electric power industry

1. turbine generator

Turbogenerators are used in thermal power plants and nuclear power plants. It is a kind of synchronous motor. Because the prime mover turbine) speed is very high, generally 3000 r/min, so the rotor of the turbine generator is thin and long to reduce the linear speed. At present, the world's largest steam turbine generator capacity has exceeded 1 million kilowatts.

2. hydro-generator

Hydrogenerators are used in hydroelectric power plants and are a type of synchronous generator. Due to the low speed of the prime mover (turbine), generally several hundred rpm or less, the rotor of the turbine generator is thick and short to increase the number of poles. Figure 2-12 shows a hydro-generator installed in the Three Gorges Power Station. The Three Gorges unit is currently the largest hydro-generator unit in the world, with a power of 700000 kilowatts. The Three Gorges Power Station has a total installed capacity of 26 units and a single unit capacity of 700000 kilowatts.

3. wind power generator

Wind power generation is the process of converting wind energy into mechanical energy through the impeller of the wind catching device, and then converting mechanical energy into electrical energy. Wind energy is the cheapest, cleanest and most valuable new energy. In the past ten years, the Chinese government has accelerated the development of wind power, and also introduced large-scale wind turbines produced abroad and advanced technology to form wind farms, which has promoted the development of wind power in my country.

According to the installed capacity, wind turbines have small, medium, large and large series. The capacity of small wind turbines is 0.1~1 kW, medium wind turbines are 1~100 kW, large wind turbines are 100~1000 kW, and extra large wind turbines are more than 1 000 kW. Almost all types of generators are used in wind power generation, the most common are synchronous, asynchronous, DC and permanent magnet generators. Recently, there are more permanent magnet outer rotor brushless DC generators for large wind turbines abroad.

industrial and agricultural production

In industrial and agricultural production, the vast majority of machinery and equipment to all kinds of motor power. Most of these motors are powered by distribution transformers, while those far away from the power grid are often powered by diesel generators or mobile devices. In machine tools, rolling mills, blowers, printing machines, water pumps, pumping units, cranes, conveyor belts, production lines and other equipment, a large number of small and medium-power induction motors are used. This is because induction motors are simple and reliable, easy to maintain, and low in cost. Induction motors account for more than 60% of all electrical load power. In recent years, the proportion of various types of new motors has also begun to increase.

1. machinery, metallurgy, light industry, chemical industry

Machine tools in machinery manufacturing plants, from traditional lathes, milling machines, planers, grinders, punching machines, to modern CNC machine tools and automatic production lines, all use Shen motors as power. And the workshop crane and other auxiliary equipment are all driven by motivation. Even for some hydraulic equipment, the oil pump is driven by an electric motor. The most commonly used planer milling machine in Dali machinery processing factory is a motor that drives each milling cutter to rotate. In fact, this machine tool has many other motors, such as a beam lift motor that drives the blood of the bed to reciprocate. Horizontal tool holder horizontal movement and vertical tool holder longitudinal movement of the screw motor, horizontal tool holder vertical movement and vertical tool holder horizontal movement of the motor and cooling water pump motor.

In a high-speed grinder, the speed of the spindle motor is as high as tens of thousands of revolutions per minute, and the speed of the motor for crushing wood to make wood pulp in a paper mill may be only a few revolutions per minute. In electric tools, a large number of use of speed control is more convenient series AC motor. Modern CNC machine tools may use all kinds of stepper motors and linear motors. In the enterprise with high degree of automation production, the motion control of industrial robot is to use a lot of servo motor.

A large number of roller motors are used in the roller tables for transporting steel ingots on the rolling mills of steel plants. Both the roller motor and the crane motor require special mechanical characteristics, such as high starting torque, high overload capacity, etc., so they are called lifting metallurgical motors. The rolling mill for producing hot-rolled steel plates, the roller table for pushing the steel plates, is driven by numerous roller motors.

