After engine start-up, which component supplies power to the DC system?

After engine start-up, which component supplies power to the DC system?

• A. Starter motor
• B. Main alternator
• C. Battery charging alternator
• D. External battery pack

Answer: (C)

After start, the engine-driven battery charging alternator takes over to supply the DC bus and keep the battery charged. The starter motor is only used to crank the engine, not to power the electrical system once the engine is running. An external battery pack is not part of normal operation. While the main alternator can contribute to the electrical supply, the unit specifically designated for feeding the DC system and charging the battery during run is the battery charging alternator, making it the best choice.

After start, the engine-driven battery charging alternator takes over to supply the DC bus and keep the battery charged. The starter motor is only used to crank the engine, not to power the electrical system once the engine is running. An external battery pack is not part of normal operation. While the main alternator can contribute to the electrical supply, the unit specifically designated for feeding the DC system and charging the battery during run is the battery charging alternator, making it the best choice.