Electrical Measurements la. 2a. - Vtustudentsparadise

06EE3s
Third Semester B.E. Degree Examination, June-July 2009
Electrical Measurements
3 hrs.
Max. Marks:100
qwestions, selecting utleast
Note : l. Answer any FIVE full
TWO questions from each Part.
2. Assume missing dato if anYla.
b.
2a.
b.
PART - A
Find the relationship between electrostatic units anci electromagnetic units.
(04 Marks)
The energy stored in parallel plate capacitor per unit voiume (energy density) is
given by W : K €u Vb d'where e is permitivitl'' ol medium. d : distance between
plates, V : voltage between plates, K: constant of proporlionality. Find values of a,
b and c using LMTI sYstem.
c. Derive the equation for finding low resistance b}' Keh'in's Bridge.
(08 N{arks)
(08IVIarks)
With the help of neat diagram, explain the construction rLnd operation of lv'legger.
( l0 N'l a rks)
Explain sources and deteitors used in A.C. briilses.
(0'l N{arks)
The bridge is shown in fig.2(c). Find the constants ot'Z.r br considering it as series
circuit.
(06 Nlarks)
i) . ,. k r-r--
1^-
Fig.Q2(c)
a. Explain clearly how shunts and multipliers are used to extend the range of
instruments.
(01Marks)
A i000/5A, 50Hz current transformer has bar primary and a rated secondary burden
of 15VA. The secondary winding has 195 turns and a leakage reactance of 0.96 mH.
The load burden is purely resistance. At rated load, the magnetizing m.m.f is 20A
c.
and core loss excitation is 12,A. Find the ratio and phase angle errors. (10 Marks)
What are the advantages of Instrument Transformer? Define Transformation ratio,
Nominal ratio of Instrument Transformers.
(06 Marks)
a. Explain with the help of neat sketch, construction of Induction type Energy meter.
(07 Marks)

. Explain the working of Low power factor wattmeter,
c. Write in brief on i) Measurement of reactive power in 3
ii) Eiectronic energy meters.
3
'\ t,
(0s Mi
phase systems ''l
i
(08 MJ
5a.
b,
PART. B
Explain the construction and operation of weston frequency meter. (t0 M,
Write a note on phase sequence indicator.
(04 Ma
Explain the operation of successive approximation type of digital voltmeter.
(06 Ma
a. Explain with the help of block diagram duar trace osciiloscope.
b. Explain the measurement of frequency using Lissajous patterns.
c. Explain the working of digital storage oscilloscope.
(08 Ma
(06 Ma
(06 Ma
a. Explain the classification of transducers with the help of examples. (08 Ma
b. Prove that gauge factor of strain gauge is given by K : , + 2V, where p is the
Poisson's ratio.
(06 NIa
c. Explain Photo conductive and Photo voltaic ceils. (06 Ma
a. Explain briefly Data acquisition system (05 Ma
b. Explain the classification of displays (03 Ma
c. Explain with the help of diagram, the operation of X - y recorders. (06 i\ra
d. Explain the working of function generator with the help of neat diagram. (06 Mar
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