Answer / vinod

Actually for DC machines input was AC Voltage (alternating in nature) so the output was also absolutely in AC. So we need to give the output in DC, that's why we use COMMUTATOR as a MECHANICAL RECTIFIER.
(Simply) COMMUTATOR is used to convert AC into DC like a RECTIFIER

Answer / dileep

commutator converts i/p DC of the motor to AC in the rotor
i.e armature .so here it is acting as an inverter ........
it acts as a rectifier in the case of DC generator

Answer / madhupriya

The purpose of commutator in dc motor is that it provides continuous unidirectional torque for the rotor to rotate

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