Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU)) B-Tech 1st Semester (First Semester) 2017-2018 REE 101 Basic Electrical Engineering Question Paper
Paper Idzzool Roll No. KW
B.Tech
(SEM 1) THEORY EXAMINATION 2017-18
BASIC ELECTRICAL ENGINEERIN G
Time: 3 Hours Total Marks: 70
N ote: 1. Attempt all Sections If require any missing data; then choose suitably.
SECTION A
1. Attempt all questions in brief. 2 x 7 = 14
a. Explain (i) Ideal current source (ii) Practical Voltage source
b A three phase Y connected balanced load is connected by 400V ,50 Hz 3 phase
supply the impedance of each phase is 10 ohm. Find the total three phase
power i
0. Define :
(i) Active and passive element (ii) bilateral and unilateral elements
di Why series resonant circuit is known as acceptor circuit & parallel resonant
circuit as rejecter circuit?
e. Why transformer is not used on DC?
f What is the power factor of a circuit having impedance of 3+j4 ohms ?
g Explain the term slip and slip speedi
SECTION B
2. Attempt any three of the following: 7 x 3 = 21
a. Determine current in 4 ohm resistor by using mesh analysis in the
circuit shown in ?gure below.
5 Q 6 9
W W
3?.-;_? 49 g 29: CD 2A
bi Derive the expression of Bandwidth of a series RLC circuit. Explain the
relationship between bandwidth and quality factor
0. Derive the relation for power factor using two wattmeter method with proper
phasor diagram and show that the reading of two wattmeter measure three
phase power
d A 25 KVA, 2000/200V transformer has full load copper & iron losses are 1.8
KW & 1.5 KW respectivelyi F ind (i)The efficiency at half the rated KVA &
at unity power factor (ii) )The efficiency at full load & at 0.8 power factor
lagging.(iii)KVA load for maximum efficiency & value of maximum
efficiency
e. Draw and discuss the construction and principle of operation of a DC. motor
and also give some of its applications
SECTION C
Attempt any one part of the following: 7 x 1 = 7
(a)
(b)
Calculate average value , rms value , form factor and peak factor of the
following waveform shown in figure
+10 V -
t(sec)
-10V
Derive the relation for star to delta and delta to star transformation
Attempt any one part of the following: 7 x 1 = 7
a)
b)
Explain the concept of phasors Derive the phasor relationship between
voltage and current phasors for purely inductive, purely capacitive and puIely
resistive circuits
A non inductive resistance of 10 ohm is connected in series with an inductive
coil across 200 V, 50 Hz ac supply The current drawn by the series
combination is 10 Amp. The resistance of coil is 2 ohms. Determine: (i)
Inductance 0f the coil (ii) Power factor (iii) Voltage across the coili
Attempt any two parts of the following: 3.5 x 2 = 7
(a)
(b)
(C)
Explain the causes of low power factor. How can it be improved?
Three similar coils of impedance Z = (8+ j6) Q are connected in delta &
supplied from 3(p, 400V, 50 Hz supply. F ind line current, power factor, total
active power, total reactive power, total volt amperesi
A moving coil ammeter has a full scale de?ection of 15 uA and a coil
resistance of 75 (2? Find the value of the shunt resistance required for the
instrument to be converted to read a full scale reading of 1 amps
Attempt any two part of the following: 3.5 x 2 = 7
(a)
(b)
(C)
Give the analogy between electric circuit and magnetic circuit
An iron ring 10 cm mean diameter is made of round iron rod 15 cm in
diameter of relative permeability 900 and has an air gap of 5 mm in length. It
has a winding of 400 turns. If the current through winding is 34 amps
Determine (a) MMF (b) Total reluctance of the circuit (c) ?ux in the ring ((1)
?ux density in the ring
Explain working of a single phase transformer and also derive the condition for
maximum ef?ciency in the transformer.
7.
Attempt any one part of the following: 7 x 1 = 7
(a)
(b)
Draw torque slip characteristic of 3 phase induction motor. A12 pole alternator
is coupled to an engine running at 500 rpm It supplies a 3 phase induction
motor having full load speed at 1440 rpm. F ind % slip and number of poles of
the motor.
Give the E?M.F. equation of a DC. generator and draw the characteristics of a
DC series motor? A 25kw, 250V, dc shunt generator has armature and field
resistances of 0.06ohm anleOohIn respectively. Determine the total armature
power developed.
This post was last modified on 29 January 2020