SKR Engineering College 2007 B.E Electrical and Electronics Engineering EE 1291 – ELECTRICAL ENGG & CONTROL SYSTEM - Question Paper

SKR ENGINEERING COLLEGE
DEPARTMENT OF ELECTRICAL& ELECTRONICS ENGG
11-YEAR - CSE
EE 1291 – ELECTRICAL ENGG & CONTROL SYSTEM
MODEL examination

DATE: 02.05.07 MAXIMUM MARKS: 100
TIME DURATION: three hours

PART –A (10x two =20)
1. State kirchoff’s laws.
2. Define power factor.
3. Define regulation of a transformer.
4. What is back e.m.f?
5. What are the applications of a variable reluctance stepper motor?
6. State Mason’s gain formula.
7. Define steady state fault.
8. What is the necessary condition for stability?
9. Define gain margin.
10. Differentiate ranging from Pneumatic and Hydraulic system.


PART –B (5 x 16 =80)
11) i) obtain the current through two O resistor in the network using loop current analysis.(8)







(OR)
ii) find the transfer function using Mason’s gain formula. (8)









12) a) i) A series RC circuit with R=20 O and C=127µF has 160V, 50Hz supply connected to it. obtain a) Impedance b) current c) power factor d) true power. (8)
ii) When a 2nd order system is subjected to a unit step input the values of ?=0.5 Wn=0.6rad/sec. Determine rise time, peak time, settling time and peak over shoot. (8)

(OR)



b) i) The power input to a three phase balanced star connected circuit is measured by 2 watt meters, which learn 1200 and 600 watts. obtain a) total power b) power factor c) the load impedance. The supply voltage is 240V. (8)
50
ii) The open loop transfer function of unity feedback system is provided by G(s) =
(1+0.1S)(S+10)
Determine the steady state fault coefficients. (8)

13) a) i) Derive e.m.f. formula of a D.C. generator. (8)

ii) Determine the stability of the system whose characteristic formula is provided by S6+2S5+2S4+30S3+5S2+6S+1 using Routh stability criterion. (8)

(OR)

b) i) discuss internal and external characteristics of shunt and series motor. (8)
ii) obtain the poles and zeros of the transfer function G(s) = (S2+3S+2) / ((S+4)(S2+6S+25)) and sketch the pole zero plot. (8)


14) a) i) What is a transformer? discuss the working principle. (8)
ii) Sketch the Bode plot and determine gain margin and phase margin for the system

G(s) = 10 (8)

S (1+0.5S)(1+0.1S)

(OR)

b) i) discuss the characteristics of a three phase induction motor.(8)
ii) For the subsequent system sketch the polar plot G(s) = 500 / (S (S+6) (S+9)). (8)

15) a) i) discuss the construction and working principle of AC servomotor.(8)
ii) Derive the transfer function for armature controlled D.C.motor. (8)

(OR)

b) i) discuss how rotating magnetic field is produced in shaded pole induction motor. (8)
ii) Write short notes on
a) Hydraulic system. (4)
b) Pneumatic system. (4)

Earning:   Approval pending.