Application Fields of Motors

Power Industry

I. Turbogenerators

Turbogenerators are used in thermal power plants and nuclear power plants. They are a type of synchronous motor. Due to the high speed of the prime mover (steam turbine), typically 3,000 rpm, turbogenerators have slender and long rotors to reduce linear velocity. The world's largest turbogenerator currently has a capacity exceeding 1 million kW.

II. Hydroelectric Generators

Hydroelectric generators are used in hydropower plants and are also a type of synchronous generator. Due to the low speed of the prime mover (water turbine), generally below a few hundred rpm, hydroelectric generators have thick and short rotors to increase the number of poles. Figure 2-12 shows a hydroelectric generator installed at the Three Gorges Power Station. The Three Gorges units are currently the world's largest hydroelectric generators, with a capacity of 700,000 kW each. The Three Gorges Power Station has a total of 26 units, each with a capacity of 700,000 kW.

III. Wind Turbine Generators

Wind power generation involves converting wind energy into mechanical energy through the blades of a wind capture device and then converting mechanical energy into electrical energy. Wind energy is the cheapest, cleanest, and most development-worthy new energy source. Over the past decade, the Chinese government has accelerated the development of wind power, introducing advanced large-scale wind turbines produced abroad to build wind farms and promote the growth of China's wind power industry.

Wind turbine generators can be categorized by installed capacity into small, medium, large, and extra-large series. Small wind turbine generators have a capacity of 0.1–1 kW, medium ones range from 1–100 kW, large ones from 100–1,000 kW, and extra-large ones exceed 1,000 kW. Almost all types of generators are used in wind power generation, with synchronous, asynchronous, DC, and permanent magnet generators being the most common. Recently, extra-large wind turbines abroad often use brushless DC generators with permanent magnet external rotors.

Industrial and Agricultural Production

In industrial and agricultural production, most mechanical equipment is powered by various types of electric motors. The majority of these motors use distribution transformers as their power source, while machinery far from the grid or mobile equipment often relies on diesel generators. Small and medium-power induction motors are widely used in equipment such as machine tools, rolling mills, blowers, printing presses, water pumps, oil pumps, cranes, conveyor belts, and production lines. This is because induction motors are simple, reliable, easy to maintain, and cost-effective. They account for over 60% of all electrical load power. In recent years, the proportion of various new types of motors has also begun to increase.