What is a DC Electric Motor?

A DC electric motor is an electromagnetic device that converts direct current electrical energy into mechanical energy. With its stable speed control performance and high starting torque, it is widely used in various fields such as industry, transportation, and household appliances. Its core working principle is based on the left-hand rule in electromagnetic induction: when a current-carrying conductor is in a magnetic field, it will be subjected to the Ampere force to produce motion, thereby realizing energy conversion.

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Structurally, a DC electric motor mainly consists of four parts: stator, rotor, commutator, and brush. The stator is the fixed part of the motor, usually containing permanent magnets or excitation windings, whose function is to generate a constant magnetic field; the rotor, also known as the armature, is composed of an iron core and an armature winding. After the winding is energized, it becomes a current-carrying conductor and rotates under force in the stator magnetic field; the commutator is a key component of the DC motor, which is connected to the rotor winding and rotates with the rotor. The brush is fixed on the stator, maintains sliding contact with the commutator, and is responsible for introducing the current from the external DC power supply into the rotor winding. It also changes the current direction in a timely manner during the rotation of the rotor to ensure that the rotor can continue to rotate in the same direction.​

According to different excitation methods, DC motors can be divided into two categories: permanent magnet DC motors and excited DC motors. The stator magnetic field of a permanent magnet DC motor is provided by permanent magnet materials (such as neodymium-iron-boron magnets), which has the characteristics of simple structure and small size, and is commonly used in toys, small fans and other equipment; the stator magnetic field of an excited DC motor is generated by the energization of the excitation winding. According to the connection mode between the excitation winding and the armature winding, it can be divided into series excitation, shunt excitation, compound excitation and other types. This type of motor can flexibly change the magnetic field strength by adjusting the excitation current, so as to achieve more precise speed control, and is mostly used in machine tools, elevators and other scenarios that require speed regulation.​

Although with the development of AC motor control technology, the application of DC motors has decreased in some fields, it still occupies an important position with its unique performance advantages in occasions requiring high-precision speed regulation and frequent start-stop, such as electric forklifts and servo systems.