Question

Given below are two statements:
Statement I: AC generators carry slip rings while DC generators require a commutator
Statement II: Voltage generated in any DC generator is alternating and only becomes DC after it has been rectified by the commutator.
In light of the above statements, choose the most appropriate answer from the options given below

• A. Both Statement I and Statement II are correct
• B. Both Statement I and Statement II are incorrect
• C. Statement I is correct but Statement II is incorrect
• D. Statement I is incorrect but Statement II is correct

Hint:

A commutator acts as a mechanical rectifier. Without it, every generator would inherently produce AC at its output terminals because electromagnetic induction naturally generates alternating voltage.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Electric generators convert mechanical energy into electrical energy using electromagnetic induction.
The core difference between AC and DC generators lies in how the generated voltage is transferred from the rotating armature to the external load circuit.

Step 2: Detailed Explanation:
Let us analyze both statements:
- Statement I: "AC generators carry slip rings while DC generators require a commutator."
This is correct.
An AC generator uses continuous metal slip rings that rotate with the armature coil, maintaining a constant electrical connection with external carbon brushes. This allows the alternating current to flow to the external circuit without any changes in polarity.
On the other hand, a DC generator uses a split-ring commutator. The commutator reverses the electrical connections of the armature coils to the external circuit at the exact moment the current changes direction inside the coil, converting the internal AC into DC.
- Statement II: "Voltage generated in any DC generator is alternating and only becomes DC after it has been rectified by the commutator."
This is correct.
According to Faraday's Law of Electromagnetic Induction, as a coil rotates in a uniform magnetic field, the magnetic flux passing through it alternates. This naturally generates an alternating voltage (AC) inside the armature conductors of both AC and DC generators.
In a DC generator, this internal AC is rectified mechanically into pulsating DC by the action of the commutator.
Therefore, both Statement I and Statement II are correct.

Step 3: Final Answer:
The correct option is (A).