Deemed University 2009 A.M.I.E.T.E Electronics

b. In the armature controlled DC motor, a voltage, is applied to the armature. Derive the transfer function of the motor and draw its block diagram. (8)


Q.4 a. Show with the help of an examples that the introduction of derivative mode of control in a feedback system with proportional control makes the system response less oscillatory? (8)

b. discuss the significance of the subsequent aspects in designing control systems
(i) Stability (ii) Disturbance rejection
(iii) Sensitivity and Robustness. (8)

Q.5 a. discuss the Routh stability criterion for a feedback control system. The characteristics formula of a feedback control system is , using Routh criterion
(i) determine the range of k for which the system be stable.
(ii) can the system be marginally stable? If so, obtain the needed value of k and the frequency of sustained oscillation. (8)

b. When a 2nd order control system is subjected to unit step input, the value of and . Determine the rise time, break time, settling time and peak overshoot. (8)
Q.6 a. Sketch the root-loci for the system with .Find the value of k
(i) for maginal stability
(ii) at break away point
(iii) for (12)

b. discuss lag-lead compensation for a linear control system. (4)

Q.7 a. Sketch the Bode plots showing the magnitude and phase as function of log frequency for transfer function

. Determine
(i) Gain crossover frequency.
(ii) Phase crossover frequency.
(iii) Phase margin
(iv) Gain margin (12)

b. explain the steady state fault for different inputs and system. (4)

Q.8 a. Sketch Nyquist plot for open loop transfer function . find gain margin and phase margin. (12)



b. What is Nichols chart? How can resonance peak and band width be identified from it? (4)

Q.9 a. define the important advantages offered by using digital computer as compensator device in a control system. elaborate main issues associated with implementation of digital control? (10)

b. discuss Robust control system. (6)

Earning:   Approval pending.