Compensators Question and Answers

 Compensators

1. Which of the following is not the correct reason to select feedback compensation over cascaded one?

a) No amplification is required as the energy transfer is from higher to lower level.

b) Suitable devices are not available for compensation(series)

c) It is economical

d) Provides greater stiffness against load disturbances

Answer: It is economical

2. Operations performed by pneumatic controllers:

a) Flexible operations

b) High torque high speed operations

c) Fire and explosion proof operation

d) All of the mentioned

Answer: Fire and explosion proof operation

3. Operations performed by hydraulic controllers:

a) Flexible operations

b) High torque high speed operations

c) Fire and explosion proof operation

d) All of the mentioned

Answer: High torque high speed operations

4. Operations performed by electronic controllers:

a) Flexible operations

b) High torque high speed operations

c) Fire and explosion proof operation

d) All of the mentioned

Answer: Flexible operations

5. The compensator G(s) =5(1+0.3s)/1+0.1s would provide a maximum phase shift of:

a) 20°

b) 30°

c) 45°

d) 60°

Answer: 30°

6. Consider the following systems:

System 1: G(s) =1/ (2s+1) and System 2: G(s) =1/ (5s+1)

The true statement regarding the system is:

a) Bandwidth of the system 1 is greater than the bandwidth of the system 2

b) Bandwidth of the system 1 is lower than the bandwidth of the system 2

c) Bandwidth of both the systems are same

d) Bandwidth of both the systems are infinite

Answer: Bandwidth of the system 1 is greater than the bandwidth of the system 2

7. With regard to the filtering capacity the lead compensator and lag compensator are respectively:

a) Low pass and high pass filter

b) High pass and low pass filter

c) Both high pass filter

d) Both low pass filters

Answer: High pass and low pass filter

8. What is the effect of phase lag compensation on the performance of a servo system?

a) For a given relative stability, the velocity constant is increased

b) For a given relative stability, the velocity constant is decreased

c) The bandwidth of the system is increased

d) The time response is made faster

Answer: For a given relative stability, the velocity constant is increased

9. A composite R-C network yielded the following transfer function when calculated from its components:

T(s) = 1+21s+20s2/1+11s+10s2. This network can be used as which one of the following?

a) Phase lead compensator

b) Phase lag compensator

c) Lag lead compensator

d) None of the mentioned

Answer: Phase lead compensator

10. The open loop transfer function of a plant is given as, G(s) =1/s^2-1. If the plant is operated in unity feedback configuration, then the lead compensator that can stabilize the control system is:

a) 10(s-1)/(s+2)

b) 10(s+4)/(s+2)

c) 10(s+2)/(s+10)

d) 10(s+2)/(s+10)

Answer: 10(s-1)/(s+2)