Question

Direction: The following item consists of two statements, one labelled as ‘Statement (I)’ and the other as ‘Statement (II)’. Examine these two statements carefully and select the answers to these items using the code given below:

Statement I: In type-0 and type-1 systems, stable operation is possible if gain is suitably reduced.

Statement II: Any one of the compensators lag, lead, lag-lead may be used to improve the performance.
1. Both Statement I and Statement II are individually true and Statement II is the correct explanation of Statement I
2. Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I
3. Statement I is true but Statement II is false
4. Statement I is false but Statement II is true

Answer 1

Correct Answer - Option 2 : Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I

In general, there are two situations in which compensation is required.

• In the first case, the system is absolutely unstable, and the compensation is required to stabilize it as well as to achieve a specified performance.
• In the second case, the system is stable, but the compensation is required to obtain the desired performance.

 

The systems which are of type-2 or higher are usually absolutely unstable. For type-2 or higher systems, only the lead compensator is required because only the lead compensator improves the margin of stability.

 

In type-1 and type-0 systems, stable operation is always possible if the gain is sufficiently reduced. In such cases, any of the three compensators, lead, lag, lag-lead may be used to obtain the desired performance.

Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I