Asynchronous motor characteristics

1. Small and lightweight.

2. It is easy to realize high-speed rotation with a speed exceeding 10 000r/min.

3. High operating efficiency at high speed and low torque.

4. There is high torque at low speed, and a wide speed control range.

5. High reliability (sturdy).

6. Low manufacturing cost.

7. Simplification of the control device.

The basic feature of the asynchronous motor is that the rotor winding does not need to be connected to other power sources, and its stator current is directly taken from the AC power system; compared with other motors, the asynchronous motor has a simple structure, is easy to manufacture, use and maintain, and has high operational reliability. Light weight and low cost. Take a three-phase asynchronous motor as an example. Compared with a DC motor of the same power and same speed, the former weighs only one-half of the latter, and the cost is only one-third. Asynchronous motors are also easy to derive various series of products according to the requirements of different environmental conditions. It also has a load characteristic close to constant speed, which can meet the requirements of most industrial and agricultural production machinery. Its limitation is that its speed and the synchronous speed of the rotating magnetic field have a fixed slip rate (see asynchronous motor), so the speed regulation performance is poor, and it is required to have a wide range of smooth speed regulation applications (such as transmission rolling mills). , Winches, large-scale machine tools, etc.), not as economical and convenient as DC motors. In addition, when the asynchronous motor is running, it draws reactive power from the power system for excitation, which will cause the power factor of the power system to deteriorate. Therefore, it is not as reasonable to use a synchronous motor in high-power, low-speed occasions (such as dragging a ball mill, compressor, etc.).

Due to the large production volume and wide application of asynchronous motors, it is required to have a wide range of varieties, specifications and various machinery. Therefore, special attention should be paid to standardization, serialization and generalization in the design and production of asynchronous motors. Among various series of products, the basic series is the three-phase asynchronous motor series with the largest output and the most widely used; in addition, there are several derivative series (series derived from the basic series with partial changes) and special series (for special needs) Designed series with special structure).