Identifying the quality of carbon brushes can be carried out in the following ways:
Visual inspection: First, observe whether the carbon brush is visibly worn, broken, or corroded. If these issues are found, it may mean that the carbon brush has been damaged or needs to be replaced
Listen to the sound: During the operation of the motor, listen carefully to the sound of the motor. If you hear unusual sounds such as friction or knocking, this may indicate a problem with the carbon brush
Measure Resistance: Use a multimeter to measure the resistance between the carbon brush and the commutator. Under normal circumstances, there should be a certain resistance value between the two. If the resistance value is abnormal, it may indicate a problem with the carbon brush.
Replacement test: The suspected problematic carbon brush is exchanged with other normal carbon brushes. If the motor runs back to normal after replacement, then it can be determined that there is a problem with the original carbon brush.
Check for overheating and spark size: If the carbon brush is overheating or has a large spark while working, this may be an indication that it needs to be replaced
Check the contact surface and spring pressure: Make sure that the contact surface between the carbon brush and the slip ring is sufficient (usually not less than 70%) and that the spring pressure is normal. Insufficient or pressure failure is also a signal for replacement.
Regular maintenance and inspection: Regularly use a DC clamp meter to measure whether the current distribution is uniform, and use an infrared thermometer to check whether there is overheating. These maintenance measures help to identify and deal with problems in a timely manner
