Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU)) B-Tech 1st Semester (First Semester) 2015-2016 EEE 101 Electrical Engineering Question Paper
Paper ll): llell/ RollNO-
(Following Paper ID and Roll No. to be ?lled in your
Answer Book)
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' B.T'ech.
(SEM. 1) THEORY EXAMINATION, 2015-16
ELECTRICAL ENGINEERING
Time : 3 hours] 4 [Total Marks : 100
Section-A
l. Attempt all questions. ? (2X10=20)
(a) De?ne linear and non-linear elements.
, (b) In an a.c. circuit the supply voltage and current is
given as: e , ,
v= 200 sin 3l4t and i =58in (314t-II/3). Find the
real power of the circuit.
(0) Draw the resonance curve for series resonant
circuit and indicate fr, A f, 1'], f2, 0n the curve.
(d) What is the principle of superposition?
(e) For a single phase transformer, if iron losses are
lOOOW and the ?ll] load copper losses are lSOOW,
then at what percent load, the transformer will
yield maximum ef?ciency?
3300 (1) P.T.O.
(0 Calculate the value of equivalent star connected
rcsistances if 3 resistances each of 99 are
connected in delta.
(g) Draw the single line diagram of electrical power 7
system. ~ -
(h) Draw the Speed Torque characteristics of DC.
Shunt motors.
(i) Draw the schematic diagram of long shunt type
cumulative compound dc motor. 5
0) Considering RYB as positive phase sequence write
the type of phase sequence for the following phase
combinations: BRY, RBY, BYR, and YBR.
? Section-B
Attempt any ?ve questions. 10 X 5=50?
State Thevenin?s theorem. Draw the Thevenin?s equivalent
c1rcu1t of F ig-l.
ZmA
5".
5m 3m
7 V 4m fRL
Fig.4
(2) EE-lOl/EEE-101
l
3. State and prove Maximum Power Transfer theorem.
Illustrate the theorem by solving a'circuit of your choice.
4. Draw and explain torque?slip characteristics of a three
phase induction motor.
A30, 60 Hz; Induction motor has 6 poles and operates
with a slip of 5% at a certain load Determine
a) The speed of the rotor w.r.t. stator.
Ab) The frequency of the rotor current.
c) The speed of the rotor magnetic ?eld w.r.t. rotor.
d) The speed of the rotor magnetic ?eld w.r.t. stator. '
e) The speed, of thr rotor magnetic ?eld w.r.t. the stator
magnetic ?eld.
7 5. Derive the expression for line voltage and phase voltage,
line current and phase current, active power, reactive
power and apparent power for a stat: (Y) connected system
with suitable circuit and phasor diagrams. A
6. A 30 kV A, 2000/200V, single phase, 50 Hz transformer
has Rl = 3.5 phms, X1 = 4.5 ohms and R2 = 3.5 ohms
X2: 0.02 ohms. Find the equivalent resistance, reactance
and impendance of transformer referred to primary side
and secondary side. Also ?nd total copper losses.
3300 (3) P.T.O.
7.
Attempt any two question of the following:
A choke coil having a resistance of 10 ohm and
inductance of 0.05 H is connected in series with a
condenser of lOOuF. Thewhole circuit has been
connected to 220 V, 50 Hz supply. Calculate: .
(a) Impedance (b) current (c) power factor (d) power
input (e) voltage across Resistance
Give the analogy between electric and magnetic circuit.
A wrought iron bar 30 cm long and 2 cm in diameter is N
bent into a circular shape with 1 mm air gap. It is then
wound with 500 turns of wire. Calcu;ate the current
required to produce a ?ux of 0.5 m Wb, pr (iron) =
4000. '
. 7 Describe the concept ofparallel resonance with relevant V
characteristic curves. Derive the relations for i mpedance, ?
current and resonant frequency. .
Section-C
(15x2=30)
10. (a) A 4-people dc shunt motor working on 220 V dc
supply takes a line current of 3 A at no load while
running at 1500 rpm. Determine the speed when
the motor takes a line current of 50A. Assume the
armature and ?eld resistances as 0.2 ohm and 400
ohm respectively. _
? (b) Derive the generated e.m.f. equation for an
3300
alternator.
(4) EE-lOl/EEE-IOI
(0)
11.
12.
3300
(a)
Explain any one method for the starting of single
phase induction motor. How the direction of
rotation of motor can be reversed?
Moving Coil Instrument gives .a flill scale
de?ection of 20 mA when a potential difference
of 50 mV is applied. Calculate the Value-of
Resistance to be Connected in Parallel to measure
_ current upto 50 A.
(b)
(C)
(a)
(b)
In a two wattmeter method. total power measured
was 30 kW at 0.7 pflagging. Find the readings of
each wattmeter.
What is Grid? What are the various advantages of
' an interconnected power system?
An inductive coil of resistance 10 ohm iand.
inductance 0.1 H is connected in parallel With a
lSOpF capacitor to a variable frequency 200 V
supply. Find the frequency at which the total current
taken from the supply is in phase with the supply
voltage.A1so ?nd the magnitude of this current.
Explain the construction and working principle of
PMMC type of instruments with neat and clean
diagram.
(c)- Calculate the current in R3 by using Nodal analysis
in ??g-Q. -
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3300? (6) EE-lOl/EEE-IOI
This post was last modified on 29 January 2020