What is an electric motor?
An electric motor (English: Electric machinery, commonly known as a "motor") is an electromagnetic device that converts or transmits electrical energy based on the law of electromagnetic induction.
In circuits, an electric motor is represented by the letter M (D in the old standard). Its main function is to generate driving torque and serve as a power source for electrical appliances or various machines. A generator is represented by the letter G in circuits. Its main function is to convert electrical energy into mechanical energy.
I. Classification and categorization of motors
1. According to the type of power supply: motors can be divided into DC motors and AC motors.
2. According to structure and working principle, motors can be divided into DC motors, asynchronous motors, and synchronous motors.
3. According to the starting and running methods, single-phase asynchronous motors can be divided into: capacitor-start single-phase asynchronous motors, capacitor-run single-phase asynchronous motors, capacitor-start-run single-phase asynchronous motors, and split-phase single-phase asynchronous motors.
4. According to their purpose, electric motors can be divided into drive motors and control motors.
5. According to the rotor structure, induction motors can be divided into: squirrel-cage induction motors (formerly known as squirrel-cage asynchronous motors) and wound-rotor induction motors (formerly known as wound-rotor asynchronous motors).
6. According to operating speed, motors can be classified as: high-speed motors, low-speed motors, constant-speed motors, and variable-speed motors. Low-speed motors are further divided into geared motors, electromagnetic geared motors, torque motors, and claw-pole synchronous motors, etc.
II. What is an electric motor?
An electric motor is a device that converts electrical energy into mechanical energy. It utilizes a rotating magnetic field generated by a current-carrying coil (stator winding) that acts on a rotor (such as a squirrel-cage closed aluminum frame) to create magnetoelectric torque. Electric motors are classified into DC motors and AC motors based on the power source they use. Most motors in power systems are AC motors, which can be synchronous or asynchronous (the stator magnetic field speed and rotor rotation speed are not synchronized). An electric motor mainly consists of a stator and a rotor. The direction of the force on a current-carrying conductor in a magnetic field depends on the direction of the current and the direction of the magnetic field lines. The working principle of an electric motor is that the magnetic field exerts a force on the current, causing the motor to rotate.
III. Basic Structure of an Electric Motor
1. The structure of a three-phase asynchronous motor consists of a stator, a rotor, and other accessories.
2. The DC motor adopts an octagonal fully laminated structure with series winding, suitable for automatic control technologies requiring forward and reverse rotation. It can also be manufactured with series winding according to user needs. Motors with a center height of 100–280 mm have no compensating winding, but motors with a center height of 250 mm and 280 mm can be manufactured with compensating winding depending on specific circumstances and needs. Motors with a center height of 315–450 mm have compensating winding. The external dimensions and technical requirements of motors with a center height of 500–710 mm conform to IEC international standards, and the mechanical dimensional tolerances of the motor conform to ISO international standards.
Is there a difference between a motor and an electric motor?
Electric motors include both electric motors and generators. The term "electric motor" is a general term encompassing both, but the two are conceptually distinct. An electric motor is simply one mode of operation; in motoring mode, it converts electrical energy into other forms of energy. Another mode of operation is as a generator, where it converts other forms of energy into electrical energy. However, some motors, such as synchronous motors, are often used as generators, but can also be used directly as electric motors. Asynchronous motors are more commonly used as electric motors, but with the addition of simple external components, they can also be used as generators.
