Which generator is associated with an approximate 13% voltage ripple (87% actual voltage)?

Which generator is associated with an approximate 13% voltage ripple (87% actual voltage)?

• A. High-frequency
• B. Three-phase 12 pulse
• C. Three-phase 6 pulse
• D. Autotransformer

Answer: (C)

Voltage ripple on the DC output after rectification depends on how many pulses the converter delivers each cycle. A three-phase six-pulse bridge creates six charging pulses per AC cycle, so the DC output has a ripple at six times the line frequency. With a typical capacitor-input filter and load, that ripple level is about 13% of the average DC, leaving roughly 87% of the peak as steady DC. If you use a twelve-pulse arrangement, the ripple drops further because the ripple frequency is effectively doubled and the output is smoother. An autotransformer by itself doesn’t change the ripple in the same way, and a high‑frequency generator alters the switching frequency rather than producing that 13% ripple figure. So the six-pulse three-phase setup matches the stated approximate ripple.

Voltage ripple on the DC output after rectification depends on how many pulses the converter delivers each cycle. A three-phase six-pulse bridge creates six charging pulses per AC cycle, so the DC output has a ripple at six times the line frequency. With a typical capacitor-input filter and load, that ripple level is about 13% of the average DC, leaving roughly 87% of the peak as steady DC. If you use a twelve-pulse arrangement, the ripple drops further because the ripple frequency is effectively doubled and the output is smoother. An autotransformer by itself doesn’t change the ripple in the same way, and a high‑frequency generator alters the switching frequency rather than producing that 13% ripple figure. So the six-pulse three-phase setup matches the stated approximate ripple.