USCG Exam PracticeElectrical basics — generators, motors, and safety
What is the primary purpose of a commutator in a DC generator?
- A. To regulate field current and control output voltage
- ✓ To reverse the external circuit connections at the instant the induced voltage would reverse, producing unidirectional outputCorrect
- C. To reduce armature reaction by countering the distorted magnetic field
- D. To increase the number of armature coils cutting through the magnetic field
Why B is correct
Per NEETS Mod. 5 §1-1, the commutator is a split ring whose segments, contacted by carbon brushes, reverse the external connections to the loop at the instant the induced voltage would reverse, ensuring the brushes always deliver current in one direction.
Cited:NEETS Mod. 5 §1-1