year.

Rice. 3. Comparison of a conventional electric motor with an energy efficient one

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

• 1. mechanical losses (including ventilation losses, losses in bearings, losses due to friction of brushes on the commutator or slip rings);
• 2. magnetic losses (losses due to hysteresis and eddy currents);
• 3. electrical losses (losses in windings when current flows).

According to the empirical law, the service life of insulation decreases by half with an increase in temperature by 100C. Thus, the service life of a motor with increased energy efficiency is somewhat longer, since losses and therefore heating of an energy-efficient motor are less.

Ways to improve engine energy efficiency:

• 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 magnetic properties steels, as a rule, deteriorate after machining);
• 3. Use of insulation with increased thermal conductivity and electrical strength;
• 4. Improving aerodynamic properties to reduce ventilation losses;
• 5. Use of high quality bearings (NSK, SKF);
• 6. Increasing the accuracy of processing and manufacturing of engine components and parts;
• 7. Using the motor in conjunction with a frequency converter.

One more 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 electric 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 electromagnetic field. Reactive power enters the motor and returns back to the network at twice the 2f network frequency, thereby creating additional losses in the supply lines. Thus, a system consisting of motors with high values Efficiency, 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 spread of energy-efficient electric drive systems:

• 1. Replacing only one or two electric motors in an entire enterprise is an insignificant measure;
• 2. Low level of consumer awareness in the field of energy efficiency classes of engines, their differences and existing standards;
• 3. Separate financing in many enterprises: the budget manager for the purchase of electric motors is often not the person who deals with issues of reducing the cost of production or incurs annual maintenance costs;
• 4. Purchase of electric motors as part of complex equipment, the manufacturers of which often install low-quality electric motors in order to reduce the cost of products;
• 5. Within the same company, the costs of purchasing equipment and energy consumption over the service life are often paid under different headings;
• 6. Many enterprises have stocks of electric motors, usually of the same type and the same efficiency class.

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

New international standards regulating the energy efficiency of electric motors.

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

The IEC 60034-30 standard establishes three energy efficiency classes for three-phase squirrel-cage induction 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 boundaries (Fig. 5) were established by the old IEC 60034-2 standard, which was replaced by the new IEC 60034-30 (Fig. 4).

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

Article taken from the site szemo.ru

An economic crisis is sweeping across the world today. One of its reasons is the energy crisis. Therefore, today the issue of energy saving is very acute. This topic is especially relevant for Russia and Ukraine, where electricity costs per unit of production are 5 times higher than in developed European countries. Reducing electricity consumption by enterprises of the fuel and energy complex of Ukraine and Russia is the main task of science, electrical engineering and electronics industries in these countries. More than 60% of the electricity used in enterprises comes from electric drives. If we take into account that its efficiency is no more than 69%, then only using energy-saving motors can save more than 120 GWh of electricity per year, which will amount to more than 240 million rubles from 100 thousand electric motors. If we add here the savings from reducing installed capacity, we get more than 10 billion rubles.

If we recalculate these figures into fuel savings, the savings will be 360-430 million tons of standard fuel per year. This figure corresponds to 30% of all domestic energy consumption in the country. If we add here the energy savings due to the use of variable frequency drives, then this number grows to 40%. In Russia, an order has already been signed to reduce energy intensity by 40% by 2020.

Since September 2008, the IEC 60034-30 standard has been adopted in Europe, where all motors are divided into 4 energy efficiency classes:

• standard(ie1);
• high(ie2);
• highest, PREMIUM (ie3);
• ultra-high, Supper-Premium (ie4).

Today, all major European manufacturers have begun producing energy-efficient engines. Moreover, all American manufacturers are replacing “high” energy efficiency engines with “higher”, PREMIUM energy efficiency engines.

• Our countries are also developing energy-efficient series of engines for general use. Manufacturers face three challenges to improve energy efficiency;
• Development and development of new energy-efficient models of low-voltage asynchronous motors that correspond to the world level of development of the electrical and mechanical engineering industries for use in the domestic and international markets;
• Increasing the efficiency values ​​of newly created energy-efficient motors in accordance with the energy efficiency standard IEC 60034-30, despite the fact that the increase in material consumption used in ie2 class motors is no more than 10 percent;
• Savings in active materials corresponding to a saving of 10 kW of power per 1 kg of winding copper should be achieved. As a result of the use of energy-efficient electric motor models, the amount of die equipment is reduced by 10-15%;

The development and implementation of high-efficiency electric motors eliminates the problem of the need to increase the installed power of electrical equipment and reduce emissions of harmful substances into the atmosphere. In addition, reducing noise and vibration, increasing the reliability of the entire electric drive is an undeniable argument in favor of the use of energy-efficient asynchronous electric motors;

Description of energy-efficient asynchronous motors 7A series

Series 7A (7AVE) squirrel-cage asynchronous motors belong to three-phase asynchronous electric motors, a general industrial series with a squirrel-cage rotor. These motors have already been adapted for use in variable frequency drive circuits. They have an efficiency 2-4% higher than that of analogues produced in Russia (EFFI). They are produced with a standard range of rotation axis: from 80 to 355 mm, designed for powers from 1 to 500 kW. The industry has mastered engines with standard speeds: 1000, 1500, 3000 rpm and voltages: 220/380, 380/660. The motors are made with a degree of protection corresponding to IP54 and insulation class F. Permissible overheating corresponds to class B.

