Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU)) B-Tech 2nd Semester (Second Semester) 2015-16 201NEE Basic Electrical Engineering Question Paper
(Following Paper 1]) and Roll No. to be ?lled in your
Answer Books)
RollNoJllIllTIll
B.TECH.
Theory Examination (Semester-II) 2015-16
BASIC ELECTRICAL ENGINEERING
Time : 3 Hours Max. Marks : 100
Section-A
1. Answer all parts in few sentences/words : (10X2=20)
(a) Distinguish between active and passive elements.
(b) A 40 V dc. source has internal resistance of 2 ohm
and supplies a resistive load. What can be maximum
power drawn by the load ?
(c) The equation of an attemating current is i = 141.4
sin 314t. What is r.m.s. value of current and
frequency?
((1) What do you mean by apparent power, active power
and reactive power ?
y (1) P.T.O.
300572-71/1534/38350
(e) In two watt meter method of power measurement in
three phase circuit the readings of both watt meters are
equal. What is power factor ?
(f) Why is scale of moving iron instruments nonlinear ?
(g) Large ampere turns are needed to create ?ux in the air
gap as compured to steel. why ?
(h) A 400v/200v single phase transformer has primary
winding resistance 1.0 ohm and secondary winding
resistance 0.2 ohm. What will be total resistance of
transformer referred to the primary side ?
(i) Draw torque v/s speed characteristics of a dc. series
motor and explain why the motor should not be started
at no load.
(j) Draw slip v/s torque characteristics of a three phase
induction motor and indicate
(i) Stable operating zone
(Ii) induction generator operatin g zone.
(2)
3005/2'71/1534/38350
Section-B
2. Answer any ?ve questions: (10 X 5 = 50)
(a) Find current in 2 ohm resistance in the following ?gure
using loop analysis method.
4Q 2Q 30
+ + +
40V 20V 10V
(b) Find average and nms. values of following voltage
wavefonn
V
10 sin wt
10 -??~? ?
0 w 2* 3* Q
(c) Explain resonance in a series RLC circuit with the help
of impedance v/s frequency diagram and derive an
expression for resonant frequency. Write properties of
sereis resonance circuit.
0) R10.
3005/2 ?1/1534/38350
(d)
(e)
(0
Three similar coils each having a resistunce of 10 ohm
and an inductance of 0.03 1 8 H in series are connected
in delta. The line voltage is 400V, 50 HZ. Calculate :
(i) phase current
(ii) line current
(iii) power factor
(iv) total power in the circuit
Explain construction and principle of operation of a
permanent magnet moving coil instrument with the help
of a neat diagrams. Why is scale uniform ?
De?ne following with respect to a magnetic circuit :
(i) I magnetomotive force
(ii) ?ux
(iii) Veluctance
(iv) Flux density
(v) magnetic ?eld intensity.
Give analogous of each tenn in corresponding electric
circuit.
(4)
3005/271/1534/38350
(g)
(11)
Note : Answer any questions of the following :
A 50 KVa transformer has a cove loss of 400 w and
a full load copper loss of 800 w. The power factor of
the load is 0.9 1055ng calculate
(i) ?1ll load e?iciency
(ii) the maximum ef?ciency and the load at which
maximum e?iciency occurs.
A 6-pole lap wound dc shunt motor has 250 armature
conductors, a ?ux of 0.04 wb/pole and runs at 1200
rpm. The armature and ?eld winding resistances are 1
ohm and 220 ohm respectively. It is connected to a
220V dc supply. Determine
(i) induced emf in the motor
(ii) armature current
(iii) input supply current
(iv) mechanical power developed in the motor
(v) torque developed.
Section - C
(15X2=30)
(a) State and prove maximum power transfer theorm.(7)
(5) P.T.O.
300M/1534/38350
(b) In the circuit shown below, determine value of RL
for maximum power transfer condition and also obtain
maximum power transferred to the load. (8)
10 Q
10 Q 50 Q
+
?N - _-_?_..
Using double revolving ?eld theory explain why single phase
induction motor is not self starting. Describe capacitor
start - capacitory nm method for starting single phase induction
motor and give two applications of such motor. (15)
(3) Why a three phase synchronous motor is not self
starting ? Discuss use of damper winding for starting a
synchronous motor. (10)
(b) Explain single phase auot transformer and give its two
applications. (5)
(9
05/771/1534/38350
This post was last modified on 29 January 2020