Cochin University of Science and Techology (CUST) 2008 B.Tech Electrical and Electronics Engineering SWITCH GEAR AND PROTECTION - Question Paper

BTS(C) - Vlll - (S) 08 -043 W

B. Tech. Degree VIII Semester (Supplementary)

Examination, September 2008

EE 804(A) SWITCH GEAR AND PROTECTION

(2002 Scheme)

Time: 3 Hours    Maximum Marks: 100

I    a) Explain the construction of Air Blast Circuit Breaker with neat figure.    (10)

b)    Explain current chopping phenomenon in detail.    (6)

c)    Discuss about restriking and recovery voltages.    (4)

OR

II    a) Explain the need of circuit breakers in detail.    (4)

b)    Explain the difference between circuit breakers and isolators.    (4)

c)    Explain various arc extinction techniques.    (12)

III    a) Discussaboutthcapplicationsofdistancerclays.    (6)

b)    Explain the operation of time delay circuit in static relays.    (4)

c)    Explain the operation of directional over current relays.    (10)

OR

IV    a) Discuss about various over current relays.    (10) b) Explain the block schematic of static relays. (10)

V    a) Discuss about the protection of t ing mains.    (6)

b)    Discuss about merzprice voltage balanced system.    (8)

c)    How an alternator can be protected against failure of excitation?    (6)

OR

VI    a) Discuss about differential protecti on of electrical machines with neat figure.    (10)

b)    Discuss about feeder protection.    (5)

c)    Explain earth fault protection of alternators.    (5)

VII    a) Briefly explain induction heating.    (10) b) Explain various methods of welding. (10)

OR

VIII    a) Briefly explain dielectric heating.    (10) b) Discuss about direct and indirect arc furnaces. (10)

IX    a) Discuss in brief about the following:

I) Factory lighting    ii) Flood lighting

iii) Street lighting    iv) Arc lamps    (12)

b) Discuss about the factors affecting the choicc of motor for various applications.    (8)

OR

X    a) What type of motors are employed for the tollovving applications? Give reasons.

i) Textile mill    ii) Hoist    (10)

b) A drawing hall 30m x 15m with ceiling height of 5i*i is to be provided with an

illumination of 120 lux taking the coefficient of utilisation as 0.5 and depreciation

factor as 1.4. Obtain the number of fluorescent tubes required, their mounting,

height, spacing and disposition.    (10)

4

Attachment: cochin-university-of-science-and-techology--cust--2008-b-tech-electrical-and-electronics-engineering-37071-1.JPG

Earning:   Approval pending.