Visvesvaraya Technological University (VTU) 2007 B.E BASIC ELECTRICAL ENGINEERING - Question Paper

06 ELE 15/25 - BASIC ELECTRICAL ENGINEERING
(Answer any five ques. by selecting at lowest 2 ques. from every part.)
PART – A
1a) Show that the equivalent resistance of 2 resistors connected in parallel is the ratio of the
product of those 2 resistances divided by the sum of those 2 resistance values. 4
b) discuss the Fleming’s rules as applied to the production of EMF and Torque. 8
c) issue on electro – magnetism / D.C. circuits. 8
2a) With usual notations show that the avg. power consumed by a pure capacitor is zero. 6
b) With reference to an a.c circuit, differentiate ranging from
i) Phase and Phase difference, ii) Reactance and Impedance,
iii) lag and lead power factors. 6
c) issue on single phase a.c circuit. 8
3a) find the relationship ranging from the line and phase volumes of balanced Star or
Delta loads. 8
b) In the course of measurement of power in 3 phase circuits the watt meter
readings are related as follows. obtain the power factor when,
i) W1 = W2, ii) W1 = 2W2, iii) W1 = 0. 6
c) issue on 3 phase circuit. 6
4a) With a neat sketch discuss the working of a single phase energy meter 8
b) Write a brief note on fuse. 4
c) discuss what is Earthing and with a neat sketch discuss the plate Earthing 8
` PART – B
5a) With usual notation derive an expression for the induced E.M.F of a D.C. machine 6
b) Draw the typical Speed - load characteristics of a D.C. series motor and comment on
its shape. Mention its practical applications. 6
c) issue on D.C. Generator or D.C. Motor. 8
6a) With usual notations derive an expression for the induced EMF in a single phase
Transformer and describe the term transformation ratio. 8
b) List out the different losses in a transformer and discuss how they vary with load and
how they are minimized. 6
c) issue on transformer. 6
7a) discuss the Salient and Non Salient pole generators and where they are preferred. 6
*b) List out the different losses in an ac generator and how its efficiency is estimated. 6
c) issue on alternator. 8
8a) describe the term ‘slip’ in an Induction motor and discuss its importance. 6
b) discuss the necessity of a starter for an Induction motor. 4
c) issue on Induction motor. 10

Earning:   Approval pending.