Electrical Craft Certification 4 Practice Test 2025 - Free Certification Practice Questions and Study Guide

When mounting a DC motor, ensuring that the brushes can be easily replaced is essential for several reasons. DC motors operate by transferring current through the brushes to the commutator, which then feeds the current to the motor windings. Over time, brushes will wear down due to friction and the heat generated during operation.

Making them easy to replace minimizes downtime and maintenance costs, allowing for quick servicing and ensuring the motor remains operational. Having a design that facilitates the replacement of brushes is helpful in maintaining efficiency and prolonging the life of the motor, as it allows for timely changes before excessive wear affects performance.

While the other choices highlight aspects of motor durability and performance, they do not address the crucial aspect of maintenance and serviceability as effectively as the ability to easily replace brushes does. For instance, securely fitting brushes is important but does not facilitate maintenance, oversized brushes can lead to heightened wear or contention, and waterproofing may not be necessary for every application depending on the environment in which the motor is used. Therefore, the ability to quickly and easily replace brushes takes precedence when mounting a DC motor.