A transformer rectifier powered from the No. 2 AC system provides emergency DC power to the ________ if both starter / generators are inoperative.

A transformer rectifier powered from the No. 2 AC system provides emergency DC power to the ________ if both starter / generators are inoperative.

• A. Battery Bus
• B. No 1 Main DC Bus
• C. No 2 Main DC Bus
• D. Both main DC Buses

Answer: (A)

When primary power is gone, an emergency DC source is needed for essential systems. The transformer-rectifier fed from the No. 2 AC system is designed to energize the Battery Bus in this situation, so that critical loads can continue to operate even with starters and generators out of service. The main DC busses normally get power from their respective generators, and without those generators they wouldn’t have a direct emergency feed from the transformer-rectifier. Therefore, the emergency DC power goes to the Battery Bus to keep essential equipment powered.

When primary power is gone, an emergency DC source is needed for essential systems. The transformer-rectifier fed from the No. 2 AC system is designed to energize the Battery Bus in this situation, so that critical loads can continue to operate even with starters and generators out of service. The main DC busses normally get power from their respective generators, and without those generators they wouldn’t have a direct emergency feed from the transformer-rectifier. Therefore, the emergency DC power goes to the Battery Bus to keep essential equipment powered.