With a D.C. generator which of the following regulation is preferred?

Answer: Option D

Voltage regulation in a D.C. generator refers to the change in terminal voltage from no-load to full-load, expressed as a percentage of the full-load voltage.

A lower percentage of voltage regulation indicates better performance because it means the generator maintains a more constant voltage under varying load conditions.

Option A: 100% regulation

100% regulation would mean that the voltage drops to zero under full load, which is highly undesirable.

Option B: Infinite regulation

Infinite regulation implies a complete loss of voltage under load, which is not practical or acceptable.

Option C: 50% regulation

50% regulation indicates a significant drop in voltage under load, which is also not preferred as it would lead to poor performance.

Option D: 1% regulation

1% regulation is ideal as it indicates very little voltage drop under load, ensuring that the generator provides a stable voltage output.

Conclusion:

Among the given options, 1% regulation is preferred because it reflects the best performance in maintaining a constant voltage.