The series dc motor factory teaches you how to improve the direction of DC motors in electric vehicles
Grinding of the brush:
The contact area and the contact area of the brush and the commutator directly affect the DC motor's change direction, the size of the spark, and the brush wear speed. Therefore, after the motor assembly is completed, it should be empty loaded. The purpose of grinding is to increase the contact area of the brush and the commutator. Generally, the contact area should reach more than 80 %, so that the good direction can be guaranteed during load. In order to shorten the grinding time, the motor speed can be increased by increasing the voltage, but the mechanical strength of the motor must be considered, and the rated speed of Gaochu can not be excessive. The contact surface of the unpolished brush and the commutator is not enough, that is, it is a local contact, so that the current density at the contact point increases, resulting in poor commutative direction, and the repair rate increases after the motor is delivered.
Why is the brush grinding discussed here alone? Because most manufacturers of DC motors for electric bicycles nowadays have omitted or neglected the important process of brush grinding. There are two reasons:
There is a need for equipment, field, and time for brush grinding. Without understanding its importance, it is saved, especially when the production task is tight;
2 The error of the vehicle factory: Because there is no regular testing equipment for the motor, the vehicle factory generally only detects the empty current and running noise of the motor, and puts forward excessive requirements for these two indicators. The motor that has not been frayed, because the contact surface of the brush and the commutator is small, sometimes reflects that the empty current and noise are still lower, and the vehicle factory is satisfied. Therefore, advising the motor manufacturer, brush grinding steps can not be saved; I also hope that the technicians of the vehicle factory will not blindly pursue small empty current and low noise. These two indicators are sufficient as long as they meet the criteria.
