Download VTU ((Visvesvaraya Technological University) B.E/B-Tech 2019 July ( Bachelor of Engineering) First & Second Semester (1st Semester & 2nd Semester) 2015 June-July 14ELE15 Basic Electrical Engineering Question Paper
selecting ONE full question from each part.
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Max. Marks:lab
ite
USN
14ELE15/25
First/ Second Semester B.E. Degree Examination, June/July 2015
Basic Electrical Engineering
Time: 3 hrs.
PART-1
1 a. State and explain Faraday's laws of electromagnetic induction. ( (06 Marks)
b. An air cored solenoid has a length of 50 cm and a diameter cm. Calculate its
c. If the total power dissipated in the circuit shown is 18W, c! 'the value of 'R.' and its
inductances if it has 1000 turns and also find the energy stored in in Nie current rises from
current.
_ cr..
(08 Marks)
zero to 5A. (06 Marks)
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2 a. State the following :
i) Fleming's right hand
ii) Fleming's left han (06 Marks)
b. A closed iron ring o diameter 12 cm is made from round iron bar of diameter 2 cm. It
has a uniform wiie, of 1000 turns. Calculate the current required to produce a flux density
of 1.5 wb/m
2
ii:e. that relative permeability is 1250. Hence calculate the self inductance.
(08 Marks)
c. What is s ? ential difference between the point x and y in the network shown? (06 Marks)
t
millok Sr Fig.Q1(c)
Fig.Q2(c)
rev
-;
PART-2
0
3 a. Explain the characteristics of DC series motor with a neat diagram. (06 Marks)
b. Explain the significance of back emf in DC motor. (05 Marks)
C.
4 pole DC shunt motor takes 22.5A from a 250V supply, R
a
= 0.50 and R
5
h = 1255. The
armature is wave wound with 300 conductors. If the flux per pole is 0.02wb. Calculate :
i) speed
ii) torque developed
iii) power developed.
(09 Marks)
1 of 2
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Note: Answer any FIVE full questions,
selecting ONE full question from each part.
cz
Max. Marks:lab
ite
USN
14ELE15/25
First/ Second Semester B.E. Degree Examination, June/July 2015
Basic Electrical Engineering
Time: 3 hrs.
PART-1
1 a. State and explain Faraday's laws of electromagnetic induction. ( (06 Marks)
b. An air cored solenoid has a length of 50 cm and a diameter cm. Calculate its
c. If the total power dissipated in the circuit shown is 18W, c! 'the value of 'R.' and its
inductances if it has 1000 turns and also find the energy stored in in Nie current rises from
current.
_ cr..
(08 Marks)
zero to 5A. (06 Marks)
OA. c
i
t
';:r4-
17
.?, v
co
6\
0
?
.C.1
.9. . g ..., .
,
?g.
. ti)
C3
? --
.0
.1
)
g
nz 8
e0
?
Z
6. ...,
1
3 03
>b st
7
6
1
2
-4 T t
E
L, et,
.
?
1:6
.c. Q
. cc ,
..,
z
I
. t
r
.
:
0
?.....
?
f?14.0
2?V
?.-.
IDO
t
NNO
1 r
A
2 a. State the following :
i) Fleming's right hand
ii) Fleming's left han (06 Marks)
b. A closed iron ring o diameter 12 cm is made from round iron bar of diameter 2 cm. It
has a uniform wiie, of 1000 turns. Calculate the current required to produce a flux density
of 1.5 wb/m
2
ii:e. that relative permeability is 1250. Hence calculate the self inductance.
(08 Marks)
c. What is s ? ential difference between the point x and y in the network shown? (06 Marks)
t
millok Sr Fig.Q1(c)
Fig.Q2(c)
rev
-;
PART-2
0
3 a. Explain the characteristics of DC series motor with a neat diagram. (06 Marks)
b. Explain the significance of back emf in DC motor. (05 Marks)
C.
4 pole DC shunt motor takes 22.5A from a 250V supply, R
a
= 0.50 and R
5
h = 1255. The
armature is wave wound with 300 conductors. If the flux per pole is 0.02wb. Calculate :
i) speed
ii) torque developed
iii) power developed.
(09 Marks)
1 of 2
C circ
46 Marks)
(06 Marks)
ice of 40 .tF is
ewer factor of the
(08 Marks)
14ELE15/25
4 a. With a neat diagram, explain the construction and working of dynamo-meter type wattmeter.
(06 Marks)
b. A 4 pole generator with wave wound armature has 51 slots, each having 24 conductors. The
flux per pole is 0.01 wb. At what speed must the armature rotate to give an induced emf of
220V? What will be the voltage developed if the winding is lap and the armature rotates at
the same speed. (10 Marks)
c. Explain with a diagram, the construction features of various parts of aDC generator. (04 Mael)
PART-3
5 a. What is meant by power factor in AC circuit? What is its significance in A
b.
Draw and explain the wiring diagram for the 3 ? way control of lamp.
c.
A series circuit with resistance of 10 S2, inductance of 0.2H and cap
supplied with a 100 V supply at 50 Hz. Find the current, power
circuit.
6 a. State form factor of an alternating quantity. Derive the expres
b. Show that the average power consumed in a pure ca
waveform for voltage, current, power.
c. With a neat diagram, explain pipe earthing.
r it.
'tltnce is zero.
(08 Marks)
Draw the neat
(06 Marks)
(06 Marks)
PARTN.,
7 a. With the usual notation, derive the expressioEg
e
r. 'rlsifF equation of an alternator. (06 Marks)
b. Establish the relationship between phase areiine values of voltage and currents in 3 phase
delta connected circuit. Show the phas diagram neatly. (06 Marks)
c. A balanced star connected load o ) Wphase is connected to 3 phase, 230V supply.
Find the line current, power facto r reactive volt-ampere and total volt-ampere. (08 Marks)
8 a. Show that the power in a bal ..d 3 ? phase circuit can be measured by 2 wattmeters. Draw
the circuit and vector dia (08 Marks)
t. ' Explain the generation ? phase AC voltage. (04 Marks)
c. A 3 ? phase, 50 Hr, ? pole generator with star connected winding has 144 slots with
-.., conductor /slot i/32fIlie flux per pole is 24.8 m wb is sinusiodally distributed. The coils are
full pitched. ktiti-T i) speed ii) the line emf. (08 Marks)
(N
s
b ,
*.?'''
PART-5
9 a. Exp - e construction and working principle of a transformer with a neat sketch.(08 Marks)
b. E the concept of rotating magnetic field in a 34) induction motor. (06 Marks)
c. equency of the emf in the stator of a 4 pole induction motor is 50 Hz and in the rotor is
Hz. What is the slip and at what speed is the motor running? (06 Marks)
? What is 'slip' in an induction motor? Explain why slip is never zero in an induction motor.
(06 Marks)
b. A single phase transformer has 400 turns primary and 1000 secondary turns. The net
cross ? sectional area of the core is 60 cm
2
. The primary winding is connected to a 500V,
50 Hz supply. Find :
i) Peak value of flux density
ii) emf induced in the secondary winding. (06 Marks)
c. The maximum efficiency at full load and unity p.f. of a single phase 25 KVA, 500/1000V,
50Hz transformer is 98%. Determine its efficiency at
i) 75% load, 0.9 p.f. and
ii) 50% load, 0.8 p.f. (08 Marks)
* * * * *
2 of 2
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This post was last modified on 01 January 2020