Motor classification 1.1 Divided by working power supply: DC motor and AC motor DC motor is divided according to structure and working principle: brushless DC motor and brushed DC motor. Brushed DC motors can be divided into permanent magnet DC motors and electromagnetic DC motors. Permanent magnet DC motors are divided into: rare earth permanent magnet DC motors, ferrite permanent magnet DC motors and Alnico permanent magnet DC motors. Electromagnetic DC motors can be divided into: series-excited DC motors, shunt-excited DC motors, separately-excited DC motors and compound-excited DC motors. AC motors can also be divided into: single-phase motors and three-phase motors. 1.2 Divided by structure and working principle: It can be divided into DC motor, asynchronous motor, synchronous motor. Synchronous motor can be divided into: permanent magnet synchronous motor, reluctance synchronous motor and hysteresis synchronous motor. Asynchronous motors can be divided into: induction motors and AC commutator motors. Induction motors can be divided into three-phase asynchronous motors, single-phase asynchronous motors and shaded-pole asynchronous motors. AC commutator motors can be divided into: single-phase series motors, AC and DC motors and repulsion motors. 1.3 Divided by starting and operating modes: capacitor-starting single-phase asynchronous motor, capacitor-operating single-phase asynchronous motor, capacitor-starting single-phase asynchronous motor and split-phase single-phase asynchronous motor. Divided by purpose: drive motors and control motors. Driving motor classification: electric tools (including drilling, polishing, polishing, slotting, cutting, reaming, etc.) motors, home appliances (including washing machines, electric fans, refrigerators, air conditioners, tape recorders, video recorders, DVD players) , Vacuum cleaners, cameras, hair dryers, electric shavers, etc.) and other general small mechanical equipment (including various small machine tools, small machinery, medical equipment, electronic instruments, etc.) motors. Control motors are divided into stepper motors and servo motors. Divided by the structure of the rotor: cage induction motors (called squirrel cage asynchronous motors in the old standard) and wound rotor induction motors (called wound asynchronous motors in the old standard). Divided by operating speed: high-speed motors, low-speed motors, constant-speed motors, and speed-regulating motors. Low-speed motors are divided into gear reduction motors, electromagnetic reduction motors, torque motors and claw-pole synchronous motors. In addition to the stepped constant speed motor, the stepless constant speed motor, the stepped variable speed motor and the stepless variable speed motor, the speed control motor can also be divided into electromagnetic speed control motor, DC speed control motor, PWM frequency conversion speed control motor and Switched reluctance speed motor. The rotor speed of an asynchronous motor is always slightly lower than the synchronous speed of the rotating magnetic field. The rotor speed of the synchronous motor has nothing to do with the size of the load and always maintains a synchronous speed. Note: 2-pole motor speed 3000 rpm/min 4-pole motor speed 1500 rpm/min 6-pole motor speed 1000 rpm/min 8-pole motor speed 750 rpm/min Motor bearing classification Motor bearing models generally use rolling bearings, sliding bearings, joint bearings, Most small and medium-sized motors with oil-impregnated bearings use rolling bearings. At present, large and medium-sized motors also use rolling bearings. Rolling bearings are divided into deep groove ball bearings, self-aligning ball bearings, cylindrical roller bearings, spherical roller bearings, spiral roller bearings, angular contact ball bearings, tapered roller bearings, thrust ball bearings, and thrust spherical roller bearings. The rolling bearings commonly used in motors are deep groove ball bearings, cylindrical roller bearings, spherical roller bearings, and angular contact ball bearings. Small motors use deep groove ball bearings at both ends of the bearings, medium-sized motors use roller bearings on the load end (usually used for high load conditions), and ball bearings on the non-load end (but the opposite is also true, such as 1050kW motors). Small motors also have large motors that use angular contact ball bearings and use spherical roller bearings. Motor bearing classification motor bearing performance requirements require no abnormal noise, low vibration, low noise, and low temperature rise. Abnormal sound is to require the bearing to have no abnormal sound caused by sliding friction. Generally, after installation, no-load operation and ear listening can distinguish electromagnetic sound and wind noise without abnormal sound. Vibration and noise are requirements for the bearing itself. After installation, the vibration value of the whole machine must be tested to meet the factory requirements. The vibration and noise values u200bu200bof the bearing itself are stipulated in national or industry standards. Vibration is divided into speed vibration level V, acceleration vibration level Z (expressed in decibels).