Basic structure of motor

Basic structure of motor

The basic structure of a motor usually consists of two main parts: stator and rotor, as well as accessories such as end caps, bearings, machine bases, junction boxes, fans, and hoods. The following is a detailed diagram of the motor structure:

Stator (stationary part):

Stator core: an important part of the motor magnetic circuit, usually made of stacked silicon steel sheets, with evenly distributed slots on the inner circle, used to embed the stator winding.

Stator winding: The circuit part of an electric motor, made of insulated copper (or aluminum) wires, used to generate a rotating magnetic field. The winding is usually embedded in the slot of the stator core and fixed by slot wedges.

Machine frame: used to support the stator iron core and fixed end cover, providing mechanical strength and stiffness. The base material is generally cast iron or cast steel, and large motors may use steel plate welding.

End cap: used to seal the motor, protect the internal structure, and support the bearings.

Bearing: used to support the rotor to rotate inside the stator.

Rotor (rotating part):

Rotor core: As a part of the motor magnetic circuit, it is usually made of stacked silicon steel sheets, with evenly distributed slots on the inner circle, used to embed the rotor winding.

Rotor winding: Similar to stator winding, it is made by winding insulated copper (or aluminum) wires, but usually has a squirrel cage or winding structure. The squirrel cage rotor winding consists of copper bars and welded copper rings inside the iron core slot, while the wound rotor winding is connected to the slip ring on the shaft through a lead wire.

Shaft: connects the rotor and the machine base to transmit rotational torque.

Other attachments:

Junction box: used to connect the output terminals of the stator winding and connect the three-phase winding into a star or triangle shape as needed.

Fan: Used for heat dissipation and improving the operating efficiency of electric motors.

Windshield: used to guide the airflow generated by the fan and protect the internal structure of the motor.

Motor type

Different types of motors, such as three-phase asynchronous motors, DC motors, AC servo motors, and three-phase full wave brushless motors, may have different structures, but their basic principles and main components are similar. For example, in the structure of a three-phase full wave brushless motor, the stator usually has multiple coils, while the rotor is a permanent magnet structure.

Working principle

The principle of a motor is to use electrical energy to generate a rotating magnetic field on the coil and drive the rotor to rotate. When three-phase AC power is applied to the stator winding, a rotating magnetic field will be generated, which will cut the rotor winding, thereby generating induced electromotive force and current in the rotor, and causing the rotor to rotate under the action of the magnetic field force.