Anna University Coimbatore 2009 B.E Electrical and Electronics Engineering Control system - Question Paper

16. Write Masons Gain formula. Masons Gain formula states that the overall gain of the system is T = 1/ __k Pk _k
k-o.of forward paths in the signal flow graph.
Pk- Forward path gain of kth forward path

_ = 1-[sum of individual loop gains ] +[sum of gain products of all possible
Combinations of 2 non touching loops]-[sum of gain products of
all possible combinations of 3 non touching loops]+…
_K - _ for that part of the graph, which is not touching kth, forward path.
17. Write the analogous electrical elements in force voltage analogy for
the elements of mechanical translational system.
Force-voltage e, Velocity v-current I ,Displacement x-charge q, Frictional coeff B-Resistance R,
Mass M- Inductance L,Stiffness K-Inverse of capacitance 1/C
18. Write the analogous electrical elements in force current analogy for
the elements of mechanical translational system.
Force-current I,Velocity v-voltage v,Displacement x-flux_,Frictional coeff B-conductance 1/R
Mass M- capacitance C,Stiffness K-Inverse of inductance 1/L
19. Write the force balance formula of ideal mass element.
F = M d2x /dt2
20. Write the force balance formula of ideal dashpot element.
F = B dx /dt
21. Write the force balance formula of ideal spring element.
F = Kx
22. Distinguish ranging from open loop and closed loop system
Open loop Closed loop
1.Innaccurate 2.Simple and economical 3.The modifications in output due to external disturbance are not corrected 4.They are generally stable right. The modifications in output due to external disturbances are corrected automatically. Great efforts are needed to design a
Stable system
23. What is servomechanism?
The servomechanism is a feedback control system in which the output is mechanical position (or time derivatives of position velocity and acceleration,) Complex and costlier
24. Why is negative feedback invariably preferred in closed loop system?
The negative feedback outcomes in better stability in steady state and rejects any disturbance signals.

UNIT II
2 Marks
1. What is Proportional controller and elaborate its advantages?
The Proportional controller is a device that produces a control signal, which is proportional to the input fault signal.
The advantages in the proportional controller are improvement in steady state tracking accuracy, disturbance signal rejection and the relative stability. It also makes a system less sensitive to parameter variations.

Earning:   Approval pending.