Question Paper for Basics of Electrical Engineering(EE100)-Special Supplementary Examination Aug/Spt 2016

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

FIRST/SECOND SEMESTER B.TECH DEGREE 
SPECIAL SUPPLEMENTARY EXAMINATION AUG/SEP 2016

EE100 BASICS OF ELECTICAL ENGINEERING


Max. Marks: 100                                                                                                     Duration: 3 Hours 

PART A

Answer all questions, each question carries 4 marks

1.State and explain Kirchhoffs law.

2.Three resistors R1=2O ohm, R2=90 ohm and R3=10 ohm are connected in star .Obtain the equivalent delta circuit.

3. Define coefficient of coupling in a magnetic circuit.
4. A 10ohm resistor & 400uF capacitor are connected in series to a 240V sinusoidal ac supply. The circuit current is SA. Calculate the supply frequency & phase angle between current & voltage.

5. Explain the advantage of three phase system compared to single phase system.

6.Draw the single line diagram of a typical power transmission scheme.

7. Derive E.M.F. equation of a Transformer.

8. Explain the principle of operation of Universal motor.

9. Draw the schematic diagram of LT switch board.

10. Explain the working of MCB and ELCB

PART B
MODULE (1-4)
Answer any four questions, each question carries 10 marks

11. Calculate the current in each branch of the circuit shown using mesh analysis (10)



12.
a)An iron ring of mean length 50cm has an air gap of 1mm and a winding of 200 turns.if the relative permeability of iron is 300 when a current of 1A flows through the coil, find flux density. Take permeability of air as 4π×10^-7H/m, (5)

b) Compare magnetic circuit and electric circuit. (5)

13 a) Detennine average value & rms value of symmetrical square wave also find the form factor. (5)



b)Distinguish between self inductance and mutual inductance. (4)

14. Three identical resistors of 20 ohm each are connected in star to 415V, 50Hz three phase supply. Calculate (i) the total power consumed, (ii) total power consumed if they are connected in delta (iii) total power consumed, if one of the resistors is opened in both star connection and delta connections.

15.With a neat schematic diagram explain Thermal power plant. (10)

16.Explain in detail the different equipment used in a substation. (10)

MODULE 5
Answer any one full question

17. The iron loss of 230/115V, 5KVA transformer is 200W.The copper loss at full load is 250W. Find efficiency of the transformer when delivering
(i) fiill load power at unity power factor. (5)
(ii) half full load power at 0.8 pf lagging. (5)

OR

18. Explain with neat diagram the construction and working principle of three phase induction motor. (10)

MODULE 6
Answer any one full question

19.a)Explain the necessity of earthing in electrical installation  (4)
b) With a neat sketch, explain the method of Plate Earthing (6)

OR

20. With the help of a diagram explain the principle of operation of compact fluorescent lamp and sodium vapour lamp.(10)



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