Elevator Mechanic Practice Exam

What action must be taken when there is slight arcing between the brush and commutator?

1. Change the brush

2. Increase brush pressure

3. None

4. Replace the commutator

The correct answer is: Change the brush

Changing the brush is a valid action to take when there is slight arcing between the brush and the commutator. This arcing often indicates that the brush is worn, improperly seated, or not making adequate contact with the commutator. By replacing the worn or damaged brush, you ensure a better fit and contact, which can reduce or eliminate arcing, leading to improved performance and longevity of the motor components. While increasing brush pressure might seem like a potentially effective solution, it can place undue stress on the brushes and commutator, potentially causing further wear or damage. Similarly, the commutator itself may not necessarily need replacement just because of slight arcing; often, addressing the brush condition suffices. Therefore, changing the brush directly addresses the cause of the arcing issue.