What is a common cause of brush arcing in motors?

A common cause of brush arcing in motors is low spring tension. When the spring tension that holds the brushes against the commutator is insufficient, the brushes may not maintain a proper contact with the commutator segments. This poor contact results in intermittent electrical contact, leading to arcing as the brushes bounce on and off the commutator.

Arcing can cause erosion of both the brushes and the commutator surface, which can further degrade performance and lead to more serious motor issues over time.

In contrast, high spring tension generally helps ensure a solid contact between the brushes and the commutator, which minimizes the chances of arcing. While dirty commutators can also lead to arcing due to poor conductivity, the specific issue of mechanical contact is most directly related to the spring tension. Overloading the motor may cause excessive heat and damage, but it is not as directly linked to the arcing caused by brush dynamics as low tension is.