Advantages of using commutators in traction motors

Update:16 Aug 2022

The DC traction motor is composed of main components such as rotor armature winding, stator excitation winding, frame and brush commutation device. Traction motors mainly use series-excited DC motors.
After the dc motor commutator is connected to the DC power supply, the excitation current will pass through the excitation winding and establish a magnetic field, which is fixed in space; when the armature winding passes current through the sliding contact between the brush and the commutator, it will be fixed. The electromagnetic force is generated by the action of the excitation magnetic field, and the direction of the force can be determined according to the left-hand rule; by controlling the voltage and current of the armature and the excitation winding, the torque and speed of the DC motor are adjusted, and the rotation of the armature rotor passes through the transmission system. The drive wheels turn to drive the locomotive.
With the increasing maturity of AC variable frequency speed regulation technology, stable and reliable stepless speed regulation of AC traction motors can be carried out, and the speed regulation range can reach 1:1000, which is larger than that of DC speed regulation, especially without the DC motor in the replacement. The existence of the direction device thus overcomes many disadvantages of the DC motor. Compared with the DC motor, the AC traction motor has a simple and reliable structure, small size and light weight, which is more suitable for the vehicle's requirements on the installation space and weight of the motor. More importantly, the AC traction motor has high power, strong overload capacity, Low noise, wide speed range (about 0~5000r/min), huge regenerative braking force, preventing wheel slip, high reliability, easy maintenance, stable and comfortable, saving 20~30% of electricity, etc., have become the modern urban rail transit. Products for traction locomotive drive motors.

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