A motor is a device that converts electrical energy into mechanical energy. It uses the energized coil (that is, the stator winding) to generate a rotating magnetic field and act on the rotor (such as a squirrel-cage closed aluminum frame) to form a magnetoelectric power rotating torque. The motor is divided into a direct current motor and an alternating current motor according to the use of power. Most of the motors in the power system are alternating current motors, which may be synchronous motors or asynchronous motors (the magnetic field speed of the stator of the motor does not keep synchronous with the rotational speed of the rotor). The motor is mainly composed of a stator and a rotor. The direction of the force-carrying wire in the magnetic field is related to the direction of the current and the direction of the magnetic induction line (magnetic field direction). The working principle of the motor is the effect of the magnetic field on the force of the current, which causes the motor to rotate.
The most widely used among various motors is an AC asynchronous motor (also called an induction motor). It is easy to use, reliable in operation, low in price, and robust in structure, but it has a low power factor and it is difficult to adjust the speed. High-capacity low-speed power machines are commonly used in synchronous motors (see Synchronous motors). Synchronous motor not only has high power factor, but also its speed has nothing to do with the load. It is only determined by the grid frequency. The work is more stable. In the case of requiring a wide range of speed control, DC motors are often used. But it has commutators, it has a complicated structure, it is expensive, it is difficult to maintain and it is not suitable for harsh environments. Since the 1970s, with the development of power electronics technology, the speed regulation technology of AC motors has gradually matured, and the price of equipment has been declining. It has begun to be applied. The maximum output mechanical power that the motor can undertake under the specified working system (continuous, short-time operation, intermittent cycle operation) without causing the motor to overheat is referred to as its rated power, and the nameplate must be used when used. . When the motor is running, care must be taken to match the characteristics of the load with the characteristics of the motor to avoid the occurrence of coasting or stalling. Electric motors can provide a wide range of power from milliwatts to tens of kilowatts. The use and control of the motor is very convenient, with the ability to start, accelerate, brake, reverse, and hold. The output power of a general motor will change with the speed when the motor speeds.
For more than a decade, the Chinese government has been committed to promoting motor speed control technology. All industries have adopted motor speed regulation to some extent. According to sample survey results of oil, electricity, building materials, steel, non-ferrous metals, coal, chemicals, paper, textiles, etc., the application of motor speed regulation in the petroleum, building materials, and chemical industries is better. Of the 400 million kW motor loads, about 50% are load changes, of which 30% can be solved by the motor speed to solve its load changes. Therefore, considering the market capacity alone, there is about 60 million kW of speed-regulating motor market. The installed capacity of various types of electric motors in China has exceeded 400 million kW, of which asynchronous motors account for about 90%, small and medium-sized electric motors account for about 80%, and wind turbines, pumps, and compressors have about 130 million kW of electric motors. Small and medium-sized motors have more than 152 series, 842 varieties, more than 4,000 specifications. In the past decade or so, the machinery industry and other relevant departments have vigorously grasped the power-saving work of electric motors, organized and led relevant research institutes and enterprises, and successively designed and made a variety of energy-saving electric motors, and explicitly issued and eliminated 63 types of high-energy-consuming electric motors and promoted 24 Kinds of energy-saving motors have achieved certain results. These energy-saving products are mainly divided into two categories: one is a high-efficiency motor that improves the efficiency of the motor, and the other is a speed-adjustable motor.
The most widely used among various motors is an AC asynchronous motor (also called an induction motor). It is easy to use, reliable in operation, low in price, and robust in structure, but it has a low power factor and it is difficult to adjust the speed. High-capacity low-speed power machines are commonly used in synchronous motors (see Synchronous motors). Synchronous motor not only has high power factor, but also its speed has nothing to do with the load. It is only determined by the grid frequency. The work is more stable. In the case of requiring a wide range of speed control, DC motors are often used. But it has commutators, it has a complicated structure, it is expensive, it is difficult to maintain and it is not suitable for harsh environments. Since the 1970s, with the development of power electronics technology, the speed regulation technology of AC motors has gradually matured, and the price of equipment has been declining. It has begun to be applied. The maximum output mechanical power that the motor can undertake under the specified working system (continuous, short-time operation, intermittent cycle operation) without causing the motor to overheat is referred to as its rated power, and the nameplate must be used when used. . When the motor is running, care must be taken to match the characteristics of the load with the characteristics of the motor to avoid the occurrence of coasting or stalling. Electric motors can provide a wide range of power from milliwatts to tens of kilowatts. The use and control of the motor is very convenient, with the ability to start, accelerate, brake, reverse, and hold. The output power of a general motor will change with the speed when the motor speeds.
For more than a decade, the Chinese government has been committed to promoting motor speed control technology. All industries have adopted motor speed regulation to some extent. According to sample survey results of oil, electricity, building materials, steel, non-ferrous metals, coal, chemicals, paper, textiles, etc., the application of motor speed regulation in the petroleum, building materials, and chemical industries is better. Of the 400 million kW motor loads, about 50% are load changes, of which 30% can be solved by the motor speed to solve its load changes. Therefore, considering the market capacity alone, there is about 60 million kW of speed-regulating motor market. The installed capacity of various types of electric motors in China has exceeded 400 million kW, of which asynchronous motors account for about 90%, small and medium-sized electric motors account for about 80%, and wind turbines, pumps, and compressors have about 130 million kW of electric motors. Small and medium-sized motors have more than 152 series, 842 varieties, more than 4,000 specifications. In the past decade or so, the machinery industry and other relevant departments have vigorously grasped the power-saving work of electric motors, organized and led relevant research institutes and enterprises, and successively designed and made a variety of energy-saving electric motors, and explicitly issued and eliminated 63 types of high-energy-consuming electric motors and promoted 24 Kinds of energy-saving motors have achieved certain results. These energy-saving products are mainly divided into two categories: one is a high-efficiency motor that improves the efficiency of the motor, and the other is a speed-adjustable motor.