Which best describes a starter-generator?

• A. A single, engine-mounted component that serves as a starter for starting the turbine engine. When the engine is running, the circuitry automatically shifts so it acts as a compound-wound generator.
• B. A separate generator used only after starting.
• C. A motor that provides braking torque.
• D. A fixed-resistance device to limit current.

Answer: (A)

A starter-generator is a single unit mounted on the engine that first acts as an electric starter to spin the turbine until it reaches self-sustaining speed. Once the engine is turning fast enough, the circuitry automatically switches the unit to act as a generator, providing electrical power to the system. This setup often uses a compound-wound configuration to help control voltage and speed during both modes. It combines starting and generating functions in one integrated unit, reducing weight and complexity.

It’s not a separate generator used only after starting, not a braking motor, and not simply a fixed-resistance device, so those descriptions don’t fit how a starter-generator operates.