Classification of Electric Motors

I. Classification by the Type of Working Power Supply
DC Motors: Powered by a DC power source, they have excellent speed regulation performance and can achieve smooth speed adjustment. They are often used in equipment with high requirements for speed regulation, such as the drive motors of electric vehicles and rolling mills.

AC Motors: Powered by an AC power source, they are divided into synchronous motors and asynchronous motors. Synchronous motors have a rotation speed that is strictly synchronized with the frequency of the alternating current and are commonly used in large generators, grid phase modifiers, etc. Asynchronous motors have a certain slip rate between their rotation speed and the synchronous speed. They have a simple structure, low cost, and are easy to maintain, and are widely used in industrial production, household appliances, and other fields.

II. Classification by Purpose
Generators: They convert other forms of energy (such as mechanical energy, thermal energy, hydraulic energy, etc.) into electrical energy and are the core equipment of the power system.

Motors: They convert electrical energy into mechanical energy to drive various mechanical equipment, such as machine tools, fans, water pumps, etc.

Control Motors: In automatic control systems, they are used to transmit and convert control signals, such as servo motors, stepper motors, tachogenerators, etc.

III. Classification by Structure and Working Principle
Electromagnetic Motors: They work based on the principle of electromagnetic induction. The interaction of the magnetic fields between the stator and the rotor generates electromagnetic torque, and they are the most common type of electric motors.

Permanent Magnet Motors: They use permanent magnet materials as the rotor poles and do not require an excitation winding. They have the advantages of high efficiency, high power density, and a simple structure, and are often used in electric vehicles, power tools, and other fields.

Reluctance Motors: They generate electromagnetic torque relying on the change of the rotor reluctance. They have a simple structure and low cost, and are suitable for some occasions where the requirements for speed regulation performance are not high.

IV. Classification by Protection Form
Open-Type Motors: They have large ventilation openings, good heat dissipation performance, but poor protection ability. They are suitable for dry and clean environments.

Protected-Type Motors: They have a certain degree of protection ability and can prevent water droplets, debris, etc. from entering the interior of the motor. They are suitable for general industrial environments.

Enclosed-Type Motors: The motor casing is completely enclosed, with good protection performance. They can be used in harsh environments such as humid, dusty, and corrosive gas environments.

Explosion-Proof Motors: They are used in flammable and explosive places and have a special explosion-proof structure to prevent the ignition of surrounding flammable and explosive gases when an explosion occurs inside the motor.