In a chemical plant. Water pump, fan. Both turning gear and axial flow fan are motor-driven equipment. Because the products produced may have flammable and explosive gases, many motors are flameproof motors. In the chemical plant all kinds of pipeline valve is indispensable, the small automatic valve is the majority of solenoid valve (by the electromagnetic coil and armature, can also be seen as a motor) drive, and large electric ball valve, electric butterfly valve, etc. require a larger torque, so are rotating motor driven, called electric valve.

In light industrial production, a large number of motor-driven machinery and equipment are also used. For example, the world's earliest linear motor is used to drive the shuttle of the textile machine, and for example, the large wood crushing machine in the paper mill generally uses a synchronous motor drive with low speed and high torque.

2. Mines and Oilfields

The rail trains used in mines are generally electric traction and can be used for narrow-gauge transportation in coal mines, mines, and forest areas. There are also some small mines that do not have the conditions for overhead power supply, which can be powered by battery or diesel generator-motor driven mine cars. For the convenience of speed regulation, most of the large tire-carrying vehicles are driven by diesel generator-traction motor. Currently. In more and more open-pit mines, in order to save energy and environmental protection, large excavators directly powered by cables are used.

Oilfield drilling equipment is generally driven by a diesel generator to drive an electric motor as power. Modern drilling techniques are beginning to rely on precise orbital control techniques. That is, in order to prevent the deviation of the drill row of several dry meters, there is a measurement while drilling technology and even a drill bit with a controllable drilling direction. Because the drill pipe may be as long as several kilometers, the drilling time is very long, the electric energy required by the sensor and the steering motor of the drill bit cannot be transmitted from the ground, and the battery cannot maintain power supply for a long time, so there is a small "while drilling generator" installed at the front end of the drill pipe ". The prime mover of the generator is a turbine driven by the drill bit mud pump, and the electrical energy output by the generator can be supplied to the sensor and the drive motor of the steerable drill bit. In this way, the drill bit is like a "missile" that slowly "launches" into the ground and will automatically steer during the drilling process.

Oil pumping unit, due to the difference between the maximum load and the minimum load is very large. There is a long time in a stroke is loaded, so the problem of large horse-drawn car is prominent, in order to save energy, need to use variable frequency motor as power.

3. port, logistics center

In modern ports, for the purpose of energy saving and emission reduction and the convenience of speed regulation, more and more machines are driven by AC variable frequency motors. Such as bridge crane/ship unloader. Rail type gantry crane, tire type gantry 1 crane, tire type single wall slewing crane, conveyor belt, port electric vehicle, etc. Taking an electric drive gantry container crane as an example, its gantry is running. The car goes along. The hoisting machine is all driven by an electric motor, and the power supply of the electric motor comes from its own diesel generator.

4. Architecture and Road and Bridge Construction

Electric motors are widely used as power in construction equipment. Such as tower crane hoisting, slewing, luffing mechanism, and even the cable reel of the power cable, all powered by the motor. In high-rise buildings, elevators and ladders are driven by electric motors. The automatic doors and revolving doors of hotels are also driven by electric motors. The water supply, heating and ventilation of buildings need water pumps, blowers, etc. These devices are also driven by electric motors. Elevator with a new type of permanent magnet traction motor, due to the permanent magnet motor speed control performance is good, you can take the speed change mechanism. The whole system is simplified. At present, many new laws are built by saying that this kind of traction motor is used.

In modern railway construction, highway construction and bridge construction, a large number of bridge erecting machines, paving machines and other giant equipment are used. The most important part of the shield machine for digging railway tunnels and subway tunnels, the cutter head, was first controlled by hydraulic pressure, and now more and more frequency conversion motors are used to drive, such as a certain type of shield machine cutter head. It is driven by 8 55kW variable frequency motors. After using variable frequency motors, it not only has less follow-up equipment, but also has greater starting torque and smaller starting impact.