Advantages of using 7A series asynchronous motors

The advantages of using 7A series asynchronous motors include their high efficiency. Saving electricity with an installed power P set = 10,000 kW, you can save up to 700 thousand dollars/year on energy savings. Another advantage of such engines is their high reliability and service life, in addition, they have a lower noise level by about 2-3 times compared to engines of previous series. They allow for a greater number of on-off switches and are more maintainable. The motors can operate with network fluctuations of up to 10% in voltage.

Design Features

The 7A series electric motors use a new type of winding that can be wound on old generation winding equipment. In the manufacture of engines of this series, new impregnating varnishes are used, providing higher hardening and high thermal conductivity. The efficiency of using magnetic materials has been significantly improved. During 2009, dimensions 160 and 180 were mastered, and during 2010-2011. Dimensions of 280, 132, 200, 225, 250, 112, 315, 355 mm were mastered.

In energy-saving engines, due to an 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 are effective when constant load. Feasibility of application energy saving engines 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%, i.e. increase in engine cost by 30-40%.

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

Increasing the efficiency of energy-saving electric motors is achieved by the following design changes:

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

· losses in copper are reduced due to the maximum use of slots 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 grooves.

· less heat is generated during operation, which makes it possible to reduce the power and size of the cooling fan, which leads to a decrease in fan losses and, consequently, a decrease in overall power losses.

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

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

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

The list price for a regular 7.5 kW electric motor is US$171, while the high efficiency motor costs US$296 (a price premium of US$125). The table shows that the payback period for an increased efficiency motor, calculated on the basis of marginal costs, is approximately 5000 hours, which is equivalent to 6.8 months of operation of the motor at rated load. At lower loads the payback period will be slightly longer.

The higher the engine load and the closer its operating mode is to constant load, the higher the efficiency of using energy-saving engines.

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

Energy saving motors series 7A (7AVE): 7AVER 160S2, 7AVER 160M2, 7AVEC 160MA2, 7AVEC 160MB2, 7AVEC 160L2, 7AVER 160S4, 7AVER 160M4, 7AVEC 160M4, 7AVEC 160L4, 7AVER 160S6, 7AVER 160M6, 7AVEC 160M6, 7AVEC 160L6, 7AVER 160S8, 7AVER 160M8, 7AVEC 160MA8, 7AVEC 160MB8 , 7AVEC 160L8

The global scientific and technical community attaches exceptional importance to the issues of energy saving and, consequently, increasing the energy efficiency of equipment.

This attention is due to two critical factors:
• 1. Increasing energy efficiency makes it possible to slow down the process of irreplaceable decline in slowly renewable energy resources, the reserves of which remain for only a few generations;
• 2. Increasing energy efficiency directly leads to an improvement in the environmental situation.

Asynchronous motors are the main energy consumers in industry, agriculture, construction, housing and communal services. They account for about 60% of all energy costs in these industries.

This energy consumption structure exists in all industrialized countries, and therefore they are actively switching to the use of electric motors with increased energy efficiency, the use of such motors is becoming mandatory.

The 7AVE series is created using Russian standard GOST R 51689-2000, version I, and the European standard CENELEC, IEC 60072-1, which will allow the installation of new energy-saving electric motors both for domestic equipment and for imported ones, where foreign-made engines are currently used.

The 7AVE series provides for an increase in efficiency from 1.1% (larger dimensions) to 5% (junior dimensions) and covers the most popular power range from 1.5 to 500 kW.

The creation of energy-efficient motors of the 7АVE series is also harmonized with such an important area in energy saving as the development of motors for variable-frequency drives, since an energy-efficient motor has better control properties, in particular, large supply at maximum torque. A simple rule applies here: the higher the energy efficiency class of a general industrial motor, the wider its area of ​​application in variable-frequency drives.

Design features of the 7АVE series engines:
• Magnetic system.
  The efficiency of using magnetic materials and system rigidity have been increased.
• Winding of a new type.
  New generation stator winding equipment is used.
• Impregnation.
  New equipment and impregnating varnishes ensured high cementation of the winding and high thermal conductivity.

Technological advantages of motors of energy efficiency classes IE2 and IE3:
• Engines new series have low noise characteristics (3-7 dB lower than the engines of the previous series), i.e. more ergonomic. A reduction in noise level by 10 dB means a reduction in its actual value by 3 times.
• 7AVE engines have higher reliability due to lower operating temperatures. These motors are manufactured with heat resistance class "F", at actual temperatures corresponding to more than low class insulation "B". This allows machines to operate with an increased service factor value, i.e. provide reliable operation with prolonged overloads by 10-15%.
• The motors have a reduced temperature rise when the rotor is locked, which allows for reliable operation in the drive system of mechanisms with frequent and difficult starts and reverses.

Motors of the 7AVE series (IE2, IE3) are adapted for operation as part of a variable-frequency electric drive. Due to the high service factor, the motors can operate as part of a VFD without forced ventilation.

The introduction of energy efficient engines ensures:
• 1. Saving electricity consumption due to higher efficiency of motors;
• 2. Savings by reducing the installed power required to operate equipment with an energy-efficient drive.

The Vladimir Electric Motor Plant (JSC VEMZ) produces energy-efficient engines of the 7АVE series.