Introduction：
High Efficiency Motor (High Efficiency Motor) refers to the higher efficiency motor, its efficiency value can reach the GB18613-2012 standard level two. High Efficiency Motor adopts new motor design, new technology and new materials to improve the output efficiency by reducing the loss of electromagnetic energy, thermal energy and mechanical energy. Compared with the standard motor, its efficiency is increased by 4% on average.
In May 2020, China announced the latest motor energy-efficiency standard "GB18613-2020 motor energy-efficiency limits and energy-efficiency levels", the standard was formally implemented on June 1, 2021, IE3 (international standards) below the energy-efficiency motors will be mandatory discontinued, and the domestic motor industry has fully entered the era of IE3 high-efficiency.
The new national standard also stipulates that since the date of implementation of the standard, IE3 efficiency will become China's lowest three-phase asynchronous motor efficiency limit value (three-level energy efficiency), lower than the IE3 energy efficiency limit value of three-phase asynchronous motor (such as IE2 series motors, etc.) is not permitted to re-production and sales, indicating that China's small and medium-sized three-phase asynchronous motor efficiency level once again to enhance the level of a grade. The new national standard also lists IE4 efficiency as a secondary energy-saving evaluation index.
GB 18613-2020 after the implementation of the new national standard motor energy efficiency labeling difference is shown below:
| Before June 1, 2021 |
| Energy Efficiency | Labeling |
| (GB1) Grade 1 energy efficiency | IE4 |
| (GB2) Grade 2 energy efficiency | IE3 |
| (GB3) Tertiary energy efficiency | IE2 |
| After June 1, 2021 |
| Energy Efficiency | Labeling |
| (GB1)Grade 1 energy efficiency | IE5 |
| (GB2) Grade 2 energy efficiency | IE4 |
| (GB3)Tertiary energy efficiency | IE3 |
For the new version of the motor energy efficiency standard GB18613-2020, Shanghai Electrical Apparatus Research Institute (Group) Co., Ltd. special adviser to the president of Mr. Chen Weihua that fans, pumps supporting the use of electric motors in the scope of the GB18613 standard, but fans, pumps unit efficiency is not covered by the standard limitations; braking motors, inverter special motors and other special design motors is not in the scope of application of the standard Within the scope of the standard.
In terms of motor companies, since June 1, 2021, less than IE3 energy efficiency limit value of the motor shall not be produced, sold, the use of units shall not be purchased, so the motor companies from the technology, equipment, technology, materials and sales and other aspects of the production and sales of IE3 and above the energy efficiency of the motor to be fully prepared.
IE3 relative to IE2, the cost of about 20% increase; IE4 relative to IE3, the cost also has a substantial increase. Therefore, motor companies to achieve the required energy-efficiency indicators in the product under the premise of the design, process and other aspects of the potential to reduce costs, there are many motor companies have begun to implement the intelligent manufacturing, so that motor products can achieve a high degree of consistency, in addition to the existing motor products in the process (such as machining accuracy), equipment and so on can be a better way to improve.
At present, China's industrial energy consumption accounts for about 70% of the total energy consumption, of which motor energy consumption accounts for about 60% to 70% of industrial energy consumption, plus non-industrial motor energy consumption, the actual energy consumption of the motor accounted for more than 50% of the total energy consumption. And now the application of energy efficient motors is low. According to the National Small and Medium-sized Motor Quality Supervision and Inspection Center on the domestic key enterprises of 198 sets of motor sampling survey, which reached more than 2 levels of energy-efficient motor proportion of only 8%, which produces a great waste of resources of the whole society.
Energy-saving measures for high-efficiency motors
Measures to improve the efficiency of electric motors. The energy saving of electric motor is a systematic project, involving the whole life cycle of electric motor, from the design and manufacture of electric motor to the selection, operation, regulation, overhaul and scrapping of electric motor, we should consider the effect of its energy saving measures from the whole life cycle of electric motor, and the domestic and foreign countries mainly consider the following aspects to improve the efficiency of electric motor in this regard.
The design of energy-saving motor refers to the use of optimization design technology, new material technology, control technology, integration technology, test and inspection technology and other modern design means to reduce the power loss of the motor, improve the efficiency of the motor, and design a high-efficiency motor.
Motor in the conversion of electrical energy into mechanical energy at the same time, itself also lose part of the energy, typical AC motor loss can be generally divided into fixed loss, variable loss and stray loss three parts.
Variable loss is changed with the load, including stator resistance loss (copper loss), rotor resistance loss and brush resistance loss; fixed loss has nothing to do with the load, including iron core loss and mechanical loss. Iron loss is composed of hysteresis loss and eddy current loss, which is proportional to the square of the voltage, of which hysteresis loss is also inversely proportional to the frequency; other stray losses are mechanical losses and other losses, including friction loss of the bearings and fan, rotor, etc. due to the rotation of the wind resistance loss.
High-efficiency motor features
1, energy saving, reduce long-term operating costs, very suitable for textiles, fans, pumps, compressors, rely on power saving one year can recover the cost of motor purchase;
2, direct start, or speed regulation with frequency converter, can be fully replaced with asynchronous motors;
3, rare earth permanent magnet energy efficient motor itself can save energy than ordinary motors more than 15℅;
4, motor power factor close to 1, improve the quality factor of the grid, without adding power factor compensator;
5, the motor current is small, saving power transmission and distribution capacity, extend the overall operating life of the system;
6, power-saving budget: 55 kilowatts of motor, for example, high-efficiency motors than the general motor to save 15℅, electricity costs per kilowatt-hour calculated at 0.5 yuan, the use of energy-saving motors within a year by saving electricity can be recovered by replacing the cost of the motor.
