NEIEP Mechanics Practice Exam

The most common cause of problems with a commutator is often attributed to insufficient brush pressure. When the brush pressure is too light, the brushes may not maintain proper contact with the commutator surface. This can lead to poor electrical connection, resulting in arcing, excessive sparking, or even uneven wear on the commutator itself. As the commutator plays a crucial role in ensuring the efficient transfer of electrical current within the motor, inadequate pressure from the brushes can degrade performance and lead to premature failure of both the brushes and the commutator.

In terms of context, while heavy brush pressure can cause excessive wear on both brushes and the commutator, worn-out brushes can be the result of inadequate pressure over time. Similarly, improper alignment of the rotor can create various problems as well, but it is less frequently identified as the primary cause of issues associated with commutators compared to the effects of brush pressure. Therefore, understanding the balance of brush pressure is essential for maintaining the longevity and efficiency of the commutator in an electric motor system.