NEIEP Mechanics Practice Exam

Why are more coils and commutator segments added to an elementary DC generator armature?

1. To increase efficiency

2. To reduce ripple

3. To enhance magnetic field strength

4. To simplify construction

The correct answer is: To reduce ripple

Adding more coils and commutator segments to an elementary DC generator armature primarily serves to reduce the ripple voltage produced during operation. When a generator produces electricity, the voltage output can be somewhat fluctuating or "rippled" due to the nature of the alternating nature of the generated currents in individual coils. By increasing the number of coils and segments, each coil contributes to a more gradual change in voltage as it generates electricity. This results in a smoother, more consistent output voltage with less fluctuation, or ripple, improving the overall quality of the electrical supply. While efficiency, magnetic field strength, and construction complexity are important factors in generator design, the specific benefit of adding more coils and segments directly relates to minimizing the ripple effect in the generated output, which is critical for applications requiring steady and reliable electrical power.