Advantages of high-efficiency motors:
Direct start, can fully replace the asynchronous motor.
Rare earth permanent magnet energy efficient motor itself can save more than 3℅ of electricity than ordinary motor.
Motor power factor is generally higher than 0.90, improve the quality factor of the grid, without adding power factor compensator.
Motor current is small, saving power transmission and distribution capacity, extending the overall operating life of the system.
Plus drive can realize soft start, soft stop, stepless speed regulation, power saving effect is further improved.
The five major losses in motors
Stator loss
Reduce the main means of motor stator I^2R loss in practice, the more widely used methods are:
1, increase the stator slot cross-sectional area, in the case of the same stator outer diameter, increase the stator slot cross-sectional area will reduce the magnetic circuit area, increase the teeth of the magnetic density;
2, increase the full slot rate of the stator slot, which is more effective for low-voltage small motors, the application of the best winding and insulation size, large wire cross-sectional area can increase the full slot rate of the stator;
3, try to shorten the stator winding end length, stator winding end loss accounted for the total loss of winding 1/4 ~ 1/2, reduce the winding end length, can improve motor efficiency. Experiments show that the length of the end is reduced by 20%, loss decreased by 10%.
Rotor loss
Motor rotor I^2R loss is mainly related to rotor current and rotor resistance, the corresponding energy-saving methods are mainly:
1, reduce the rotor current, which can be considered from improving the voltage and motor power factor;
2, increase the rotor slot cross-sectional area;
3, reduce the resistance of the rotor winding, such as the use of thick wire and low resistance materials, which is more meaningful for small motors, because small motors are generally cast aluminum rotor, if the use of cast copper rotor, the total loss of the motor can be reduced by 10% to 15%, but today's cast copper rotor required to manufacture high temperature and technology has not yet been popularized, and its cost is higher than that of the cast aluminum rotor 15% to 20%.
Iron consumption
Motor iron consumption can be reduced by the following measures:
1, reduce the magnetic density, increase the length of the iron core to reduce the magnetic flux density, but the amount of iron used by the motor increases;
2, reduce the thickness of the iron chip to reduce the loss of induced current, such as cold rolled silicon steel instead of hot rolled silicon steel can reduce the thickness of silicon steel, but the thin iron chip will increase the number of iron chips and motor manufacturing Chenben;
3, the use of cold rolled silicon steel sheet with good magnetic conductivity to reduce hysteresis loss;
4, the use of high-performance iron chip insulation coating;
5, heat treatment and manufacturing technology, iron chip processing residual stress will seriously affect the motor loss, silicon steel sheet processing, cutting direction, punching and shearing stress has a greater impact on the iron core loss. Cutting in the direction of the milling of silicon steel sheet, and heat treatment of silicon steel punching can reduce the loss of 10% to 20% and other methods to achieve.
Stray Loss
Today's understanding of the motor stray loss is still in the research stage, now some of the main methods to reduce stray loss are:
1, the use of heat treatment and finishing to reduce the rotor surface short circuit;
2, Insulation treatment of rotor slot inner surface;
3、Reducing harmonics by improving stator winding design;
4, improve the rotor slot with the design and coordination to reduce harmonics, increase the stator, rotor teeth groove, the rotor slot shape designed as a slant slot, the use of series connected sinusoidal windings, scattered windings and short pitch windings can greatly reduce the high harmonics; the use of magnetic slotted mud or magnetic slot wedge to replace the traditional insulation slot wedge, with magnetic slot mud to fill the slot in the core of the motor stator is to reduce the additional spurious loss of the effective methods.
Wind friction loss
To people should pay attention to, it accounts for about 25% of the total loss of the motor. Friction loss is mainly caused by bearings and seals, which can be reduced by the following measures:
1, minimize the size of the shaft, but need to meet the requirements of the output torque and rotor dynamics;
2、Use of high-efficiency bearings;
3, the use of high-efficiency lubrication system and lubricants;
Summarize
Motor products as industrial power, the country's development speed and industrial policy depends on a large, so how to seize the market opportunity, timely adjustment of product structure, the development of marketable products, choose a good differentiation of energy-saving motor products, follow the national industrial policy is the focus. From a global perspective, the motor industry is developing in the direction of high efficiency and energy saving, the development potential is huge. All developed countries have successively formulated the energy efficiency standards for motors. Europe and the United States and other developed countries continue to improve the motor energy efficiency access standards, basically all energy efficient motors have been used, and some regions have begun to use ultra-high efficiency energy-saving motors.
Example
An enterprise before the Y series of ordinary 7.5KW motors, a total of 10 units in the factory at the same time, running 8 hours a day, running 300 days a year. This year, this enterprise upgraded the equipment, replaced 10 sets of model IE3-132M-4P-7.5KW motor, the power is still the same, but it saves a lot of electricity.
7.5KW of the same power, ordinary Y motor efficiency of 87%, energy efficient motor efficiency 90.1%, then the whole year:
◆ Y-132M-4P-7.5KW running a year of electricity is: (7.5/0.87)8300=20,689.6 degrees
◆ IE3-132M-4P-7.5KW running a year of electricity for:
(7.5/0.901)8300=19,977.8 degrees
◆ The use of energy-efficient motors after a full-year power savings: 20,689.6 - 19977.8 = 711.8 degrees
The enterprise uses 10 sets of 7.5KW energy-efficient motors, the annual power savings of 7118 degrees!
