🔍 Key Concepts

• Six-pulse converter operation in a three-phase system • Phase shift created by delta–wye vs delta–delta transformers • How phase displacement between two rectifier bridges affects the number of pulses (i.e., 6-pulse vs 12-pulse systems)

💭 Think About

• Look at the transformer connections feeding the two rectifier bridges. How does a delta–wye connection shift the secondary line-to-line voltage phasor relative to a delta–delta connection? • In a 12‑pulse arrangement made from two 6‑pulse bridges, what phase displacement between the two bridges is needed so that their DC ripple components interleave? • Relate the phase displacement between the AC supplies of the two bridges to the effective electrical degrees between their DC output ripple peaks. What common value is used in practice?

✅ Before You Answer

• Confirm how many pulses per cycle a single three‑phase bridge produces and how that relates to 360 electrical degrees. • Verify the standard phase displacement between secondaries of delta–delta and delta–wye transformer pairs used in 12‑pulse converters. • Ensure the angle you choose matches a realistic transformer phase shift used in marine AC‑DC‑AC propulsion drives (not an arbitrary value like 45°).