EE36
RAMAIAH
USN
Institute of Technology
1
M
S
(Autonomous Institute, Affiliated to VTU)
(Approved by AICTE, New Delhi & Govt. of Karnataka)
Accredited by NBA & NAAC with ‘A’ Grade
SEMESTER END EXAMINATIONS FEBRUARY - MARCH 2021
Program
B.E. : Electrical and Electronics
Engineering
Electrical and Electronic
:
Measurements
:
Course Name
Course Code
:
EE36
Semester
:
III
Max. Marks :
100
Duration
3 Hrs
:
Instructions to the Candidates:
 Answer one full question from each unit.
1.
a)
b)
c)
UNIT- I
Draw the diagram of a Schering bridge and with the help of phasor
diagram, deduce the condition for balancing the bridge.
Discuss briefly taking suitable examples:
i) Absolute Units ii) Fundamental units iii) Derived units.
Use the dimensional analysis to find whether the following equation is
dimensionally correct or not.
CO2
(08)
CO1
(06)
CO1
(06)
CO2
(07)
CO2
(07)
CO1
(06)
CO3
(08)
CO3
CO3
(02)
(10)
CO4
(08)
CO3
(02)
Where R1,R2, R3 and R4 are resistances, C3 is capacitance while ω is
angular frequency. If the equation is not correct, find the error and
correct it.
2
a)
b)
c)
3.
a)
b)
c)
4.
a)
b)
The values of various arms of a Wheatstone bridge are p=1000Ω,
q=100Ω, r=2010Ω, and s=200Ω. The battery has an EMF of 8V and
negligible internal resistance. The galvanometer has a current
sensitivity of 10mm/µA and an internal resistance of 100Ω. Calculate
the deflection of galvanometer and the sensitivity of the bridge in terms
of deflection per unit change in resistance.
Derive the equations of balance for an Anderson’s bridge. Draw the
phasor diagram for conditions under balance.
Obtain the dimensions of:
(i) Force (ii) Surface tension (iii) Torque (iv) Power.
UNIT – II
A current transformer has a bar primary and 200 secondary winding
turns. The secondary winding burden is an ammeter of resistance 1.2Ω
and reactance 0.5Ω, the secondary winding has a resistance of 0.2Ω
and reactance of 0.3Ω. The core requires the equivalent of an mmf of
100A for magnetization and 50A for core losses. Find the ratio error and
phase angle error.
Mention the major sources of error in current transformer.
Derive the expression for transformation ratio and phase angle from
equivalent circuit and phasor diagram of a current transformer for a
lagging load.
What are shunts and multipliers? Derive an expression for both, with
reference to the meters used in electrical circuits.
Define:
i.
Transformation Ratio
ii.
Nominal Ratio.
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EE36
c)
5.
6.
b)
c)
UNIT – III
Explain the working principle of Q meter. Draw the circuit of a practical
Q meter.
Write a short note on Integrating type digital voltmeter.
What are the advantages of Electronic Voltmeter?
a)
A
a)
b)
c)
7.
a)
b)
c)
8.
a)
b)
c)
9.
a)
b)
c)
10.
A potential transformer of ratio 1000/100 V has the following
constants: primary resistance=94.5, secondary resistance=0.86,
primary reactance=66.2, total equivalent reactance of primary=110
and Io=0.02A at 0.4 power factor. Calculate the phase angle error at
no-load. Also determine the secondary volt-ampere at unity power
factor at which the phase angle will be zero.
a)
b)
c)
digital voltmeter is used for voltage measurements:
i) Find its resolution
ii) How would 12.98V be displayed on 10V range?
iii) How would 0.7893 be displayed on 1 V range?
With proper derivation explain the operation of static type phase
sequence indicator.
Draw the block diagram of ramp type digital voltmeter.
UNIT – IV
Derive the torque equation of single phase electrodynamometer type
wattmeter.
The name plate details of 1-ph kWh meter reads as 230 V, 15A,
1800 rev/kWh. The meter is tested at 0.75% of load at UPF. The meter
makes 20 revolutions in 10 sec. Find the % error in reading of energy
meter.
Explain the special features of LPF dynamometer type wattmeter.
Explain the adjustments and calibration of single and three phase
energy meters.
The constant of energy meter is 1000 revolutions /KWh. Calculate the
number of revolutions made by it, when connected to a load carrying
100A at 230V & 0.78 p.f in 30 seconds. If it makes 100 revolutions in
30 seconds ,find the percentage errors.
With neat block diagram, explain the functioning of electronic energy
meter.
UNIT – V
What is LVDT? Explain its working with necessary diagram and
characteristics.
What is the resistance temperature detector(RTD)? Discuss the
construction and working of it.
Write a short note on Thermistors.
What is an electrical transducer? What are the basic requirements of a
transducer? Give the classification of transducers.
With the help of a block diagram, explain the various parts of a Digital
data acquisition system.
Discuss the factors to be considered for the selection of Transducers.
CO3
(10)
CO5
(08)
CO5
CO4
(08)
(04)
CO4
(08)
CO5
(08)
CO5
(04)
CO4
(08)
CO4
(06)
CO4
(06)
CO4
(06)
CO4
(08)
CO4
(06)
CO4
(08)
CO2
(08)
CO2
(04)
CO
(08)
CO5
(08)
CO2
(04)
****************
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