What do generator GCU do? Four things.

What do generator GCU do? Four things.

• A. Parallels; Protects; Regulates voltage; Selective disengaging of generator for faults
• B. Parallels; Overloads; Regulates current; Manual disengagement
• C. Parallels; Regulates frequency; Maintains temperature; Automatic shutoff
• D. Protects; Regulates voltage; Switches to battery power; Repairs faults

Answer: (A)

A generator control unit coordinates how a generator connects to and protects the aircraft’s electrical system, while keeping the output stable. It does four things: paralleling, protecting, regulating voltage, and selectively disengaging a generator when faults occur. Paralleling means the GCU allows generators to operate together on the same electrical bus. It does this by aligning voltage and frequency so they can share load without fighting each other, which keeps the system stable when multiple sources are supplying power. Protection is about sensing abnormal conditions such as overcurrent or voltage/frequency excursions. If something goes out of limits, the GCU trips the generator or intervenes to prevent damage, maintaining overall system safety. Regulating voltage involves keeping the bus voltage within the required range. The GCU works with the generator controls (and often an automatic voltage regulator) to adjust the field current and maintain a steady output despite load changes. Selective disengagement means if a generator develops a fault or cannot meet the needed electrical requirements, the GCU can disconnect just that unit from the bus while the others continue to operate, ensuring continued power availability. Other options mix in items that aren’t typically responsibilities of the GCU, like manual actions, temperature control, or switching to battery power, which aren’t core generator control unit functions.

A generator control unit coordinates how a generator connects to and protects the aircraft’s electrical system, while keeping the output stable. It does four things: paralleling, protecting, regulating voltage, and selectively disengaging a generator when faults occur.

Paralleling means the GCU allows generators to operate together on the same electrical bus. It does this by aligning voltage and frequency so they can share load without fighting each other, which keeps the system stable when multiple sources are supplying power.

Protection is about sensing abnormal conditions such as overcurrent or voltage/frequency excursions. If something goes out of limits, the GCU trips the generator or intervenes to prevent damage, maintaining overall system safety.

Regulating voltage involves keeping the bus voltage within the required range. The GCU works with the generator controls (and often an automatic voltage regulator) to adjust the field current and maintain a steady output despite load changes.

Selective disengagement means if a generator develops a fault or cannot meet the needed electrical requirements, the GCU can disconnect just that unit from the bus while the others continue to operate, ensuring continued power availability.

Other options mix in items that aren’t typically responsibilities of the GCU, like manual actions, temperature control, or switching to battery power, which aren’t core generator control unit functions.