A commutator in dc machine provides which type of rectification

Electrical Engineering XYZ MCQs

A commutator in dc machine provides:

  1. Half wave controlled rectification
  2. Full wave controlled rectification
  3. Half wave rectification
  4. Full wave rectification

Correct answer: 4. Full wave rectification

Explanation: A commutator is a critical component found in DC (Direct Current) machines, such as DC generators and DC motors. Its primary function is to convert alternating current (AC) induced in the armature coils into direct current (DC) output.

In a DC generator, the armature coil rotates within a magnetic field, inducing an alternating current. The commutator, consisting of split copper segments connected to the ends of the armature coil, ensures that the output current flows in one direction only. As each armature coil rotates through the magnetic field, the commutator segments reverse the direction of current flow, effectively converting AC to DC.

While rectification refers to the process of converting AC to DC, “Full wave rectification” is achieved when both halves of the alternating current waveform are utilized, resulting in a smoother DC output. In contrast, “Half wave rectification” utilizes only one half of the AC waveform, resulting in a pulsating DC output.

Therefore, a commutator in a DC machine provides full wave rectification, ensuring a continuous and unidirectional flow of current in the output circuit.

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