Traction motors are power machines that enable urban rail transit vehicles to achieve traction and electric braking. Under various working conditions such as starting, traction and braking, the speed of the traction engine is changed through the electric drive control system to achieve the purpose of vehicle speed regulation.
 
The working principle of the traction motor is the same as that of the general DC motor, but there are special working conditions, such as the space size is limited by the diameter of the track and the moving wheel.
 
Traction motors also have many requirements in design and structure. For example, to make full use of the internal space of the body to make the structure compact, high insulating materials and magnetic conductive materials must be used, and parts and components must have high mechanical strength and rigidity. Good ventilation and heat dissipation conditions and dust and moisture resistance are required, and special measures must be taken to cope with the more difficult "reversing" conditions to reduce sparks under the carbon brushes.
 
In motor-driven production equipment, in order to improve the quality of production products, increase the quantity, rational use of energy and reduce production costs, the requirements for motor control in the industrial production process are getting higher and higher.