The classification of three-phase asynchronous motors depends mainly on several key factors, including the number of poles, energy efficiency rating, and actual application scenarios. The following is a detailed explanation of these classification methods:
1. Classification by number of poles
The number of poles refers to the number of magnetic pole pairs generated by the motor stator winding. The fewer the number of poles, the higher the synchronous speed, and the more the number of poles, the lower the synchronous speed. Three-phase asynchronous motors are usually classified by the following number of poles:
2-pole motor:
Speed: The operating speed is about 2800-3000 revolutions per minute (rpm).
4-pole motor:
Speed: The operating speed is about 1400-1500 rpm.
6-pole motor:
Speed: The operating speed is about 900-1000 rpm.
8-pole and above motors:
Speed: The operating speed is less than 750 rpm.
2. Classification by energy efficiency rating
The energy efficiency rating measures the efficiency of the motor in converting electrical energy into mechanical energy during operation. According to my country's GB/T 18613 standard (or similar standards in other countries), three-phase asynchronous motors are generally divided into the following energy efficiency levels:
Level 1 efficiency: The highest efficiency and the lowest energy consumption are suitable for applications with strict energy efficiency requirements, such as green buildings and energy-saving projects.
Level 2 efficiency: Slightly lower than level 1, but still very efficient, suitable for most industrial and commercial applications.
Level 3 efficiency: Meets basic energy efficiency requirements and is suitable for general industrial equipment.
3. Classification by actual application
According to the actual application needs of use, three-phase asynchronous motors can also be balanced according to their pole number and design. Motor designers and engineers select the appropriate pole number motor to achieve the best balance between current, power, torque and speed:
High-speed applications: Select 2-pole motors for equipment that requires high speed and relatively low torque (such as centrifugal pumps).
Medium-speed applications: Select 4-pole motors for equipment that requires speed and torque balance (such as industrial fans and compressors).
Low speed, high torque applications: Choose 6-pole or 8-pole motors for applications that require lower speeds but higher torques (e.g. large mixers, winches).
By carefully selecting the number of poles and efficiency level, three-phase asynchronous motors can achieve optimal performance and efficiency in a wide range of industrial applications.
