How many electrical generators are there on the 737?

• A. 2 total
• B. 3 total, 2 engine-driven and 1 APU-driven
• C. 4 total
• D. 5 total

Answer: (B)

Electrical power on a 737 comes from three generators: one on each engine and one APU-driven generator. The two engine-driven generators provide primary power when the engines are running, delivering power to the aircraft’s electrical buses during flight or while taxiing with engines active. The APU-driven generator can supply power when the engines are off or when extra power is needed, such as during start or on the ground, serving as a backup and helping with systems like air conditioning. Because of this setup, there are three generators in total. The other counts don’t fit the standard configuration: there aren’t only two, nor four, nor five generators on a typical 737.