What are the main components of the rotor?

The rotating part of a DC motor is called the rotor, also known as the armature. The rotor consists of the armature core, armature winding, commutator, shaft, bearings, and fan.

The armature core-the armature core-is both a component of the main magnetic circuit and supports the armature windings, which are embedded in the armature core's slots. To reduce eddy current losses within the armature core, the core is typically constructed from 0.5mm thick DR530 or DR510 silicon steel sheets with teeth and slots, which are laminated and clamped together. In small motors, the armature core laminations are press-fitted directly onto the shaft. In large motors, the armature core laminations are first press-fitted onto the rotor bracket, which is then secured to the shaft. To improve ventilation, the laminations can be divided into several sections along the axial direction to form radial ventilation ducts.

Armature Winding - The armature winding consists of a number of armature coils connected in a specific pattern. It forms the circuit portion of a DC motor and is responsible for generating electromotive force, electromagnetic torque, and electromechanical energy conversion. The coils are wound with insulated circular or rectangular wire and embedded in the armature core slots in two layers. The upper and lower layers, as well as the coils and the armature core, must be properly insulated and secured with slot wedges. The ends of the armature windings in large motors are typically fastened to the winding support.

Commutator - As mentioned earlier, the commutator performs rectification in DC generators and inverter functions in DC motors. Therefore, the commutator is a key component of DC motors. The commutator consists of numerous dove-tail commutator segments arranged in a cylindrical cylinder, insulated with mica sheets and clamped at both ends with two V-rings. The leads at the beginning and end of each armature coil are soldered to the raised segments of the corresponding commutator segments. Plastic commutators are commonly used in small motors. This type of commutator is made of commutator segments arranged in a cylinder and then made of plastic by hot pressing.