Assertion–Reason (inverters and commutation): Assertion (A) “An inverter does not require forced commutation.” Reason (R) “A series inverter is a forced-commutation inverter.” Determine the correct choice.

Introduction / Context:
Thyristor inverters require means to turn devices off. Depending on topology, commutation can be natural (line-commutated), forced using auxiliary circuits, or inherent via self-commutated switches (IGBT/MOSFET). This item checks clarity on forced commutation in classical SCR inverters and the nature of series inverters.

Given Data / Assumptions:

• Assertion says “inverter does not require forced commutation” (general claim).
• Reason states “series inverter is a forced-commutation inverter.”

Concept / Approach:

Many SCR-based inverters away from a stiff AC grid must force current to zero to turn off the SCRs. Series inverters are prime examples using resonant LC paths for forced commutation. Therefore the universal statement in A is wrong; R is true.

Step-by-Step Solution:

Verification / Alternative check:

Textbook classifications: line-commutated vs forced-commutated; series/parallel inverters are under forced commutation families.

Why Other Options Are Wrong:

• Options A/B/C assume Assertion is true; it is not.

Common Pitfalls:

Generalizing from self-commutated IGBT inverters (gate turn-off) to all inverter types; here “forced commutation” is a specific SCR technique.

Final Answer:

A is wrong but R is correct