Download AKTU B-Tech 2nd Sem 2016-17 REE201 Basic Electrical Engineering Question Paper

Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU)) B-Tech 2nd Semester (Second Semester) 2016-17 REE201 Basic Electrical Engineering Question Paper

Printed Pagesz2 RollNo.I I I I I I I I I I I REE201
B.TECH.
THEORY EXAMINATION (SEM?II) 2016-17
BASIC ELECTRICAL ENGINEERING
T ime : 3 Hours Max. Marks : 70
Note .' Be precise in your answer. In case ofnumericalproblem assume data wherever not provided.
SECTION ? A
1. Attempt any seven of the following: 7 x 2 = 14
a) Write two characteristics of Active elements
b) The two voltage waves are given: VA: 1503in(wt+45?) VB = 75 sin (wt-15?)
Which voltage wave is leading with other and what will be the phase angle between VA and
VB.
0) What is series resonance?
(1) State Norton?s Theorem.
e) Write four advantages of Three Phase System.
f) Why Damping torque is provided to an indicating instrument?
g) Define Magnetomotive Force (mmf).
h) Write two differences between a transformer and an autotransformer.
i) Write two applications of Synchronous motor.
SECTION ? B
2. Attempt any three parts of the following questions: 3 x 7 = 21
a) Using Nodal analysis ?nd the current through 1 Q resistance shown in Fig. 1.
2 Q
3 ?2 5 Q (B 2 A
=#
2 V
Fig.1
b) Draw the phasor diagram for the following voltages. Calculate the resultant voltage. Also find
the r.m.s. voltage.
V1=1005in 500t V2=2005in (500t +H / 3)
V3: ? 50003 500t V4=15031n (500t ? H / 4)
0) Explain the principle and construction of PMMC type instruments. Discuss their merits and
demerits.
d) Deduce analogy between electric circuits and magnetic circuits. Also explain B?H curve and
discuss its effect on hysteresis loss
e) Derive emf equation of DC. machine. Also deduce the expression for torque of a dc machine.
SECTION ? C
Attempt any ?ve parts of the following questions: 5 x 7 = 35

10.
In a 25 kVA, 2000 V/200 V transformer the iron and copper losses are 200 W and 400 W
respectively. Calculate the efficiency of half load and 0.8 pf. lagging. Also determine the
maximum efficiency and corresponding load.
Single phase induction motor is not self?starting. Explain? Name various starting methods of
single phase induction motor and explain capacitor run motor.
Explain series resonance in RLC circuit. What are the bandwidth and quality factor of the
circuit? Derive expressions for lower and upper half power frequencies for a series RLC
circuit.
A 46 mH inductive coil has a resistance of 10 ohm. How much current will it draw, if
connected across 100 V, 50 Hz source? Also determine the value of capacitance that must be
connected across the coil to make the power factor of the circuit to be unity.
A balanced star connected load of (8 + j6) Q per phase is connected to a 3?phase 400 V supply.
Find the line current, power factor, 3?phase power and 3-phase volt-amperes. Also draw the
phasor diagram.
Define power factor. Discuss reasons for poor power factor. How can power factor be
improved?
A dc shunt generator delivers 50 kW at 250 V when running at 500 rpm. The armature and
field resistances are 0.05 Q and 125 Q respectively. Calculate the speed of the same machine
and developed torque when running as a shunt motor and taking 50 kW at 250 V.
State and prove maximum power transfer theorem. Find the Value of RL that we can transfer
maximum power to it & also calculate the maximum power transferred as shown in Fig.2.
31>- 11).
10v "-7 29- RL?
Fig. 2