1. By power supply: motors are divided into DC and AC motors. AC motors include single-phase and three-phase types.
2. By structure and operating principle: motors are divided into DC, asynchronous and synchronous motors.
Synchronous motors include permanent-magnet, reluctance and hysteresis synchronous motors.
Asynchronous motors include induction and AC commutator motors. Induction motors include three-phase, single-phase and shaded-pole types. AC commutator motors include single-phase series-wound, universal AC/DC and repulsion motors.
DC motors include brushless and brushed types. Brushed DC motors include permanent-magnet and electromagnetic motors. Electromagnetic motors can be series-wound, shunt-wound, separately excited or compound-wound. Permanent-magnet types include rare-earth, ferrite and aluminium-nickel-cobalt motors.
3. By starting and running method: single-phase asynchronous motors include capacitor-start, capacitor-run, capacitor-start/capacitor-run and split-phase motors.
4. By application: motors are divided into drive motors and control motors.
Drive motors are used in power tools such as drills, polishing, grinding, grooving, cutting and reaming tools; household appliances such as washing machines, fans, refrigerators, air conditioners, recording and video equipment, vacuum cleaners, cameras, hair dryers and shavers; and general small machinery including machine tools, medical devices and electronic instruments.
Control motors include stepper and servo motors.
5. By rotor structure: motors include cage induction motors and wound-rotor induction motors.
6. By operating speed: motors include high-speed, low-speed, constant-speed and variable-speed types.
Low-speed types include geared motors, electromagnetic reduction motors, torque motors and claw-pole synchronous motors.
Variable-speed motors can have stepped or stepless constant-speed or variable-speed control. Other types include electromagnetic speed-control, DC speed-control, PWM variable-frequency and switched-reluctance motors.