What is the primary function of the generator circuit breaker in a turbine engine starter-generator system?

What is the primary function of the generator circuit breaker in a turbine engine starter-generator system?

• A. It connects the generator to the ignition exciter during starting.
• B. It interrupts generator output to the bus to protect the system in fault conditions.
• C. It controls the speed of the turbine.
• D. It ensures ignition timing is correct.

Answer: (B)

The generator circuit breaker is the protective link between the starter-generator and the aircraft electrical bus. Its main job is to disconnect the generator’s output from the bus when something goes wrong. If a fault occurs—such as an overload, short circuit, or abnormal generator voltage/current—the breaker opens to stop current flow and prevent damage to the generator, the bus, or other electrical equipment. It also allows the generator to be isolated for starting, maintenance, or protection from back-feeding when the system isn’t ready to be energized. In normal operation the breaker is closed so the generator can supply power to the bus, and it trips open automatically if faults are detected.

The generator circuit breaker is the protective link between the starter-generator and the aircraft electrical bus. Its main job is to disconnect the generator’s output from the bus when something goes wrong. If a fault occurs—such as an overload, short circuit, or abnormal generator voltage/current—the breaker opens to stop current flow and prevent damage to the generator, the bus, or other electrical equipment. It also allows the generator to be isolated for starting, maintenance, or protection from back-feeding when the system isn’t ready to be energized. In normal operation the breaker is closed so the generator can supply power to the bus, and it trips open automatically if faults are detected.