Commutators are used to do this on ____________ generators:

• A. mechanical means to rectify/convert AC to DC in the armature
• B. increase efficiency of insulation
• C. balance load
• D. cool the windings

Answer: (A)

Commutators act as a mechanical rectifier in DC machines. As the armature turns, each winding generates an alternating emf, but the commutator is arranged with insulated copper segments so that the connection to the external circuit is reversed with each half turn. This keeps the current delivered to the load in one direction, effectively converting the AC produced in the armature into DC for the output. The other options don’t reflect the function of a commutator—they relate to insulation, load balancing, or cooling, which aren’t what the commutator does.